/* Install given context. Copyright (C) 2001-2012 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 <http://www.gnu.org/licenses/>. */ #include <sysdep.h> #include "ucontext_i.h" ENTRY(__setcontext) /* Load address of the context data structure. */ movl 4(%esp), %eax /* Get the current signal mask. Note that we preserve EBX in case the system call fails and we return from the function with an error. */ pushl %ebx cfi_adjust_cfa_offset (4) xorl %edx, %edx leal oSIGMASK(%eax), %ecx movl $SIG_SETMASK, %ebx cfi_rel_offset (ebx, 0) movl $__NR_sigprocmask, %eax ENTER_KERNEL popl %ebx cfi_adjust_cfa_offset (-4) cfi_restore (ebx) cmpl $-4095, %eax /* Check %eax for error. */ jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */ /* EAX was modified, reload it. */ movl 4(%esp), %eax /* Restore the floating-point context. Not the registers, only the rest. */ movl 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), %ecx movw %cx, %fs /* Fetch the address to return to. */ movl oEIP(%eax), %ecx /* Load the new stack pointer. */ cfi_def_cfa (eax, 0) cfi_offset (edi, oEDI) cfi_offset (esi, oESI) cfi_offset (ebp, oEBP) cfi_offset (ebx, oEBX) cfi_offset (edx, oEDX) cfi_offset (ecx, oECX) 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 /* End FDE here, we fall into another context. */ cfi_endproc cfi_startproc /* The following 'ret' will pop the address of the code and jump to it. */ L(pseudo_end): ret PSEUDO_END(__setcontext) weak_alias (__setcontext, setcontext)