/* Copyright (C) 2001-2018 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/>.  */

#include <sysdep.h>

#include <jmpbuf-offsets.h>

#include <jmp_buf-ssp.h>

#include <asm-syntax.h>

#include <stap-probe.h>

/* Don't restore shadow stack register if

   1. Shadow stack isn't enabled.  Or

   2. __longjmp is defined for __longjmp_cancel.

 */

#if !SHSTK_ENABLED || defined __longjmp

# undef SHADOW_STACK_POINTER_OFFSET

#endif

/* Jump to the position specified by ENV, causing the

   setjmp call there to return VAL, or 1 if VAL is 0.

   void __longjmp (__jmp_buf env, int val).  */

	.text

ENTRY(__longjmp)

	/* Restore registers.  */

	mov (JB_RSP*8)(%rdi),%R8_LP

	mov (JB_RBP*8)(%rdi),%R9_LP

	mov (JB_PC*8)(%rdi),%RDX_LP

#ifdef PTR_DEMANGLE

	PTR_DEMANGLE (%R8_LP)

	PTR_DEMANGLE (%R9_LP)

	PTR_DEMANGLE (%RDX_LP)

# ifdef __ILP32__

	/* We ignored the high bits of the %rbp value because only the low

	   bits are mangled.  But we cannot presume that %rbp is being used

	   as a pointer and truncate it, so recover the high bits.  */

	movl (JB_RBP*8 + 4)(%rdi), %eax

	shlq $32, %rax

	orq %rax, %r9

# endif

#endif

#ifdef SHADOW_STACK_POINTER_OFFSET

# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET

	/* Check if Shadow Stack is enabled.  */

	testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET

	jz L(skip_ssp)

# else

	xorl %eax, %eax

# endif

	/* Check and adjust the Shadow-Stack-Pointer.  */

	/* Get the current ssp.  */

	rdsspq %rax

	/* And compare it with the saved ssp value.  */

	subq SHADOW_STACK_POINTER_OFFSET(%rdi), %rax

	je L(skip_ssp)

	/* Count the number of frames to adjust and adjust it

	   with incssp instruction.  The instruction can adjust

	   the ssp by [0..255] value only thus use a loop if

	   the number of frames is bigger than 255.  */

	negq %rax

	shrq $3, %rax

	/* NB: We saved Shadow-Stack-Pointer of setjmp.  Since we are

	       restoring Shadow-Stack-Pointer of setjmp's caller, we

	       need to unwind shadow stack by one more frame.  */

	addq $1, %rax

	movl $255, %ebx

L(loop):

	cmpq %rbx, %rax

	cmovb %rax, %rbx

	incsspq %rbx

	subq %rbx, %rax

	ja L(loop)

L(skip_ssp):

#endif

	LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)

	/* We add unwind information for the target here.  */

	cfi_def_cfa(%rdi, 0)

	cfi_register(%rsp,%r8)

	cfi_register(%rbp,%r9)

	cfi_register(%rip,%rdx)

	cfi_offset(%rbx,JB_RBX*8)

	cfi_offset(%r12,JB_R12*8)

	cfi_offset(%r13,JB_R13*8)

	cfi_offset(%r14,JB_R14*8)

	cfi_offset(%r15,JB_R15*8)

	movq (JB_RBX*8)(%rdi),%rbx

	movq (JB_R12*8)(%rdi),%r12

	movq (JB_R13*8)(%rdi),%r13

	movq (JB_R14*8)(%rdi),%r14

	movq (JB_R15*8)(%rdi),%r15

	/* Set return value for setjmp.  */

	mov %esi, %eax

	mov %R8_LP,%RSP_LP

	movq %r9,%rbp

	LIBC_PROBE (longjmp_target, 3,

		    LP_SIZE@%RDI_LP, -4@%eax, LP_SIZE@%RDX_LP)

	jmpq *%rdx

END (__longjmp)