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/* Copyright (C) 2001-2022 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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <pointer_guard.h>
#include <jmpbuf-offsets.h>
#include <tcb-offsets.h>
#include <asm-syntax.h>
#include <signal-defines.h>
/* #include <signal.h> */
#define SS_ONSTACK 1
.section .rodata.str1.1,"aMS",@progbits,1
.type longjmp_msg,@object
longjmp_msg:
.string "longjmp causes uninitialized stack frame"
.size longjmp_msg, .-longjmp_msg
#ifdef PIC
# define CALL_FAIL movl %ebx, %ecx; /* TODO: what's this mov good for? */ \
cfi_register(%ebx,%ecx); \
LOAD_PIC_REG (bx); \
leal longjmp_msg@GOTOFF(%ebx), %eax; \
movl %eax, (%esp); \
call HIDDEN_JUMPTARGET(__fortify_fail)
#else
# define CALL_FAIL movl $longjmp_msg, %eax; \
movl %eax, (%esp); \
call HIDDEN_JUMPTARGET(__fortify_fail)
#endif
.text
ENTRY (____longjmp_chk)
movl 4(%esp), %eax /* User's jmp_buf in %eax. */
/* Save the return address now. */
movl (JB_PC*4)(%eax), %edx
/* Get the stack pointer. */
movl (JB_SP*4)(%eax), %ecx
cfi_undefined(%ecx)
#ifdef PTR_DEMANGLE
PTR_DEMANGLE (%edx)
PTR_DEMANGLE (%ecx)
#endif
movw %ds, %si
movw %gs, %di
cmpw %si, %di
jz .Lok /* TLS not initialized yet */
movl %gs:SIGSTATE_OFFSET, %edi
testl %edi, %edi
jz .Lok /* sigstate not initialized yet */
testl $SS_ONSTACK, (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%edi)
jnz .Lonstack
/* We were on the main stack */
cmpl %ecx, %esp
/* Jumping to a higher-address frame is always allowed. */
jbe .Lok
/* Otherwise it's not allowed. */
CALL_FAIL
.Lonstack:
/* We were on the alternate stack, can't really easily check anything
since longjmp may get us out of the alternate stack. */
cmpl (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SP__OFFSET)(%edi), %ecx
jb .Loks /* We jump below the alternate stack, switch. */
movl (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SP__OFFSET)(%edi), %ebx
addl (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_SIZE__OFFSET)(%edi), %ebx
cmpl %ebx, %ecx
jb .Lok /* We jump inside the alternate stack, do not switch. */
/* We jump above the alternate stack, switch. */
.Loks: /* We jump out of the alternate stack, clear SS_ONSTACK flag. */
andl $~(SS_ONSTACK), (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%edi)
.Lok: /* We add unwind information for the target here. */
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)
movl 8(%esp), %eax /* Second argument is return value. */
movl %ecx, %esp
/* Jump to saved PC. */
jmp *%edx
END (____longjmp_chk)
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