| 1 | /* Copyright (C) 1999-2024 Free Software Foundation, Inc. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | |
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| 4 | The GNU C Library is free software; you can redistribute it and/or |
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| 5 | modify it under the terms of the GNU Lesser General Public |
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| 6 | License as published by the Free Software Foundation; either |
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| 7 | version 2.1 of the License, or (at your option) any later version. |
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| 8 | |
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| 9 | The GNU C Library is distributed in the hope that it will be useful, |
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| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | Lesser General Public License for more details. |
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| 13 | |
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| 14 | You should have received a copy of the GNU Lesser General Public |
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| 15 | License along with the GNU C Library. If not, see |
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| 16 | <https://www.gnu.org/licenses/>. */ |
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| 17 | |
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| 18 | #include <sysdep.h> |
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| 19 | |
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| 20 | /* If no SA_RESTORER function was specified by the application we use |
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| 21 | one of these. This avoids the need for the kernel to synthesise a return |
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| 22 | instruction on the stack, which would involve expensive cache flushes. |
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| 23 | |
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| 24 | Nowadays (2.6 series, and somewhat earlier) the kernel uses a high page |
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| 25 | for signal trampolines, so the cache flushes are not an issue. But since |
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| 26 | we do not have a vDSO, continue to use these so that we can provide |
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| 27 | unwind information. |
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| 28 | |
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| 29 | Start the unwind tables at least one instruction before the signal |
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| 30 | trampoline, because the unwinder will assume we are returning after |
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| 31 | a call site. */ |
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| 32 | |
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| 33 | /* Used in ENTRY. */ |
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| 34 | #undef cfi_startproc |
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| 35 | #define cfi_startproc \ |
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| 36 | .cfi_startproc simple; \ |
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| 37 | .cfi_signal_frame |
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| 38 | |
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| 39 | /* The CFA is not computed / used correctly here; this is neither trivial to |
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| 40 | do, nor is it needed. */ |
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| 41 | #define CFI \ |
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| 42 | cfi_def_cfa (sp, 0); \ |
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| 43 | cfi_offset (r0, OFFSET + 0 * 4); \ |
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| 44 | cfi_offset (r1, OFFSET + 1 * 4); \ |
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| 45 | cfi_offset (r2, OFFSET + 2 * 4); \ |
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| 46 | cfi_offset (r3, OFFSET + 3 * 4); \ |
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| 47 | cfi_offset (r4, OFFSET + 4 * 4); \ |
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| 48 | cfi_offset (r5, OFFSET + 5 * 4); \ |
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| 49 | cfi_offset (r6, OFFSET + 6 * 4); \ |
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| 50 | cfi_offset (r7, OFFSET + 7 * 4); \ |
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| 51 | cfi_offset (r8, OFFSET + 8 * 4); \ |
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| 52 | cfi_offset (r9, OFFSET + 9 * 4); \ |
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| 53 | cfi_offset (r10, OFFSET + 10 * 4); \ |
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| 54 | cfi_offset (r11, OFFSET + 11 * 4); \ |
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| 55 | cfi_offset (r12, OFFSET + 12 * 4); \ |
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| 56 | cfi_offset (r13, OFFSET + 13 * 4); \ |
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| 57 | cfi_offset (r14, OFFSET + 14 * 4); \ |
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| 58 | cfi_offset (r15, OFFSET + 15 * 4) |
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| 59 | |
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| 60 | #define OFFSET 32 |
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| 61 | .fnstart |
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| 62 | .save {r0-r15} |
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| 63 | .pad #OFFSET |
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| 64 | nop |
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| 65 | ENTRY(__default_sa_restorer) |
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| 66 | CFI |
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| 67 | mov r7, $SYS_ify(sigreturn) |
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| 68 | swi 0x0 |
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| 69 | .fnend |
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| 70 | END(__default_sa_restorer) |
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| 71 | #undef OFFSET |
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| 72 | |
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| 73 | #define OFFSET 160 |
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| 74 | .fnstart |
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| 75 | .save {r0-r15} |
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| 76 | .pad #OFFSET |
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| 77 | nop |
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| 78 | ENTRY(__default_rt_sa_restorer) |
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| 79 | CFI |
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| 80 | mov r7, $SYS_ify(rt_sigreturn) |
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| 81 | swi 0x0 |
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| 82 | .fnend |
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| 83 | END(__default_rt_sa_restorer) |
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| 84 | #undef OFFSET |
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| 85 | |
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