Blame kpatch-build/create-diff-object.c

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/*
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 * create-diff-object.c
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 *
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 * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com>
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 * Copyright (C) 2013-2014 Josh Poimboeuf <jpoimboe@redhat.com>
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public License
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 * as published by the Free Software Foundation; either version 2
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 * of the License, or (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA,
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 * 02110-1301, USA.
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 */
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/*
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 * This file contains the heart of the ELF object differencing engine.
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 *
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 * The tool takes two ELF objects from two versions of the same source
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 * file; a "base" object and a "patched" object.  These object need to have
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 * been compiled with the -ffunction-sections and -fdata-sections GCC options.
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 *
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 * The tool compares the objects at a section level to determine what
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 * sections have changed.  Once a list of changed sections has been generated,
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 * various rules are applied to determine any object local sections that
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 * are dependencies of the changed section and also need to be included in
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 * the output object.
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 */
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <error.h>
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#include <gelf.h>
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#include <argp.h>
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#include <libgen.h>
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#include <unistd.h>
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#include "list.h"
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#include "lookup.h"
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#include "asm/insn.h"
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#include "kpatch-patch.h"
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#include "kpatch-elf.h"
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#include "kpatch-intermediate.h"
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#include "kpatch.h"
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#define DIFF_FATAL(format, ...) \
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({ \
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	fprintf(stderr, "ERROR: %s: " format "\n", childobj, ##__VA_ARGS__); \
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	error(EXIT_STATUS_DIFF_FATAL, 0, "unreconcilable difference"); \
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})
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#ifdef __powerpc64__
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#define ABSOLUTE_RELA_TYPE R_PPC64_ADDR64
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#else
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#define ABSOLUTE_RELA_TYPE R_X86_64_64
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#endif
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char *childobj;
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enum subsection {
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	SUBSECTION_NORMAL,
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	SUBSECTION_HOT,
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	SUBSECTION_UNLIKELY
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};
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enum loglevel loglevel = NORMAL;
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bool KLP_ARCH;
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/*******************
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 * Data structures
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 * ****************/
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struct special_section {
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	char *name;
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	int (*group_size)(struct kpatch_elf *kelf, int offset);
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};
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/*************
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 * Functions
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 * **********/
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static int is_bundleable(struct symbol *sym)
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{
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	if (sym->type == STT_FUNC &&
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	    !strncmp(sym->sec->name, ".text.",6) &&
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	    !strcmp(sym->sec->name + 6, sym->name))
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		return 1;
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	if (sym->type == STT_FUNC &&
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	    !strncmp(sym->sec->name, ".text.unlikely.",15) &&
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	    (!strcmp(sym->sec->name + 15, sym->name) ||
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			 (strstr(sym->name, ".cold.") &&
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			  !strncmp(sym->sec->name + 15, sym->name, strlen(sym->sec->name) - 15))))
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		return 1;
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	if (sym->type == STT_FUNC &&
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	    !strncmp(sym->sec->name, ".text.hot.",10) &&
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	    !strcmp(sym->sec->name + 10, sym->name))
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		return 1;
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	if (sym->type == STT_OBJECT &&
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	   !strncmp(sym->sec->name, ".data.",6) &&
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	   !strcmp(sym->sec->name + 6, sym->name))
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		return 1;
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	if (sym->type == STT_OBJECT &&
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	    !strncmp(sym->sec->name, ".data.rel.", 10) &&
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	    !strcmp(sym->sec->name + 10, sym->name))
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		return 1;
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	if (sym->type == STT_OBJECT &&
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	    !strncmp(sym->sec->name, ".data.rel.ro.", 13) &&
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	    !strcmp(sym->sec->name + 13, sym->name))
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		return 1;
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	if (sym->type == STT_OBJECT &&
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	   !strncmp(sym->sec->name, ".rodata.",8) &&
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	   !strcmp(sym->sec->name + 8, sym->name))
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		return 1;
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	if (sym->type == STT_OBJECT &&
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	   !strncmp(sym->sec->name, ".bss.",5) &&
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	   !strcmp(sym->sec->name + 5, sym->name))
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		return 1;
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	return 0;
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}
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#ifdef __powerpc64__
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/* Symbol st_others value for powerpc */
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#define STO_PPC64_LOCAL_BIT     5
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#define STO_PPC64_LOCAL_MASK    (7 << STO_PPC64_LOCAL_BIT)
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#define PPC64_LOCAL_ENTRY_OFFSET(other)                                 \
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	        (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
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/*
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 * On ppc64le, the function prologue generated by GCC 6+ has the sequence:
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 *
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 *	.globl my_func
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 *	.type my_func, @function
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 *	.quad .TOC.-my_func
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 * my_func:
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 *	.reloc ., R_PPC64_ENTRY ; optional
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 *	ld r2,-8(r12)
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 *	add r2,r2,r12
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 *	.localentry my_func, .-my_func
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 *
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 * my_func is the global entry point, which, when called, sets up the TOC.
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 * .localentry is the local entry point, for calls to the function from within
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 * the object file.  The local entry point is 8 bytes after the global entry
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 * point.
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 */
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static int is_gcc6_localentry_bundled_sym(struct symbol *sym)
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{
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	return ((PPC64_LOCAL_ENTRY_OFFSET(sym->sym.st_other) != 0) &&
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		sym->sym.st_value == 8);
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}
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#else
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static int is_gcc6_localentry_bundled_sym(struct symbol *sym)
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{
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	return 0;
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}
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#endif
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/*
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 * On ppc64le, when a function references data, it does so indirectly, via the
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 * .toc section.  So there are *two* levels of relas:
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 *
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 *   1) the original function rela, referring to the .toc section; and
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 *
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 *   2) the .toc section rela, referring to the data needed by the function.
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 *
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 * For example:
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 *
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 *   Relocation section '.rela.text.netlink_release' at offset 0xcadf0 contains 44 entries:
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 *   ...
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 *   0000000000000398  0000007300000032 R_PPC64_TOC16_HA    0000000000000000 .toc + 138
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 *   00000000000003a0  0000007300000040 R_PPC64_TOC16_LO_DS 0000000000000000 .toc + 138
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 *
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 *   Relocation section '.rela.toc' at offset 0xcc6b0 contains 46 entries:
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 *   ...
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 *   0000000000000138  0000002a00000026 R_PPC64_ADDR64      0000000000000000 .text.deferred_put_nlk_sk + 8
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 *
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 * The below function takes the "first level" rela as input, and, if it refers
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 * to .toc, returns the "second level" rela, which is the one that refers to
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 * the actual data symbol.
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 *
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 * In some rare cases, a .toc entry has constant data, and thus has no
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 * corresponding rela.  In that case, NULL is returned.
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 */
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static struct rela *toc_rela(const struct rela *rela)
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{
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	if (rela->type != R_PPC64_TOC16_HA &&
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	    rela->type != R_PPC64_TOC16_LO_DS)
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		return (struct rela *)rela;
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	/* Only constants in toc */
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	if (!rela->sym->sec->rela)
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		return NULL;
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	/* Will return NULL for .toc constant entries */
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	return find_rela_by_offset(rela->sym->sec->rela,
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				   (unsigned int)rela->addend);
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}
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/*
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 * When compiling with -ffunction-sections and -fdata-sections, almost every
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 * symbol gets its own dedicated section.  We call such symbols "bundled"
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 * symbols.  They're indicated by "sym->sec->sym == sym".
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 */
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static void kpatch_bundle_symbols(struct kpatch_elf *kelf)
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{
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	struct symbol *sym;
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	list_for_each_entry(sym, &kelf->symbols, list) {
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		if (is_bundleable(sym)) {
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			if (sym->sym.st_value != 0 &&
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			    !is_gcc6_localentry_bundled_sym(sym)) {
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				ERROR("symbol %s at offset %lu within section %s, expected 0",
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				      sym->name, sym->sym.st_value,
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				      sym->sec->name);
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			}
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			sym->sec->sym = sym;
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		}
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	}
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}
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static struct symbol *kpatch_lookup_parent(struct kpatch_elf *kelf,
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					   const char *symname,
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					   const char *child_suffix)
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{
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	struct symbol *parent;
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	char *pname;
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	pname = strndup(symname, child_suffix - symname);
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	if (!pname)
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		ERROR("strndup");
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	parent = find_symbol_by_name(&kelf->symbols, pname);
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	free(pname);
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	return parent;
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}
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/*
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 * During optimization gcc may move unlikely execution branches into *.cold
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 * subfunctions. Some functions can also be split into multiple *.part
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 * functions.
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 * kpatch_detect_child_functions detects such subfunctions and
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 * crossreferences them with their parent functions through parent/child
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 * pointers.
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 */
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static void kpatch_detect_child_functions(struct kpatch_elf *kelf)
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{
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	struct symbol *sym;
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	list_for_each_entry(sym, &kelf->symbols, list) {
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		char *childstr;
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		if (sym->type != STT_FUNC)
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			continue;
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		childstr = strstr(sym->name, ".cold.");
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		if (childstr) {
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			sym->parent = kpatch_lookup_parent(kelf, sym->name,
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							   childstr);
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			if (!sym->parent)
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				ERROR("failed to find parent function for %s",
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				      sym->name);
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		} else {
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			childstr = strstr(sym->name, ".part.");
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			if (!childstr)
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				continue;
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			sym->parent = kpatch_lookup_parent(kelf, sym->name,
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							   childstr);
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		}
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		if (sym->parent)
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			list_add_tail(&sym->subfunction_node, &sym->parent->children);
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	}
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}
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static bool is_dynamic_debug_symbol(struct symbol *sym)
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{
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	if (sym->type == STT_OBJECT && !strcmp(sym->sec->name, "__verbose"))
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		return true;
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	if (sym->type == STT_SECTION && !strcmp(sym->name, "__verbose"))
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		return true;
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	return false;
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}
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/*
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 * This function detects whether the given symbol is a "special" static local
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 * variable (for lack of a better term).
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 *
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 * Special static local variables should never be correlated and should always
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 * be included if they are referenced by an included function.
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 */
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static int is_special_static(struct symbol *sym)
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{
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	static char *prefixes[] = {
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		"__key.",
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		"__warned.",
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		"__func__.",
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		"__FUNCTION__.",
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		"_rs.",
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		"CSWTCH.",
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		NULL,
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	};
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	char **prefix;
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	if (!sym)
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		return 0;
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	/* pr_debug() uses static local variables in the __verbose section */
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	if (is_dynamic_debug_symbol(sym))
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		return 1;
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	if (sym->type == STT_SECTION) {
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		/* make sure section is bundled */
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		if (!sym->sec->sym)
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			return 0;
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		/* use bundled object/function symbol for matching */
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		sym = sym->sec->sym;
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	}
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	if (sym->type != STT_OBJECT || sym->bind != STB_LOCAL)
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		return 0;
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	for (prefix = prefixes; *prefix; prefix++)
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		if (!strncmp(sym->name, *prefix, strlen(*prefix)))
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			return 1;
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	return 0;
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}
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/*
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 * This is like strcmp, but for gcc-mangled symbols.  It skips the comparison
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 * of any substring which consists of '.' followed by any number of digits.
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 */
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static int kpatch_mangled_strcmp(char *s1, char *s2)
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{
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	/*
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	 * ELF string sections aren't mangled, though they look that way.  Just
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	 * compare them normally.
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	 */
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	if (strstr(s1, ".str1."))
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		return strcmp(s1, s2);
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	while (*s1 == *s2) {
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		if (!*s1)
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			return 0;
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		if (*s1 == '.' && isdigit(s1[1])) {
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			if (!isdigit(s2[1]))
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				return 1;
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			while (isdigit(*++s1))
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				;
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			while (isdigit(*++s2))
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				;
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		} else {
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			s1++;
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			s2++;
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		}
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	}
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	return 1;
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}
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static bool rela_equal(struct rela *rela1, struct rela *rela2)
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{
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	struct rela *rela_toc1, *rela_toc2;
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	unsigned long toc_data1 = 0, toc_data2 = 0; /* = 0 to prevent gcc warning */
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	if (rela1->type != rela2->type ||
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	    rela1->offset != rela2->offset)
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		return false;
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	/*
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	 * On x86, .altinstr_aux is used to store temporary code which allows
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	 * static_cpu_has() to work before apply_alternatives() has run.  This
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	 * code is completely inert for modules, because apply_alternatives()
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	 * runs during module init, before the module is fully formed.  Any
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	 * changed references to it (i.e. changed addend) can be ignored.  As
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	 * long as they're both references to .altinstr_aux, they can be
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	 * considered equal, even if the addends differ.
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	 */
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	if (!strcmp(rela1->sym->name, ".altinstr_aux") &&
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	    !strcmp(rela2->sym->name, ".altinstr_aux"))
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		return true;
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	/*
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	 * With -mcmodel=large on ppc64le, GCC might generate entries in the .toc
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	 * section for relocation symbol references.   The .toc offsets may change
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	 * between the original and patched .o, so comparing ".toc + offset" isn't
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	 * right.  Compare the .toc-based symbols by reading the corresponding relas
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	 * from the .toc section.
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	 */
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	rela_toc1 = toc_rela(rela1);
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	if (!rela_toc1) {
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		/*
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		 * .toc section entries are mostly place holder for relocation entries, specified
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		 * in .rela.toc section. Sometimes, .toc section may have constants as entries.
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		 * These constants are not reference to any symbols, but plain instructions mostly
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		 * due to some arithmetics in the functions referring them.
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		 *
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		 * They are referred by the functions like normal .toc entries, these entries can
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		 * not be resolved to any symbols.
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		 *
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		 * Disassembly of section .toc:
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		 *
Packit Service ac8aad
		 * 0000000000000000 <.toc>:
Packit Service ac8aad
		 *         ...
Packit Service ac8aad
		 *                        148: R_PPC64_ADDR64     .data.capacity_margin
Packit Service ac8aad
		 *  150:   0b d7 a3 70     andi.   r3,r5,55051
Packit Service ac8aad
		 *  154:   3d 0a d7 a3     lhz     r30,2621(r23)
Packit Service ac8aad
		 *                        158: R_PPC64_ADDR64     sched_max_numa_distance
Packit Service ac8aad
		 *
Packit Service ac8aad
		 * Relocation section '.rela.toc' at offset 0xadac0 contains 160 entries:
Packit Service ac8aad
		 *     Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
Packit Service ac8aad
		 *     ...
Packit Service ac8aad
		 * 0000000000000148  0000009100000026 R_PPC64_ADDR64         0000000000000000 .data.capacity_margin + 0
Packit Service ac8aad
		 * 0000000000000158  000001a500000026 R_PPC64_ADDR64         0000000000000000 sched_max_numa_distance + 0
Packit Service ac8aad
		 *
Packit Service ac8aad
		 * Relocation section '.rela.text.select_task_rq_fair' at offset 0x90e98 contains 37 entries:
Packit Service ac8aad
		 *     Offset             Info             Type               Symbol's Value  Symbol's Name + Addend
Packit Service ac8aad
		 *     ...
Packit Service ac8aad
		 * 00000000000004a0  0000008800000032 R_PPC64_TOC16_HA       0000000000000000 .toc + 148
Packit Service ac8aad
		 * 00000000000004ac  0000008800000040 R_PPC64_TOC16_LO_DS    0000000000000000 .toc + 148
Packit Service ac8aad
		 * 0000000000000514  0000008800000032 R_PPC64_TOC16_HA       0000000000000000 .toc + 150
Packit Service ac8aad
		 * 000000000000051c  0000008800000040 R_PPC64_TOC16_LO_DS    0000000000000000 .toc + 150
Packit Service ac8aad
		 */
Packit Service ac8aad
		memcpy(&toc_data1, rela1->sym->sec->data->d_buf + rela1->addend, sizeof(toc_data1));
Packit Service ac8aad
		if (!toc_data1)
Packit Service da4517
			ERROR(".toc entry not found %s + %lx", rela1->sym->name, rela1->addend);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	rela_toc2 = toc_rela(rela2);
Packit Service ac8aad
	if (!rela_toc2) {
Packit Service ac8aad
		memcpy(&toc_data2, rela2->sym->sec->data->d_buf + rela2->addend, sizeof(toc_data2));
Packit Service ac8aad
		if (!toc_data2)
Packit Service da4517
			ERROR(".toc entry not found %s + %lx", rela2->sym->name, rela2->addend);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!rela_toc1 && !rela_toc2)
Packit Service ac8aad
		return toc_data1 == toc_data2;
Packit Service ac8aad
Packit Service da4517
	if (!rela_toc1 || !rela_toc2)
Packit Service da4517
		return false;
Packit Service da4517
Packit Service ac8aad
	if (rela_toc1->string)
Packit Service ac8aad
		return rela_toc2->string && !strcmp(rela_toc1->string, rela_toc2->string);
Packit Service ac8aad
Packit Service ac8aad
	if (rela_toc1->addend != rela_toc2->addend)
Packit Service da4517
		return false;
Packit Service ac8aad
Packit Service da4517
	return !kpatch_mangled_strcmp(rela_toc1->sym->name, rela_toc2->sym->name);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_compare_correlated_rela_section(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela1, *rela2 = NULL;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * On ppc64le, don't compare the .rela.toc section.  The .toc and
Packit Service ac8aad
	 * .rela.toc sections are included as standard elements.
