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30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
133 lines
3.6 KiB
ArmAsm
133 lines
3.6 KiB
ArmAsm
/* Save current context.
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Copyright (C) 2001-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <asm/prctl.h>
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#include "ucontext_i.h"
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ENTRY(__getcontext)
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/* Load address of the context data structure. */
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movl 4(%esp), %eax
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/* Save the preserved register values and the return address. */
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movl %edi, oEDI(%eax)
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movl %esi, oESI(%eax)
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movl %ebp, oEBP(%eax)
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movl (%esp), %ecx
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movl %ecx, oEIP(%eax)
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leal 4(%esp), %ecx /* Exclude the return address. */
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movl %ecx, oESP(%eax)
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movl %ebx, oEBX(%eax)
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/* Save the FS segment register. We don't touch the GS register
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since it is used for threads. */
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xorl %edx, %edx
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movw %fs, %dx
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movl %edx, oFS(%eax)
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#if SHSTK_ENABLED
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/* Check if shadow stack is enabled. */
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testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
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jz L(no_shstk)
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/* Save EAX in EDX. */
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movl %eax, %edx
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xorl %eax, %eax
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cmpl %gs:SSP_BASE_OFFSET, %eax
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jnz L(shadow_stack_bound_recorded)
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/* Save EBX in the first scratch register slot. */
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movl %ebx, oSCRATCH1(%edx)
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/* Get the base address and size of the default shadow stack
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which must be the current shadow stack since nothing has
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been recorded yet. */
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sub $24, %esp
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mov %esp, %ecx
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movl $ARCH_CET_STATUS, %ebx
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movl $__NR_arch_prctl, %eax
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ENTER_KERNEL
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testl %eax, %eax
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jz L(continue_no_err)
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/* This should never happen. */
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hlt
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L(continue_no_err):
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/* Restore EBX from the first scratch register slot. */
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movl oSCRATCH1(%edx), %ebx
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/* Record the base of the current shadow stack. */
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movl 8(%esp), %eax
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movl %eax, %gs:SSP_BASE_OFFSET
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add $24, %esp
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L(shadow_stack_bound_recorded):
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/* Load address of the context data structure. */
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movl 4(%esp), %eax
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/* Get the current shadow stack pointer. */
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rdsspd %edx
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/* NB: Save the caller's shadow stack so that we can jump back
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to the caller directly. */
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addl $4, %edx
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movl %edx, oSSP(%eax)
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/* Save the current shadow stack base in ucontext. */
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movl %gs:SSP_BASE_OFFSET, %edx
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movl %edx, (oSSP + 4)(%eax)
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L(no_shstk):
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#endif
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/* We have separate floating-point register content memory on the
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stack. We use the __fpregs_mem block in the context. Set the
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links up correctly. */
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leal oFPREGSMEM(%eax), %ecx
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movl %ecx, oFPREGS(%eax)
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/* Save the floating-point context. */
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fnstenv (%ecx)
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/* And load it right back since the processor changes the mask.
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Intel thought this opcode to be used in interrupt handlers which
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would block all exceptions. */
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fldenv (%ecx)
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/* Save the current signal mask. */
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pushl %ebx
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cfi_adjust_cfa_offset (4)
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cfi_rel_offset (ebx, 0)
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leal oSIGMASK(%eax), %edx
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xorl %ecx, %ecx
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movl $SIG_BLOCK, %ebx
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movl $__NR_sigprocmask, %eax
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ENTER_KERNEL
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popl %ebx
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cfi_adjust_cfa_offset (-4)
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cfi_restore (ebx)
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cmpl $-4095, %eax /* Check %eax for error. */
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jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
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/* All done, return 0 for success. */
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xorl %eax, %eax
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ret
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PSEUDO_END(__getcontext)
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weak_alias (__getcontext, getcontext)
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