1 /* libunwind - a platform-independent unwind library 2 Copyright (C) 2012 Tommi Rantala <tt.rantala (at) gmail.com> 3 4 This file is part of libunwind. 5 6 Permission is hereby granted, free of charge, to any person obtaining 7 a copy of this software and associated documentation files (the 8 "Software"), to deal in the Software without restriction, including 9 without limitation the rights to use, copy, modify, merge, publish, 10 distribute, sublicense, and/or sell copies of the Software, and to 11 permit persons to whom the Software is furnished to do so, subject to 12 the following conditions: 13 14 The above copyright notice and this permission notice shall be 15 included in all copies or substantial portions of the Software. 16 17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 18 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 20 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 21 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 22 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 23 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ 24 25 #include "unwind_i.h" 26 27 /* Disassembly of the Linux VDSO sigreturn functions: 28 29 00000000 <__kernel_sigreturn>: 30 0: 05 93 mov.w e <__kernel_sigreturn+0xe>,r3 ! 77 31 2: 10 c3 trapa #16 32 4: 0b 20 or r0,r0 33 6: 0b 20 or r0,r0 34 8: 0b 20 or r0,r0 35 a: 0b 20 or r0,r0 36 c: 0b 20 or r0,r0 37 e: 77 00 .word 0x0077 38 10: 09 00 nop 39 12: 09 00 nop 40 14: 09 00 nop 41 16: 09 00 nop 42 18: 09 00 nop 43 1a: 09 00 nop 44 1c: 09 00 nop 45 1e: 09 00 nop 46 47 00000020 <__kernel_rt_sigreturn>: 48 20: 05 93 mov.w 2e <__kernel_rt_sigreturn+0xe>,r3 ! ad 49 22: 10 c3 trapa #16 50 24: 0b 20 or r0,r0 51 26: 0b 20 or r0,r0 52 28: 0b 20 or r0,r0 53 2a: 0b 20 or r0,r0 54 2c: 0b 20 or r0,r0 55 2e: ad 00 mov.w @(r0,r10),r0 56 30: 09 00 nop 57 32: 09 00 nop 58 34: 09 00 nop 59 36: 09 00 nop 60 38: 09 00 nop 61 3a: 09 00 nop 62 3c: 09 00 nop 63 3e: 09 00 nop 64 */ 65 66 PROTECTED int 67 unw_is_signal_frame (unw_cursor_t *cursor) 68 { 69 #ifdef __linux__ 70 struct cursor *c = (struct cursor *) cursor; 71 unw_word_t w0, ip; 72 unw_addr_space_t as; 73 unw_accessors_t *a; 74 void *arg; 75 int ret; 76 77 as = c->dwarf.as; 78 a = unw_get_accessors (as); 79 arg = c->dwarf.as_arg; 80 81 ip = c->dwarf.ip; 82 83 ret = (*a->access_mem) (as, ip, &w0, 0, arg); 84 if (ret < 0) 85 return ret; 86 87 if (w0 != 0xc3109305) 88 return 0; 89 90 ret = (*a->access_mem) (as, ip+4, &w0, 0, arg); 91 if (ret < 0) 92 return ret; 93 94 if (w0 != 0x200b200b) 95 return 0; 96 97 ret = (*a->access_mem) (as, ip+8, &w0, 0, arg); 98 if (ret < 0) 99 return ret; 100 101 if (w0 != 0x200b200b) 102 return 0; 103 104 ret = (*a->access_mem) (as, ip+12, &w0, 0, arg); 105 if (ret < 0) 106 return ret; 107 108 if (w0 == 0x0077200b) 109 return 1; /* non-RT */ 110 else if (w0 == 0x00ad200b) 111 return 2; /* RT */ 112 113 /* does not look like a signal frame */ 114 return 0; 115 116 #else 117 return -UNW_ENOINFO; 118 #endif 119 } 120