Packit Service ac8aad
	 */
Packit Service ac8aad
	if (!strcmp(sec->name, ".rela.toc")) {
Packit Service ac8aad
		sec->status = SAME;
Packit Service ac8aad
		return;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	rela2 = list_entry(sec->twin->relas.next, struct rela, list);
Packit Service ac8aad
	list_for_each_entry(rela1, &sec->relas, list) {
Packit Service ac8aad
		if (rela_equal(rela1, rela2)) {
Packit Service ac8aad
			rela2 = list_entry(rela2->list.next, struct rela, list);
Packit Service ac8aad
			continue;
Packit Service ac8aad
		}
Packit Service ac8aad
		sec->status = CHANGED;
Packit Service ac8aad
		return;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	sec->status = SAME;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_compare_correlated_nonrela_section(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec1 = sec, *sec2 = sec->twin;
Packit Service ac8aad
Packit Service ac8aad
	if (sec1->sh.sh_type != SHT_NOBITS &&
Packit Service ac8aad
	    memcmp(sec1->data->d_buf, sec2->data->d_buf, sec1->data->d_size))
Packit Service ac8aad
		sec->status = CHANGED;
Packit Service ac8aad
	else
Packit Service ac8aad
		sec->status = SAME;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_compare_correlated_section(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec1 = sec, *sec2 = sec->twin;
Packit Service ac8aad
Packit Service ac8aad
	/* Compare section headers (must match or fatal) */
Packit Service ac8aad
	if (sec1->sh.sh_type != sec2->sh.sh_type ||
Packit Service ac8aad
	    sec1->sh.sh_flags != sec2->sh.sh_flags ||
Packit Service da4517
	    sec1->sh.sh_entsize != sec2->sh.sh_entsize ||
Packit Service da4517
	    (sec1->sh.sh_addralign != sec2->sh.sh_addralign &&
Packit Service da4517
	     !is_text_section(sec1)))
Packit Service da4517
		DIFF_FATAL("%s section header details differ from %s", sec1->name, sec2->name);
Packit Service ac8aad
Packit Service ac8aad
	/* Short circuit for mcount sections, we rebuild regardless */
Packit Service ac8aad
	if (!strcmp(sec->name, ".rela__mcount_loc") ||
Packit Service ac8aad
	    !strcmp(sec->name, "__mcount_loc")) {
Packit Service ac8aad
		sec->status = SAME;
Packit Service ac8aad
		goto out;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (sec1->sh.sh_size != sec2->sh.sh_size ||
Packit Service ac8aad
	    sec1->data->d_size != sec2->data->d_size) {
Packit Service ac8aad
		sec->status = CHANGED;
Packit Service ac8aad
		goto out;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (is_rela_section(sec))
Packit Service ac8aad
		kpatch_compare_correlated_rela_section(sec);
Packit Service ac8aad
	else
Packit Service ac8aad
		kpatch_compare_correlated_nonrela_section(sec);
Packit Service ac8aad
out:
Packit Service ac8aad
	if (sec->status == CHANGED)
Packit Service ac8aad
		log_debug("section %s has changed\n", sec->name);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
#ifdef __x86_64__
Packit Service ac8aad
/*
Packit Service ac8aad
 * Determine if a section has changed only due to a WARN* or might_sleep
Packit Service ac8aad
 * macro call's embedding of the line number into an instruction operand.
Packit Service ac8aad
 *
Packit Service ac8aad
 * Warning: Hackery lies herein.  It's hopefully justified by the fact that
Packit Service ac8aad
 * this issue is very common.
Packit Service ac8aad
 *
Packit Service ac8aad
 * Example WARN*:
Packit Service ac8aad
 *
Packit Service ac8aad
 *  938:   be 70 00 00 00          mov    $0x70,%esi
Packit Service ac8aad
 *  93d:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
Packit Service ac8aad
 *                         940: R_X86_64_32S       .rodata.tcp_conn_request.str1.8+0x88
Packit Service ac8aad
 *  944:   c6 05 00 00 00 00 01    movb   $0x1,0x0(%rip)        # 94b <tcp_conn_request+0x94b>
Packit Service ac8aad
 *                         946: R_X86_64_PC32      .data.unlikely-0x1
Packit Service ac8aad
 *  94b:   e8 00 00 00 00          callq  950 <tcp_conn_request+0x950>
Packit Service ac8aad
 *                         94c: R_X86_64_PC32      warn_slowpath_null-0x4
Packit Service ac8aad
 *
Packit Service ac8aad
 * Example might_sleep:
Packit Service ac8aad
 *
Packit Service ac8aad
 *  50f:   be f7 01 00 00          mov    $0x1f7,%esi
Packit Service ac8aad
 *  514:   48 c7 c7 00 00 00 00    mov    $0x0,%rdi
Packit Service ac8aad
 *                         517: R_X86_64_32S       .rodata.do_select.str1.8+0x98
Packit Service ac8aad
 *  51b:   e8 00 00 00 00          callq  520 <do_select+0x520>
Packit Service ac8aad
 *                         51c: R_X86_64_PC32      ___might_sleep-0x4
Packit Service ac8aad
 *
Packit Service ac8aad
 * The pattern which applies to all cases:
Packit Service ac8aad
 * 1) immediate move of the line number to %esi
Packit Service ac8aad
 * 2) (optional) string section rela
Packit Service ac8aad
 * 3) (optional) __warned.xxxxx static local rela
Packit Service ac8aad
 * 4) warn_slowpath_* or __might_sleep or some other similar rela
Packit Service ac8aad
 */
Packit Service ac8aad
static int kpatch_line_macro_change_only(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	struct insn insn1, insn2;
Packit Service ac8aad
	unsigned long start1, start2, size, offset, length;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	int lineonly = 0, found;
Packit Service ac8aad
Packit Service ac8aad
	if (sec->status != CHANGED ||
Packit Service ac8aad
	    is_rela_section(sec) ||
Packit Service ac8aad
	    !is_text_section(sec) ||
Packit Service ac8aad
	    sec->sh.sh_size != sec->twin->sh.sh_size ||
Packit Service ac8aad
	    !sec->rela ||
Packit Service ac8aad
	    sec->rela->status != SAME)
Packit Service ac8aad
		return 0;
Packit Service ac8aad
Packit Service ac8aad
	start1 = (unsigned long)sec->twin->data->d_buf;
Packit Service ac8aad
	start2 = (unsigned long)sec->data->d_buf;
Packit Service ac8aad
	size = sec->sh.sh_size;
Packit Service ac8aad
	for (offset = 0; offset < size; offset += length) {
Packit Service ac8aad
		insn_init(&insn1, (void *)(start1 + offset), 1);
Packit Service ac8aad
		insn_init(&insn2, (void *)(start2 + offset), 1);
Packit Service ac8aad
		insn_get_length(&insn1);
Packit Service ac8aad
		insn_get_length(&insn2);
Packit Service ac8aad
		length = insn1.length;
Packit Service ac8aad
Packit Service ac8aad
		if (!insn1.length || !insn2.length)
Packit Service ac8aad
			ERROR("can't decode instruction in section %s at offset 0x%lx",
Packit Service ac8aad
			      sec->name, offset);
Packit Service ac8aad
Packit Service ac8aad
		if (insn1.length != insn2.length)
Packit Service ac8aad
			return 0;
Packit Service ac8aad
Packit Service ac8aad
		if (!memcmp((void *)start1 + offset, (void *)start2 + offset,
Packit Service ac8aad
			    length))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		/* verify it's a mov immediate to %edx or %esi */
Packit Service ac8aad
		insn_get_opcode(&insn1);
Packit Service ac8aad
		insn_get_opcode(&insn2);
Packit Service ac8aad
		if (!(insn1.opcode.value == 0xba && insn2.opcode.value == 0xba) &&
Packit Service ac8aad
		    !(insn1.opcode.value == 0xbe && insn2.opcode.value == 0xbe))
Packit Service ac8aad
			return 0;
Packit Service ac8aad
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * Verify zero or more string relas followed by a
Packit Service ac8aad
		 * warn_slowpath_* or another similar rela.
Packit Service ac8aad
		 */
Packit Service ac8aad
		found = 0;
Packit Service ac8aad
		list_for_each_entry(rela, &sec->rela->relas, list) {
Packit Service ac8aad
			if (rela->offset < offset + length)
Packit Service ac8aad
				continue;
Packit Service ac8aad
			if (rela->string)
Packit Service ac8aad
				continue;
Packit Service ac8aad
			if (!strncmp(rela->sym->name, "__warned.", 9))
Packit Service ac8aad
				continue;
Packit Service ac8aad
			if (!strncmp(rela->sym->name, "warn_slowpath_", 14) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "__warn_printk")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "__might_sleep")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "___might_sleep")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "__might_fault")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "printk")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "lockdep_rcu_suspicious"))) {
Packit Service ac8aad
				found = 1;
Packit Service ac8aad
				break;
Packit Service ac8aad
			}
Packit Service ac8aad
			return 0;
Packit Service ac8aad
		}
Packit Service ac8aad
		if (!found)
Packit Service ac8aad
			return 0;
Packit Service ac8aad
Packit Service ac8aad
		lineonly = 1;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!lineonly)
Packit Service ac8aad
		ERROR("no instruction changes detected for changed section %s",
Packit Service ac8aad
		      sec->name);
Packit Service ac8aad
Packit Service ac8aad
	return 1;
Packit Service ac8aad
}
Packit Service ac8aad
#elif __powerpc64__
Packit Service ac8aad
#define PPC_INSTR_LEN 4
Packit Service ac8aad
#define PPC_RA_OFFSET 16
Packit Service ac8aad
Packit Service ac8aad
static int kpatch_line_macro_change_only(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	unsigned long start1, start2, size, offset;
Packit Service ac8aad
	unsigned int instr1, instr2;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	int lineonly = 0, found;
Packit Service ac8aad
Packit Service ac8aad
	if (sec->status != CHANGED ||
Packit Service ac8aad
	    is_rela_section(sec) ||
Packit Service ac8aad
	    !is_text_section(sec) ||
Packit Service ac8aad
	    sec->sh.sh_size != sec->twin->sh.sh_size ||
Packit Service ac8aad
	    !sec->rela ||
Packit Service ac8aad
	    sec->rela->status != SAME)
Packit Service ac8aad
		return 0;
Packit Service ac8aad
Packit Service ac8aad
	start1 = (unsigned long)sec->twin->data->d_buf;
Packit Service ac8aad
	start2 = (unsigned long)sec->data->d_buf;
Packit Service ac8aad
	size = sec->sh.sh_size;
Packit Service ac8aad
	for (offset = 0; offset < size; offset += PPC_INSTR_LEN) {
Packit Service ac8aad
		if (!memcmp((void *)start1 + offset, (void *)start2 + offset,
Packit Service ac8aad
			    PPC_INSTR_LEN))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		instr1 = *(unsigned int *)(start1 + offset) >> PPC_RA_OFFSET;
Packit Service ac8aad
		instr2 = *(unsigned int *)(start2 + offset) >> PPC_RA_OFFSET;
Packit Service ac8aad
Packit Service ac8aad
		/* verify it's a load immediate to r5 */
Packit Service ac8aad
		if (!(instr1 == 0x38a0 && instr2 == 0x38a0))
Packit Service ac8aad
			return 0;
Packit Service ac8aad
Packit Service ac8aad
		found = 0;
Packit Service ac8aad
		list_for_each_entry(rela, &sec->rela->relas, list) {
Packit Service ac8aad
			if (rela->offset < offset + PPC_INSTR_LEN)
Packit Service ac8aad
				continue;
Packit Service ac8aad
			if (toc_rela(rela) && toc_rela(rela)->string)
Packit Service ac8aad
				continue;
Packit Service ac8aad
			if (!strncmp(rela->sym->name, "__warned.", 9))
Packit Service ac8aad
				continue;
Packit Service ac8aad
			if (!strncmp(rela->sym->name, "warn_slowpath_", 14) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "__warn_printk")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "__might_sleep")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "___might_sleep")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "__might_fault")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "printk")) ||
Packit Service ac8aad
			   (!strcmp(rela->sym->name, "lockdep_rcu_suspicious"))) {
Packit Service ac8aad
				found = 1;
Packit Service ac8aad
				break;
Packit Service ac8aad
			}
Packit Service ac8aad
			return 0;
Packit Service ac8aad
		}
Packit Service ac8aad
		if (!found)
Packit Service ac8aad
			return 0;
Packit Service ac8aad
Packit Service ac8aad
		lineonly = 1;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!lineonly)
Packit Service ac8aad
		ERROR("no instruction changes detected for changed section %s",
Packit Service ac8aad
		      sec->name);
Packit Service ac8aad
Packit Service ac8aad
	return 1;
Packit Service ac8aad
}
Packit Service ac8aad
#else
Packit Service ac8aad
static int kpatch_line_macro_change_only(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	return 0;
Packit Service ac8aad
}
Packit Service ac8aad
#endif
Packit Service ac8aad
Packit Service da4517
/*
Packit Service da4517
 * Child functions with "*.cold" names don't have _fentry_ calls, but "*.part",
Packit Service da4517
 * often do. In the later case, it is not necessary to include the parent
Packit Service da4517
 * in the output object when the child function has changed.
Packit Service da4517
 */
Packit Service da4517
static bool kpatch_changed_child_needs_parent_profiling(struct symbol *sym)
Packit Service da4517
{
Packit Service da4517
	struct symbol *child;
Packit Service da4517
Packit Service da4517
	list_for_each_entry(child, &sym->children, subfunction_node) {
Packit Service da4517
		if (child->has_func_profiling)
Packit Service da4517
			continue;
Packit Service da4517
		if (child->sec->status == CHANGED ||
Packit Service da4517
		    kpatch_changed_child_needs_parent_profiling(child))
Packit Service da4517
			return true;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	return false;
Packit Service da4517
}
Packit Service da4517
Packit Service ac8aad
static void kpatch_compare_sections(struct list_head *seclist)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
Packit Service ac8aad
	/* compare all sections */
Packit Service ac8aad
	list_for_each_entry(sec, seclist, list) {
Packit Service ac8aad
		if (sec->twin)
Packit Service ac8aad
			kpatch_compare_correlated_section(sec);
Packit Service ac8aad
		else
Packit Service ac8aad
			sec->status = NEW;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* exclude WARN-only, might_sleep changes */
Packit Service ac8aad
	list_for_each_entry(sec, seclist, list) {
Packit Service ac8aad
		if (kpatch_line_macro_change_only(sec)) {
Packit Service ac8aad
			log_debug("reverting macro / line number section %s status to SAME\n",
Packit Service ac8aad
				  sec->name);
Packit Service ac8aad
			sec->status = SAME;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* sync symbol status */
Packit Service ac8aad
	list_for_each_entry(sec, seclist, list) {
Packit Service ac8aad
		if (is_rela_section(sec)) {
Packit Service ac8aad
			if (sec->base->sym && sec->base->sym->status != CHANGED)
Packit Service ac8aad
				sec->base->sym->status = sec->status;
Packit Service ac8aad
		} else {
Packit Service da4517
			struct symbol *sym = sec->sym;
Packit Service da4517
Packit Service da4517
			if (sym && sym->status != CHANGED)
Packit Service da4517
				sym->status = sec->status;
Packit Service da4517
Packit Service da4517
			if (sym && sym->status == SAME &&
Packit Service da4517
			    kpatch_changed_child_needs_parent_profiling(sym))
Packit Service da4517
				sym->status = CHANGED;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static enum subsection kpatch_subsection_type(struct section *sec)
Packit Service da4517
{
Packit Service da4517
	if (!strncmp(sec->name, ".text.unlikely.", 15))
Packit Service da4517
		return SUBSECTION_UNLIKELY;
Packit Service da4517
Packit Service da4517
	if (!strncmp(sec->name, ".text.hot.", 10))
Packit Service da4517
		return SUBSECTION_HOT;
Packit Service da4517
Packit Service da4517
	return SUBSECTION_NORMAL;
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static int kpatch_subsection_changed(struct section *sec1, struct section *sec2)
Packit Service da4517
{
Packit Service da4517
	return kpatch_subsection_type(sec1) != kpatch_subsection_type(sec2);
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static struct symbol *kpatch_get_correlated_parent(struct symbol *sym)
Packit Service da4517
{
Packit Service da4517
	while (sym->parent && !sym->parent->twin)
Packit Service da4517
		sym = sym->parent;
Packit Service da4517
	return sym->parent;
Packit Service da4517
}
Packit Service da4517
Packit Service ac8aad
static void kpatch_compare_correlated_symbol(struct symbol *sym)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym1 = sym, *sym2 = sym->twin;
Packit Service ac8aad
Packit Service ac8aad
	if (sym1->sym.st_info != sym2->sym.st_info ||
Packit Service ac8aad
	    (sym1->sec && !sym2->sec) ||
Packit Service ac8aad
	    (sym2->sec && !sym1->sec))
Packit Service ac8aad
		DIFF_FATAL("symbol info mismatch: %s", sym1->name);
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * If two symbols are correlated but their sections are not, then the
Packit Service ac8aad
	 * symbol has changed sections.  This is only allowed if the symbol is
Packit Service da4517
	 * moving out of an ignored section, or moving between normal/hot/unlikely
Packit Service da4517
	 * subsections.
Packit Service ac8aad
	 */
Packit Service ac8aad
	if (sym1->sec && sym2->sec && sym1->sec->twin != sym2->sec) {
Packit Service da4517
		if ((sym2->sec->twin && sym2->sec->twin->ignore) ||
Packit Service da4517
		    kpatch_subsection_changed(sym1->sec, sym2->sec))
Packit Service ac8aad
			sym->status = CHANGED;
Packit Service ac8aad
		else
Packit Service ac8aad
			DIFF_FATAL("symbol changed sections: %s", sym1->name);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (sym1->type == STT_OBJECT &&
Packit Service ac8aad
	    sym1->sym.st_size != sym2->sym.st_size)
Packit Service ac8aad
		DIFF_FATAL("object size mismatch: %s", sym1->name);
Packit Service ac8aad
Packit Service ac8aad
	if (sym1->sym.st_shndx == SHN_UNDEF ||
Packit Service ac8aad
	     sym1->sym.st_shndx == SHN_ABS)
Packit Service ac8aad
		sym1->status = SAME;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * The status of LOCAL symbols is dependent on the status of their
Packit Service ac8aad
	 * matching section and is set during section comparison.
