/* Machine-dependent ELF dynamic relocation inline functions.  PowerPC version.

   Copyright (C) 1995-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#ifndef dl_machine_h

#define dl_machine_h

#define ELF_MACHINE_NAME "powerpc"

#include <assert.h>

#include <dl-tls.h>

#include <dl-irel.h>

#include <hwcapinfo.h>

/* Translate a processor specific dynamic tag to the index

   in l_info array.  */

#define DT_PPC(x) (DT_PPC_##x - DT_LOPROC + DT_NUM)

/* Return nonzero iff ELF header is compatible with the running host.  */

static inline int

elf_machine_matches_host (const Elf32_Ehdr *ehdr)

{

  return ehdr->e_machine == EM_PPC;

}

/* Return the value of the GOT pointer.  */

static inline Elf32_Addr * __attribute__ ((const))

ppc_got (void)

{

  Elf32_Addr *got;

  asm ("bcl 20,31,1f\n"

       "1:	mflr %0\n"

       "	addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n"

       "	addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n"

       : "=b" (got) : : "lr");

  return got;

}

/* Return the link-time address of _DYNAMIC, stored as

   the first value in the GOT. */

static inline Elf32_Addr __attribute__ ((const))

elf_machine_dynamic (void)

{

  return *ppc_got ();

}

/* Return the run-time load address of the shared object.  */

static inline Elf32_Addr __attribute__ ((const))

elf_machine_load_address (void)

{

  Elf32_Addr *branchaddr;

  Elf32_Addr runtime_dynamic;

  /* This is much harder than you'd expect.  Possibly I'm missing something.

     The 'obvious' way:

       Apparently, "bcl 20,31,$+4" is what should be used to load LR

       with the address of the next instruction.

       I think this is so that machines that do bl/blr pairing don't

       get confused.

     asm ("bcl 20,31,0f ;"

	  "0: mflr 0 ;"

	  "lis %0,0b@ha;"

	  "addi %0,%0,0b@l;"

	  "subf %0,%0,0"

	  : "=b" (addr) : : "r0", "lr");

     doesn't work, because the linker doesn't have to (and in fact doesn't)

     update the @ha and @l references; the loader (which runs after this

     code) will do that.

     Instead, we use the following trick:

     The linker puts the _link-time_ address of _DYNAMIC at the first

     word in the GOT. We could branch to that address, if we wanted,

     by using an @local reloc; the linker works this out, so it's safe

     to use now. We can't, of course, actually branch there, because

     we'd cause an illegal instruction exception; so we need to compute

     the address ourselves. That gives us the following code: */

  /* Get address of the 'b _DYNAMIC@local'...  */

  asm ("bcl 20,31,0f;"

       "b _DYNAMIC@local;"

       "0:"

       : "=l" (branchaddr));

  /* So now work out the difference between where the branch actually points,

     and the offset of that location in memory from the start of the file.  */

  runtime_dynamic = ((Elf32_Addr) branchaddr

		     + ((Elf32_Sword) (*branchaddr << 6 & 0xffffff00) >> 6));

  return runtime_dynamic - elf_machine_dynamic ();

}

#define ELF_MACHINE_BEFORE_RTLD_RELOC(dynamic_info) /* nothing */

/* The PLT uses Elf32_Rela relocs.  */

#define elf_machine_relplt elf_machine_rela

/* Mask identifying addresses reserved for the user program,

   where the dynamic linker should not map anything.  */

#define ELF_MACHINE_USER_ADDRESS_MASK	0xf0000000UL

/* The actual _start code is in dl-start.S.  Use a really

   ugly bit of assembler to let dl-start.o see _dl_start.  */

#define RTLD_START asm (".globl _dl_start");

/* Decide where a relocatable object should be loaded.  */

extern ElfW(Addr)

__elf_preferred_address(struct link_map *loader, size_t maplength,

			ElfW(Addr) mapstartpref);

#define ELF_PREFERRED_ADDRESS(loader, maplength, mapstartpref) \

  __elf_preferred_address (loader, maplength, mapstartpref)

/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so

   PLT entries should not be allowed to define the value.

   ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one

   of the main executable's symbols, as for a COPY reloc.  */

/* We never want to use a PLT entry as the destination of a

   reloc, when what is being relocated is a branch. This is

   partly for efficiency, but mostly so we avoid loops.  */

#define elf_machine_type_class(type)			\

  ((((type) == R_PPC_JMP_SLOT				\

    || (type) == R_PPC_REL24				\

    || ((type) >= R_PPC_DTPMOD32 /* contiguous TLS */	\

	&& (type) <= R_PPC_DTPREL32)			\

    || (type) == R_PPC_ADDR24) * ELF_RTYPE_CLASS_PLT)	\

   | (((type) == R_PPC_COPY) * ELF_RTYPE_CLASS_COPY))

/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */

#define ELF_MACHINE_JMP_SLOT	R_PPC_JMP_SLOT

/* The PowerPC never uses REL relocations.  */

#define ELF_MACHINE_NO_REL 1

#define ELF_MACHINE_NO_RELA 0

/* We define an initialization function to initialize HWCAP/HWCAP2 and

   platform data so it can be copied into the TCB later.  This is called

   very early in _dl_sysdep_start for dynamically linked binaries.  */

#ifdef SHARED

# define DL_PLATFORM_INIT dl_platform_init ()

static inline void __attribute__ ((unused))

dl_platform_init (void)

{

  __tcb_parse_hwcap_and_convert_at_platform ();

}

#endif

/* Set up the loaded object described by MAP so its unrelocated PLT

   entries will jump to the on-demand fixup code in dl-runtime.c.

   Also install a small trampoline to be used by entries that have

   been relocated to an address too far away for a single branch.  */

extern int __elf_machine_runtime_setup (struct link_map *map,

					int lazy, int profile);

static inline int

elf_machine_runtime_setup (struct link_map *map,

			   int lazy, int profile)

{

  if (map->l_info[DT_JMPREL] == 0)

    return lazy;

  if (map->l_info[DT_PPC(GOT)] == 0)

    /* Handle old style PLT.  */

    return __elf_machine_runtime_setup (map, lazy, profile);

  /* New style non-exec PLT consisting of an array of addresses.  */

  map->l_info[DT_PPC(GOT)]->d_un.d_ptr += map->l_addr;

  if (lazy)

    {

      Elf32_Addr *plt, *got, glink;

      Elf32_Word num_plt_entries;

      void (*dlrr) (void);

      extern void _dl_runtime_resolve (void);

      extern void _dl_prof_resolve (void);

      if (__glibc_likely (!profile))

	dlrr = _dl_runtime_resolve;

      else

	{

	  if (GLRO(dl_profile) != NULL

	      &&_dl_name_match_p (GLRO(dl_profile), map))

	    GL(dl_profile_map) = map;

	  dlrr = _dl_prof_resolve;

	}

      got = (Elf32_Addr *) map->l_info[DT_PPC(GOT)]->d_un.d_ptr;

      glink = got[1];

      got[1] = (Elf32_Addr) dlrr;

      got[2] = (Elf32_Addr) map;

      /* Relocate everything in .plt by the load address offset.  */

      plt = (Elf32_Addr *) D_PTR (map, l_info[DT_PLTGOT]);

      num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val

			 / sizeof (Elf32_Rela));

      /* If a library is prelinked but we have to relocate anyway,

	 we have to be able to undo the prelinking of .plt section.

