/* longjmp for i386.
- Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+ Copyright (C) 1995-2019 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 Library General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ 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
- Library General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If not,
- write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
#include <sysdep.h>
-#define _ASM
-#define _SETJMP_H
-#include <bits/setjmp.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
+
+ .text
ENTRY (__longjmp)
+#ifdef PTR_DEMANGLE
+ movl 4(%esp), %eax /* User's jmp_buf in %eax. */
+
+# 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, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# else
+ xorl %edx, %edx
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%eax), %edx
+ 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. */
+ negl %edx
+ shrl $2, %edx
+ /* 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. */
+ addl $1, %edx
+ movl $255, %ebx
+L(loop):
+ cmpl %ebx, %edx
+ cmovb %edx, %ebx
+ incsspd %ebx
+ subl %ebx, %edx
+ ja L(loop)
+L(skip_ssp):
+# endif
+ /* Save the return address now. */
+ movl (JB_PC*4)(%eax), %edx
+ /* Get the stack pointer. */
+ movl (JB_SP*4)(%eax), %ecx
+ PTR_DEMANGLE (%edx)
+ PTR_DEMANGLE (%ecx)
+ LIBC_PROBE (longjmp, 3, 4@%eax, -4@8(%esp), 4@%edx)
+ cfi_def_cfa(%eax, 0)
+ cfi_register(%eip, %edx)
+ cfi_register(%esp, %ecx)
+ cfi_offset(%ebx, JB_BX*4)
+ cfi_offset(%esi, JB_SI*4)
+ cfi_offset(%edi, JB_DI*4)
+ cfi_offset(%ebp, JB_BP*4)
+ /* Restore registers. */
+ movl (JB_BX*4)(%eax), %ebx
+ movl (JB_SI*4)(%eax), %esi
+ movl (JB_DI*4)(%eax), %edi
+ movl (JB_BP*4)(%eax), %ebp
+ cfi_restore(%ebx)
+ cfi_restore(%esi)
+ cfi_restore(%edi)
+ cfi_restore(%ebp)
+
+ LIBC_PROBE (longjmp_target, 3, 4@%eax, -4@8(%esp), 4@%edx)
+ movl 8(%esp), %eax /* Second argument is return value. */
+ movl %ecx, %esp
+#else
movl 4(%esp), %ecx /* User's jmp_buf in %ecx. */
movl 8(%esp), %eax /* Second argument is return value. */
- /* Restore registers. */
+# ifdef SHADOW_STACK_POINTER_OFFSET
+# if IS_IN (libc) && defined SHARED
+ /* Check if Shadow Stack is enabled. */
+ testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
+ jz L(skip_ssp)
+# endif
+ /* Check and adjust the Shadow-Stack-Pointer. */
+ xorl %edx, %edx
+ /* Get the current ssp. */
+ rdsspd %edx
+ /* And compare it with the saved ssp value. */
+ subl SHADOW_STACK_POINTER_OFFSET(%ecx), %edx
+ 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. */
+ negl %edx
+ shrl $2, %edx
+ /* 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. */
+ addl $1, %edx
+ movl $255, %ebx
+L(loop):
+ cmpl %ebx, %edx
+ cmovb %edx, %ebx
+ incsspd %ebx
+ subl %ebx, %edx
+ ja L(loop)
+L(skip_ssp):
+# endif
+ /* Save the return address now. */
+ movl (JB_PC*4)(%ecx), %edx
+ LIBC_PROBE (longjmp, 3, 4@%ecx, -4@%eax, 4@%edx)
+ /* Restore registers. */
movl (JB_BX*4)(%ecx), %ebx
movl (JB_SI*4)(%ecx), %esi
movl (JB_DI*4)(%ecx), %edi
movl (JB_BP*4)(%ecx), %ebp
movl (JB_SP*4)(%ecx), %esp
+ LIBC_PROBE (longjmp_target, 3, 4@%ecx, -4@%ecx, 4@%edx)
+#endif
/* Jump to saved PC. */
- movl (JB_PC*4)(%ecx), %ecx
- jmp *%ecx
+ jmp *%edx
END (__longjmp)
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