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author | Thomas Schwinge <thomas@codesourcery.com> | 2019-12-29 16:04:51 +0100 |
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committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2019-12-29 16:54:08 +0100 |
commit | a678c13b8f9fa67c6cffe6ecf4ba1d5e53479e1b (patch) | |
tree | cb62c6fb5a84d4cdcb6d46f78318fb1818481af3 /sysdeps/mach/hurd/i386/swapcontext.S | |
parent | 344e755248ce02c0f8d095d11cc49e340703d926 (diff) | |
download | glibc-a678c13b8f9fa67c6cffe6ecf4ba1d5e53479e1b.tar.gz glibc-a678c13b8f9fa67c6cffe6ecf4ba1d5e53479e1b.tar.xz glibc-a678c13b8f9fa67c6cffe6ecf4ba1d5e53479e1b.zip |
hurd: Add getcontext, makecontext, setcontext, swapcontext
Adapted from the Linux x86 functions. Not thoroughly tested, but manual testing as well as glibc tests look fine, and manual -lpthread testing also looks fine (within the given bounds for a new stack to be used with makecontext). This has also been in use in Debian since 2013.
Diffstat (limited to 'sysdeps/mach/hurd/i386/swapcontext.S')
-rw-r--r-- | sysdeps/mach/hurd/i386/swapcontext.S | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/i386/swapcontext.S b/sysdeps/mach/hurd/i386/swapcontext.S new file mode 100644 index 0000000000..45d1e2cb2b --- /dev/null +++ b/sysdeps/mach/hurd/i386/swapcontext.S @@ -0,0 +1,110 @@ +/* Save current context and install the given one. + Copyright (C) 2001-2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2001. + + 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 "ucontext_i.h" + + +ENTRY(__swapcontext) + /* Load address of the context data structure we save in. */ + movl 4(%esp), %eax + + /* Return value of swapcontext. EAX is the only register whose + value is not preserved. */ + movl $0, oEAX(%eax) + + /* Save the 32-bit register values and the return address. */ + movl %ecx, oECX(%eax) + movl %edx, oEDX(%eax) + movl %edi, oEDI(%eax) + movl %esi, oESI(%eax) + movl %ebp, oEBP(%eax) + movl (%esp), %ecx + movl %ecx, oEIP(%eax) + leal 4(%esp), %ecx + movl %ecx, oESP(%eax) + movl %ebx, oEBX(%eax) + + /* Save the FS segment register. */ + xorl %edx, %edx + movw %fs, %dx + movl %edx, oFS(%eax) + + leal oFPREGS(%eax), %ecx + /* Save the floating-point context. */ + fnstenv (%ecx) + + /* Load address of the context data structure we have to load. */ + movl 8(%esp), %ecx + + /* Save the current signal mask and install the new one. */ + subl $12, %esp + cfi_adjust_cfa_offset (12) + leal oSIGMASK(%eax), %eax + movl %eax, 8(%esp) + leal oSIGMASK(%ecx), %eax + movl %eax, 4(%esp) + movl $SIG_SETMASK, (%esp) + call HIDDEN_JUMPTARGET (__sigprocmask) + addl $12, %esp + cfi_adjust_cfa_offset (-12) + testl %eax, %eax + jne L(pseudo_end) + + /* EAX was modified, reload it. */ + movl 8(%esp), %eax + + /* Restore the floating-point context. Not the registers, only the + rest. */ + leal oFPREGS(%eax), %ecx + fldenv (%ecx) + + /* Restore the FS segment register. We don't touch the GS register + since it is used for threads. */ + movl oFS(%eax), %edx + movw %dx, %fs + + /* Fetch the address to return to. */ + movl oEIP(%eax), %ecx + + /* Load the new stack pointer. */ + movl oESP(%eax), %esp + + /* Push the return address on the new stack so we can return there. */ + pushl %ecx + + /* Load the values of all the 32-bit registers (except ESP). + Since we are loading from EAX, it must be last. */ + movl oEDI(%eax), %edi + movl oESI(%eax), %esi + movl oEBP(%eax), %ebp + movl oEBX(%eax), %ebx + movl oEDX(%eax), %edx + movl oECX(%eax), %ecx + movl oEAX(%eax), %eax + + /* The following 'ret' will pop the address of the code and jump + to it. */ + +L(pseudo_end): + ret +PSEUDO_END(__swapcontext) + +weak_alias (__swapcontext, swapcontext) |