	 The prelinker saved us at got[1] address of .glink

	 section's start.  */

      if (glink)

	{

	  glink += map->l_addr;

	  while (num_plt_entries-- != 0)

	    *plt++ = glink, glink += 4;

	}

      else

	while (num_plt_entries-- != 0)

	  *plt++ += map->l_addr;

    }

  return lazy;

}

/* Change the PLT entry whose reloc is 'reloc' to call the actual routine.  */

extern Elf32_Addr __elf_machine_fixup_plt (struct link_map *map,

					   Elf32_Addr *reloc_addr,

					   Elf32_Addr finaladdr);

static inline Elf32_Addr

elf_machine_fixup_plt (struct link_map *map, lookup_t t,

		       const ElfW(Sym) *refsym, const ElfW(Sym) *sym,

		       const Elf32_Rela *reloc,

		       Elf32_Addr *reloc_addr, Elf64_Addr finaladdr)

{

  if (map->l_info[DT_PPC(GOT)] == 0)

    /* Handle old style PLT.  */

    return __elf_machine_fixup_plt (map, reloc_addr, finaladdr);

  *reloc_addr = finaladdr;

  return finaladdr;

}

/* Return the final value of a plt relocation.  */

static inline Elf32_Addr

elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,

		       Elf32_Addr value)

{

  return value + reloc->r_addend;

}

/* Names of the architecture-specific auditing callback functions.  */

#define ARCH_LA_PLTENTER ppc32_gnu_pltenter

#define ARCH_LA_PLTEXIT ppc32_gnu_pltexit

#endif /* dl_machine_h */

#ifdef RESOLVE_MAP

/* Do the actual processing of a reloc, once its target address

   has been determined.  */

extern void __process_machine_rela (struct link_map *map,

				    const Elf32_Rela *reloc,

				    struct link_map *sym_map,

				    const Elf32_Sym *sym,

				    const Elf32_Sym *refsym,

				    Elf32_Addr *const reloc_addr,

				    Elf32_Addr finaladdr,

				    int rinfo) attribute_hidden;

/* Call _dl_signal_error when a resolved value overflows a relocated area.  */

extern void _dl_reloc_overflow (struct link_map *map,

				const char *name,

				Elf32_Addr *const reloc_addr,

				const Elf32_Sym *refsym) attribute_hidden;

/* Perform the relocation specified by RELOC and SYM (which is fully resolved).

   LOADADDR is the load address of the object; INFO is an array indexed

   by DT_* of the .dynamic section info.  */

auto inline void __attribute__ ((always_inline))

elf_machine_rela (struct link_map *map, const Elf32_Rela *reloc,

		  const Elf32_Sym *sym, const struct r_found_version *version,

		  void *const reloc_addr_arg, int skip_ifunc)

{

  Elf32_Addr *const reloc_addr = reloc_addr_arg;

  const Elf32_Sym *const refsym = sym;

  Elf32_Addr value;

  const int r_type = ELF32_R_TYPE (reloc->r_info);

  struct link_map *sym_map = NULL;

#ifndef RESOLVE_CONFLICT_FIND_MAP

  if (r_type == R_PPC_RELATIVE)

    {

      *reloc_addr = map->l_addr + reloc->r_addend;

      return;

    }

  if (__glibc_unlikely (r_type == R_PPC_NONE))

    return;

  /* binutils on ppc32 includes st_value in r_addend for relocations

     against local symbols.  */

  if (__builtin_expect (ELF32_ST_BIND (sym->st_info) == STB_LOCAL, 0)

      && sym->st_shndx != SHN_UNDEF)

    {

      sym_map = map;

      value = map->l_addr;

    }

  else

    {

      sym_map = RESOLVE_MAP (&sym, version, r_type);

      value = SYMBOL_ADDRESS (sym_map, sym, true);

    }

  value += reloc->r_addend;

#else

  value = reloc->r_addend;

#endif

  if (sym != NULL

      && __builtin_expect (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC, 0)

      && __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)

      && __builtin_expect (!skip_ifunc, 1))

    value = elf_ifunc_invoke (value);

  /* A small amount of code is duplicated here for speed.  In libc,

     more than 90% of the relocs are R_PPC_RELATIVE; in the X11 shared

     libraries, 60% are R_PPC_RELATIVE, 24% are R_PPC_GLOB_DAT or

     R_PPC_ADDR32, and 16% are R_PPC_JMP_SLOT (which this routine

     wouldn't usually handle).  As an bonus, doing this here allows

     the switch statement in __process_machine_rela to work.  */

  switch (r_type)

