1/* Install given context.
2 Copyright (C) 2002-2016 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Andreas Jaeger <aj@suse.de>, 2002.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#include <sysdep.h>
21
22#include "ucontext_i.h"
23
24
25/* int __setcontext (const ucontext_t *ucp)
26
27 Restores the machine context in UCP and thereby resumes execution
28 in that context.
29
30 This implementation is intended to be used for *synchronous* context
31 switches only. Therefore, it does not have to restore anything
32 other than the PRESERVED state. */
33
34ENTRY(__setcontext)
35 /* Save argument since syscall will destroy it. */
36 pushq %rdi
37 cfi_adjust_cfa_offset(8)
38
39 /* Set the signal mask with
40 rt_sigprocmask (SIG_SETMASK, mask, NULL, _NSIG/8). */
41 leaq oSIGMASK(%rdi), %rsi
42 xorl %edx, %edx
43 movl $SIG_SETMASK, %edi
44 movl $_NSIG8,%r10d
45 movl $__NR_rt_sigprocmask, %eax
46 syscall
47 popq %rdi /* Reload %rdi, adjust stack. */
48 cfi_adjust_cfa_offset(-8)
49 cmpq $-4095, %rax /* Check %rax for error. */
50 jae SYSCALL_ERROR_LABEL /* Jump to error handler if error. */
51
52 /* Restore the floating-point context. Not the registers, only the
53 rest. */
54 movq oFPREGS(%rdi), %rcx
55 fldenv (%rcx)
56 ldmxcsr oMXCSR(%rdi)
57
58
59 /* Load the new stack pointer, the preserved registers and
60 registers used for passing args. */
61 cfi_def_cfa(%rdi, 0)
62 cfi_offset(%rbx,oRBX)
63 cfi_offset(%rbp,oRBP)
64 cfi_offset(%r12,oR12)
65 cfi_offset(%r13,oR13)
66 cfi_offset(%r14,oR14)
67 cfi_offset(%r15,oR15)
68 cfi_offset(%rsp,oRSP)
69 cfi_offset(%rip,oRIP)
70
71 movq oRSP(%rdi), %rsp
72 movq oRBX(%rdi), %rbx
73 movq oRBP(%rdi), %rbp
74 movq oR12(%rdi), %r12
75 movq oR13(%rdi), %r13
76 movq oR14(%rdi), %r14
77 movq oR15(%rdi), %r15
78
79 /* The following ret should return to the address set with
80 getcontext. Therefore push the address on the stack. */
81 movq oRIP(%rdi), %rcx
82 pushq %rcx
83
84 movq oRSI(%rdi), %rsi
85 movq oRDX(%rdi), %rdx
86 movq oRCX(%rdi), %rcx
87 movq oR8(%rdi), %r8
88 movq oR9(%rdi), %r9
89
90 /* Setup finally %rdi. */
91 movq oRDI(%rdi), %rdi
92
93 /* End FDE here, we fall into another context. */
94 cfi_endproc
95 cfi_startproc
96
97 /* Clear rax to indicate success. */
98 xorl %eax, %eax
99 ret
100PSEUDO_END(__setcontext)
101
102weak_alias (__setcontext, setcontext)
103