| /* libunwind - a platform-independent unwind library |
| Copyright (C) 2006-2007 IBM |
| Contributed by |
| Corey Ashford <cjashfor@us.ibm.com> |
| Jose Flavio Aguilar Paulino <jflavio@br.ibm.com> <joseflavio@gmail.com> |
| |
| This file is part of libunwind. |
| |
| Permission is hereby granted, free of charge, to any person obtaining |
| a copy of this software and associated documentation files (the |
| "Software"), to deal in the Software without restriction, including |
| without limitation the rights to use, copy, modify, merge, publish, |
| distribute, sublicense, and/or sell copies of the Software, and to |
| permit persons to whom the Software is furnished to do so, subject to |
| the following conditions: |
| |
| The above copyright notice and this permission notice shall be |
| included in all copies or substantial portions of the Software. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
| LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
| OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
| WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ |
| |
| #include <libunwind_i.h> |
| |
| PROTECTED int |
| unw_is_signal_frame (unw_cursor_t * cursor) |
| { |
| struct cursor *c = (struct cursor *) cursor; |
| unw_word_t w0, w1, ip; |
| unw_addr_space_t as; |
| unw_accessors_t *a; |
| void *arg; |
| int ret; |
| |
| as = c->dwarf.as; |
| as->validate = 1; /* Don't trust the ip */ |
| arg = c->dwarf.as_arg; |
| |
| /* Check if return address points at sigreturn sequence. |
| on ppc64 Linux that is (see libc.so): |
| 0x38210080 addi r1, r1, 128 // pop the stack |
| 0x380000ac li r0, 172 // invoke system service 172 |
| 0x44000002 sc |
| */ |
| |
| ip = c->dwarf.ip; |
| if (ip == 0) |
| return 0; |
| |
| /* Read up two 8-byte words at the IP. We are only looking at 3 |
| consecutive 32-bit words, so the second 8-byte word needs to be |
| shifted right by 32 bits (think big-endian) */ |
| |
| a = unw_get_accessors (as); |
| if ((ret = (*a->access_mem) (as, ip, &w0, 0, arg)) < 0 |
| || (ret = (*a->access_mem) (as, ip + 8, &w1, 0, arg)) < 0) |
| return 0; |
| w1 >>= 32; |
| return (w0 == 0x38210080380000ac && w1 == 0x44000002); |
| |
| } |