glibc/sysdeps/i386/setjmp.S
Florian Weimer 88f4b6929c Introduce <pointer_guard.h>, extracted from <sysdep.h>
This allows us to define a generic no-op version of PTR_MANGLE and
PTR_DEMANGLE.  In the future, we can use PTR_MANGLE and PTR_DEMANGLE
unconditionally in C sources, avoiding an unintended loss of hardening
due to missing include files or unlucky header inclusion ordering.

In i386 and x86_64, we can avoid a <tls.h> dependency in the C
code by using the computed constant from <tcb-offsets.h>.  <sysdep.h>
no longer includes these definitions, so there is no cyclic dependency
anymore when computing the <tcb-offsets.h> constants.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-10-18 17:03:55 +02:00

81 lines
2.4 KiB
ArmAsm

/* setjmp for i386.
Copyright (C) 1995-2022 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 <jmp_buf-ssp.h>
#include <asm-syntax.h>
#include <stap-probe.h>
#define PARMS 4 /* no space for saved regs */
#define JMPBUF PARMS
#define SIGMSK JMPBUF+4
/* Don't save shadow stack register if shadow stack isn't enabled. */
#if !SHSTK_ENABLED
# undef SHADOW_STACK_POINTER_OFFSET
#endif
ENTRY (__sigsetjmp)
movl JMPBUF(%esp), %eax
/* Save registers. */
movl %ebx, (JB_BX*4)(%eax)
movl %esi, (JB_SI*4)(%eax)
movl %edi, (JB_DI*4)(%eax)
leal JMPBUF(%esp), %ecx /* Save SP as it will be after we return. */
#ifdef PTR_MANGLE
PTR_MANGLE (%ecx)
#endif
movl %ecx, (JB_SP*4)(%eax)
movl 0(%esp), %ecx /* Save PC we are returning to now. */
LIBC_PROBE (setjmp, 3, 4@%eax, -4@SIGMSK(%esp), 4@%ecx)
#ifdef PTR_MANGLE
PTR_MANGLE (%ecx)
#endif
movl %ecx, (JB_PC*4)(%eax)
movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer. */
#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 %ecx, %ecx
# endif
/* Get the current Shadow-Stack-Pointer and save it. */
rdsspd %ecx
movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
L(skip_ssp):
# endif
#endif
#if IS_IN (rtld)
/* In ld.so we never save the signal mask. */
xorl %eax, %eax
ret
#else
/* Make a tail call to __sigjmp_save; it takes the same args. */
jmp __sigjmp_save
#endif
END (__sigsetjmp)
hidden_def (__sigsetjmp)