Packit Service ac8aad
	 */
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_compare_symbols(struct list_head *symlist)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, symlist, list) {
Packit Service ac8aad
		if (sym->twin)
Packit Service ac8aad
			kpatch_compare_correlated_symbol(sym);
Packit Service ac8aad
		else
Packit Service ac8aad
			sym->status = NEW;
Packit Service ac8aad
Packit Service ac8aad
		log_debug("symbol %s is %s\n", sym->name, status_str(sym->status));
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
#define CORRELATE_ELEMENT(_e1_, _e2_, kindstr)			\
Packit Service da4517
do {								\
Packit Service da4517
	typeof(_e1_) e1 = (_e1_);				\
Packit Service da4517
	typeof(_e2_) e2 = (_e2_);				\
Packit Service da4517
	e1->twin = e2;						\
Packit Service da4517
	e2->twin = e1;						\
Packit Service da4517
	/* set initial status, might change */			\
Packit Service da4517
	e1->status = e2->status = SAME;				\
Packit Service da4517
	if (strcmp(e1->name, e2->name)) {			\
Packit Service da4517
		/* Rename mangled element */			\
Packit Service da4517
		log_debug("renaming %s %s to %s\n",		\
Packit Service da4517
			  kindstr, e2->name, e1->name);		\
Packit Service da4517
		e2->name = strdup(e1->name);			\
Packit Service da4517
	}							\
Packit Service da4517
} while (0)
Packit Service da4517
Packit Service da4517
#define UNCORRELATE_ELEMENT(_elem_)				\
Packit Service da4517
do {								\
Packit Service da4517
	typeof(_elem_) elem = (_elem_);				\
Packit Service da4517
	elem->twin->twin = NULL;				\
Packit Service da4517
	elem->twin = NULL;					\
Packit Service da4517
} while (0)
Packit Service da4517
Packit Service da4517
static void __kpatch_correlate_section(struct section *sec1, struct section *sec2)
Packit Service da4517
{
Packit Service da4517
	CORRELATE_ELEMENT(sec1, sec2, "section");
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static void kpatch_correlate_symbol(struct symbol *sym1, struct symbol *sym2)
Packit Service da4517
{
Packit Service da4517
	CORRELATE_ELEMENT(sym1, sym2, "symbol");
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static void kpatch_correlate_static_local(struct symbol *sym1, struct symbol *sym2)
Packit Service da4517
{
Packit Service da4517
	CORRELATE_ELEMENT(sym1, sym2, "static local");
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static void kpatch_correlate_section(struct section *sec1, struct section *sec2)
Packit Service da4517
{
Packit Service da4517
	__kpatch_correlate_section(sec1, sec2);
Packit Service da4517
Packit Service da4517
	if (is_rela_section(sec1)) {
Packit Service da4517
		__kpatch_correlate_section(sec1->base, sec2->base);
Packit Service da4517
		sec1 = sec1->base;
Packit Service da4517
		sec2 = sec2->base;
Packit Service da4517
	} else if (sec1->rela) {
Packit Service da4517
		__kpatch_correlate_section(sec1->rela, sec2->rela);
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	if (sec1->secsym)
Packit Service da4517
		kpatch_correlate_symbol(sec1->secsym, sec2->secsym);
Packit Service da4517
	if (sec1->sym)
Packit Service da4517
		kpatch_correlate_symbol(sec1->sym, sec2->sym);
Packit Service da4517
}
Packit Service da4517
Packit Service ac8aad
static void kpatch_correlate_sections(struct list_head *seclist1, struct list_head *seclist2)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec1, *sec2;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sec1, seclist1, list) {
Packit Service da4517
		if (sec1->twin)
Packit Service da4517
			continue;
Packit Service ac8aad
		list_for_each_entry(sec2, seclist2, list) {
Packit Service da4517
			if (kpatch_mangled_strcmp(sec1->name, sec2->name) ||
Packit Service da4517
			    sec2->twin)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			if (is_special_static(is_rela_section(sec1) ?
Packit Service ac8aad
					      sec1->base->secsym :
Packit Service ac8aad
					      sec1->secsym))
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			/*
Packit Service ac8aad
			 * Group sections must match exactly to be correlated.
Packit Service ac8aad
			 * Changed group sections are currently not supported.
Packit Service ac8aad
			 */
Packit Service ac8aad
			if (sec1->sh.sh_type == SHT_GROUP) {
Packit Service ac8aad
				if (sec1->data->d_size != sec2->data->d_size)
Packit Service ac8aad
					continue;
Packit Service ac8aad
				if (memcmp(sec1->data->d_buf, sec2->data->d_buf,
Packit Service ac8aad
				           sec1->data->d_size))
Packit Service ac8aad
					continue;
Packit Service ac8aad
			}
Packit Service da4517
Packit Service da4517
			kpatch_correlate_section(sec1, sec2);
Packit Service ac8aad
			break;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_correlate_symbols(struct list_head *symlist1, struct list_head *symlist2)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym1, *sym2;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym1, symlist1, list) {
Packit Service da4517
		if (sym1->twin)
Packit Service da4517
			continue;
Packit Service ac8aad
		list_for_each_entry(sym2, symlist2, list) {
Packit Service da4517
			if (kpatch_mangled_strcmp(sym1->name, sym2->name) ||
Packit Service da4517
			    sym1->type != sym2->type || sym2->twin)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			if (is_special_static(sym1))
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			/*
Packit Service ac8aad
			 * The .LCx symbols point to strings, usually used for
Packit Service ac8aad
			 * the bug table.  Don't correlate and compare the
Packit Service ac8aad
			 * symbols themselves, because the suffix number might
Packit Service ac8aad
			 * change.
Packit Service ac8aad
			 *
Packit Service ac8aad
			 * If the symbol is used by the bug table (usual case),
Packit Service ac8aad
			 * it may get pulled in by
Packit Service ac8aad
			 * kpatch_regenerate_special_section().
Packit Service ac8aad
			 *
Packit Service ac8aad
			 * If the symbol is used outside of the bug table (not
Packit Service ac8aad
			 * sure if this actually happens anywhere), any string
Packit Service ac8aad
			 * changes will be detected elsewhere in rela_equal().
Packit Service ac8aad
			 */
Packit Service ac8aad
			if (sym1->type == STT_NOTYPE &&
Packit Service ac8aad
			    !strncmp(sym1->name, ".LC", 3))
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			/* group section symbols must have correlated sections */
Packit Service ac8aad
			if (sym1->sec &&
Packit Service ac8aad
			    sym1->sec->sh.sh_type == SHT_GROUP &&
Packit Service ac8aad
			    sym1->sec->twin != sym2->sec)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service da4517
			kpatch_correlate_symbol(sym1, sym2);
Packit Service ac8aad
			break;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_compare_elf_headers(Elf *elf1, Elf *elf2)
Packit Service ac8aad
{
Packit Service ac8aad
	GElf_Ehdr eh1, eh2;
Packit Service ac8aad
Packit Service ac8aad
	if (!gelf_getehdr(elf1, &eh1))
Packit Service ac8aad
		ERROR("gelf_getehdr");
Packit Service ac8aad
Packit Service ac8aad
	if (!gelf_getehdr(elf2, &eh2))
Packit Service ac8aad
		ERROR("gelf_getehdr");
Packit Service ac8aad
Packit Service ac8aad
	if (memcmp(eh1.e_ident, eh2.e_ident, EI_NIDENT) ||
Packit Service ac8aad
	    eh1.e_type != eh2.e_type ||
Packit Service ac8aad
	    eh1.e_machine != eh2.e_machine ||
Packit Service ac8aad
	    eh1.e_version != eh2.e_version ||
Packit Service ac8aad
	    eh1.e_entry != eh2.e_entry ||
Packit Service ac8aad
	    eh1.e_phoff != eh2.e_phoff ||
Packit Service ac8aad
	    eh1.e_flags != eh2.e_flags ||
Packit Service ac8aad
	    eh1.e_ehsize != eh2.e_ehsize ||
Packit Service ac8aad
	    eh1.e_phentsize != eh2.e_phentsize ||
Packit Service ac8aad
	    eh1.e_shentsize != eh2.e_shentsize)
Packit Service ac8aad
		DIFF_FATAL("ELF headers differ");
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_check_program_headers(Elf *elf)
Packit Service ac8aad
{
Packit Service ac8aad
	size_t ph_nr;
Packit Service ac8aad
Packit Service ac8aad
	if (elf_getphdrnum(elf, &ph_nr))
Packit Service ac8aad
		ERROR("elf_getphdrnum");
Packit Service ac8aad
Packit Service ac8aad
	if (ph_nr != 0)
Packit Service ac8aad
		DIFF_FATAL("ELF contains program header");
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_mark_grouped_sections(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *groupsec, *sec;
Packit Service ac8aad
	unsigned int *data, *end;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(groupsec, &kelf->sections, list) {
Packit Service ac8aad
		if (groupsec->sh.sh_type != SHT_GROUP)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		data = groupsec->data->d_buf;
Packit Service ac8aad
		end = groupsec->data->d_buf + groupsec->data->d_size;
Packit Service ac8aad
		data++; /* skip first flag word (e.g. GRP_COMDAT) */
Packit Service ac8aad
		while (data < end) {
Packit Service ac8aad
			sec = find_section_by_index(&kelf->sections, *data);
Packit Service ac8aad
			if (!sec)
Packit Service ac8aad
				ERROR("group section not found");
Packit Service ac8aad
			sec->grouped = 1;
Packit Service ac8aad
			log_debug("marking section %s (%d) as grouped\n",
Packit Service ac8aad
			          sec->name, sec->index);
Packit Service ac8aad
			data++;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static char *kpatch_section_function_name(struct section *sec)
Packit Service ac8aad
{
Packit Service da4517
	if (is_rela_section(sec))
Packit Service da4517
		sec = sec->base;
Packit Service da4517
	return sec->sym ? sec->sym->name : sec->name;
Packit Service da4517
}
Packit Service ac8aad
Packit Service da4517
static struct symbol *kpatch_find_uncorrelated_rela(struct section *rela_sec,
Packit Service da4517
						    struct symbol *sym)
Packit Service da4517
{
Packit Service da4517
	struct rela *rela, *rela_toc;
Packit Service ac8aad
Packit Service da4517
	/* find the patched object's corresponding variable */
Packit Service da4517
	list_for_each_entry(rela, &rela_sec->relas, list) {
Packit Service da4517
		struct symbol *patched_sym;
Packit Service ac8aad
Packit Service da4517
		rela_toc = toc_rela(rela);
Packit Service da4517
		if (!rela_toc)
Packit Service da4517
			continue; /* skip toc constants */
Packit Service ac8aad
Packit Service da4517
		patched_sym = rela_toc->sym;
Packit Service ac8aad
Packit Service da4517
		if (patched_sym->twin)
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service da4517
		if (sym->type != patched_sym->type ||
Packit Service da4517
		    (sym->type == STT_OBJECT &&
Packit Service da4517
		     sym->sym.st_size != patched_sym->sym.st_size))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service da4517
		if (kpatch_mangled_strcmp(patched_sym->name, sym->name))
Packit Service ac8aad
			continue;
Packit Service da4517
Packit Service da4517
		return patched_sym;
Packit Service ac8aad
	}
Packit Service da4517
Packit Service da4517
	return NULL;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static struct symbol *kpatch_find_static_twin_in_children(struct symbol *parent,
Packit Service da4517
							  struct symbol *sym)
Packit Service ac8aad
{
Packit Service da4517
	struct symbol *child;
Packit Service da4517
Packit Service da4517
	list_for_each_entry(child, &parent->children, subfunction_node) {
Packit Service da4517
		struct symbol *res;
Packit Service da4517
Packit Service da4517
		/* Only look in children whose rela section differ from the parent's */
Packit Service da4517
		if (child->sec->rela == parent->sec->rela || !child->sec->rela)
Packit Service da4517
			continue;
Packit Service da4517
Packit Service da4517
		res = kpatch_find_uncorrelated_rela(child->sec->rela, sym);
Packit Service da4517
		/* Need to go deeper */
Packit Service da4517
		if (!res)
Packit Service da4517
			res = kpatch_find_static_twin_in_children(child, sym);
Packit Service da4517
		if (res != NULL)
Packit Service da4517
			return res;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	return NULL;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
/*
Packit Service ac8aad
 * Given a static local variable symbol and a rela section which references it
Packit Service ac8aad
 * in the base object, find a corresponding usage of a similarly named symbol
Packit Service ac8aad
 * in the patched object.
Packit Service ac8aad
 */
Packit Service ac8aad
static struct symbol *kpatch_find_static_twin(struct section *sec,
Packit Service ac8aad
					      struct symbol *sym)
Packit Service ac8aad
{
Packit Service da4517
	struct symbol *res;
Packit Service ac8aad
Packit Service da4517
	if (!sec->twin && sec->base->sym) {
Packit Service da4517
		struct symbol *parent = NULL;
Packit Service ac8aad
Packit Service da4517
		/*
Packit Service da4517
		 * The static twin might have been in a .part. symbol in the
Packit Service da4517
		 * original object that got removed in the patched object.
Packit Service da4517
		 */
Packit Service da4517
		parent = kpatch_get_correlated_parent(sec->base->sym);
Packit Service da4517
		if (parent)
Packit Service da4517
			sec = parent->sec->rela;
Packit Service ac8aad
Packit Service da4517
	}
Packit Service ac8aad
Packit Service da4517
	if (!sec->twin)
Packit Service da4517
		return NULL;
Packit Service ac8aad
Packit Service da4517
	res = kpatch_find_uncorrelated_rela(sec->twin, sym);
Packit Service da4517
	if (res != NULL)
Packit Service da4517
		return res;
Packit Service ac8aad
Packit Service da4517
	/* Look if reference might have moved to child functions' sections */
Packit Service da4517
	if (sec->twin->base->sym)
Packit Service da4517
		return kpatch_find_static_twin_in_children(sec->twin->base->sym,
Packit Service da4517
							   sym);
Packit Service ac8aad
Packit Service ac8aad
	return NULL;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int kpatch_is_normal_static_local(struct symbol *sym)
Packit Service ac8aad
{
Packit Service ac8aad
	if (sym->type != STT_OBJECT || sym->bind != STB_LOCAL)
Packit Service ac8aad
		return 0;
Packit Service ac8aad
Packit Service ac8aad
	if (!strchr(sym->name, '.'))
Packit Service ac8aad
		return 0;
Packit Service ac8aad
Packit Service ac8aad
	if (is_special_static(sym))
Packit Service ac8aad
		return 0;
Packit Service ac8aad
Packit Service ac8aad
	return 1;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static struct rela *kpatch_find_static_twin_ref(struct section *rela_sec, struct symbol *sym)
Packit Service da4517
{
Packit Service da4517
	struct rela *rela;
Packit Service da4517
Packit Service da4517
	list_for_each_entry(rela, &rela_sec->relas, list) {
Packit Service da4517
		if (rela->sym == sym->twin)
Packit Service da4517
			return rela;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	/* Reference to static variable might have moved to child function section */
Packit Service da4517
	if (rela_sec->base->sym) {
Packit Service da4517
		struct symbol *parent = rela_sec->base->sym;
Packit Service da4517
		struct symbol *child;
Packit Service da4517
Packit Service da4517
		list_for_each_entry(child, &parent->children, subfunction_node) {
Packit Service da4517
			/* Only look in children whose rela section differ from the parent's */
Packit Service da4517
			if (child->sec->rela == parent->sec->rela ||
Packit Service da4517
			    !child->sec->rela)
Packit Service da4517
				continue;
Packit Service da4517
Packit Service da4517
			rela = kpatch_find_static_twin_ref(child->sec->rela, sym);
Packit Service da4517
			if (rela)
Packit Service da4517
				return rela;
Packit Service da4517
		}
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	return NULL;
Packit Service da4517
}
Packit Service da4517
Packit Service ac8aad
/*
Packit Service ac8aad
 * gcc renames static local variables by appending a period and a number.  For
Packit Service ac8aad
 * example, __foo could be renamed to __foo.31452.  Unfortunately this number
Packit Service ac8aad
 * can arbitrarily change.  Correlate them by comparing which functions
Packit Service ac8aad
 * reference them, and rename the patched symbols to match the base symbol
Packit Service ac8aad
 * names.
Packit Service ac8aad
 *
Packit Service ac8aad
 * Some surprising facts about static local variable symbols:
Packit Service ac8aad
 *
Packit Service ac8aad
 * - It's possible for multiple functions to use the same
Packit Service ac8aad
 *   static local variable if the variable is defined in an
Packit Service ac8aad
 *   inlined function.
Packit Service ac8aad
 *
Packit Service ac8aad
 * - It's also possible for multiple static local variables
Packit Service ac8aad
 *   with the same name to be used in the same function if they
Packit Service ac8aad
 *   have different scopes.  (We have to assume that in such
Packit Service ac8aad
 *   cases, the order in which they're referenced remains the
Packit Service ac8aad
 *   same between the base and patched objects, as there's no
Packit Service ac8aad
 *   other way to distinguish them.)
Packit Service ac8aad
 *
Packit Service ac8aad
 * - Static locals are usually referenced by functions, but
Packit Service ac8aad
 *   they can occasionally be referenced by data sections as
Packit Service ac8aad
 *   well.
Packit Service ac8aad
 */
Packit Service ac8aad
static void kpatch_correlate_static_local_variables(struct kpatch_elf *base,
Packit Service ac8aad
						    struct kpatch_elf *patched)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym, *patched_sym;
Packit Service ac8aad
	struct section *sec;
Packit Service da4517
	struct rela *rela;
Packit Service da4517
	int bundled, patched_bundled;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * First undo the correlations for all static locals.  Two static
Packit Service ac8aad
	 * locals can have the same numbered suffix in the base and patched
Packit Service ac8aad
	 * objects by coincidence.
Packit Service ac8aad
	 */
Packit Service ac8aad
	list_for_each_entry(sym, &base->symbols, list) {
Packit Service ac8aad
Packit Service ac8aad
		if (!kpatch_is_normal_static_local(sym))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service da4517
		if (sym->twin)
Packit Service da4517
			UNCORRELATE_ELEMENT(sym);
Packit Service ac8aad
Packit Service ac8aad
		bundled = sym == sym->sec->sym;
Packit Service ac8aad
		if (bundled && sym->sec->twin) {
Packit Service da4517
			UNCORRELATE_ELEMENT(sym->sec);
Packit Service ac8aad
Packit Service da4517
			UNCORRELATE_ELEMENT(sym->sec->secsym);
Packit Service ac8aad
Packit Service da4517
			if (sym->sec->rela)
Packit Service da4517
				UNCORRELATE_ELEMENT(sym->sec->rela);
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Do the correlations: for each section reference to a static local,
Packit Service ac8aad
	 * look for a corresponding reference in the section's twin.
Packit Service ac8aad
	 */
Packit Service ac8aad
	list_for_each_entry(sec, &base->sections, list) {
Packit Service ac8aad
Packit Service ac8aad
		if (!is_rela_section(sec) ||
Packit Service ac8aad
		    is_debug_section(sec) ||
Packit Service ac8aad
		    !strcmp(sec->name, ".rela.toc"))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
Packit Service ac8aad
			if (!toc_rela(rela))
Packit Service ac8aad
				continue; /* skip toc constants */
Packit Service ac8aad
			sym = toc_rela(rela)->sym;
Packit Service ac8aad
Packit Service ac8aad
			if (!kpatch_is_normal_static_local(sym))
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			if (sym->twin)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			bundled = sym == sym->sec->sym;
Packit Service ac8aad
			if (bundled && sym->sec == sec->base) {
Packit Service ac8aad
				/*
Packit Service ac8aad
				 * A rare case where a static local data
Packit Service ac8aad
				 * structure references itself.  There's no
Packit Service ac8aad
				 * reliable way to correlate this.  Hopefully
Packit Service ac8aad
				 * there's another reference to the symbol
Packit Service ac8aad
				 * somewhere that can be used.