    {

    case R_PPC_GLOB_DAT:

    case R_PPC_ADDR32:

      *reloc_addr = value;

      break;

#ifndef RESOLVE_CONFLICT_FIND_MAP

# ifdef RTLD_BOOTSTRAP

#  define NOT_BOOTSTRAP 0

# else

#  define NOT_BOOTSTRAP 1

# endif

    case R_PPC_DTPMOD32:

      if (map->l_info[DT_PPC(OPT)]

	  && (map->l_info[DT_PPC(OPT)]->d_un.d_val & PPC_OPT_TLS))

	{

	  if (!NOT_BOOTSTRAP)

	    {

	      reloc_addr[0] = 0;

	      reloc_addr[1] = (sym_map->l_tls_offset - TLS_TP_OFFSET

			       + TLS_DTV_OFFSET);

	      break;

	    }

	  else if (sym_map != NULL)

	    {

# ifndef SHARED

	      CHECK_STATIC_TLS (map, sym_map);

# else

	      if (TRY_STATIC_TLS (map, sym_map))

# endif

		{

		  reloc_addr[0] = 0;

		  /* Set up for local dynamic.  */

		  reloc_addr[1] = (sym_map->l_tls_offset - TLS_TP_OFFSET

				   + TLS_DTV_OFFSET);

		  break;

		}

	    }

	}

      if (!NOT_BOOTSTRAP)

	/* During startup the dynamic linker is always index 1.  */

	*reloc_addr = 1;

      else if (sym_map != NULL)

	/* Get the information from the link map returned by the

	   RESOLVE_MAP function.  */

	*reloc_addr = sym_map->l_tls_modid;

      break;

    case R_PPC_DTPREL32:

      if (map->l_info[DT_PPC(OPT)]

	  && (map->l_info[DT_PPC(OPT)]->d_un.d_val & PPC_OPT_TLS))

	{

	  if (!NOT_BOOTSTRAP)

	    {

	      *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc);

	      break;

	    }

	  else if (sym_map != NULL)

	    {

	      /* This reloc is always preceded by R_PPC_DTPMOD32.  */

# ifndef SHARED

	      assert (HAVE_STATIC_TLS (map, sym_map));

# else

	      if (HAVE_STATIC_TLS (map, sym_map))

# endif

		{

		  *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc);

		  break;

		}

	    }

	}

      /* During relocation all TLS symbols are defined and used.

	 Therefore the offset is already correct.  */

      if (NOT_BOOTSTRAP && sym_map != NULL)

	*reloc_addr = TLS_DTPREL_VALUE (sym, reloc);

      break;

    case R_PPC_TPREL32:

      if (!NOT_BOOTSTRAP || sym_map != NULL)

	{

	  if (NOT_BOOTSTRAP)

	    CHECK_STATIC_TLS (map, sym_map);

	  *reloc_addr = TLS_TPREL_VALUE (sym_map, sym, reloc);

	}

      break;

#endif

    case R_PPC_JMP_SLOT:

#ifdef RESOLVE_CONFLICT_FIND_MAP

      RESOLVE_CONFLICT_FIND_MAP (map, reloc_addr);

#endif

      if (map->l_info[DT_PPC(GOT)] != 0)

	{

	  *reloc_addr = value;

	  break;

	}

      /* FALLTHROUGH */

    default:

      __process_machine_rela (map, reloc, sym_map, sym, refsym,

			      reloc_addr, value, r_type);

    }

}

auto inline void __attribute__ ((always_inline))

elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,

			   void *const reloc_addr_arg)

{

  Elf32_Addr *const reloc_addr = reloc_addr_arg;

  *reloc_addr = l_addr + reloc->r_addend;

}

auto inline void __attribute__ ((always_inline))

elf_machine_lazy_rel (struct link_map *map,

		      Elf32_Addr l_addr, const Elf32_Rela *reloc,

		      int skip_ifunc)

{

  /* elf_machine_runtime_setup handles this. */

}

#endif /* RESOLVE_MAP */