mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-11 22:00:08 +00:00
04277e02d7
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
94 lines
2.7 KiB
ArmAsm
94 lines
2.7 KiB
ArmAsm
/* Copyright (C) 2001-2019 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 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>
|
|
#define _ERRNO_H 1
|
|
#include <bits/errno.h>
|
|
#include <tcb-offsets.h>
|
|
|
|
#if SHSTK_ENABLED
|
|
/* The shadow stack prevents us from pushing the saved return PC onto
|
|
the stack and returning normally. Instead we pop the shadow stack
|
|
and return directly. This is the safest way to return and ensures
|
|
any stack manipulations done by the vfork'd child doesn't cause the
|
|
parent to terminate when CET is enabled. */
|
|
# undef SYSCALL_ERROR_HANDLER
|
|
# define SYSCALL_ERROR_HANDLER \
|
|
0: \
|
|
SYSCALL_SET_ERRNO; \
|
|
or $-1, %RAX_LP; \
|
|
jmp 1b;
|
|
# undef SYSCALL_ERROR_LABEL
|
|
# define SYSCALL_ERROR_LABEL 0f
|
|
#endif
|
|
|
|
/* Clone the calling process, but without copying the whole address space.
|
|
The calling process is suspended until the new process exits or is
|
|
replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
|
|
and the process ID of the new process to the old process. */
|
|
|
|
ENTRY (__vfork)
|
|
|
|
/* Pop the return PC value into RDI. We need a register that
|
|
is preserved by the syscall and that we're allowed to destroy. */
|
|
popq %rdi
|
|
cfi_adjust_cfa_offset(-8)
|
|
cfi_register(%rip, %rdi)
|
|
|
|
/* Stuff the syscall number in RAX and enter into the kernel. */
|
|
movl $SYS_ify (vfork), %eax
|
|
syscall
|
|
|
|
#if !SHSTK_ENABLED
|
|
/* Push back the return PC. */
|
|
pushq %rdi
|
|
cfi_adjust_cfa_offset(8)
|
|
#endif
|
|
|
|
cmpl $-4095, %eax
|
|
jae SYSCALL_ERROR_LABEL /* Branch forward if it failed. */
|
|
|
|
#if SHSTK_ENABLED
|
|
1:
|
|
/* Check if shadow stack is in use. */
|
|
xorl %esi, %esi
|
|
rdsspq %rsi
|
|
testq %rsi, %rsi
|
|
/* Normal return if shadow stack isn't in use. */
|
|
je L(no_shstk)
|
|
|
|
/* Pop return address from shadow stack and jump back to caller
|
|
directly. */
|
|
movl $1, %esi
|
|
incsspq %rsi
|
|
jmp *%rdi
|
|
|
|
L(no_shstk):
|
|
/* Push back the return PC. */
|
|
pushq %rdi
|
|
cfi_adjust_cfa_offset(8)
|
|
#endif
|
|
|
|
/* Normal return. */
|
|
ret
|
|
|
|
PSEUDO_END (__vfork)
|
|
libc_hidden_def (__vfork)
|
|
|
|
weak_alias (__vfork, vfork)
|
|
strong_alias (__vfork, __libc_vfork)
|