Packit Service ac8aad
				 */
Packit Service ac8aad
				log_debug("can't correlate static local %s's reference to itself\n",
Packit Service ac8aad
					  sym->name);
Packit Service ac8aad
				continue;
Packit Service ac8aad
			}
Packit Service ac8aad
Packit Service ac8aad
			patched_sym = kpatch_find_static_twin(sec, sym);
Packit Service ac8aad
			if (!patched_sym)
Packit Service ac8aad
				DIFF_FATAL("reference to static local variable %s in %s was removed",
Packit Service ac8aad
					   sym->name,
Packit Service ac8aad
					   kpatch_section_function_name(sec));
Packit Service ac8aad
Packit Service ac8aad
			patched_bundled = patched_sym == patched_sym->sec->sym;
Packit Service ac8aad
			if (bundled != patched_bundled)
Packit Service ac8aad
				ERROR("bundle mismatch for symbol %s", sym->name);
Packit Service ac8aad
			if (!bundled && sym->sec->twin != patched_sym->sec)
Packit Service da4517
				ERROR("sections %s and %s aren't correlated for symbol %s",
Packit Service da4517
				      sym->sec->name, patched_sym->sec->name, sym->name);
Packit Service ac8aad
Packit Service da4517
			kpatch_correlate_static_local(sym, patched_sym);
Packit Service ac8aad
Packit Service da4517
			if (bundled)
Packit Service da4517
				kpatch_correlate_section(sym->sec, patched_sym->sec);
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Make sure that:
Packit Service ac8aad
	 *
Packit Service ac8aad
	 * 1. all the base object's referenced static locals have been
Packit Service ac8aad
	 *    correlated; and
Packit Service ac8aad
	 *
Packit Service ac8aad
	 * 2. each reference to a static local in the base object has a
Packit Service ac8aad
	 *    corresponding reference in the patched object (because a static
Packit Service ac8aad
	 *    local can be referenced by more than one section).
Packit Service ac8aad
	 */
Packit Service ac8aad
	list_for_each_entry(sec, &base->sections, list) {
Packit Service ac8aad
Packit Service ac8aad
		if (!is_rela_section(sec) ||
Packit Service ac8aad
		    is_debug_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service da4517
			struct section *target_sec = sec;
Packit Service ac8aad
Packit Service ac8aad
			sym = rela->sym;
Packit Service ac8aad
			if (!kpatch_is_normal_static_local(sym))
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service da4517
			if (!sec->twin && sec->base->sym) {
Packit Service da4517
				struct symbol *parent = NULL;
Packit Service ac8aad
Packit Service da4517
				parent = kpatch_get_correlated_parent(sec->base->sym);
Packit Service da4517
				if (parent)
Packit Service da4517
					target_sec = parent->sec->rela;
Packit Service ac8aad
			}
Packit Service ac8aad
Packit Service da4517
			if (!sym->twin || !target_sec->twin)
Packit Service da4517
				DIFF_FATAL("reference to static local variable %s in %s was removed",
Packit Service da4517
					   sym->name,
Packit Service da4517
					   kpatch_section_function_name(target_sec));
Packit Service da4517
Packit Service da4517
			if (!kpatch_find_static_twin_ref(target_sec->twin, sym))
Packit Service ac8aad
				DIFF_FATAL("static local %s has been correlated with %s, but patched %s is missing a reference to it",
Packit Service ac8aad
					   sym->name, sym->twin->name,
Packit Service da4517
					   kpatch_section_function_name(target_sec->twin));
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Now go through the patched object and look for any uncorrelated
Packit Service ac8aad
	 * static locals to see if we need to print any warnings about new
Packit Service ac8aad
	 * variables.
Packit Service ac8aad
	 */
Packit Service ac8aad
	list_for_each_entry(sec, &patched->sections, list) {
Packit Service ac8aad
Packit Service ac8aad
		if (!is_rela_section(sec) ||
Packit Service ac8aad
		    is_debug_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
Packit Service ac8aad
			sym = rela->sym;
Packit Service ac8aad
			if (!kpatch_is_normal_static_local(sym))
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			if (sym->twin)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			log_normal("WARNING: unable to correlate static local variable %s used by %s, assuming variable is new\n",
Packit Service ac8aad
				   sym->name,
Packit Service ac8aad
				   kpatch_section_function_name(sec));
Packit Service ac8aad
			return;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_correlate_elfs(struct kpatch_elf *kelf1, struct kpatch_elf *kelf2)
Packit Service ac8aad
{
Packit Service ac8aad
	kpatch_correlate_sections(&kelf1->sections, &kelf2->sections);
Packit Service ac8aad
	kpatch_correlate_symbols(&kelf1->symbols, &kelf2->symbols);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_compare_correlated_elements(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	/* lists are already correlated at this point */
Packit Service ac8aad
	kpatch_compare_sections(&kelf->sections);
Packit Service ac8aad
	kpatch_compare_symbols(&kelf->symbols);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
#ifdef __x86_64__
Packit Service da4517
static void rela_insn(const struct section *sec, const struct rela *rela,
Packit Service da4517
		      struct insn *insn)
Packit Service ac8aad
{
Packit Service ac8aad
	unsigned long insn_addr, start, end, rela_addr;
Packit Service ac8aad
Packit Service ac8aad
	start = (unsigned long)sec->base->data->d_buf;
Packit Service ac8aad
	end = start + sec->base->sh.sh_size;
Packit Service da4517
Packit Service da4517
	if (end <= start)
Packit Service da4517
		ERROR("bad section size");
Packit Service da4517
Packit Service ac8aad
	rela_addr = start + rela->offset;
Packit Service ac8aad
	for (insn_addr = start; insn_addr < end; insn_addr += insn->length) {
Packit Service ac8aad
		insn_init(insn, (void *)insn_addr, 1);
Packit Service ac8aad
		insn_get_length(insn);
Packit Service ac8aad
		if (!insn->length)
Packit Service ac8aad
			ERROR("can't decode instruction in section %s at offset 0x%lx",
Packit Service ac8aad
			      sec->base->name, insn_addr);
Packit Service ac8aad
		if (rela_addr >= insn_addr &&
Packit Service ac8aad
		    rela_addr < insn_addr + insn->length)
Packit Service ac8aad
			return;
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
#endif
Packit Service ac8aad
Packit Service da4517
static bool is_callback_section(struct section *sec) {
Packit Service da4517
Packit Service da4517
	static char *callback_sections[] = {
Packit Service da4517
		".kpatch.callbacks.pre_patch",
Packit Service da4517
		".kpatch.callbacks.post_patch",
Packit Service da4517
		".kpatch.callbacks.pre_unpatch",
Packit Service da4517
		".kpatch.callbacks.post_unpatch",
Packit Service da4517
		".rela.kpatch.callbacks.pre_patch",
Packit Service da4517
		".rela.kpatch.callbacks.post_patch",
Packit Service da4517
		".rela.kpatch.callbacks.pre_unpatch",
Packit Service da4517
		".rela.kpatch.callbacks.post_unpatch",
Packit Service da4517
		NULL,
Packit Service da4517
	};
Packit Service da4517
	char **callback_sec;
Packit Service da4517
Packit Service da4517
	for (callback_sec = callback_sections; *callback_sec; callback_sec++)
Packit Service da4517
		if (!strcmp(sec->name, *callback_sec))
Packit Service da4517
			return true;
Packit Service da4517
Packit Service da4517
	return false;
Packit Service da4517
}
Packit Service da4517
Packit Service ac8aad
/*
Packit Service ac8aad
 * Mangle the relas a little.  The compiler will sometimes use section symbols
Packit Service ac8aad
 * to reference local objects and functions rather than the object or function
Packit Service ac8aad
 * symbols themselves.  We substitute the object/function symbols for the
Packit Service ac8aad
 * section symbol in this case so that the relas can be properly correlated and
Packit Service ac8aad
 * so that the existing object/function in vmlinux can be linked to.
Packit Service ac8aad
 */
Packit Service ac8aad
static void kpatch_replace_sections_syms(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	struct symbol *sym;
Packit Service da4517
	unsigned int add_off;
Packit Service ac8aad
Packit Service ac8aad
	log_debug("\n");
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!is_rela_section(sec) ||
Packit Service ac8aad
		    is_debug_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
Packit Service da4517
			if (rela->sym->type != STT_SECTION || !rela->sym->sec)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			/*
Packit Service ac8aad
			 * Replace references to bundled sections with their
Packit Service ac8aad
			 * symbols.
Packit Service ac8aad
			 */
Packit Service da4517
			if (rela->sym->sec->sym) {
Packit Service ac8aad
				rela->sym = rela->sym->sec->sym;
Packit Service ac8aad
Packit Service da4517
				/*
Packit Service da4517
				 * On ppc64le with GCC6+, even with
Packit Service da4517
				 * -ffunction-sections, the function symbol
Packit Service da4517
				 *  starts 8 bytes past the beginning of the
Packit Service da4517
				 *  section, because the .TOC pointer is at the
Packit Service da4517
				 *  beginning, right before the code.  So even
Packit Service da4517
				 *  though the symbol is bundled, we can't
Packit Service da4517
				 *  assume it's at offset 0 in the section.
Packit Service da4517
				 */
Packit Service da4517
				rela->addend -= rela->sym->sym.st_value;
Packit Service da4517
Packit Service ac8aad
				continue;
Packit Service ac8aad
			}
Packit Service ac8aad
Packit Service ac8aad
#ifdef __powerpc64__
Packit Service ac8aad
			add_off = 0;
Packit Service ac8aad
#else
Packit Service da4517
			if (rela->type == R_X86_64_PC32 ||
Packit Service da4517
			    rela->type == R_X86_64_PLT32) {
Packit Service ac8aad
				struct insn insn;
Packit Service ac8aad
				rela_insn(sec, rela, &insn);
Packit Service da4517
				add_off = (unsigned int)((long)insn.next_byte -
Packit Service ac8aad
					  (long)sec->base->data->d_buf -
Packit Service da4517
					  rela->offset);
Packit Service ac8aad
			} else if (rela->type == R_X86_64_64 ||
Packit Service ac8aad
				   rela->type == R_X86_64_32S)
Packit Service ac8aad
				add_off = 0;
Packit Service ac8aad
			else
Packit Service ac8aad
				continue;
Packit Service ac8aad
#endif
Packit Service ac8aad
Packit Service ac8aad
			/*
Packit Service ac8aad
			 * Attempt to replace references to unbundled sections
Packit Service ac8aad
			 * with their symbols.
Packit Service ac8aad
			 */
Packit Service ac8aad
			list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service da4517
				long start, end;
Packit Service ac8aad
Packit Service ac8aad
				if (sym->type == STT_SECTION ||
Packit Service ac8aad
				    sym->sec != rela->sym->sec)
Packit Service ac8aad
					continue;
Packit Service ac8aad
Packit Service ac8aad
				start = sym->sym.st_value;
Packit Service ac8aad
				end = sym->sym.st_value + sym->sym.st_size;
Packit Service ac8aad
Packit Service ac8aad
				if (!is_text_section(sym->sec) &&
Packit Service ac8aad
				    rela->type == R_X86_64_32S &&
Packit Service da4517
				    rela->addend == (long)sym->sec->sh.sh_size &&
Packit Service da4517
				    end == (long)sym->sec->sh.sh_size) {
Packit Service ac8aad
Packit Service ac8aad
					/*
Packit Service ac8aad
					 * A special case where gcc needs a
Packit Service ac8aad
					 * pointer to the address at the end of
Packit Service ac8aad
					 * a data section.
Packit Service ac8aad
					 *
Packit Service ac8aad
					 * This is usually used with a compare
Packit Service ac8aad
					 * instruction to determine when to end
Packit Service ac8aad
					 * a loop.  The code doesn't actually
Packit Service ac8aad
					 * dereference the pointer so this is
Packit Service ac8aad
					 * "normal" and we just replace the
Packit Service ac8aad
					 * section reference with a reference
Packit Service ac8aad
					 * to the last symbol in the section.
Packit Service ac8aad
					 *
Packit Service ac8aad
					 * Note that this only catches the
Packit Service ac8aad
					 * issue when it happens at the end of
Packit Service ac8aad
					 * a section.  It can also happen in
Packit Service ac8aad
					 * the middle of a section.  In that
Packit Service ac8aad
					 * case, the wrong symbol will be
Packit Service ac8aad
					 * associated with the reference.  But
Packit Service ac8aad
					 * that's ok because:
Packit Service ac8aad
					 *
Packit Service ac8aad
					 * 1) This situation only occurs when
Packit Service ac8aad
					 *    gcc is trying to get the address
Packit Service ac8aad
					 *    of the symbol, not the contents
Packit Service ac8aad
					 *    of its data; and
Packit Service ac8aad
					 *
Packit Service ac8aad
					 * 2) Because kpatch doesn't allow data
Packit Service ac8aad
					 *    sections to change,
Packit Service ac8aad
					 *    &(var1+sizeof(var1)) will always
Packit Service ac8aad
					 *    be the same as &var2.
Packit Service ac8aad
					 */
Packit Service ac8aad
Packit Service ac8aad
				} else if (rela->addend + add_off < start ||
Packit Service ac8aad
					   rela->addend + add_off >= end)
Packit Service ac8aad
					continue;
Packit Service ac8aad
Packit Service da4517
				log_debug("%s: replacing %s+%ld reference with %s+%ld\n",
Packit Service ac8aad
					  sec->name,
Packit Service ac8aad
					  rela->sym->name, rela->addend,
Packit Service ac8aad
					  sym->name, rela->addend - start);
Packit Service ac8aad
Packit Service ac8aad
				rela->sym = sym;
Packit Service ac8aad
				rela->addend -= start;
Packit Service ac8aad
				break;
Packit Service ac8aad
			}
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
	log_debug("\n");
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_check_func_profiling_calls(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	int errs = 0;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service da4517
		if (sym->type != STT_FUNC || sym->status != CHANGED ||
Packit Service da4517
		    (sym->parent && sym->parent->status == CHANGED))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		if (!sym->twin->has_func_profiling) {
Packit Service ac8aad
			log_normal("function %s has no fentry/mcount call, unable to patch\n",
Packit Service ac8aad
				   sym->name);
Packit Service ac8aad
			errs++;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (errs)
Packit Service ac8aad
		DIFF_FATAL("%d function(s) can not be patched", errs);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_verify_patchability(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	int errs = 0;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (sec->status == CHANGED && !sec->include) {
Packit Service ac8aad
			log_normal("changed section %s not selected for inclusion\n",
Packit Service ac8aad
				   sec->name);
Packit Service ac8aad
			errs++;
Packit Service ac8aad
		}
Packit Service ac8aad
Packit Service ac8aad
		if (sec->status != SAME && sec->grouped) {
Packit Service ac8aad
			log_normal("changed section %s is part of a section group\n",
Packit Service ac8aad
				   sec->name);
Packit Service ac8aad
			errs++;
Packit Service ac8aad
		}
Packit Service ac8aad
Packit Service ac8aad
		if (sec->sh.sh_type == SHT_GROUP && sec->status == NEW) {
Packit Service ac8aad
			log_normal("new/changed group sections are not supported\n");
Packit Service ac8aad
			errs++;
Packit Service ac8aad
		}
Packit Service ac8aad
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * ensure we aren't including .data.* or .bss.*
Packit Service ac8aad
		 * (.data.unlikely and .data.once is ok b/c it only has __warned vars)
Packit Service ac8aad
		 */
Packit Service ac8aad
		if (sec->include && sec->status != NEW &&
Packit Service ac8aad
		    (!strncmp(sec->name, ".data", 5) || !strncmp(sec->name, ".bss", 4)) &&
Packit Service ac8aad
		    (strcmp(sec->name, ".data.unlikely") && strcmp(sec->name, ".data.once"))) {
Packit Service ac8aad
			log_normal("data section %s selected for inclusion\n",
Packit Service ac8aad
				   sec->name);
Packit Service ac8aad
			errs++;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (errs)
Packit Service ac8aad
		DIFF_FATAL("%d unsupported section change(s)", errs);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_include_symbol(struct symbol *sym);
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_include_section(struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
Packit Service ac8aad
	/* Include the section and its section symbol */
Packit Service ac8aad
	if (sec->include)
Packit Service ac8aad
		return;
Packit Service ac8aad
	sec->include = 1;
Packit Service ac8aad
	if (sec->secsym)
Packit Service ac8aad
		sec->secsym->include = 1;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Include the section's rela section and then recursively include the
Packit Service ac8aad
	 * symbols needed by its relas.
Packit Service ac8aad
	 */
Packit Service ac8aad
	if (!sec->rela)
Packit Service ac8aad
		return;
Packit Service ac8aad
	sec->rela->include = 1;
Packit Service ac8aad
	list_for_each_entry(rela, &sec->rela->relas, list)
Packit Service ac8aad
		kpatch_include_symbol(rela->sym);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_include_symbol(struct symbol *sym)
Packit Service ac8aad
{
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * This function is called recursively from kpatch_include_section().
Packit Service ac8aad
	 * Make sure we don't get into an endless loop.
Packit Service ac8aad
	 */
Packit Service ac8aad
	if (sym->include)
Packit Service ac8aad
		return;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * The symbol gets included even if its section isn't needed, as it
Packit Service ac8aad
	 * might be needed: either permanently for a rela, or temporarily for
Packit Service ac8aad
	 * the later creation of a dynrela.
Packit Service ac8aad
	 */
Packit Service ac8aad
	sym->include = 1;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * For a function/object symbol, if it has a section, we only need to
Packit Service ac8aad
	 * include the section if it has changed.  Otherwise the symbol will be
Packit Service ac8aad
	 * used by relas/dynrelas to link to the real symbol externally.
Packit Service ac8aad
	 *
Packit Service ac8aad
	 * For section symbols, we always include the section because
Packit Service ac8aad
	 * references to them can't otherwise be resolved externally.
Packit Service ac8aad
	 */
Packit Service ac8aad
	if (sym->sec && (sym->type == STT_SECTION || sym->status != SAME))
Packit Service ac8aad
		kpatch_include_section(sym->sec);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_include_standard_elements(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * Include the following sections even if they haven't changed.
Packit Service ac8aad
		 *
Packit Service ac8aad
		 * Notes about some of the more interesting sections:
Packit Service ac8aad
		 *
Packit Service ac8aad
		 * - With -fdata-sections, .rodata is only used for:
Packit Service ac8aad
		 *
Packit Service ac8aad
		 *     switch jump tables;
Packit Service ac8aad
		 *     KASAN data (with KASAN enabled, which is rare); and
Packit Service ac8aad
		 *     an ugly hack in vmx_vcpu_run().
Packit Service ac8aad
		 *
Packit Service ac8aad
		 *   Those data are all local to the functions which use them.
