mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 08:40:07 +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
251 lines
6.6 KiB
ArmAsm
251 lines
6.6 KiB
ArmAsm
/* Save current context and install the given one.
|
|
Copyright (C) 2002-2022 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"
|
|
|
|
|
|
/* int __swapcontext (ucontext_t *oucp, const ucontext_t *ucp);
|
|
|
|
Saves the machine context in oucp such that when it is activated,
|
|
it appears as if __swapcontextt() returned again, restores the
|
|
machine context in ucp and thereby resumes execution in that
|
|
context.
|
|
|
|
This implementation is intended to be used for *synchronous* context
|
|
switches only. Therefore, it does not have to save anything
|
|
other than the PRESERVED state. */
|
|
|
|
ENTRY(__swapcontext)
|
|
/* Save the preserved registers, the registers used for passing args,
|
|
and the return address. */
|
|
movq %rbx, oRBX(%rdi)
|
|
movq %rbp, oRBP(%rdi)
|
|
movq %r12, oR12(%rdi)
|
|
movq %r13, oR13(%rdi)
|
|
movq %r14, oR14(%rdi)
|
|
movq %r15, oR15(%rdi)
|
|
|
|
movq %rdi, oRDI(%rdi)
|
|
movq %rsi, oRSI(%rdi)
|
|
movq %rdx, oRDX(%rdi)
|
|
movq %rcx, oRCX(%rdi)
|
|
movq %r8, oR8(%rdi)
|
|
movq %r9, oR9(%rdi)
|
|
|
|
movq (%rsp), %rcx
|
|
movq %rcx, oRIP(%rdi)
|
|
leaq 8(%rsp), %rcx /* Exclude the return address. */
|
|
movq %rcx, oRSP(%rdi)
|
|
|
|
/* We have separate floating-point register content memory on the
|
|
stack. We use the __fpregs_mem block in the context. Set the
|
|
links up correctly. */
|
|
leaq oFPREGSMEM(%rdi), %rcx
|
|
movq %rcx, oFPREGS(%rdi)
|
|
/* Save the floating-point environment. */
|
|
fnstenv (%rcx)
|
|
stmxcsr oMXCSR(%rdi)
|
|
|
|
|
|
/* The syscall destroys some registers, save them. */
|
|
movq %rsi, %r12
|
|
movq %rdi, %r9
|
|
|
|
/* Save the current signal mask and install the new one with
|
|
rt_sigprocmask (SIG_BLOCK, newset, oldset,_NSIG/8). */
|
|
leaq oSIGMASK(%rdi), %rdx
|
|
leaq oSIGMASK(%rsi), %rsi
|
|
movl $SIG_SETMASK, %edi
|
|
movl $_NSIG8,%r10d
|
|
movl $__NR_rt_sigprocmask, %eax
|
|
syscall
|
|
cmpq $-4095, %rax /* Check %rax for error. */
|
|
jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
|
|
|
|
/* Restore destroyed register into RDX. The choice is arbitrary,
|
|
but leaving RDI and RSI available for use later can avoid
|
|
shuffling values. */
|
|
movq %r12, %rdx
|
|
|
|
/* Restore the floating-point context. Not the registers, only the
|
|
rest. */
|
|
movq oFPREGS(%rdx), %rcx
|
|
fldenv (%rcx)
|
|
ldmxcsr oMXCSR(%rdx)
|
|
|
|
/* Load the new stack pointer and the preserved registers. */
|
|
movq oRSP(%rdx), %rsp
|
|
movq oRBX(%rdx), %rbx
|
|
movq oRBP(%rdx), %rbp
|
|
movq oR12(%rdx), %r12
|
|
movq oR13(%rdx), %r13
|
|
movq oR14(%rdx), %r14
|
|
movq oR15(%rdx), %r15
|
|
|
|
#if SHSTK_ENABLED
|
|
/* Check if shadow stack is enabled. */
|
|
testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
|
|
jz L(no_shstk)
|
|
|
|
xorl %eax, %eax
|
|
cmpq %fs:SSP_BASE_OFFSET, %rax
|
|
jnz L(shadow_stack_bound_recorded)
|
|
|
|
/* Get the base address and size of the default shadow stack
|
|
which must be the current shadow stack since nothing has
|
|
been recorded yet. */
|
|
sub $24, %RSP_LP
|
|
mov %RSP_LP, %RSI_LP
|
|
movl $ARCH_CET_STATUS, %edi
|
|
movl $__NR_arch_prctl, %eax
|
|
syscall
|
|
testq %rax, %rax
|
|
jz L(continue_no_err)
|
|
|
|
/* This should never happen. */
