mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-02 01:40:07 +00:00
581c785bf3
I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
253 lines
6.6 KiB
ArmAsm
253 lines
6.6 KiB
ArmAsm
/* Create new context.
|
|
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 <asm/prctl.h>
|
|
|
|
#include "ucontext_i.h"
|
|
|
|
|
|
ENTRY(__makecontext)
|
|
movl 4(%esp), %eax
|
|
|
|
/* Load the address of the function we are supposed to run. */
|
|
movl 8(%esp), %ecx
|
|
|
|
/* Compute the address of the stack. The information comes from
|
|
to us_stack element. */
|
|
movl oSS_SP(%eax), %edx
|
|
movl %ecx, oEIP(%eax)
|
|
addl oSS_SIZE(%eax), %edx
|
|
|
|
/* Remember the number of parameters for the exit handler since
|
|
it has to remove them. We store the number in the EBX register
|
|
which the function we will call must preserve. */
|
|
movl 12(%esp), %ecx
|
|
movl %ecx, oEBX(%eax)
|
|
|
|
/* Make room on the new stack for the parameters.
|
|
Room for the arguments, return address (== L(exitcode)) and
|
|
oLINK pointer is needed. One of the pointer sizes is subtracted
|
|
after aligning the stack. */
|
|
negl %ecx
|
|
leal -4(%edx,%ecx,4), %edx
|
|
negl %ecx
|
|
|
|
/* Align the stack. */
|
|
andl $0xfffffff0, %edx
|
|
subl $4, %edx
|
|
|
|
/* Store the future stack pointer. */
|
|
movl %edx, oESP(%eax)
|
|
|
|
/* Put the next context on the new stack (from the uc_link
|
|
element). */
|
|
movl oLINK(%eax), %eax
|
|
movl %eax, 4(%edx,%ecx,4)
|
|
|
|
/* Copy all the parameters. */
|
|
jecxz 2f
|
|
1: movl 12(%esp,%ecx,4), %eax
|
|
movl %eax, (%edx,%ecx,4)
|
|
decl %ecx
|
|
jnz 1b
|
|
2:
|
|
|
|
#if SHSTK_ENABLED
|
|
/* Check if Shadow Stack is enabled. */
|
|
testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
|
|
jz L(skip_ssp)
|
|
|
|
/* Reload the pointer to ucontext. */
|
|
movl 4(%esp), %eax
|
|
|
|
/* Shadow stack is enabled. We need to allocate a new shadow
|
|
stack. */
|
|
subl oSS_SP(%eax), %edx
|
|
shrl $STACK_SIZE_TO_SHADOW_STACK_SIZE_SHIFT, %edx
|
|
|
|
/* Align shadow stack size to 8 bytes. */
|
|
addl $7, %edx
|
|
andl $-8, %edx
|
|
|
|
/* Store shadow stack size in __ssp[2]. */
|
|
movl %edx, (oSSP + 8)(%eax)
|
|
|
|
/* Save ESI in the second scratch register slot. */
|
|
movl %esi, oSCRATCH2(%eax)
|
|
/* Save EDI in the third scratch register slot. */
|
|
movl %edi, oSCRATCH3(%eax)
|
|
|
|
/* Save the pointer to ucontext. */
|
|
movl %eax, %edi
|
|
|
|
/* Get the original shadow stack pointer. */
|
|
rdsspd %esi
|
|
|
|
/* Align the saved original shadow stack pointer to the next
|
|
8 byte aligned boundary. */
|
|
andl $-8, %esi
|
|
|
|
/* Load the top of the new stack into EDX. */
|
|
movl oESP(%eax), %edx
|
|
|
|
/* We need to terminate the FDE here because the unwinder looks
|
|
at ra-1 for unwind information. */
|
|
cfi_endproc
|
|
|
|
/* Swap the original stack pointer with the top of the new
|
|
stack. */
|
|
xchgl %esp, %edx
|
|
|
|
/* Add 4 bytes since CALL will push the 4-byte return address
|
|
onto stack. */
|
|
addl $4, %esp
|
|
|
|
/* Allocate the new shadow stack. Save EBX in the first scratch
|
|
register slot. */
|
|
movl %ebx, oSCRATCH1(%eax)
|
|
|
|
/* CET syscall takes 64-bit sizes. */
|
|
subl $16, %esp
|
|
movl (oSSP + 8)(%eax), %ecx
|
|
movl %ecx, (%esp)
|
|
movl $0, 4(%esp)
|
|
movl %ecx, 8(%esp)
|
|
movl $0, 12(%esp)
|
|
movl %esp, %ecx
|
|
|
|
movl $ARCH_CET_ALLOC_SHSTK, %ebx
|
|
