1 /* DWARF2 EH unwinding support for SPARC Solaris.
2 Copyright (C) 2009-2020 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
28 #include <ucontext.h>
29 #include <sys/frame.h>
30 #include <sys/stack.h>
31
32 #ifdef __arch64__
33
34 #define IS_SIGHANDLER sparc64_is_sighandler
35
36 static int
sparc64_is_sighandler(unsigned int * pc,void * cfa,int * nframes)37 sparc64_is_sighandler (unsigned int *pc, void *cfa, int *nframes)
38 {
39 if (/* Solaris 8+ - multi-threaded
40 ----------------------------
41 <__sighndlr>: save %sp, -176, %sp
42 <__sighndlr+4>: mov %i0, %o0
43 <__sighndlr+8>: mov %i1, %o1
44 <__sighndlr+12>: call %i3
45 <__sighndlr+16>: mov %i2, %o2
46 <__sighndlr+20>: ret <--- PC
47 <__sighndlr+24>: restore */
48 pc[-5] == 0x9de3bf50
49 && pc[-4] == 0x90100018
50 && pc[-3] == 0x92100019
51 && pc[-2] == 0x9fc6c000
52 && pc[-1] == 0x9410001a
53 && pc[ 0] == 0x81c7e008
54 && pc[ 1] == 0x81e80000)
55 {
56 /* We have observed different calling frames among different
57 versions of the operating system, so that we need to
58 discriminate using the upper frame. We look for the return
59 address of the caller frame (there is an offset of 15 double
60 words between the frame address and the place where this return
61 address is stored) in order to do some more pattern matching. */
62 unsigned int cuh_pattern
63 = *(unsigned int *)(*(unsigned long *)(cfa + 15*8) - 4);
64
65 if (cuh_pattern == 0x92100019)
66 /* This matches the call_user_handler pattern in Solaris 11
67 libc.so.1:
68
69 <call_user_handler+864>: mov %i1, %o1
70 <call_user_handler+868>: call __sighndlr */
71 *nframes = 3;
72
73 return 1;
74 }
75
76 return 0;
77 }
78
79 #define MD_FALLBACK_FRAME_STATE_FOR sparc64_fallback_frame_state
80
81 #define MD_FROB_UPDATE_CONTEXT sparc64_frob_update_context
82
83 static void
sparc64_frob_update_context(struct _Unwind_Context * context,_Unwind_FrameState * fs)84 sparc64_frob_update_context (struct _Unwind_Context *context,
85 _Unwind_FrameState *fs)
86 {
87 /* The column of %sp contains the old CFA, not the old value of %sp.
88 The CFA offset already comprises the stack bias so, when %sp is the
89 CFA register, we must avoid counting the stack bias twice. */
90 if (fs->regs.cfa_reg == __builtin_dwarf_sp_column ()
91 && fs->regs.cfa_how == CFA_REG_OFFSET
92 && fs->regs.cfa_offset != 0)
93 {
94 long i;
95
96 context->cfa -= STACK_BIAS;
97
98 for (i = 0; i < __LIBGCC_DWARF_FRAME_REGISTERS__ + 1; ++i)
99 if (fs->regs.reg[i].how == REG_SAVED_OFFSET)
100 _Unwind_SetGRPtr (context, i,
101 _Unwind_GetGRPtr (context, i) - STACK_BIAS);
102 }
103 }
104
105 #else
106
107 #define IS_SIGHANDLER sparc_is_sighandler
108
109 static int
sparc_is_sighandler(unsigned int * pc,void * cfa,int * nframes)110 sparc_is_sighandler (unsigned int *pc, void *cfa, int *nframes)
111 {
112 if(/* Solaris 8+ - multi-threaded
113 ----------------------------
114 <__sighndlr>: save %sp, -96, %sp
115 <__sighndlr+4>: mov %i0, %o0
116 <__sighndlr+8>: mov %i1, %o1
117 <__sighndlr+12>: call %i3
118 <__sighndlr+16>: mov %i2, %o2
119 <__sighndlr+20>: ret <--- PC
120 <__sighndlr+24>: restore */
121 pc[-5] == 0x9de3bfa0
122 && pc[-4] == 0x90100018
123 && pc[-3] == 0x92100019
124 && pc[-2] == 0x9fc6c000
125 && pc[-1] == 0x9410001a
126 && pc[ 0] == 0x81c7e008
127 && pc[ 1] == 0x81e80000)
128 {
129 /* We have observed different calling frames among different
130 versions of the operating system, so that we need to
131 discriminate using the upper frame. We look for the return
132 address of the caller frame (there is an offset of 15 words
