Mercurial > hg > CbC > CbC_gcc
comparison gcc/config/xtensa/linux-unwind.h @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
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1 /* DWARF2 EH unwinding support for Xtensa. | |
2 Copyright (C) 2008, 2009 Free Software Foundation, Inc. | |
3 | |
4 This file is part of GCC. | |
5 | |
6 GCC is free software; you can redistribute it and/or modify | |
7 it under the terms of the GNU General Public License as published by | |
8 the Free Software Foundation; either version 3, or (at your option) | |
9 any later version. | |
10 | |
11 GCC is distributed in the hope that it will be useful, | |
12 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 GNU General Public License for more details. | |
15 | |
16 Under Section 7 of GPL version 3, you are granted additional | |
17 permissions described in the GCC Runtime Library Exception, version | |
18 3.1, as published by the Free Software Foundation. | |
19 | |
20 You should have received a copy of the GNU General Public License and | |
21 a copy of the GCC Runtime Library Exception along with this program; | |
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 <http://www.gnu.org/licenses/>. */ | |
24 | |
25 /* Do code reading to identify a signal frame, and set the frame | |
26 state data appropriately. See unwind-dw2-xtensa.c for the structs. | |
27 Don't use this at all if inhibit_libc is used. */ | |
28 | |
29 #ifndef inhibit_libc | |
30 | |
31 #include <signal.h> | |
32 #include <sys/ucontext.h> | |
33 | |
34 /* Encoded bytes for Xtensa instructions: | |
35 movi a2, __NR_rt_sigreturn | |
36 syscall | |
37 entry (first byte only) | |
38 Some of the bytes are endian-dependent. */ | |
39 | |
40 #define MOVI_BYTE0 0x22 | |
41 #define MOVI_BYTE2 225 /* __NR_rt_sigreturn */ | |
42 #define SYSC_BYTE0 0 | |
43 #define SYSC_BYTE2 0 | |
44 | |
45 #ifdef __XTENSA_EB__ | |
46 #define MOVI_BYTE1 0x0a | |
47 #define SYSC_BYTE1 0x05 | |
48 #define ENTRY_BYTE 0x6c | |
49 #else | |
50 #define MOVI_BYTE1 0xa0 | |
51 #define SYSC_BYTE1 0x50 | |
52 #define ENTRY_BYTE 0x36 | |
53 #endif | |
54 | |
55 #define MD_FALLBACK_FRAME_STATE_FOR xtensa_fallback_frame_state | |
56 | |
57 static _Unwind_Reason_Code | |
58 xtensa_fallback_frame_state (struct _Unwind_Context *context, | |
59 _Unwind_FrameState *fs) | |
60 { | |
61 unsigned char *pc = context->ra; | |
62 struct sigcontext *sc; | |
63 | |
64 struct rt_sigframe { | |
65 struct siginfo info; | |
66 struct ucontext uc; | |
67 } *rt_; | |
68 | |
69 /* movi a2, __NR_rt_sigreturn; syscall */ | |
70 if (pc[0] != MOVI_BYTE0 | |
71 || pc[1] != MOVI_BYTE1 | |
72 || pc[2] != MOVI_BYTE2 | |
73 || pc[3] != SYSC_BYTE0 | |
74 || pc[4] != SYSC_BYTE1 | |
75 || pc[5] != SYSC_BYTE2) | |
76 return _URC_END_OF_STACK; | |
77 | |
78 rt_ = context->sp; | |
79 sc = &rt_->uc.uc_mcontext; | |
80 fs->signal_regs = (_Unwind_Word *) sc->sc_a; | |
81 | |
82 /* If the signal arrived just before an ENTRY instruction, find the return | |
83 address and pretend the signal arrived before executing the CALL. */ | |
84 if (*(unsigned char *) sc->sc_pc == ENTRY_BYTE) | |
85 { | |
86 unsigned callinc = (sc->sc_ps >> 16) & 3; | |
87 fs->signal_ra = ((sc->sc_a[callinc << 2] & XTENSA_RA_FIELD_MASK) | |
88 | context->ra_high_bits) - 3; | |
89 } | |
90 else | |
91 fs->signal_ra = sc->sc_pc; | |
92 | |
93 fs->signal_frame = 1; | |
94 return _URC_NO_REASON; | |
95 } | |
96 | |
97 #endif /* ifdef inhibit_libc */ |