Packit Service ac8aad
		 *   So it's safe to include .rodata.
Packit Service ac8aad
		 *
Packit Service ac8aad
		 * - On ppc64le, the .toc section is used for all data
Packit Service ac8aad
		 *   accesses.
Packit Service ac8aad
		 *
Packit Service ac8aad
		 * Note that if any of these sections have rela sections, they
Packit Service ac8aad
		 * will also be included in their entirety.  That may result in
Packit Service ac8aad
		 * some extra (unused) dynrelas getting created, which should
Packit Service ac8aad
		 * be harmless.
Packit Service ac8aad
		 */
Packit Service ac8aad
		if (!strcmp(sec->name, ".shstrtab") ||
Packit Service ac8aad
		    !strcmp(sec->name, ".strtab") ||
Packit Service ac8aad
		    !strcmp(sec->name, ".symtab") ||
Packit Service ac8aad
		    !strcmp(sec->name, ".toc") ||
Packit Service ac8aad
		    !strcmp(sec->name, ".rodata") ||
Packit Service ac8aad
		    (!strncmp(sec->name, ".rodata.", 8) &&
Packit Service ac8aad
		     strstr(sec->name, ".str1."))) {
Packit Service ac8aad
			kpatch_include_section(sec);
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* include the NULL symbol */
Packit Service ac8aad
	list_entry(kelf->symbols.next, struct symbol, list)->include = 1;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int kpatch_include_callback_elements(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	int found = 0;
Packit Service ac8aad
Packit Service ac8aad
	/* include load/unload sections */
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service da4517
		if (!is_callback_section(sec))
Packit Service da4517
			continue;
Packit Service ac8aad
Packit Service da4517
		sec->include = 1;
Packit Service da4517
		found = 1;
Packit Service da4517
		if (is_rela_section(sec)) {
Packit Service da4517
			/* include callback dependencies */
Packit Service da4517
			rela = list_entry(sec->relas.next, struct rela, list);
Packit Service da4517
			sym = rela->sym;
Packit Service da4517
			log_normal("found callback: %s\n",sym->name);
Packit Service da4517
			kpatch_include_symbol(sym);
Packit Service da4517
		} else {
Packit Service da4517
			sec->secsym->include = 1;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service da4517
	/* Strip temporary structure symbols used by the callback macros. */
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service da4517
		if (sym->type == STT_OBJECT && sym->sec &&
Packit Service da4517
		    is_callback_section(sym->sec))
Packit Service da4517
			sym->include = 0;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return found;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_include_force_elements(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
Packit Service ac8aad
	/* include force sections */
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!strcmp(sec->name, ".kpatch.force") ||
Packit Service ac8aad
		    !strcmp(sec->name, ".rela.kpatch.force")) {
Packit Service ac8aad
			sec->include = 1;
Packit Service ac8aad
			if (!is_rela_section(sec)) {
Packit Service ac8aad
				/* .kpatch.force */
Packit Service ac8aad
				sec->secsym->include = 1;
Packit Service ac8aad
				continue;
Packit Service ac8aad
			}
Packit Service ac8aad
			/* .rela.kpatch.force */
Packit Service ac8aad
			list_for_each_entry(rela, &sec->relas, list)
Packit Service ac8aad
				log_normal("function '%s' marked with KPATCH_FORCE_UNSAFE!\n",
Packit Service ac8aad
				           rela->sym->name);
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* strip temporary global kpatch_force_func_* symbols */
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list)
Packit Service ac8aad
		if (!strncmp(sym->name, "__kpatch_force_func_",
Packit Service ac8aad
		            strlen("__kpatch_force_func_")))
Packit Service ac8aad
			sym->include = 0;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int kpatch_include_new_globals(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	int nr = 0;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service ac8aad
		if (sym->bind == STB_GLOBAL && sym->sec &&
Packit Service ac8aad
		    sym->status == NEW) {
Packit Service ac8aad
			kpatch_include_symbol(sym);
Packit Service ac8aad
			nr++;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return nr;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int kpatch_include_changed_functions(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	int changed_nr = 0;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service ac8aad
		if (sym->status == CHANGED &&
Packit Service ac8aad
		    sym->type == STT_FUNC) {
Packit Service ac8aad
			changed_nr++;
Packit Service ac8aad
			kpatch_include_symbol(sym);
Packit Service ac8aad
		}
Packit Service ac8aad
Packit Service ac8aad
		if (sym->type == STT_FILE)
Packit Service ac8aad
			sym->include = 1;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return changed_nr;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_print_changes(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service da4517
		if (!sym->include || !sym->sec || sym->type != STT_FUNC || sym->parent)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		if (sym->status == NEW)
Packit Service ac8aad
			log_normal("new function: %s\n", sym->name);
Packit Service ac8aad
		else if (sym->status == CHANGED)
Packit Service ac8aad
			log_normal("changed function: %s\n", sym->name);
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_migrate_symbols(struct list_head *src,
Packit Service ac8aad
				   struct list_head *dst,
Packit Service ac8aad
				   int (*select)(struct symbol *))
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym, *safe;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry_safe(sym, safe, src, list) {
Packit Service ac8aad
		if (select && !select(sym))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		list_del(&sym->list);
Packit Service ac8aad
		list_add_tail(&sym->list, dst);
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_migrate_included_elements(struct kpatch_elf *kelf, struct kpatch_elf **kelfout)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec, *safesec;
Packit Service ac8aad
	struct symbol *sym, *safesym;
Packit Service ac8aad
	struct kpatch_elf *out;
Packit Service ac8aad
Packit Service ac8aad
	/* allocate output kelf */
Packit Service ac8aad
	out = malloc(sizeof(*out));
Packit Service ac8aad
	if (!out)
Packit Service ac8aad
		ERROR("malloc");
Packit Service ac8aad
	memset(out, 0, sizeof(*out));
Packit Service ac8aad
	INIT_LIST_HEAD(&out->sections);
Packit Service ac8aad
	INIT_LIST_HEAD(&out->symbols);
Packit Service ac8aad
	INIT_LIST_HEAD(&out->strings);
Packit Service ac8aad
Packit Service ac8aad
	/* migrate included sections from kelf to out */
Packit Service ac8aad
	list_for_each_entry_safe(sec, safesec, &kelf->sections, list) {
Packit Service ac8aad
		if (!sec->include)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		list_del(&sec->list);
Packit Service ac8aad
		list_add_tail(&sec->list, &out->sections);
Packit Service ac8aad
		sec->index = 0;
Packit Service ac8aad
		if (!is_rela_section(sec) && sec->secsym && !sec->secsym->include)
Packit Service ac8aad
			/* break link to non-included section symbol */
Packit Service ac8aad
			sec->secsym = NULL;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* migrate included symbols from kelf to out */
Packit Service ac8aad
	list_for_each_entry_safe(sym, safesym, &kelf->symbols, list) {
Packit Service ac8aad
		if (!sym->include)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		list_del(&sym->list);
Packit Service ac8aad
		list_add_tail(&sym->list, &out->symbols);
Packit Service ac8aad
		sym->index = 0;
Packit Service ac8aad
		sym->strip = 0;
Packit Service ac8aad
		if (sym->sec && !sym->sec->include)
Packit Service ac8aad
			/* break link to non-included section */
Packit Service ac8aad
			sym->sec = NULL;
Packit Service ac8aad
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	*kelfout = out;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_reorder_symbols(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	LIST_HEAD(symbols);
Packit Service ac8aad
Packit Service ac8aad
	/* migrate NULL sym */
Packit Service ac8aad
	kpatch_migrate_symbols(&kelf->symbols, &symbols, is_null_sym);
Packit Service ac8aad
	/* migrate LOCAL FILE sym */
Packit Service ac8aad
	kpatch_migrate_symbols(&kelf->symbols, &symbols, is_file_sym);
Packit Service ac8aad
	/* migrate LOCAL FUNC syms */
Packit Service ac8aad
	kpatch_migrate_symbols(&kelf->symbols, &symbols, is_local_func_sym);
Packit Service ac8aad
	/* migrate all other LOCAL syms */
Packit Service ac8aad
	kpatch_migrate_symbols(&kelf->symbols, &symbols, is_local_sym);
Packit Service ac8aad
	/* migrate all other (GLOBAL) syms */
Packit Service ac8aad
	kpatch_migrate_symbols(&kelf->symbols, &symbols, NULL);
Packit Service ac8aad
Packit Service ac8aad
	list_replace(&symbols, &kelf->symbols);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int bug_table_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	static int size = 0;
Packit Service ac8aad
	char *str;
Packit Service ac8aad
Packit Service ac8aad
	if (!size) {
Packit Service ac8aad
		str = getenv("BUG_STRUCT_SIZE");
Packit Service ac8aad
		if (!str)
Packit Service ac8aad
			ERROR("BUG_STRUCT_SIZE not set");
Packit Service ac8aad
		size = atoi(str);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return size;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int ex_table_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	static int size = 0;
Packit Service ac8aad
	char *str;
Packit Service ac8aad
Packit Service ac8aad
	if (!size) {
Packit Service ac8aad
		str = getenv("EX_STRUCT_SIZE");
Packit Service ac8aad
		if (!str)
Packit Service ac8aad
			ERROR("EX_STRUCT_SIZE not set");
Packit Service ac8aad
		size = atoi(str);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return size;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static int jump_table_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	static int size = 0;
Packit Service ac8aad
	char *str;
Packit Service ac8aad
Packit Service ac8aad
	if (!size) {
Packit Service da4517
		str = getenv("JUMP_STRUCT_SIZE");
Packit Service ac8aad
		if (!str)
Packit Service da4517
			ERROR("JUMP_STRUCT_SIZE not set");
Packit Service ac8aad
		size = atoi(str);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return size;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
#ifdef __x86_64__
Packit Service da4517
static int parainstructions_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	static int size = 0;
Packit Service ac8aad
	char *str;
Packit Service ac8aad
Packit Service ac8aad
	if (!size) {
Packit Service da4517
		str = getenv("PARA_STRUCT_SIZE");
Packit Service da4517
		if (!str)
Packit Service da4517
			ERROR("PARA_STRUCT_SIZE not set");
Packit Service da4517
		size = atoi(str);
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	return size;
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static int altinstructions_group_size(struct kpatch_elf *kelf, int offset)
Packit Service da4517
{
Packit Service da4517
	static int size = 0;
Packit Service da4517
	char *str;
Packit Service da4517
Packit Service da4517
	if (!size) {
Packit Service da4517
		str = getenv("ALT_STRUCT_SIZE");
Packit Service ac8aad
		if (!str)
Packit Service ac8aad
			ERROR("ALT_STRUCT_SIZE not set");
Packit Service ac8aad
		size = atoi(str);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return size;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int smp_locks_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	return 4;
Packit Service ac8aad
}
Packit Service ac8aad
#endif
Packit Service ac8aad
#ifdef __powerpc64__
Packit Service ac8aad
static int fixup_entry_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	static int size = 0;
Packit Service ac8aad
	char *str;
Packit Service ac8aad
Packit Service ac8aad
	if (!size) {
Packit Service ac8aad
		str = getenv("FIXUP_STRUCT_SIZE");
Packit Service ac8aad
		if (!str)
Packit Service ac8aad
			ERROR("FIXUP_STRUCT_SIZE not set");
Packit Service ac8aad
		size = atoi(str);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	return size;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int fixup_lwsync_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service da4517
	return 8;
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static int fixup_barrier_nospec_group_size(struct kpatch_elf *kelf, int offset)
Packit Service da4517
{
Packit Service da4517
	return 8;
Packit Service ac8aad
}
Packit Service ac8aad
#endif
Packit Service ac8aad
Packit Service ac8aad
/*
Packit Service ac8aad
 * The rela groups in the .fixup section vary in size.  The beginning of each
Packit Service ac8aad
 * .fixup rela group is referenced by the __ex_table section. To find the size
Packit Service ac8aad
 * of a .fixup rela group, we have to traverse the __ex_table relas.
Packit Service ac8aad
 */
Packit Service ac8aad
static int fixup_group_size(struct kpatch_elf *kelf, int offset)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	int found;
Packit Service ac8aad
Packit Service ac8aad
	sec = find_section_by_name(&kelf->sections, ".rela__ex_table");
Packit Service ac8aad
	if (!sec)
Packit Service ac8aad
		ERROR("missing .rela__ex_table section");
Packit Service ac8aad
Packit Service ac8aad
	/* find beginning of this group */
Packit Service ac8aad
	found = 0;
Packit Service ac8aad
	list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
		if (!strcmp(rela->sym->name, ".fixup") &&
Packit Service ac8aad
		    rela->addend == offset) {
Packit Service ac8aad
				found = 1;
Packit Service ac8aad
				break;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!found)
Packit Service ac8aad
		ERROR("can't find .fixup rela group at offset %d\n", offset);
Packit Service ac8aad
Packit Service ac8aad
	/* find beginning of next group */
Packit Service ac8aad
	found = 0;
Packit Service ac8aad
	list_for_each_entry_continue(rela, &sec->relas, list) {
Packit Service ac8aad
		if (!strcmp(rela->sym->name, ".fixup") &&
Packit Service ac8aad
		    rela->addend > offset) {
Packit Service ac8aad
			found = 1;
Packit Service ac8aad
			break;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!found) {
Packit Service ac8aad
		/* last group */
Packit Service ac8aad
		struct section *fixupsec;
Packit Service ac8aad
		fixupsec = find_section_by_name(&kelf->sections, ".fixup");
Packit Service da4517
		if (!fixupsec)
Packit Service da4517
			ERROR("missing .fixup section");
Packit Service da4517
		return (int)(fixupsec->sh.sh_size - offset);
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service da4517
	return (int)(rela->addend - offset);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static struct special_section special_sections[] = {
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= "__bug_table",
Packit Service ac8aad
		.group_size	= bug_table_group_size,
Packit Service ac8aad
	},
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= ".fixup",
Packit Service ac8aad
		.group_size	= fixup_group_size,
Packit Service ac8aad
	},
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= "__ex_table", /* must come after .fixup */
Packit Service ac8aad
		.group_size	= ex_table_group_size,
Packit Service ac8aad
	},
Packit Service da4517
	{
Packit Service da4517
		.name		= "__jump_table",
Packit Service da4517
		.group_size	= jump_table_group_size,
Packit Service da4517
	},
Packit Service ac8aad
#ifdef __x86_64__
Packit Service ac8aad
	{
Packit Service da4517
		.name		= ".smp_locks",
Packit Service da4517
		.group_size	= smp_locks_group_size,
Packit Service da4517
	},
Packit Service da4517
	{
Packit Service da4517
		.name		= ".parainstructions",
Packit Service da4517
		.group_size	= parainstructions_group_size,
Packit Service da4517
	},
Packit Service da4517
	{
Packit Service ac8aad
		.name		= ".altinstructions",
Packit Service ac8aad
		.group_size	= altinstructions_group_size,
Packit Service ac8aad
	},
Packit Service ac8aad
#endif
Packit Service ac8aad
#ifdef __powerpc64__
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= "__ftr_fixup",
Packit Service ac8aad
		.group_size	= fixup_entry_group_size,
Packit Service ac8aad
	},
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= "__mmu_ftr_fixup",
Packit Service ac8aad
		.group_size	= fixup_entry_group_size,
Packit Service ac8aad
	},
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= "__fw_ftr_fixup",
Packit Service ac8aad
		.group_size	= fixup_entry_group_size,
Packit Service ac8aad
	},
Packit Service ac8aad
	{
Packit Service ac8aad
		.name		= "__lwsync_fixup",
Packit Service ac8aad
		.group_size	= fixup_lwsync_group_size,
Packit Service ac8aad
	},
Packit Service da4517
	{
Packit Service da4517
		.name		= "__barrier_nospec_fixup",
Packit Service da4517
		.group_size	= fixup_barrier_nospec_group_size,
Packit Service da4517
	},
Packit Service ac8aad
#endif
Packit Service ac8aad
	{},
Packit Service ac8aad
};
Packit Service ac8aad
Packit Service da4517
static bool should_keep_jump_label(struct lookup_table *lookup,
Packit Service da4517
				   struct section *sec,
Packit Service da4517
				   unsigned int group_offset,
Packit Service da4517
				   unsigned int group_size,
Packit Service da4517
				   int *jump_labels_found)
Packit Service da4517
{
Packit Service da4517
	struct rela *code = NULL, *key = NULL, *rela;
Packit Service da4517
	bool tracepoint = false, dynamic_debug = false;
Packit Service da4517
	struct lookup_result symbol;
Packit Service da4517
	int i = 0;
Packit Service da4517
Packit Service da4517
	/*
Packit Service da4517
	 * Here we hard-code knowledge about the contents of the jump_entry
Packit Service da4517
	 * struct.  It has three fields: code, target, and key.  Each field has
Packit Service da4517
	 * a relocation associated with it.
Packit Service da4517
	 */
Packit Service da4517
	list_for_each_entry(rela, &sec->relas, list) {
Packit Service da4517
		if (rela->offset >= group_offset &&
Packit Service da4517
		    rela->offset < group_offset + group_size) {
Packit Service da4517
			if (i == 0)
Packit Service da4517
				code = rela;
Packit Service da4517
			else if (i == 2)
Packit Service da4517
				key = rela;
Packit Service da4517
			i++;
Packit Service da4517
		}
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	if (i != 3 || !key || !code)
Packit Service da4517
		ERROR("BUG: __jump_table has an unexpected format");
Packit Service da4517
Packit Service da4517
	if (!strncmp(key->sym->name, "__tracepoint_", 13))
Packit Service da4517
		tracepoint = true;
Packit Service da4517
Packit Service da4517
	if (is_dynamic_debug_symbol(key->sym))
Packit Service da4517
		dynamic_debug = true;
Packit Service da4517
Packit Service da4517
	if (KLP_ARCH) {
Packit Service da4517
		/*
Packit Service da4517
		 * On older kernels (with .klp.arch support), jump labels
Packit Service da4517
		 * aren't supported at all.  Error out when they occur in a
Packit Service da4517
		 * replacement function, with the exception of tracepoints and
Packit Service da4517
		 * dynamic debug printks.  An inert tracepoint or printk is
Packit Service da4517
		 * harmless enough, but a broken jump label can cause
Packit Service da4517
		 * unexpected behavior.
Packit Service da4517
		 */
Packit Service da4517
		if (tracepoint || dynamic_debug)
Packit Service da4517
			return false;
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * This will be upgraded to an error after all jump labels have
Packit Service da4517
		 * been reported.
