1 /* DWARF2 EH unwinding support for Linux/m68k.
2 Copyright (C) 2006-2023 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 /* Do code reading to identify a signal frame, and set the frame
26 state data appropriately. See unwind-dw2.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
33 /* <sys/ucontext.h> is unfortunately broken right now. */
34 struct uw_ucontext {
35 unsigned long uc_flags;
36 ucontext_t *uc_link;
37 stack_t uc_stack;
38 mcontext_t uc_mcontext;
39 unsigned long uc_filler[80];
40 sigset_t uc_sigmask;
41 };
42
43 #define MD_FALLBACK_FRAME_STATE_FOR m68k_fallback_frame_state
44
45 #ifdef __mcoldfire__
46 #define M68K_FP_SIZE 8
47 #else
48 #define M68K_FP_SIZE 12
49 #endif
50
51 static _Unwind_Reason_Code
52 m68k_fallback_frame_state (struct _Unwind_Context *context,
53 _Unwind_FrameState *fs)
54 {
55 unsigned short *pc = context->ra;
56 long cfa;
57
58 /* moveq #__NR_sigreturn,%d0; trap #0 */
59 if (pc[0] == 0x7077 && pc[1] == 0x4e40)
60 {
61 struct sigcontext *sc;
62
63 /* Context is passed as the 3rd argument. */
64 sc = *(struct sigcontext **) (context->cfa + 8);
65
66 cfa = sc->sc_usp;
67 fs->regs.cfa_how = CFA_REG_OFFSET;
68 fs->regs.cfa_reg = 15;
69 fs->regs.cfa_offset = cfa - (long) context->cfa;
70
71 fs->regs.how[0] = REG_SAVED_OFFSET;
72 fs->regs.reg[0].loc.offset = (long) &sc->sc_d0 - cfa;
73 fs->regs.how[1] = REG_SAVED_OFFSET;
74 fs->regs.reg[1].loc.offset = (long) &sc->sc_d1 - cfa;
75 fs->regs.how[8] = REG_SAVED_OFFSET;
76 fs->regs.reg[8].loc.offset = (long) &sc->sc_a0 - cfa;
77 fs->regs.how[9] = REG_SAVED_OFFSET;
78 fs->regs.reg[9].loc.offset = (long) &sc->sc_a1 - cfa;
79
80 #ifdef __uClinux__
81 fs->regs.how[13] = REG_SAVED_OFFSET;
82 fs->regs.reg[13].loc.offset = (long) &sc->sc_a5 - cfa;
83 #endif
84
85 fs->regs.how[24] = REG_SAVED_OFFSET;
86 fs->regs.reg[24].loc.offset = (long) &sc->sc_pc - cfa;
87
88 #ifndef __uClinux__
89 if (*(int *) sc->sc_fpstate)
90 {
91 int *fpregs = (int *) sc->sc_fpregs;
92
93 fs->regs.how[16] = REG_SAVED_OFFSET;
94 fs->regs.reg[16].loc.offset = (long) &fpregs[0] - cfa;
95 fs->regs.how[17] = REG_SAVED_OFFSET;
96 fs->regs.reg[17].loc.offset = (long) &fpregs[M68K_FP_SIZE/4] - cfa;
97 }
98 #elif defined __mcffpu__
99 # error Implement this when uClinux kernel is ported to an FPU architecture
100 #endif
101 }
102 #ifdef __mcoldfire__
103 /* move.l #__NR_rt_sigreturn,%d0; trap #0 */
104 else if (pc[0] == 0x203c && pc[1] == 0x0000 &&
105 pc[2] == 0x00ad && pc[3] == 0x4e40)
106 #else
107 /* moveq #~__NR_rt_sigreturn,%d0; not.b %d0; trap #0 */
108 else if (pc[0] == 0x7052 && pc[1] == 0x4600 && pc[2] == 0x4e40)
109 #endif
110 {
111 struct uw_ucontext *uc;
112 greg_t *gregs;
113 int i;
114
115 /* Context is passed as the 3rd argument. */
116 uc = *(struct uw_ucontext **) (context->cfa + 8);
117
118 gregs = uc->uc_mcontext.gregs;
119 cfa = gregs[15];
120 fs->regs.cfa_how = CFA_REG_OFFSET;
121 fs->regs.cfa_reg = 15;
122 fs->regs.cfa_offset = cfa - (long) context->cfa;
123
124 /* register %d0-%d7/%a0-%a6 */
125 for (i = 0; i <= 14; i++)
126 {
127 fs->regs.how[i] = REG_SAVED_OFFSET;
128 fs->regs.reg[i].loc.offset = (long) &gregs[i] - cfa;
129 }
130
131 /* return address */
132 fs->regs.how[24] = REG_SAVED_OFFSET;
133 fs->regs.reg[24].loc.offset = (long) &gregs[16] - cfa;
134
135 #define uc_fpstate uc_filler[0]
136
137 if (uc->uc_fpstate)
138 {
139 long fpregs = (long) uc->uc_mcontext.fpregs.f_fpregs;
140
141 /* register %fp0-%fp7 */
142 for (i = 16; i <= 23; i++)
143 {
144 fs->regs.how[i] = REG_SAVED_OFFSET;
145 fs->regs.reg[i].loc.offset = fpregs - cfa;
146 fpregs += M68K_FP_SIZE;
147 }
148 }
149 }
150 else
151 return _URC_END_OF_STACK;
152
153 fs->retaddr_column = 24;
154 fs->signal_frame = 1;
155
156 return _URC_NO_REASON;
157 }
158 #endif /* ifdef inhibit_libc */