|
|
hlt
|
|
|
|
L(continue_no_err):
|
|
/* Record the base of the current shadow stack. */
|
|
movq 8(%rsp), %rax
|
|
movq %rax, %fs:SSP_BASE_OFFSET
|
|
add $24, %RSP_LP
|
|
|
|
L(shadow_stack_bound_recorded):
|
|
/* If we unwind the stack, we can't undo stack unwinding. Just
|
|
save the target shadow stack pointer as the current shadow
|
|
stack pointer. */
|
|
movq oSSP(%rdx), %rcx
|
|
movq %rcx, oSSP(%r9)
|
|
|
|
/* Save the base of the current shadow stack. */
|
|
movq %fs:SSP_BASE_OFFSET, %rax
|
|
movq %rax, (oSSP + 8)(%r9)
|
|
|
|
/* If the base of the target shadow stack is the same as the
|
|
base of the current shadow stack, we unwind the shadow
|
|
stack. Otherwise it is a stack switch and we look for a
|
|
restore token. */
|
|
movq oSSP(%rdx), %rsi
|
|
movq %rsi, %rdi
|
|
|
|
/* Get the base of the target shadow stack. */
|
|
movq (oSSP + 8)(%rdx), %rcx
|
|
cmpq %fs:SSP_BASE_OFFSET, %rcx
|
|
je L(unwind_shadow_stack)
|
|
|
|
L(find_restore_token_loop):
|
|
/* Look for a restore token. */
|
|
movq -8(%rsi), %rax
|
|
andq $-8, %rax
|
|
cmpq %rsi, %rax
|
|
je L(restore_shadow_stack)
|
|
|
|
/* Try the next slot. */
|
|
subq $8, %rsi
|
|
jmp L(find_restore_token_loop)
|
|
|
|
L(restore_shadow_stack):
|
|
/* The target shadow stack will be restored. Save the current
|
|
shadow stack pointer. */
|
|
rdsspq %rcx
|
|
movq %rcx, oSSP(%r9)
|
|
|
|
/* Restore the target shadow stack. */
|
|
rstorssp -8(%rsi)
|
|
|
|
/* Save the restore token on the old shadow stack. NB: This
|
|
restore token may be checked by setcontext or swapcontext
|
|
later. */
|
|
saveprevssp
|
|
|
|
/* Record the new shadow stack base that was switched to. */
|
|
movq (oSSP + 8)(%rdx), %rax
|
|
movq %rax, %fs:SSP_BASE_OFFSET
|
|
|
|
L(unwind_shadow_stack):
|
|
rdsspq %rcx
|
|
subq %rdi, %rcx
|
|
je L(skip_unwind_shadow_stack)
|
|
negq %rcx
|
|
shrq $3, %rcx
|
|
movl $255, %esi
|
|
L(loop):
|
|
cmpq %rsi, %rcx
|
|
cmovb %rcx, %rsi
|
|
incsspq %rsi
|
|
subq %rsi, %rcx
|
|
ja L(loop)
|
|
|
|
L(skip_unwind_shadow_stack):
|
|
/* Setup registers used for passing args. */
|
|
movq oRDI(%rdx), %rdi
|
|
movq oRSI(%rdx), %rsi
|
|
movq oRCX(%rdx), %rcx
|
|
movq oR8(%rdx), %r8
|
|
movq oR9(%rdx), %r9
|
|
|
|
/* Get the return address set with getcontext. */
|
|
movq oRIP(%rdx), %r10
|
|
|
|
/* Setup finally %rdx. */
|
|
movq oRDX(%rdx), %rdx
|
|
|
|
/* Check if return address is valid for the case when setcontext
|
|
is invoked from __start_context with linked context. */
|
|
rdsspq %rax
|
|
cmpq (%rax), %r10
|
|
/* Clear rax to indicate success. NB: Don't use xorl to keep
|
|
EFLAGS for jne. */
|
|
movl $0, %eax
|
|
jne L(jmp)
|
|
/* Return to the new context if return address valid. */
|
|
pushq %r10
|
|
ret
|
|
|
|
L(jmp):
|
|
/* Jump to the new context directly. */
|
|
jmp *%r10
|
|
|
|
L(no_shstk):
|
|
#endif
|
|
/* The following ret should return to the address set with
|
|
getcontext. Therefore push the address on the stack. */
|
|
movq oRIP(%rdx), %rcx
|
|
pushq %rcx
|
|
|
|
/* Setup registers used for passing args. */
|
|
movq oRDI(%rdx), %rdi
|
|
movq oRSI(%rdx), %rsi
|
|
movq oRCX(%rdx), %rcx
|
|
movq oR8(%rdx), %r8
|
|
movq oR9(%rdx), %r9
|
|
|
|
/* Setup finally %rdx. */
|
|
movq oRDX(%rdx), %rdx
|
|
|
|
/* Clear rax to indicate success. */
|
|
xorl %eax, %eax
|
|
ret
|
|
PSEUDO_END(__swapcontext)
|
|
|
|
weak_alias (__swapcontext, swapcontext)
|