| 1 | /* Common target dependent code for GNU/Linux on ARM systems. |
| 2 | |
| 3 | Copyright (C) 1999-2015 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #ifndef ARM_LINUX_H |
| 21 | #define ARM_LINUX_H |
| 22 | |
| 23 | /* There are a couple of different possible stack layouts that |
| 24 | we need to support. |
| 25 | |
| 26 | Before version 2.6.18, the kernel used completely independent |
| 27 | layouts for non-RT and RT signals. For non-RT signals the stack |
| 28 | began directly with a struct sigcontext. For RT signals the stack |
| 29 | began with two redundant pointers (to the siginfo and ucontext), |
| 30 | and then the siginfo and ucontext. |
| 31 | |
| 32 | As of version 2.6.18, the non-RT signal frame layout starts with |
| 33 | a ucontext and the RT signal frame starts with a siginfo and then |
| 34 | a ucontext. Also, the ucontext now has a designated save area |
| 35 | for coprocessor registers. |
| 36 | |
| 37 | For RT signals, it's easy to tell the difference: we look for |
| 38 | pinfo, the pointer to the siginfo. If it has the expected |
| 39 | value, we have an old layout. If it doesn't, we have the new |
| 40 | layout. |
| 41 | |
| 42 | For non-RT signals, it's a bit harder. We need something in one |
| 43 | layout or the other with a recognizable offset and value. We can't |
| 44 | use the return trampoline, because ARM usually uses SA_RESTORER, |
| 45 | in which case the stack return trampoline is not filled in. |
| 46 | We can't use the saved stack pointer, because sigaltstack might |
| 47 | be in use. So for now we guess the new layout... */ |
| 48 | |
| 49 | /* There are three words (trap_no, error_code, oldmask) in |
| 50 | struct sigcontext before r0. */ |
| 51 | #define ARM_SIGCONTEXT_R0 0xc |
| 52 | |
| 53 | /* There are five words (uc_flags, uc_link, and three for uc_stack) |
| 54 | in the ucontext_t before the sigcontext. */ |
| 55 | #define ARM_UCONTEXT_SIGCONTEXT 0x14 |
| 56 | |
| 57 | /* There are three elements in an rt_sigframe before the ucontext: |
| 58 | pinfo, puc, and info. The first two are pointers and the third |
| 59 | is a struct siginfo, with size 128 bytes. We could follow puc |
| 60 | to the ucontext, but it's simpler to skip the whole thing. */ |
| 61 | #define ARM_OLD_RT_SIGFRAME_SIGINFO 0x8 |
| 62 | #define ARM_OLD_RT_SIGFRAME_UCONTEXT 0x88 |
| 63 | |
| 64 | #define ARM_NEW_RT_SIGFRAME_UCONTEXT 0x80 |
| 65 | |
| 66 | #define ARM_NEW_SIGFRAME_MAGIC 0x5ac3c35a |
| 67 | |
| 68 | int |
| 69 | arm_linux_sigreturn_next_pc_offset (unsigned long sp, |
| 70 | unsigned long sp_data, |
| 71 | unsigned long svc_number, |
| 72 | int is_sigreturn); |
| 73 | |
| 74 | #endif /* ARM_LINUX_H */ |