1/* Copyright (C) 2012-2022 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 <rtld-global-offsets.h>
20
21#include "ucontext_i.h"
22
23 .syntax unified
24 .text
25
26/* int getcontext (ucontext_t *ucp) */
27
28ENTRY(__getcontext)
29 /* No need to save r0-r3, d0-d7, or d16-d31. */
30 add r1, r0, #MCONTEXT_ARM_R4
31 stmia r1, {r4-r11}
32
33 /* Save R13 separately as Thumb can't STM it. */
34 str r13, [r0, #MCONTEXT_ARM_SP]
35 str r14, [r0, #MCONTEXT_ARM_LR]
36 /* Return to LR */
37 str r14, [r0, #MCONTEXT_ARM_PC]
38 /* Return zero */
39 mov r2, #0
40 str r2, [r0, #MCONTEXT_ARM_R0]
41
42 /* Save ucontext_t * across the next call. */
43 mov r4, r0
44
45 /* __sigprocmask(SIG_BLOCK, NULL, &(ucontext->uc_sigmask)) */
46 mov r0, #SIG_BLOCK
47 mov r1, #0
48 add r2, r4, #UCONTEXT_SIGMASK
49 bl PLTJMP(__sigprocmask)
50
51 /* Store FP regs. Much of the FP code is copied from arm/setjmp.S. */
52
53#ifdef SHARED
54 ldr r2, 1f
55 ldr r1, .Lrtld_global_ro
560: add r2, pc, r2
57 ldr r2, [r2, r1]
58 ldr r2, [r2, #RTLD_GLOBAL_RO_DL_HWCAP_OFFSET]
59#else
60 ldr r2, .Lhwcap
61 ldr r2, [r2, #0]
62#endif
63
64 add r0, r4, #UCONTEXT_REGSPACE
65
66#ifdef __SOFTFP__
67 tst r2, #HWCAP_ARM_VFP
68 beq .Lno_vfp
69#endif
70
71 /* Store the VFP registers.
72 Don't use VFP instructions directly because this code
73 is used in non-VFP multilibs. */
74 /* Following instruction is vstmia r0!, {d8-d15}. */
75 stc p11, cr8, [r0], #64
76 /* Store the floating-point status register. */
77 /* Following instruction is vmrs r1, fpscr. */
78 mrc p10, 7, r1, cr1, cr0, 0
79 str r1, [r0], #4
80.Lno_vfp:
81
82 tst r2, #HWCAP_ARM_IWMMXT
83 beq .Lno_iwmmxt
84
85 /* Save the call-preserved iWMMXt registers. */
86 /* Following instructions are wstrd wr10, [r0], #8 (etc.) */
87 stcl p1, cr10, [r0], #8
88 stcl p1, cr11, [r0], #8
89 stcl p1, cr12, [r0], #8
90 stcl p1, cr13, [r0], #8
91 stcl p1, cr14, [r0], #8
92 stcl p1, cr15, [r0], #8
93.Lno_iwmmxt:
94
95 /* Restore the clobbered R4 and LR. */
96 ldr r14, [r4, #MCONTEXT_ARM_LR]
97 ldr r4, [r4, #MCONTEXT_ARM_R4]
98
99 mov r0, #0
100
101 DO_RET(r14)
102
103END(__getcontext)
104
105#ifdef SHARED
1061: .long _GLOBAL_OFFSET_TABLE_ - 0b - PC_OFS
107.Lrtld_global_ro:
108 .long C_SYMBOL_NAME(_rtld_global_ro)(GOT)
109#else
110.Lhwcap:
111 .long C_SYMBOL_NAME(_dl_hwcap)
112#endif
113
114
115weak_alias(__getcontext, getcontext)
116

source code of glibc/sysdeps/unix/sysv/linux/arm/getcontext.S