1 | /* Copyright (C) 1999-2022 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 | |
20 | /* If no SA_RESTORER function was specified by the application we use |
21 | one of these. This avoids the need for the kernel to synthesise a return |
22 | instruction on the stack, which would involve expensive cache flushes. |
23 | |
24 | Nowadays (2.6 series, and somewhat earlier) the kernel uses a high page |
25 | for signal trampolines, so the cache flushes are not an issue. But since |
26 | we do not have a vDSO, continue to use these so that we can provide |
27 | unwind information. |
28 | |
29 | Start the unwind tables at least one instruction before the signal |
30 | trampoline, because the unwinder will assume we are returning after |
31 | a call site. */ |
32 | |
33 | /* Used in ENTRY. */ |
34 | #undef cfi_startproc |
35 | #define cfi_startproc \ |
36 | .cfi_startproc simple; \ |
37 | .cfi_signal_frame |
38 | |
39 | /* The CFA is not computed / used correctly here; this is neither trivial to |
40 | do, nor is it needed. */ |
41 | #define CFI \ |
42 | cfi_def_cfa (sp, 0); \ |
43 | cfi_offset (r0, OFFSET + 0 * 4); \ |
44 | cfi_offset (r1, OFFSET + 1 * 4); \ |
45 | cfi_offset (r2, OFFSET + 2 * 4); \ |
46 | cfi_offset (r3, OFFSET + 3 * 4); \ |
47 | cfi_offset (r4, OFFSET + 4 * 4); \ |
48 | cfi_offset (r5, OFFSET + 5 * 4); \ |
49 | cfi_offset (r6, OFFSET + 6 * 4); \ |
50 | cfi_offset (r7, OFFSET + 7 * 4); \ |
51 | cfi_offset (r8, OFFSET + 8 * 4); \ |
52 | cfi_offset (r9, OFFSET + 9 * 4); \ |
53 | cfi_offset (r10, OFFSET + 10 * 4); \ |
54 | cfi_offset (r11, OFFSET + 11 * 4); \ |
55 | cfi_offset (r12, OFFSET + 12 * 4); \ |
56 | cfi_offset (r13, OFFSET + 13 * 4); \ |
57 | cfi_offset (r14, OFFSET + 14 * 4); \ |
58 | cfi_offset (r15, OFFSET + 15 * 4) |
59 | |
60 | #define OFFSET 32 |
61 | .fnstart |
62 | .save {r0-r15} |
63 | .pad #OFFSET |
64 | nop |
65 | ENTRY(__default_sa_restorer) |
66 | CFI |
67 | mov r7, $SYS_ify(sigreturn) |
68 | swi 0x0 |
69 | .fnend |
70 | END(__default_sa_restorer) |
71 | #undef OFFSET |
72 | |
73 | #define OFFSET 160 |
74 | .fnstart |
75 | .save {r0-r15} |
76 | .pad #OFFSET |
77 | nop |
78 | ENTRY(__default_rt_sa_restorer) |
79 | CFI |
80 | mov r7, $SYS_ify(rt_sigreturn) |
81 | swi 0x0 |
82 | .fnend |
83 | END(__default_rt_sa_restorer) |
84 | #undef OFFSET |
85 | |