movl $__NR_arch_prctl, %eax
|
|
ENTER_KERNEL
|
|
testl %eax, %eax
|
|
jne L(hlt) /* This should never happen. */
|
|
|
|
/* Copy the base address of the new shadow stack to __ssp[1]. */
|
|
movl (%esp), %eax
|
|
movl %eax, (oSSP + 4)(%edi)
|
|
|
|
addl $16, %esp
|
|
|
|
/* Restore EBX from the first scratch register slot. */
|
|
movl oSCRATCH1(%edi), %ebx
|
|
|
|
/* Get the size of the new shadow stack. */
|
|
movl (oSSP + 8)(%edi), %ecx
|
|
|
|
/* Use the restore stoken to restore the new shadow stack. */
|
|
rstorssp -8(%eax, %ecx)
|
|
|
|
/* Save the restore token at the next 8 byte aligned boundary
|
|
on the original shadow stack. */
|
|
saveprevssp
|
|
|
|
/* Push the address of "jmp exitcode" onto the new stack as
|
|
well as the new shadow stack. */
|
|
call 1f
|
|
jmp L(exitcode)
|
|
1:
|
|
|
|
/* Get the new shadow stack pointer. */
|
|
rdsspd %eax
|
|
|
|
/* Use the restore stoken to restore the original shadow stack. */
|
|
rstorssp -8(%esi)
|
|
|
|
/* Save the restore token on the new shadow stack. */
|
|
saveprevssp
|
|
|
|
/* Store the new shadow stack pointer in __ssp[0]. */
|
|
movl %eax, oSSP(%edi)
|
|
|
|
/* Restore the original stack. */
|
|
mov %edx, %esp
|
|
|
|
cfi_startproc
|
|
|
|
/* Restore ESI from the second scratch register slot. */
|
|
movl oSCRATCH2(%edi), %esi
|
|
/* Restore EDI from the third scratch register slot. */
|
|
movl oSCRATCH3(%edi), %edi
|
|
|
|
ret
|
|
|
|
L(skip_ssp):
|
|
#endif
|
|
|
|
/* If the function we call returns we must continue with the
|
|
context which is given in the uc_link element. To do this
|
|
set the return address for the function the user provides
|
|
to a little bit of helper code which does the magic (see
|
|
below). */
|
|
#ifdef PIC
|
|
call 1f
|
|
cfi_adjust_cfa_offset (4)
|
|
1: popl %ecx
|
|
cfi_adjust_cfa_offset (-4)
|
|
addl $L(exitcode)-1b, %ecx
|
|
movl %ecx, (%edx)
|
|
#else
|
|
movl $L(exitcode), (%edx)
|
|
#endif
|
|
/* We need to terminate the FDE here instead of after ret because
|
|
the unwinder looks at ra-1 for unwind information. */
|
|
cfi_endproc
|
|
|
|
/* 'makecontext' returns no value. */
|
|
ret
|
|
|
|
/* This is the helper code which gets called if a function which
|
|
is registered with 'makecontext' returns. In this case we
|
|
have to install the context listed in the uc_link element of
|
|
the context 'makecontext' manipulated at the time of the
|
|
'makecontext' call. If the pointer is NULL the process must
|
|
terminate. */
|
|
L(exitcode):
|
|
/* This removes the parameters passed to the function given to
|
|
'makecontext' from the stack. EBX contains the number of
|
|
parameters (see above). */
|
|
leal (%esp,%ebx,4), %esp
|
|
|
|
cmpl $0, (%esp) /* Check the next context. */
|
|
je 2f /* If it is zero exit. */
|
|
|
|
call HIDDEN_JUMPTARGET(__setcontext)
|
|
/* If this returns (which can happen if the syscall fails) we'll
|
|
exit the program with the return error value (-1). */
|
|
jmp L(call_exit)
|
|
|
|
2:
|
|
/* Exit with status 0. */
|
|
xorl %eax, %eax
|
|
|
|
L(call_exit):
|
|
/* Align the stack and pass the exit code (from %eax). */
|
|
andl $0xfffffff0, %esp
|
|
subl $12, %esp
|
|
pushl %eax
|
|
|
|
call HIDDEN_JUMPTARGET(exit)
|
|
/* The 'exit' call should never return. In case it does cause
|
|
the process to terminate. */
|
|
L(hlt):
|
|
hlt
|
|
cfi_startproc
|
|
END(__makecontext)
|
|
|
|
weak_alias (__makecontext, makecontext)
|