Packit Service da4517
		 */
Packit Service da4517
		log_normal("Found a jump label at %s()+0x%lx, using key %s.  Jump labels aren't supported with this kernel.  Use static_key_enabled() instead.\n",
Packit Service da4517
			   code->sym->name, code->addend, key->sym->name);
Packit Service da4517
		(*jump_labels_found)++;
Packit Service da4517
		return false;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	/*
Packit Service da4517
	 * On newer (5.8+) kernels, jump labels are supported in the case where
Packit Service da4517
	 * the corresponding static key lives in vmlinux.  That's because such
Packit Service da4517
	 * kernels apply vmlinux-specific .klp.rela sections at the same time
Packit Service da4517
	 * (in the klp module load) as normal relas, before jump label init.
Packit Service da4517
	 * On the other hand, jump labels based on static keys which are
Packit Service da4517
	 * defined in modules aren't supported, because late module patching
Packit Service da4517
	 * can result in the klp relas getting applied *after* the klp module's
Packit Service da4517
	 * jump label init.
Packit Service da4517
	 */
Packit Service da4517
Packit Service da4517
	if (lookup_symbol(lookup, key->sym->name, &symbol) &&
Packit Service da4517
	    strcmp(symbol.objname, "vmlinux")) {
Packit Service da4517
Packit Service da4517
		/* The static key lives in a module -- not supported */
Packit Service da4517
Packit Service da4517
		/* Inert tracepoints and dynamic debug printks are harmless */
Packit Service da4517
		if (tracepoint || dynamic_debug)
Packit Service da4517
			return false;
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * This will be upgraded to an error after all jump labels have
Packit Service da4517
		 * been reported.
Packit Service da4517
		 */
Packit Service da4517
		log_normal("Found a jump label at %s()+0x%lx, using key %s, which is defined in a module.  Use static_key_enabled() instead.\n",
Packit Service da4517
			   code->sym->name, code->addend, key->sym->name);
Packit Service da4517
		(*jump_labels_found)++;
Packit Service da4517
		return false;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	/* The static key lives in vmlinux or the patch module itself */
Packit Service da4517
	return true;
Packit Service da4517
}
Packit Service da4517
Packit Service da4517
static bool should_keep_rela_group(struct lookup_table *lookup,
Packit Service da4517
				   struct section *sec, unsigned int offset,
Packit Service da4517
				   unsigned int size, int *jump_labels_found)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela;
Packit Service da4517
	bool found = false;
Packit Service ac8aad
Packit Service ac8aad
	/* check if any relas in the group reference any changed functions */
Packit Service ac8aad
	list_for_each_entry(rela, &sec->relas, list) {
Packit Service da4517
		if (rela->offset >= offset &&
Packit Service da4517
		    rela->offset < offset + size &&
Packit Service ac8aad
		    rela->sym->type == STT_FUNC &&
Packit Service ac8aad
		    rela->sym->sec->include) {
Packit Service da4517
			found = true;
Packit Service ac8aad
			log_debug("new/changed symbol %s found in special section %s\n",
Packit Service ac8aad
				  rela->sym->name, sec->name);
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service da4517
	if (!found)
Packit Service da4517
		return false;
Packit Service da4517
Packit Service da4517
	if (!strcmp(sec->name, ".rela__jump_table"))
Packit Service da4517
		return should_keep_jump_label(lookup, sec, offset, size,
Packit Service da4517
					      jump_labels_found);
Packit Service da4517
Packit Service da4517
	return true;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
/*
Packit Service ac8aad
 * When updating .fixup, the corresponding addends in .ex_table need to be
Packit Service ac8aad
 * updated too. Stash the result in rela.r_addend so that the calculation in
Packit Service ac8aad
 * fixup_group_size() is not affected.
Packit Service ac8aad
 */
Packit Service ac8aad
static void kpatch_update_ex_table_addend(struct kpatch_elf *kelf,
Packit Service ac8aad
					  struct special_section *special,
Packit Service ac8aad
					  int src_offset, int dest_offset,
Packit Service ac8aad
					  int group_size)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
Packit Service ac8aad
	sec = find_section_by_name(&kelf->sections, ".rela__ex_table");
Packit Service ac8aad
	if (!sec)
Packit Service ac8aad
		ERROR("missing .rela__ex_table section");
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
		if (!strcmp(rela->sym->name, ".fixup") &&
Packit Service ac8aad
		    rela->addend >= src_offset &&
Packit Service ac8aad
		    rela->addend < src_offset + group_size)
Packit Service ac8aad
			rela->rela.r_addend = rela->addend - (src_offset - dest_offset);
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_regenerate_special_section(struct kpatch_elf *kelf,
Packit Service da4517
					      struct lookup_table *lookup,
Packit Service ac8aad
					      struct special_section *special,
Packit Service ac8aad
					      struct section *sec)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela, *safe;
Packit Service ac8aad
	char *src, *dest;
Packit Service da4517
	unsigned int group_size, src_offset, dest_offset;
Packit Service da4517
	int jump_labels_found = 0;
Packit Service ac8aad
Packit Service ac8aad
	LIST_HEAD(newrelas);
Packit Service ac8aad
Packit Service ac8aad
	src = sec->base->data->d_buf;
Packit Service ac8aad
	/* alloc buffer for new base section */
Packit Service ac8aad
	dest = malloc(sec->base->sh.sh_size);
Packit Service ac8aad
	if (!dest)
Packit Service ac8aad
		ERROR("malloc");
Packit Service ac8aad
Packit Service ac8aad
	/* Restore the stashed r_addend from kpatch_update_ex_table_addend. */
Packit Service ac8aad
	if (!strcmp(special->name, "__ex_table")) {
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
			if (!strcmp(rela->sym->name, ".fixup"))
Packit Service ac8aad
				rela->addend = rela->rela.r_addend;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	src_offset = 0;
Packit Service ac8aad
	dest_offset = 0;
Packit Service ac8aad
	for ( ; src_offset < sec->base->sh.sh_size; src_offset += group_size) {
Packit Service ac8aad
Packit Service ac8aad
		group_size = special->group_size(kelf, src_offset);
Packit Service ac8aad
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * In some cases the struct has padding at the end to ensure
Packit Service ac8aad
		 * that all structs after it are properly aligned.  But the
Packit Service ac8aad
		 * last struct in the section may not be padded.  In that case,
Packit Service ac8aad
		 * shrink the group_size such that it still (hopefully)
Packit Service ac8aad
		 * contains the data but doesn't go past the end of the
Packit Service ac8aad
		 * section.
Packit Service ac8aad
		 */
Packit Service ac8aad
		if (src_offset + group_size > sec->base->sh.sh_size)
Packit Service da4517
			group_size = (unsigned int)(sec->base->sh.sh_size - src_offset);
Packit Service ac8aad
Packit Service da4517
		if (!should_keep_rela_group(lookup, sec, src_offset, group_size,
Packit Service da4517
					    &jump_labels_found))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * Copy all relas in the group.  It's possible that the relas
Packit Service ac8aad
		 * aren't sorted (e.g. .rela.fixup), so go through the entire
Packit Service ac8aad
		 * rela list each time.
Packit Service ac8aad
		 */
Packit Service ac8aad
		list_for_each_entry_safe(rela, safe, &sec->relas, list) {
Packit Service ac8aad
			if (rela->offset >= src_offset &&
Packit Service ac8aad
			    rela->offset < src_offset + group_size) {
Packit Service ac8aad
				/* copy rela entry */
Packit Service ac8aad
				list_del(&rela->list);
Packit Service ac8aad
				list_add_tail(&rela->list, &newrelas);
Packit Service ac8aad
Packit Service ac8aad
				rela->offset -= src_offset - dest_offset;
Packit Service ac8aad
				rela->rela.r_offset = rela->offset;
Packit Service ac8aad
Packit Service ac8aad
				rela->sym->include = 1;
Packit Service ac8aad
Packit Service ac8aad
				if (!strcmp(special->name, ".fixup"))
Packit Service ac8aad
					kpatch_update_ex_table_addend(kelf, special,
Packit Service ac8aad
								      src_offset,
Packit Service ac8aad
								      dest_offset,
Packit Service ac8aad
								      group_size);
Packit Service ac8aad
			}
Packit Service ac8aad
		}
Packit Service ac8aad
Packit Service ac8aad
		/* copy base section group */
Packit Service ac8aad
		memcpy(dest + dest_offset, src + src_offset, group_size);
Packit Service ac8aad
		dest_offset += group_size;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service da4517
	if (jump_labels_found)
Packit Service da4517
		ERROR("Found %d jump label(s) in the patched code. Jump labels aren't currently supported. Use static_key_enabled() instead.",
Packit Service da4517
		      jump_labels_found);
Packit Service da4517
Packit Service ac8aad
	if (!dest_offset) {
Packit Service ac8aad
		/* no changed or global functions referenced */
Packit Service ac8aad
		sec->status = sec->base->status = SAME;
Packit Service ac8aad
		sec->include = sec->base->include = 0;
Packit Service ac8aad
		free(dest);
Packit Service ac8aad
		return;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* overwrite with new relas list */
Packit Service ac8aad
	list_replace(&newrelas, &sec->relas);
Packit Service ac8aad
Packit Service ac8aad
	/* include both rela and base sections */
Packit Service ac8aad
	sec->include = 1;
Packit Service ac8aad
	sec->base->include = 1;
Packit Service ac8aad
	/* include secsym so .kpatch.arch relas can point to section symbols */
Packit Service ac8aad
	sec->base->secsym->include = 1;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Update text section data buf and size.
Packit Service ac8aad
	 *
Packit Service ac8aad
	 * The rela section's data buf and size will be regenerated in
Packit Service ac8aad
	 * kpatch_rebuild_rela_section_data().
Packit Service ac8aad
	 */
Packit Service ac8aad
	sec->base->data->d_buf = dest;
Packit Service ac8aad
	sec->base->data->d_size = dest_offset;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
#define ORC_IP_PTR_SIZE 4
Packit Service ac8aad
Packit Service ac8aad
/*
Packit Service ac8aad
 * This function is similar to kpatch_regenerate_special_section(), but
Packit Service ac8aad
 * customized for the ORC-related sections.  ORC is more special than the other
Packit Service ac8aad
 * special sections because each ORC entry is split into .orc_unwind (struct
Packit Service ac8aad
 * orc_entry) and .orc_unwind_ip.
Packit Service ac8aad
 */
Packit Service ac8aad
static void kpatch_regenerate_orc_sections(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela, *safe;
Packit Service ac8aad
	char *src, *dest, *str;
Packit Service ac8aad
	unsigned int src_idx = 0, dest_idx = 0, orc_entry_size;
Packit Service ac8aad
	struct section *orc_sec, *ip_sec;
Packit Service ac8aad
Packit Service ac8aad
Packit Service ac8aad
	str = getenv("ORC_STRUCT_SIZE");
Packit Service ac8aad
	if (!str)
Packit Service ac8aad
		return;
Packit Service ac8aad
	orc_entry_size = atoi(str);
Packit Service ac8aad
Packit Service da4517
	if (!orc_entry_size)
Packit Service da4517
		ERROR("bad ORC_STRUCT_SIZE");
Packit Service da4517
Packit Service ac8aad
	LIST_HEAD(newrelas);
Packit Service ac8aad
Packit Service ac8aad
	orc_sec = find_section_by_name(&kelf->sections, ".orc_unwind");
Packit Service ac8aad
	ip_sec  = find_section_by_name(&kelf->sections, ".orc_unwind_ip");
Packit Service ac8aad
Packit Service ac8aad
	if (!orc_sec || !ip_sec)
Packit Service ac8aad
		return;
Packit Service ac8aad
Packit Service ac8aad
	if (orc_sec->sh.sh_size % orc_entry_size != 0)
Packit Service ac8aad
		ERROR("bad .orc_unwind size");
Packit Service ac8aad
Packit Service ac8aad
	if (ip_sec->sh.sh_size !=
Packit Service ac8aad
	    (orc_sec->sh.sh_size / orc_entry_size) * ORC_IP_PTR_SIZE)
Packit Service ac8aad
		ERROR(".orc_unwind/.orc_unwind_ip size mismatch");
Packit Service ac8aad
Packit Service ac8aad
	src = orc_sec->data->d_buf;
Packit Service ac8aad
	dest = malloc(orc_sec->sh.sh_size);
Packit Service ac8aad
	if (!dest)
Packit Service ac8aad
		ERROR("malloc");
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry_safe(rela, safe, &ip_sec->rela->relas, list) {
Packit Service ac8aad
Packit Service ac8aad
		if (rela->sym->type != STT_FUNC || !rela->sym->sec->include)
Packit Service ac8aad
			goto next;
Packit Service ac8aad
Packit Service ac8aad
		/* copy orc entry */
Packit Service ac8aad
		memcpy(dest + (dest_idx * orc_entry_size),
Packit Service ac8aad
		       src + (src_idx * orc_entry_size),
Packit Service ac8aad
		       orc_entry_size);
Packit Service ac8aad
Packit Service ac8aad
		/* move ip rela */
Packit Service ac8aad
		list_del(&rela->list);
Packit Service ac8aad
		list_add_tail(&rela->list, &newrelas);
Packit Service ac8aad
		rela->offset = dest_idx * ORC_IP_PTR_SIZE;
Packit Service ac8aad
		rela->sym->include = 1;
Packit Service ac8aad
Packit Service ac8aad
		dest_idx++;
Packit Service ac8aad
next:
Packit Service ac8aad
		src_idx++;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!dest_idx) {
Packit Service ac8aad
		/* no changed or global functions referenced */
Packit Service ac8aad
		orc_sec->status = ip_sec->status = ip_sec->rela->status = SAME;
Packit Service ac8aad
		orc_sec->include = ip_sec->include = ip_sec->rela->include = 0;
Packit Service ac8aad
		free(dest);
Packit Service ac8aad
		return;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* overwrite with new relas list */
Packit Service ac8aad
	list_replace(&newrelas, &ip_sec->rela->relas);
Packit Service ac8aad
Packit Service ac8aad
	/* include the sections */
Packit Service ac8aad
	orc_sec->include = ip_sec->include = ip_sec->rela->include = 1;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Update data buf/size.
Packit Service ac8aad
	 *
Packit Service ac8aad
	 * The ip section can keep its old (zeroed data), though its size has
Packit Service ac8aad
	 * possibly decreased.  The ip rela section's data buf and size will be
Packit Service ac8aad
	 * regenerated in kpatch_rebuild_rela_section_data().
Packit Service ac8aad
	 */
Packit Service ac8aad
	orc_sec->data->d_buf = dest;
Packit Service ac8aad
	orc_sec->data->d_size = dest_idx * orc_entry_size;
Packit Service ac8aad
	ip_sec->data->d_size = dest_idx * ORC_IP_PTR_SIZE;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_check_relocations(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	Elf_Data *sdata;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!is_rela_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service ac8aad
			if (rela->sym->sec) {
Packit Service ac8aad
				sdata = rela->sym->sec->data;
Packit Service da4517
				if (rela->addend > (long)sdata->d_size) {
Packit Service da4517
					ERROR("out-of-range relocation %s+%lx in %s", rela->sym->sec->name,
Packit Service ac8aad
							rela->addend, sec->name);
Packit Service ac8aad
				}
Packit Service ac8aad
			}
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_include_debug_sections(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct rela *rela, *saferela;
Packit Service ac8aad
Packit Service ac8aad
	/* include all .debug_* sections */
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (is_debug_section(sec)) {
Packit Service ac8aad
			sec->include = 1;
Packit Service ac8aad
			if (!is_rela_section(sec))
Packit Service ac8aad
				sec->secsym->include = 1;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * Go through the .rela.debug_ sections and strip entries
Packit Service ac8aad
	 * referencing unchanged symbols
Packit Service ac8aad
	 */
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!is_rela_section(sec) || !is_debug_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		list_for_each_entry_safe(rela, saferela, &sec->relas, list)
Packit Service ac8aad
			if (!rela->sym->sec->include)
Packit Service ac8aad
				list_del(&rela->list);
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_mark_ignored_sections(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec, *strsec, *ignoresec;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	char *name;
Packit Service ac8aad
Packit Service ac8aad
	/* Ignore any discarded sections */
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!strncmp(sec->name, ".discard", 8) ||
Packit Service ac8aad
		    !strncmp(sec->name, ".rela.discard", 13))
Packit Service ac8aad
			sec->ignore = 1;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	sec = find_section_by_name(&kelf->sections, ".kpatch.ignore.sections");
Packit Service ac8aad
	if (!sec)
Packit Service ac8aad
		return;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(rela, &sec->rela->relas, list) {
Packit Service ac8aad
		strsec = rela->sym->sec;
Packit Service ac8aad
		strsec->status = CHANGED;
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * Include the string section here.  This is because the
Packit Service ac8aad
		 * KPATCH_IGNORE_SECTION() macro is passed a literal string
Packit Service ac8aad
		 * by the patch author, resulting in a change to the string
Packit Service ac8aad
		 * section.  If we don't include it, then we will potentially
Packit Service ac8aad
		 * get a "changed section not included" error in
Packit Service ac8aad
		 * kpatch_verify_patchability() if no other function based change
Packit Service ac8aad
		 * also changes the string section.  We could try to exclude each
Packit Service ac8aad
		 * literal string added to the section by KPATCH_IGNORE_SECTION()
Packit Service ac8aad
		 * from the section data comparison, but this is a simpler way.
