1 /* DWARF2 EH unwinding support for SH Linux.
2 Copyright (C) 2004-2023 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
26 /* Do code reading to identify a signal frame, and set the frame
27 state data appropriately. See unwind-dw2.c for the structs.
28 Don't use this at all if inhibit_libc is used. */
29
30 #ifndef inhibit_libc
31
32 #include <signal.h>
33 #include <sys/ucontext.h>
34 #include "insn-constants.h"
35
36 #define SH_DWARF_FRAME_GP0 0
37 #define SH_DWARF_FRAME_FP0 25
38 #define SH_DWARF_FRAME_XD0 87
39 #define SH_DWARF_FRAME_PR 17
40 #define SH_DWARF_FRAME_GBR 18
41 #define SH_DWARF_FRAME_MACH 20
42 #define SH_DWARF_FRAME_MACL 21
43 #define SH_DWARF_FRAME_PC 16
44 #define SH_DWARF_FRAME_SR 22
45 #define SH_DWARF_FRAME_FPUL 23
46 #define SH_DWARF_FRAME_FPSCR 24
47
48 #define MD_FALLBACK_FRAME_STATE_FOR sh_fallback_frame_state
49
50 static _Unwind_Reason_Code
51 sh_fallback_frame_state (struct _Unwind_Context *context,
52 _Unwind_FrameState *fs)
53 {
54 unsigned char *pc = context->ra;
55 struct sigcontext *sc;
56 long new_cfa;
57 int i;
58 #if defined (__SH3E__) || defined (__SH4__)
59 int r;
60 #endif
61
62 /* mov.w 1f,r3; trapa #0x10; 1: .short 0x77 (sigreturn) */
63 /* mov.w 1f,r3; trapa #0x10; 1: .short 0xad (rt_sigreturn) */
64 /* Newer kernel uses pad instructions to avoid an SH-4 core bug. */
65 /* mov.w 1f,r3; trapa #0x10; or r0,r0; or r0,r0; or r0,r0; or r0,r0;
66 or r0,r0; 1: .short 0x77 (sigreturn) */
67 /* mov.w 1f,r3; trapa #0x10; or r0,r0; or r0,r0; or r0,r0; or r0,r0;
68 or r0,r0; 1: .short 0xad (rt_sigreturn) */
69 if (((*(unsigned short *) (pc+0) == 0x9300)
70 && (*(unsigned short *) (pc+2) == 0xc310)
71 && (*(unsigned short *) (pc+4) == 0x0077))
72 || (((*(unsigned short *) (pc+0) == 0x9305)
73 && (*(unsigned short *) (pc+2) == 0xc310)
74 && (*(unsigned short *) (pc+14) == 0x0077))))
75 sc = context->cfa;
76 else if (((*(unsigned short *) (pc+0) == 0x9300)
77 && (*(unsigned short *) (pc+2) == 0xc310)
78 && (*(unsigned short *) (pc+4) == 0x00ad))
79 || (((*(unsigned short *) (pc+0) == 0x9305)
80 && (*(unsigned short *) (pc+2) == 0xc310)
81 && (*(unsigned short *) (pc+14) == 0x00ad))))
82 {
83 struct rt_sigframe {
84 siginfo_t info;
85 ucontext_t uc;
86 } *rt_ = context->cfa;
87 /* The void * cast is necessary to avoid an aliasing warning.
88 The aliasing warning is correct, but should not be a problem
89 because it does not alias anything. */
90 sc = (struct sigcontext *) (void *) &rt_->uc.uc_mcontext;
91 }
92 else
93 return _URC_END_OF_STACK;
94
95 new_cfa = sc->sc_regs[15];
96 fs->regs.cfa_how = CFA_REG_OFFSET;
97 fs->regs.cfa_reg = 15;
98 fs->regs.cfa_offset = new_cfa - (long) context->cfa;
99
100 for (i = 0; i < 15; i++)
101 {
102 fs->regs.how[i] = REG_SAVED_OFFSET;
103 fs->regs.reg[i].loc.offset
104 = (long)&(sc->sc_regs[i]) - new_cfa;
105 }
106
107 fs->regs.how[SH_DWARF_FRAME_PR] = REG_SAVED_OFFSET;
108 fs->regs.reg[SH_DWARF_FRAME_PR].loc.offset
109 = (long)&(sc->sc_pr) - new_cfa;
110 fs->regs.how[SH_DWARF_FRAME_SR] = REG_SAVED_OFFSET;
111 fs->regs.reg[SH_DWARF_FRAME_SR].loc.offset
112 = (long)&(sc->sc_sr) - new_cfa;
113 fs->regs.how[SH_DWARF_FRAME_GBR] = REG_SAVED_OFFSET;
114 fs->regs.reg[SH_DWARF_FRAME_GBR].loc.offset
115 = (long)&(sc->sc_gbr) - new_cfa;
116 fs->regs.how[SH_DWARF_FRAME_MACH] = REG_SAVED_OFFSET;
117 fs->regs.reg[SH_DWARF_FRAME_MACH].loc.offset
118 = (long)&(sc->sc_mach) - new_cfa;
119 fs->regs.how[SH_DWARF_FRAME_MACL] = REG_SAVED_OFFSET;
120 fs->regs.reg[SH_DWARF_FRAME_MACL].loc.offset
121 = (long)&(sc->sc_macl) - new_cfa;
122
123 #if defined (__SH3E__) || defined (__SH4__)
124 r = SH_DWARF_FRAME_FP0;
125 for (i = 0; i < 16; i++)
126 {
127 fs->regs.how[r+i] = REG_SAVED_OFFSET;
128 fs->regs.reg[r+i].loc.offset
129 = (long)&(sc->sc_fpregs[i]) - new_cfa;
130 }
131
132 r = SH_DWARF_FRAME_XD0;
133 for (i = 0; i < 8; i++)
134 {
135 fs->regs.how[r+i] = REG_SAVED_OFFSET;
136 fs->regs.reg[r+i].loc.offset
137 = (long)&(sc->sc_xfpregs[2*i]) - new_cfa;
138 }
139
140 fs->regs.how[SH_DWARF_FRAME_FPUL] = REG_SAVED_OFFSET;
141 fs->regs.reg[SH_DWARF_FRAME_FPUL].loc.offset
142 = (long)&(sc->sc_fpul) - new_cfa;
143 fs->regs.how[SH_DWARF_FRAME_FPSCR] = REG_SAVED_OFFSET;
144 fs->regs.reg[SH_DWARF_FRAME_FPSCR].loc.offset
145 = (long)&(sc->sc_fpscr) - new_cfa;
146 #endif
147
148 fs->regs.how[SH_DWARF_FRAME_PC] = REG_SAVED_OFFSET;
149 fs->regs.reg[SH_DWARF_FRAME_PC].loc.offset
150 = (long)&(sc->sc_pc) - new_cfa;
151 fs->retaddr_column = SH_DWARF_FRAME_PC;
152 fs->signal_frame = 1;
153 return _URC_NO_REASON;
154 }
155
156 #endif /* inhibit_libc */