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 | |
34 | ENTRY(__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 |
100 | PSEUDO_END(__setcontext) |
101 | |
102 | weak_alias (__setcontext, setcontext) |
103 | |