Packit Service ac8aad
		 */
Packit Service ac8aad
		strsec->include = 1;
Packit Service da4517
		strsec->secsym->include = 1;
Packit Service ac8aad
		name = strsec->data->d_buf + rela->addend;
Packit Service ac8aad
		ignoresec = find_section_by_name(&kelf->sections, name);
Packit Service ac8aad
		if (!ignoresec)
Packit Service ac8aad
			ERROR("KPATCH_IGNORE_SECTION: can't find %s", name);
Packit Service ac8aad
		log_normal("ignoring section: %s\n", name);
Packit Service ac8aad
		if (is_rela_section(ignoresec))
Packit Service ac8aad
			ignoresec = ignoresec->base;
Packit Service ac8aad
		ignoresec->ignore = 1;
Packit Service ac8aad
		if (ignoresec->twin)
Packit Service ac8aad
			ignoresec->twin->ignore = 1;
Packit Service ac8aad
	}
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_mark_ignored_sections_same(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!sec->ignore)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		sec->status = SAME;
Packit Service ac8aad
		if (!is_rela_section(sec)) {
Packit Service ac8aad
			if (sec->secsym)
Packit Service ac8aad
				sec->secsym->status = SAME;
Packit Service ac8aad
			if (sec->rela)
Packit Service ac8aad
				sec->rela->status = SAME;
Packit Service ac8aad
		}
Packit Service ac8aad
		list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service ac8aad
			if (sym->sec != sec)
Packit Service ac8aad
				continue;
Packit Service ac8aad
			sym->status = SAME;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* strip temporary global __UNIQUE_ID_kpatch_ignore_section_* symbols */
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list)
Packit Service ac8aad
		if (!strncmp(sym->name, "__UNIQUE_ID_kpatch_ignore_section_",
Packit Service ac8aad
		            strlen("__UNIQUE_ID_kpatch_ignore_section_")))
Packit Service ac8aad
			sym->status = SAME;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static void kpatch_mark_ignored_children_same(struct symbol *sym)
Packit Service da4517
{
Packit Service da4517
	struct symbol *child;
Packit Service da4517
Packit Service da4517
	list_for_each_entry(child, &sym->children, subfunction_node) {
Packit Service da4517
		child->status = SAME;
Packit Service da4517
		kpatch_mark_ignored_children_same(child);
Packit Service da4517
	}
Packit Service da4517
}
Packit Service da4517
Packit Service ac8aad
static void kpatch_mark_ignored_functions_same(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
Packit Service ac8aad
	sec = find_section_by_name(&kelf->sections, ".kpatch.ignore.functions");
Packit Service ac8aad
	if (!sec)
Packit Service ac8aad
		return;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(rela, &sec->rela->relas, list) {
Packit Service ac8aad
		if (!rela->sym->sec)
Packit Service ac8aad
			ERROR("expected bundled symbol");
Packit Service ac8aad
		if (rela->sym->type != STT_FUNC)
Packit Service ac8aad
			ERROR("expected function symbol");
Packit Service ac8aad
		log_normal("ignoring function: %s\n", rela->sym->name);
Packit Service ac8aad
		if (rela->sym->status != CHANGED)
Packit Service ac8aad
			log_normal("NOTICE: no change detected in function %s, unnecessary KPATCH_IGNORE_FUNCTION()?\n", rela->sym->name);
Packit Service ac8aad
		rela->sym->status = SAME;
Packit Service ac8aad
		rela->sym->sec->status = SAME;
Packit Service da4517
Packit Service da4517
		kpatch_mark_ignored_children_same(rela->sym);
Packit Service da4517
Packit Service ac8aad
		if (rela->sym->sec->secsym)
Packit Service ac8aad
			rela->sym->sec->secsym->status = SAME;
Packit Service ac8aad
		if (rela->sym->sec->rela)
Packit Service ac8aad
			rela->sym->sec->rela->status = SAME;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* strip temporary global kpatch_ignore_func_* symbols */
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list)
Packit Service ac8aad
		if (!strncmp(sym->name, "__kpatch_ignore_func_",
Packit Service ac8aad
		            strlen("__kpatch_ignore_func_")))
Packit Service ac8aad
			sym->status = SAME;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_create_kpatch_arch_section(struct kpatch_elf *kelf, char *objname)
Packit Service ac8aad
{
Packit Service ac8aad
	struct special_section *special;
Packit Service ac8aad
	struct symbol *strsym;
Packit Service ac8aad
	struct section *sec, *karch_sec;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	int nr, index = 0;
Packit Service ac8aad
Packit Service da4517
	if (!KLP_ARCH)
Packit Service da4517
		return;
Packit Service da4517
Packit Service ac8aad
	nr = sizeof(special_sections) / sizeof(special_sections[0]);
Packit Service da4517
	karch_sec = create_section_pair(kelf, ".kpatch.arch", sizeof(struct kpatch_arch), nr);
Packit Service ac8aad
Packit Service ac8aad
	/* lookup strings symbol */
Packit Service ac8aad
	strsym = find_symbol_by_name(&kelf->symbols, ".kpatch.strings");
Packit Service ac8aad
	if (!strsym)
Packit Service ac8aad
		ERROR("can't find .kpatch.strings symbol");
Packit Service ac8aad
Packit Service ac8aad
	for (special = special_sections; special->name; special++) {
Packit Service ac8aad
		if (strcmp(special->name, ".parainstructions") &&
Packit Service ac8aad
		    strcmp(special->name, ".altinstructions"))
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		sec = find_section_by_name(&kelf->sections, special->name);
Packit Service ac8aad
		if (!sec)
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		/* entries[index].sec */
Packit Service ac8aad
		ALLOC_LINK(rela, &karch_sec->rela->relas);
Packit Service ac8aad
		rela->sym = sec->secsym;
Packit Service ac8aad
		rela->type = ABSOLUTE_RELA_TYPE;
Packit Service ac8aad
		rela->addend = 0;
Packit Service da4517
		rela->offset = (unsigned int)(index * sizeof(struct kpatch_arch) + \
Packit Service da4517
			       offsetof(struct kpatch_arch, sec));
Packit Service ac8aad
Packit Service ac8aad
		/* entries[index].objname */
Packit Service ac8aad
		ALLOC_LINK(rela, &karch_sec->rela->relas);
Packit Service ac8aad
		rela->sym = strsym;
Packit Service ac8aad
		rela->type = ABSOLUTE_RELA_TYPE;
Packit Service ac8aad
		rela->addend = offset_of_string(&kelf->strings, objname);
Packit Service da4517
		rela->offset = (unsigned int)(index * sizeof(struct kpatch_arch) + \
Packit Service da4517
			       offsetof(struct kpatch_arch, objname));
Packit Service ac8aad
Packit Service ac8aad
		index++;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	karch_sec->data->d_size = index * sizeof(struct kpatch_arch);
Packit Service ac8aad
	karch_sec->sh.sh_size = karch_sec->data->d_size;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static void kpatch_process_special_sections(struct kpatch_elf *kelf,
Packit Service da4517
					    struct lookup_table *lookup)
Packit Service ac8aad
{
Packit Service ac8aad
	struct special_section *special;
Packit Service ac8aad
	struct section *sec;
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	struct rela *rela;
Packit Service ac8aad
	int altinstr = 0;
Packit Service ac8aad
Packit Service ac8aad
	for (special = special_sections; special->name; special++) {
Packit Service ac8aad
		sec = find_section_by_name(&kelf->sections, special->name);
Packit Service da4517
		if (!sec || !sec->rela)
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service da4517
		kpatch_regenerate_special_section(kelf, lookup, special, sec->rela);
Packit Service ac8aad
Packit Service da4517
		if (!strcmp(special->name, ".altinstructions") && sec->include)
Packit Service ac8aad
			altinstr = 1;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service ac8aad
	 * The following special sections don't have relas which reference
Packit Service ac8aad
	 * non-included symbols, so their entire rela section can be included.
Packit Service ac8aad
	 */
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (strcmp(sec->name, ".altinstr_replacement"))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		/*
Packit Service ac8aad
		 * Only include .altinstr_replacement if .altinstructions
Packit Service ac8aad
		 * is also included.
Packit Service ac8aad
		 */
Packit Service ac8aad
		if (!altinstr)
Packit Service ac8aad
			break;
Packit Service ac8aad
Packit Service ac8aad
		/* include base section */
Packit Service ac8aad
		sec->include = 1;
Packit Service ac8aad
Packit Service ac8aad
		/* include all symbols in the section */
Packit Service ac8aad
		list_for_each_entry(sym, &kelf->symbols, list)
Packit Service ac8aad
			if (sym->sec == sec)
Packit Service ac8aad
				sym->include = 1;
Packit Service ac8aad
Packit Service ac8aad
		/* include rela section */
Packit Service ac8aad
		if (sec->rela) {
Packit Service ac8aad
			sec->rela->include = 1;
Packit Service ac8aad
			/* include all symbols referenced by relas */
Packit Service ac8aad
			list_for_each_entry(rela, &sec->rela->relas, list)
Packit Service da4517
				kpatch_include_symbol(rela->sym);
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service da4517
	if (KLP_ARCH) {
Packit Service da4517
		/*
Packit Service da4517
		 * The following special sections aren't supported with older
Packit Service da4517
		 * kernels, so make sure we don't ever try to include them.
Packit Service da4517
		 * Otherwise the kernel will see the jump table during module
Packit Service da4517
		 * loading and get confused.  Generally it should be safe to
Packit Service da4517
		 * exclude them, it just means that you can't modify jump
Packit Service da4517
		 * labels and enable tracepoints in a patched function.
Packit Service da4517
		 */
Packit Service da4517
		list_for_each_entry(sec, &kelf->sections, list) {
Packit Service da4517
			if (strcmp(sec->name, "__jump_table") &&
Packit Service da4517
			    strcmp(sec->name, "__tracepoints") &&
Packit Service da4517
			    strcmp(sec->name, "__tracepoints_ptrs") &&
Packit Service da4517
			    strcmp(sec->name, "__tracepoints_strings"))
Packit Service da4517
				continue;
Packit Service ac8aad
Packit Service da4517
			sec->status = SAME;
Packit Service da4517
			sec->include = 0;
Packit Service da4517
			if (sec->rela) {
Packit Service da4517
				sec->rela->status = SAME;
Packit Service da4517
				sec->rela->include = 0;
Packit Service da4517
			}
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	kpatch_regenerate_orc_sections(kelf);
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static struct sym_compare_type *kpatch_elf_locals(struct kpatch_elf *kelf)
Packit Service ac8aad
{
Packit Service ac8aad
	struct symbol *sym;
Packit Service ac8aad
	int i = 0, sym_num = 0;
Packit Service ac8aad
	struct sym_compare_type *sym_array;
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service ac8aad
		if (sym->bind != STB_LOCAL)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		if (sym->type != STT_FUNC && sym->type != STT_OBJECT)
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		sym_num++;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	if (!sym_num)
Packit Service ac8aad
		return NULL;
Packit Service ac8aad
Packit Service ac8aad
	sym_array = malloc((sym_num + 1) * sizeof(struct sym_compare_type));
Packit Service ac8aad
	if (!sym_array)
Packit Service ac8aad
		ERROR("malloc");
Packit Service ac8aad
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service ac8aad
		if (sym->bind != STB_LOCAL)
Packit Service ac8aad
			continue;
Packit Service ac8aad
		if (sym->type != STT_FUNC && sym->type != STT_OBJECT)
Packit Service ac8aad
			continue;
Packit Service ac8aad
Packit Service ac8aad
		sym_array[i].type = sym->type;
Packit Service da4517
		sym_array[i++].name = strdup(sym->name);
Packit Service ac8aad
	}
Packit Service ac8aad
	sym_array[i].type = 0;
Packit Service ac8aad
	sym_array[i].name = NULL;
Packit Service ac8aad
Packit Service ac8aad
	return sym_array;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static void kpatch_create_patches_sections(struct kpatch_elf *kelf,
Packit Service ac8aad
					   struct lookup_table *table,
Packit Service ac8aad
					   char *objname)
Packit Service ac8aad
{
Packit Service ac8aad
	int nr, index, objname_offset;
Packit Service ac8aad
	struct section *sec, *relasec;
Packit Service ac8aad
	struct symbol *sym, *strsym;
Packit Service ac8aad
	struct rela *rela;
Packit Service da4517
	struct lookup_result symbol;
Packit Service ac8aad
	struct kpatch_patch_func *funcs;
Packit Service ac8aad
Packit Service ac8aad
	/* count patched functions */
Packit Service ac8aad
	nr = 0;
Packit Service da4517
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service da4517
		if (sym->type != STT_FUNC || sym->status != CHANGED ||
Packit Service da4517
		    sym->parent)
Packit Service da4517
			continue;
Packit Service da4517
		nr++;
Packit Service da4517
	}
Packit Service ac8aad
Packit Service ac8aad
	/* create text/rela section pair */
Packit Service ac8aad
	sec = create_section_pair(kelf, ".kpatch.funcs", sizeof(*funcs), nr);
Packit Service ac8aad
	relasec = sec->rela;
Packit Service ac8aad
	funcs = sec->data->d_buf;
Packit Service ac8aad
Packit Service ac8aad
	/* lookup strings symbol */
Packit Service ac8aad
	strsym = find_symbol_by_name(&kelf->symbols, ".kpatch.strings");
Packit Service ac8aad
	if (!strsym)
Packit Service ac8aad
		ERROR("can't find .kpatch.strings symbol");
Packit Service ac8aad
Packit Service ac8aad
	/* add objname to strings */
Packit Service ac8aad
	objname_offset = offset_of_string(&kelf->strings, objname);
Packit Service ac8aad
Packit Service ac8aad
	/* populate sections */
Packit Service ac8aad
	index = 0;
Packit Service ac8aad
	list_for_each_entry(sym, &kelf->symbols, list) {
Packit Service da4517
		if (sym->type != STT_FUNC || sym->status != CHANGED ||
Packit Service da4517
		    sym->parent)
Packit Service da4517
			continue;
Packit Service ac8aad
Packit Service da4517
		if (!lookup_symbol(table, sym->name, &symbol))
Packit Service da4517
			ERROR("can't find symbol '%s' in symbol table", sym->name);
Packit Service ac8aad
Packit Service da4517
		if (sym->bind == STB_LOCAL && symbol.global)
Packit Service da4517
			ERROR("can't find local symbol '%s' in symbol table", sym->name);
Packit Service ac8aad
Packit Service da4517
		log_debug("lookup for %s: obj=%s sympos=%lu size=%lu",
Packit Service da4517
			  sym->name, symbol.objname, symbol.sympos,
Packit Service da4517
			  symbol.size);
Packit Service ac8aad
Packit Service da4517
		/*
Packit Service da4517
		 * Convert global symbols to local so other objects in the
Packit Service da4517
		 * patch module (like the patch callback object's init code)
Packit Service da4517
		 * won't link to this function and call it before its
Packit Service da4517
		 * relocations have been applied.
Packit Service da4517
		 */
Packit Service da4517
		sym->bind = STB_LOCAL;
Packit Service da4517
		sym->sym.st_info = (unsigned char)
Packit Service da4517
				   GELF_ST_INFO(sym->bind, sym->type);
Packit Service ac8aad
Packit Service da4517
		/* add entry in text section */
Packit Service da4517
		funcs[index].old_addr = symbol.addr;
Packit Service da4517
		funcs[index].old_size = symbol.size;
Packit Service da4517
		funcs[index].new_size = sym->sym.st_size;
Packit Service da4517
		funcs[index].sympos = symbol.sympos;
Packit Service ac8aad
Packit Service da4517
		/*
Packit Service da4517
		 * Add a relocation that will populate the
Packit Service da4517
		 * funcs[index].new_addr field at module load time.
Packit Service da4517
		 */
Packit Service da4517
		ALLOC_LINK(rela, &relasec->relas);
Packit Service da4517
		rela->sym = sym;
Packit Service da4517
		rela->type = ABSOLUTE_RELA_TYPE;
Packit Service da4517
		rela->addend = 0;
Packit Service da4517
		rela->offset = (unsigned int)(index * sizeof(*funcs));
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * Add a relocation that will populate the funcs[index].name
Packit Service da4517
		 * field.
Packit Service da4517
		 */
Packit Service da4517
		ALLOC_LINK(rela, &relasec->relas);
Packit Service da4517
		rela->sym = strsym;
Packit Service da4517
		rela->type = ABSOLUTE_RELA_TYPE;
Packit Service da4517
		rela->addend = offset_of_string(&kelf->strings, sym->name);
Packit Service da4517
		rela->offset = (unsigned int)(index * sizeof(*funcs) +
Packit Service da4517
			       offsetof(struct kpatch_patch_func, name));
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * Add a relocation that will populate the funcs[index].objname
Packit Service da4517
		 * field.
Packit Service da4517
		 */
Packit Service da4517
		ALLOC_LINK(rela, &relasec->relas);
Packit Service da4517
		rela->sym = strsym;
Packit Service da4517
		rela->type = ABSOLUTE_RELA_TYPE;
Packit Service da4517
		rela->addend = objname_offset;
Packit Service da4517
		rela->offset = (unsigned int)(index * sizeof(*funcs) +
Packit Service da4517
			       offsetof(struct kpatch_patch_func,objname));
Packit Service da4517
Packit Service da4517
		index++;
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* sanity check, index should equal nr */
Packit Service ac8aad
	if (index != nr)
Packit Service ac8aad
		ERROR("size mismatch in funcs sections");
Packit Service ac8aad
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int kpatch_is_core_module_symbol(char *name)
Packit Service ac8aad
{
Packit Service ac8aad
	return (!strcmp(name, "kpatch_shadow_alloc") ||
Packit Service ac8aad
		!strcmp(name, "kpatch_shadow_free") ||
Packit Service ac8aad
		!strcmp(name, "kpatch_shadow_get"));
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service ac8aad
static int function_ptr_rela(const struct rela *rela)
Packit Service ac8aad
{
Packit Service ac8aad
	const struct rela *rela_toc = toc_rela(rela);
Packit Service ac8aad
Packit Service ac8aad
	return (rela_toc && rela_toc->sym->type == STT_FUNC &&
Packit Service da4517
		!rela_toc->sym->parent &&
Packit Service ac8aad
		rela_toc->addend == (int)rela_toc->sym->sym.st_value &&
Packit Service ac8aad
		(rela->type == R_X86_64_32S ||
Packit Service ac8aad
		rela->type == R_PPC64_TOC16_HA ||
Packit Service ac8aad
		rela->type == R_PPC64_TOC16_LO_DS));
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
static bool need_dynrela(struct lookup_table *table, const struct rela *rela)
Packit Service ac8aad
{
Packit Service da4517
	struct lookup_result symbol;
Packit Service da4517
Packit Service ac8aad
	/*
Packit Service da4517
	 * These references are treated specially by the module loader and
Packit Service ac8aad
	 * should never be converted to dynrelas.
Packit Service ac8aad
	 */
Packit Service ac8aad
	if (rela->type == R_PPC64_REL16_HA || rela->type == R_PPC64_REL16_LO ||
Packit Service da4517
	    rela->type == R_PPC64_REL64 || rela->type == R_PPC64_ENTRY)
Packit Service da4517
		return false;
Packit Service ac8aad
Packit Service da4517
	/*
Packit Service da4517
	 * On powerpc, the function prologue generated by GCC 6 has the
Packit Service da4517
	 * sequence:
Packit Service da4517
	 *
Packit Service da4517
	 *	.globl my_func
Packit Service da4517
	 *	.type my_func, @function
Packit Service da4517
	 *	.quad .TOC.-my_func
Packit Service da4517
	 * my_func:
Packit Service da4517
	 *	.reloc ., R_PPC64_ENTRY ; optional
Packit Service da4517
	 *	ld r2,-8(r12)
Packit Service da4517
	 *	add r2,r2,r12
Packit Service da4517
	 *	.localentry my_func, .-my_func
Packit Service da4517
	 *
Packit Service da4517
	 * The R_PPC64_ENTRY is optional and its symbol might have an empty
Packit Service da4517
	 * name.  Leave it as a normal rela.
