1/* Copyright (C) 2001-2024 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <sysdep.h>
19#include <features.h>
20
21#include "ucontext_i.h"
22
23#include <shlib-compat.h>
24
25/* __getcontext (const ucontext_t *ucp)
26
27 Saves the machine context in UCP such that when it is activated,
28 it appears as if __getcontext() returned again.
29
30 This implementation is intended to be used for *synchronous* context
31 switches only. Therefore, it does not have to save anything
32 other than the PRESERVED state. */
33
34ENTRY(__getcontext)
35 lgr %r0,%r2
36
37 /* rt_sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask, sigsetsize). */
38 la %r4,SC_MASK(%r2)
39 la %r2,SIG_BLOCK
40 slgr %r3,%r3
41 lghi %r5,_NSIG8
42 lghi %r1,SYS_ify(rt_sigprocmask)
43 svc 0
44
45 /* Store fpu context. */
46 lgr %r1,%r0
47 stfpc SC_FPC(%r1)
48 std %f0,SC_FPRS(%r1)
49 std %f1,SC_FPRS+8(%r1)
50 std %f2,SC_FPRS+16(%r1)
51 std %f3,SC_FPRS+24(%r1)
52 std %f4,SC_FPRS+32(%r1)
53 std %f5,SC_FPRS+40(%r1)
54 std %f6,SC_FPRS+48(%r1)
55 std %f7,SC_FPRS+56(%r1)
56 std %f8,SC_FPRS+64(%r1)
57 std %f9,SC_FPRS+72(%r1)
58 std %f10,SC_FPRS+80(%r1)
59 std %f11,SC_FPRS+88(%r1)
60 std %f12,SC_FPRS+96(%r1)
61 std %f13,SC_FPRS+104(%r1)
62 std %f14,SC_FPRS+112(%r1)
63 std %f15,SC_FPRS+120(%r1)
64
65 /* Set __getcontext return value to 0. */
66 slgr %r2,%r2
67
68 /* Store access registers. */
69 stam %a0,%a15,SC_ACRS(%r1)
70
71 /* Store general purpose registers. */
72 stmg %r0,%r15,SC_GPRS(%r1)
73
74 /* Store psw mask to 0x0 and addr to return address. Then the address
75 can be retrieved from the ucontext structure in the same way as if it
76 is created by kernel and passed to a signal-handler. */
77 stg %r2,SC_PSW+0(%r1)
78 stg %r14,SC_PSW+8(%r1)
79
80 /* Return. */
81 br %r14
82END(__getcontext)
83
84#if defined SHARED && SHLIB_COMPAT (libc, GLIBC_2_19, GLIBC_2_20)
85/* In glibc release 2.19 a new version of getcontext was introduced,
86 but was reverted before 2.20. Thus both versions are the same function. */
87weak_alias (__getcontext, __v1__getcontext)
88weak_alias (__getcontext, __v2__getcontext)
89versioned_symbol (libc, __v1__getcontext, getcontext, GLIBC_2_1)
90compat_symbol (libc, __v2__getcontext, getcontext, GLIBC_2_19)
91
92#else
93
94weak_alias (__getcontext, getcontext)
95
96#endif /* !(defined SHARED && SHLIB_COMPAT (libc, GLIBC_2_19, GLIBC_2_20)) */
97

source code of glibc/sysdeps/unix/sysv/linux/s390/s390-64/getcontext.S