2019-12-29 15:04:51 +00:00
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/* Save current context and install the given one.
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2021-01-02 19:32:25 +00:00
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Copyright (C) 2001-2021 Free Software Foundation, Inc.
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2019-12-29 15:04:51 +00:00
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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 "ucontext_i.h"
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ENTRY(__swapcontext)
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/* Load address of the context data structure we save in. */
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movl 4(%esp), %eax
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/* Return value of swapcontext. EAX is the only register whose
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value is not preserved. */
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movl $0, oEAX(%eax)
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/* Save the 32-bit register values and the return address. */
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movl %ecx, oECX(%eax)
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movl %edx, oEDX(%eax)
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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
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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. */
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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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leal oFPREGS(%eax), %ecx
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/* Save the floating-point context. */
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fnstenv (%ecx)
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/* Load address of the context data structure we have to load. */
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movl 8(%esp), %ecx
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/* Save the current signal mask and install the new one. */
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subl $12, %esp
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cfi_adjust_cfa_offset (12)
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leal oSIGMASK(%eax), %eax
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movl %eax, 8(%esp)
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leal oSIGMASK(%ecx), %eax
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movl %eax, 4(%esp)
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movl $SIG_SETMASK, (%esp)
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call HIDDEN_JUMPTARGET (__sigprocmask)
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addl $12, %esp
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cfi_adjust_cfa_offset (-12)
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testl %eax, %eax
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jne L(pseudo_end)
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/* EAX was modified, reload it. */
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movl 8(%esp), %eax
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/* Restore the floating-point context. Not the registers, only the
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rest. */
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leal oFPREGS(%eax), %ecx
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fldenv (%ecx)
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/* Restore 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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movl oFS(%eax), %edx
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movw %dx, %fs
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/* Fetch the address to return to. */
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movl oEIP(%eax), %ecx
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/* Load the new stack pointer. */
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movl oESP(%eax), %esp
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/* Push the return address on the new stack so we can return there. */
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pushl %ecx
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/* Load the values of all the 32-bit registers (except ESP).
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Since we are loading from EAX, it must be last. */
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movl oEDI(%eax), %edi
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movl oESI(%eax), %esi
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movl oEBP(%eax), %ebp
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movl oEBX(%eax), %ebx
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movl oEDX(%eax), %edx
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movl oECX(%eax), %ecx
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movl oEAX(%eax), %eax
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/* The following 'ret' will pop the address of the code and jump
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to it. */
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L(pseudo_end):
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ret
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PSEUDO_END(__swapcontext)
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weak_alias (__swapcontext, swapcontext)
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