Packit Service da4517
	 */
Packit Service da4517
	if (rela->type == R_PPC64_ENTRY)
Packit Service da4517
		return false;
Packit Service ac8aad
Packit Service ac8aad
	/*
Packit Service da4517
	 * Allow references to core module symbols to remain as normal
Packit Service da4517
	 * relas.  They should be exported.
Packit Service ac8aad
	 */
Packit Service da4517
	if (kpatch_is_core_module_symbol(rela->sym->name))
Packit Service da4517
		return false;
Packit Service da4517
Packit Service da4517
	if (rela->sym->sec) {
Packit Service da4517
		/*
Packit Service da4517
		 * Internal symbols usually don't need dynrelas, because they
Packit Service da4517
		 * live in the patch module and can be relocated normally.
Packit Service da4517
		 *
Packit Service da4517
		 * There's one exception: function pointers.
Packit Service da4517
		 *
Packit Service da4517
		 * If the rela references a function pointer, we convert it to
Packit Service da4517
		 * a dynrela, so that the function pointer will refer to the
Packit Service da4517
		 * original function rather than the patched function.  This
Packit Service da4517
		 * can prevent crashes in cases where the function pointer is
Packit Service da4517
		 * called asynchronously after the patch module has been
Packit Service da4517
		 * unloaded.
Packit Service da4517
		 */
Packit Service da4517
		if (!function_ptr_rela(rela))
Packit Service da4517
			return false;
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * Function pointers which refer to _nested_ functions are a
Packit Service da4517
		 * special case.  They are not supposed to be visible outside
Packit Service da4517
		 * of the function that defines them.  Their names may differ
Packit Service da4517
		 * in the original and the patched kernels which makes it
Packit Service da4517
		 * difficult to use dynrelas.  Fortunately, nested functions
Packit Service da4517
		 * are rare and are unlikely to be used as asynchronous
Packit Service da4517
		 * callbacks, so the patched code can refer to them directly.
Packit Service da4517
		 * It seems, one can only distinguish such functions by their
Packit Service da4517
		 * names containing a dot.  Other kinds of functions with such
Packit Service da4517
		 * names (e.g. optimized copies of functions) are unlikely to
Packit Service da4517
		 * be used as callbacks.
Packit Service da4517
		 *
Packit Service da4517
		 * Function pointers to *new* functions don't have this issue,
Packit Service da4517
		 * just use a normal rela for them.
Packit Service da4517
		 */
Packit Service da4517
		return toc_rela(rela)->sym->status != NEW &&
Packit Service da4517
			!strchr(toc_rela(rela)->sym->name, '.');
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	if (!lookup_symbol(table, rela->sym->name, &symbol)) {
Packit Service da4517
		/*
Packit Service da4517
		 * Assume the symbol lives in another .o in the patch module.
Packit Service da4517
		 * A normal rela should work.
Packit Service da4517
		 */
Packit Service da4517
		return false;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	if (rela->sym->bind == STB_LOCAL) {
Packit Service da4517
Packit Service da4517
		if (symbol.global)
Packit Service da4517
			ERROR("can't find local symbol '%s' in symbol table",
Packit Service da4517
			      rela->sym->name);
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * The symbol is (formerly) local.  Use a dynrela to access the
Packit Service da4517
		 * original version of the symbol in the patched object.
Packit Service da4517
		 */
Packit Service da4517
		return true;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	if (symbol.exported) {
Packit Service da4517
Packit Service da4517
		if (is_gcc6_localentry_bundled_sym(rela->sym)) {
Packit Service da4517
			/*
Packit Service da4517
			 * On powerpc, the symbol is global and exported, but
Packit Service da4517
			 * it was also in the changed object file.  In this
Packit Service da4517
			 * case the rela refers to the 'localentry' point, so a
Packit Service da4517
			 * normal rela wouldn't work.  Force a dynrela so it
Packit Service da4517
			 * can be handled correctly by the livepatch relocation
Packit Service da4517
			 * code.
Packit Service da4517
			 */
Packit Service da4517
			return true;
Packit Service da4517
		}
Packit Service da4517
Packit Service da4517
		if (!strcmp(symbol.objname, "vmlinux")) {
Packit Service da4517
			/*
Packit Service da4517
			 * The symbol is exported by vmlinux.  Use a normal
Packit Service da4517
			 * rela.
Packit Service da4517
			 */
Packit Service da4517
			return false;
Packit Service da4517
		}
Packit Service da4517
Packit Service da4517
		/*
Packit Service da4517
		 * The symbol is exported by the to-be-patched module, or by
Packit Service da4517
		 * another module which the patched module depends on.  Use a
Packit Service da4517
		 * dynrela because of late module loading: the patch module may
Packit Service da4517
		 * be loaded before the to-be-patched (or other) module.
Packit Service da4517
		 */
Packit Service da4517
		return true;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	if (symbol.global) {
Packit Service da4517
		/*
Packit Service da4517
		 * The symbol is global in the to-be-patched object, but not
Packit Service da4517
		 * exported.  Use a dynrela to work around the fact that it's
Packit Service da4517
		 * an unexported sybmbol.
Packit Service da4517
		 */
Packit Service da4517
		return true;
Packit Service da4517
	}
Packit Service da4517
Packit Service da4517
	/*
Packit Service da4517
	 * The symbol is global and not exported, but it's not in the parent
Packit Service da4517
	 * object.  The only explanation is that it's defined in another object
Packit Service da4517
	 * in the patch module.  A normal rela should resolve it.
Packit Service da4517
	 */
Packit Service da4517
	return false;
Packit Service ac8aad
}
Packit Service ac8aad
Packit Service da4517
/*
Packit Service da4517
 * kpatch_create_intermediate_sections()
Packit Service da4517
 *
Packit Service da4517
 * The primary purpose of this function is to convert some relas (also known as
Packit Service da4517
 * relocations) to dynrelas (also known as dynamic relocations or livepatch
Packit Service da4517
 * relocations or klp relas).
Packit Service da4517
 *
Packit Service da4517
 * If the patched code refers to a symbol, for example, if it calls a function
Packit Service da4517
 * or stores a pointer to a function somewhere or accesses some global data,
Packit Service da4517
 * the address of that symbol must be resolved somehow before the patch is
Packit Service da4517
 * applied.
Packit Service da4517
 *
Packit Service da4517
 * If the symbol lives outside the patch module, and if it's not exported by
Packit Service da4517
 * vmlinux (e.g., with EXPORT_SYMBOL) then the rela needs to be converted to a
Packit Service da4517
 * dynrela so the livepatch code can resolve it at runtime.
Packit Service da4517
 */
Packit Service ac8aad
static void kpatch_create_intermediate_sections(struct kpatch_elf *kelf,
Packit Service ac8aad
						struct lookup_table *table,
Packit Service ac8aad
						char *objname,
Packit Service ac8aad
						char *pmod_name)
Packit Service ac8aad
{
Packit Service ac8aad
	int nr, index;
Packit Service ac8aad
	struct section *sec, *ksym_sec, *krela_sec;
Packit Service ac8aad
	struct rela *rela, *rela2, *safe;
Packit Service ac8aad
	struct symbol *strsym, *ksym_sec_sym;
Packit Service ac8aad
	struct kpatch_symbol *ksyms;
Packit Service ac8aad
	struct kpatch_relocation *krelas;
Packit Service da4517
	struct lookup_result symbol;
Packit Service da4517
	bool special;
Packit Service da4517
	bool vmlinux = !strcmp(objname, "vmlinux");
Packit Service da4517
	struct special_section *s;
Packit Service ac8aad
Packit Service ac8aad
	/* count rela entries that need to be dynamic */
Packit Service ac8aad
	nr = 0;
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!is_rela_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		if (!strcmp(sec->name, ".rela.kpatch.funcs"))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		list_for_each_entry(rela, &sec->relas, list) {
Packit Service da4517
Packit Service da4517
			/* upper bound on number of kpatch relas and symbols */
Packit Service da4517
			nr++;
Packit Service da4517
Packit Service ac8aad
			/*
Packit Service da4517
			 * We set 'need_dynrela' here in the first pass because
Packit Service da4517
			 * the .toc section's 'need_dynrela' values are
Packit Service da4517
			 * dependent on all the other sections.  Otherwise, if
Packit Service da4517
			 * we did this analysis in the second pass, we'd have
Packit Service da4517
			 * to convert .toc dynrelas at the very end.
Packit Service ac8aad
			 *
Packit Service da4517
			 * Specifically, this is needed for the powerpc
Packit Service da4517
			 * internal symbol function pointer check which is done
Packit Service da4517
			 * via .toc indirection in need_dynrela().
Packit Service ac8aad
			 */
Packit Service da4517
			if (need_dynrela(table, rela))
Packit Service ac8aad
				toc_rela(rela)->need_dynrela = 1;
Packit Service ac8aad
		}
Packit Service ac8aad
	}
Packit Service ac8aad
Packit Service ac8aad
	/* create .kpatch.relocations text/rela section pair */
Packit Service ac8aad
	krela_sec = create_section_pair(kelf, ".kpatch.relocations", sizeof(*krelas), nr);
Packit Service ac8aad
	krelas = krela_sec->data->d_buf;
Packit Service ac8aad
Packit Service ac8aad
	/* create .kpatch.symbols text/rela section pair */
Packit Service ac8aad
	ksym_sec = create_section_pair(kelf, ".kpatch.symbols", sizeof(*ksyms), nr);
Packit Service ac8aad
	ksyms = ksym_sec->data->d_buf;
Packit Service ac8aad
Packit Service ac8aad
	/* create .kpatch.symbols section symbol (to set rela->sym later) */
Packit Service ac8aad
	ALLOC_LINK(ksym_sec_sym, &kelf->symbols);
Packit Service ac8aad
	ksym_sec_sym->sec = ksym_sec;
Packit Service ac8aad
	ksym_sec_sym->sym.st_info = GELF_ST_INFO(STB_LOCAL, STT_SECTION);
Packit Service ac8aad
	ksym_sec_sym->type = STT_SECTION;
Packit Service ac8aad
	ksym_sec_sym->bind = STB_LOCAL;
Packit Service ac8aad
	ksym_sec_sym->name = ".kpatch.symbols";
Packit Service ac8aad
Packit Service ac8aad
	/* lookup strings symbol */
Packit Service ac8aad
	strsym = find_symbol_by_name(&kelf->symbols, ".kpatch.strings");
Packit Service ac8aad
	if (!strsym)
Packit Service ac8aad
		ERROR("can't find .kpatch.strings symbol");
Packit Service ac8aad
Packit Service ac8aad
	/* populate sections */
Packit Service ac8aad
	index = 0;
Packit Service ac8aad
	list_for_each_entry(sec, &kelf->sections, list) {
Packit Service ac8aad
		if (!is_rela_section(sec))
Packit Service ac8aad
			continue;
Packit Service ac8aad
		if (!strcmp(sec->name, ".rela.kpatch.funcs") ||
Packit Service da4517
		    !strcmp(sec->name, ".rela.kpatch.relocations") ||
Packit Service da4517
		    !strcmp(sec->name, ".rela.kpatch.symbols"))
Packit Service ac8aad
			continue;
Packit Service da4517
Packit Service da4517
		special = false;
Packit Service da4517
		for (s = special_sections; s->name; s++)
Packit Service da4517
			if (!strcmp(sec->base->name, s->name))
Packit Service da4517
				special = true;
Packit Service da4517
Packit Service ac8aad
		list_for_each_entry_safe(rela, safe, &sec->relas, list) {
Packit Service ac8aad
			if (!rela->need_dynrela)
Packit Service ac8aad
				continue;
Packit Service ac8aad
Packit Service ac8aad
			/*
Packit Service da4517
			 * Starting with Linux 5.8, .klp.arch sections are no
Packit Service da4517
			 * longer supported: now that vmlinux relocations are
Packit Service da4517
			 * written early, before paravirt and alternative
Packit Service da4517
			 * module init, .klp.arch is technically not needed.
Packit Service ac8aad
			 *
Packit Service da4517
			 * For sanity we just need to make sure that there are
Packit Service da4517
			 * no .klp.rela.{module}.{section} sections for special
Packit Service da4517
			 * sections.  Otherwise there might be ordering issues,
Packit Service da4517
			 * if the .klp.relas are applied after the module
Packit Service da4517
			 * special section init code (e.g., apply_paravirt)
Packit Service da4517
			 * runs due to late module patching.
Packit Service ac8aad
			 */
Packit Service da4517
			if (!KLP_ARCH && !vmlinux && special)
Packit Service da4517
				ERROR("unsupported dynrela reference to symbol '%s' in module-specific special section '%s'",
Packit Service da4517
				      rela->sym->name, sec->base->name);
Packit Service ac8aad
Packit Service da4517
			if (!lookup_symbol(table, rela->sym->name, &symbol))
Packit Service da4517
				ERROR("can't find symbol '%s' in symbol table",
Packit Service da4517
				      rela->sym->name);
Packit Service ac8aad
Packit Service da4517
			log_debug("lookup for %s: obj=%s sympos=%lu",
Packit Service da4517
			          rela->sym->name, symbol.objname,
Packit Service da4517
				  symbol.sympos);
Packit Service ac8aad
Packit Service ac8aad
			/* Fill in ksyms[index] */
Packit Service ac8aad
			if (vmlinux)
Packit Service da4517
				ksyms[index].src = symbol.addr;
Packit Service ac8aad
			else
Packit Service ac8aad
				/* for modules, src is discovered at runtime */
Packit Service ac8aad
				ksyms[index].src = 0;
Packit Service da4517
			ksyms[index].sympos = symbol.sympos;
Packit Service ac8aad
			ksyms[index].type = rela->sym->type;
Packit Service ac8aad
			ksyms[index].bind = rela->sym->bind;
Packit Service ac8aad
Packit Service ac8aad
			/* add rela to fill in ksyms[index].name field */
Packit Service ac8aad
			ALLOC_LINK(rela2, &ksym_sec->rela->relas);
Packit Service ac8aad
			rela2->sym = strsym;
Packit Service ac8aad
			rela2->type = ABSOLUTE_RELA_TYPE;
Packit Service ac8aad
			rela2->addend = offset_of_string(&kelf->strings, rela->sym->name);
Packit Service da4517
			rela2->offset = (unsigned int)(index * sizeof(*ksyms) + \
Packit Service da4517
					offsetof(struct kpatch_symbol, name));
Packit Service ac8aad
Packit Service ac8aad
			/* add rela to fill in ksyms[index].objname field */
Packit Service ac8aad
			ALLOC_LINK(rela2, &ksym_sec->rela->relas);
Packit Service ac8aad
			rela2->sym = strsym;
Packit Service ac8aad
			rela2->type = ABSOLUTE_RELA_TYPE;
Packit Service da4517
			rela2->addend = offset_of_string(&kelf->strings, symbol.objname);
Packit Service da4517
			rela2->offset = (unsigned int)(index * sizeof(*ksyms) + \
Packit Service da4517
					offsetof(struct kpatch_symbol, objname));
Packit Service ac8aad
Packit Service ac8aad
			/* Fill in krelas[index] */
Packit Service ac8aad
			if (is_gcc6_localentry_bundled_sym(rela->sym) &&
Packit Service ac8aad
			    rela->addend == (int)rela->sym->sym.st_value)
Packit Service ac8aad
				rela->addend -= rela->sym->sym.st_value;
Packit Service ac8aad
			krelas[index].addend = rela->addend;
Packit Service ac8aad
			krelas[index].type = rela->type;
Packit Service da4517
			krelas[index].external = !vmlinux && symbol.exported;
Packit Service ac8aad
Packit Service ac8aad
			/* add rela to fill in krelas[index].dest field */
Packit Service ac8aad
			ALLOC_LINK(rela2, &krela_sec->rela->relas);
Packit Service ac8aad
			if (sec->base->secsym)
Packit Service ac8aad
				rela2->sym = sec->base->secsym;
Packit Service ac8aad
			else
Packit Service ac8aad
				ERROR("can't create dynrela for section %s (symbol %s): no bundled or section symbol",
Packit Service ac8aad
				      sec->name, rela->sym->name);
Packit Service ac8aad
Packit Service ac8aad
			rela2->type = ABSOLUTE_RELA_TYPE;
Packit Service ac8aad
			rela2->addend = rela->offset;
Packit Service da4517
			rela2->offset = (unsigned int)(index * sizeof(*krelas) + \
Packit Service da4517
					offsetof(struct kpatch_relocation, dest));
Packit Service ac8aad
Packit Service ac8aad
			/* add rela to fill in krelas[index].objname field */
Packit Service ac8aad
			ALLOC_LINK(rela2, &krela_sec->rela->relas);
Packit Service ac8aad
			rela2->sym = strsym;
Packit Service ac8aad
			rela2->type = ABSOLUTE_RELA_TYPE;
Packit Service ac8aad
			rela2->addend = offset_of_string(&kelf->strings, objname);
Packit Service da4517
			rela2->offset = (unsigned int)(index * sizeof(*krelas) + \
Packit Service da4517
				offsetof(struct kpatch_relocation, objname));
Packit Service ac8aad
Packit Service ac8aad
			/* add rela to fill in krelas[index].ksym field */
Packit Service ac8aad
			ALLOC_LINK(rela2, &krela_sec->rela->relas);
Packit Service ac8aad
			rela2->sym = ksym_sec_sym;
Packit Service ac8aad
			rela2->type = ABSOLUTE_RELA_TYPE;
Packit Service da4517
			rela2->addend = (unsigned int)(index * sizeof(*ksyms));
Packit Service da4517
			rela2->offset = (unsigned int)(index * sizeof(*krelas) + \
Packit Service da4517
				offsetof(struct kpatch_relocation, ksym));
Packit Service ac8aad
Packit Service ac8aad
			/*
Packit Service ac8aad
			 * Mark the referred to symbol for removal but
Packit Service ac8aad
			 * only if it is not from this object file.
Packit Service ac8aad
			 * The symbols from this object file may be needed
Packit Service ac8aad
			 * later (for example, they may have relocations
Packit Service ac8aad
			 * of their own which should be processed).
Packit Service ac8aad
			 */
Packit Service ac8aad
			if (!rela->sym->sec)
Packit Service ac8aad
				rela->sym->strip = 1;
Packit Service ac8aad
			list_del(&rela->list);
Packit Service