1/* Install given context.
2 Copyright (C) 2001-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sysdep.h>
20
21#include "ucontext_i.h"
22
23
24ENTRY(__setcontext)
25 /* Load address of the context data structure. */
26 movl 4(%esp), %eax
27
28 /* Get the current signal mask. */
29 subl $12, %esp
30 cfi_adjust_cfa_offset (12)
31 movl $0, 8(%esp)
32 leal oSIGMASK(%eax), %eax
33 movl %eax, 4(%esp)
34 movl $SIG_SETMASK, (%esp)
35 call HIDDEN_JUMPTARGET (__sigprocmask)
36 addl $12, %esp
37 cfi_adjust_cfa_offset (-12)
38 testl %eax, %eax
39 jne L(pseudo_end)
40
41 /* EAX was modified, reload it. */
42 movl 4(%esp), %eax
43
44 /* Restore the floating-point context. Not the registers, only the
45 rest. */
46 leal oFPREGS(%eax), %ecx
47 fldenv (%ecx)
48
49 /* Restore the FS segment register. We don't touch the GS register
50 since it is used for threads. */
51 movl oFS(%eax), %ecx
52 movw %cx, %fs
53
54 /* Fetch the address to return to. */
55 movl oEIP(%eax), %ecx
56
57 /* Load the new stack pointer. */
58 cfi_def_cfa (eax, 0)
59 cfi_offset (edi, oEDI)
60 cfi_offset (esi, oESI)
61 cfi_offset (ebp, oEBP)
62 cfi_offset (ebx, oEBX)
63 cfi_offset (edx, oEDX)
64 cfi_offset (ecx, oECX)
65 movl oESP(%eax), %esp
66
67 /* Push the return address on the new stack so we can return there. */
68 pushl %ecx
69
70 /* Load the values of all the 32-bit registers (except ESP).
71 Since we are loading from EAX, it must be last. */
72 movl oEDI(%eax), %edi
73 movl oESI(%eax), %esi
74 movl oEBP(%eax), %ebp
75 movl oEBX(%eax), %ebx
76 movl oEDX(%eax), %edx
77 movl oECX(%eax), %ecx
78 movl oEAX(%eax), %eax
79
80 /* End FDE here, we fall into another context. */
81 cfi_endproc
82 cfi_startproc
83
84 /* The following 'ret' will pop the address of the code and jump
85 to it. */
86
87L(pseudo_end):
88 ret
89PSEUDO_END(__setcontext)
90libc_hidden_def (__setcontext)
91
92weak_alias (__setcontext, setcontext)
93

source code of glibc/sysdeps/mach/hurd/i386/setcontext.S