133 between the frame address and the place where this return
134 address is stored) in order to do some more pattern matching. */
135 unsigned int cuh_pattern
136 = *(unsigned int *)(*(unsigned int *)(cfa + 15*4) - 4);
137
138 if (cuh_pattern == 0x92100019)
139 /* This matches the call_user_handler pattern in Solaris 11
140 libc.so.1:
141
142 <call_user_handler+876>: mov %i1, %o1
143 <call_user_handler+880>: call __sighndlr */
144 *nframes = 3;
145
146 return 1;
147 }
148
149 return 0;
150 }
151
152 #define MD_FALLBACK_FRAME_STATE_FOR sparc_fallback_frame_state
153
154 #endif
155
156 static _Unwind_Reason_Code
MD_FALLBACK_FRAME_STATE_FOR(struct _Unwind_Context * context,_Unwind_FrameState * fs)157 MD_FALLBACK_FRAME_STATE_FOR (struct _Unwind_Context *context,
158 _Unwind_FrameState *fs)
159 {
160 void *pc = context->ra;
161 void *this_cfa = context->cfa;
162 int nframes = 0;
163 long new_cfa;
164 void *ra_location, *shifted_ra_location;
165 mcontext_t *mctx;
166 int i;
167
168 /* Deal with frame-less function from which a signal was raised. */
169 if (_Unwind_IsSignalFrame (context))
170 {
171 /* The CFA is by definition unmodified in this case. */
172 fs->regs.cfa_how = CFA_REG_OFFSET;
173 fs->regs.cfa_reg = __builtin_dwarf_sp_column ();
174 fs->regs.cfa_offset = 0;
175
176 /* This is the canonical RA column. */
177 fs->retaddr_column = 15;
178
179 return _URC_NO_REASON;
180 }
181
182 /* Do some pattern matching at the return address. */
183 if (IS_SIGHANDLER (pc, this_cfa, &nframes))
184 {
185 struct frame *fp = (struct frame *) this_cfa;
186 struct handler_args {
187 struct frame frwin;
188 ucontext_t ucontext;
189 } *handler_args;
190 ucontext_t *ucp;
191
192 /* this_cfa points into the frame after the saved frame pointer and
193 saved pc (struct frame).
194
195 The ucontext_t structure is in the kernel frame after a struct
196 frame. Since the frame sizes vary even within OS releases, we
197 need to walk the stack to get there. */
198 for (i = 0; i < nframes; i++)
199 fp = (struct frame *) ((char *)fp->fr_savfp + STACK_BIAS);
200
201 handler_args = (struct handler_args *) fp;
202 ucp = &handler_args->ucontext;
203 mctx = &ucp->uc_mcontext;
204 }
205 else
206 return _URC_END_OF_STACK;
207
208 /* The frame address is %sp + STACK_BIAS in 64-bit mode. */
209 new_cfa = mctx->gregs[REG_SP] + STACK_BIAS;
210
211 fs->regs.cfa_how = CFA_REG_OFFSET;
212 fs->regs.cfa_reg = __builtin_dwarf_sp_column ();
213 fs->regs.cfa_offset = new_cfa - (long) this_cfa + STACK_BIAS;
214
215 /* Restore global and out registers (in this order) from the
216 ucontext_t structure, uc_mcontext.gregs field. */
217 for (i = 1; i < 16; i++)
218 {
219 /* We never restore %sp as everything is purely CFA-based. */
220 if ((unsigned int) i == __builtin_dwarf_sp_column ())
221 continue;
222
223 /* First the global registers and then the out registers. */
224 fs->regs.reg[i].how = REG_SAVED_OFFSET;
225 fs->regs.reg[i].loc.offset = (long)&mctx->gregs[REG_Y + i] - new_cfa;
226 }
227
228 /* Just above the stack pointer there are 16 extended words in which
229 the register window (in and local registers) was saved. */
230 for (i = 0; i < 16; i++)
231 {
232 fs->regs.reg[i + 16].how = REG_SAVED_OFFSET;
233 fs->regs.reg[i + 16].loc.offset = i * sizeof(long);
234 }
235
236 /* Check whether we need to restore FPU registers. */
237 if (mctx->fpregs.fpu_qcnt)
238 {
239 for (i = 0; i < 32; i++)
240 {
241 fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
242 fs->regs.reg[i + 32].loc.offset
243 = (long)&mctx->fpregs.fpu_fr.fpu_regs[i] - new_cfa;
244 }
245
246 #ifdef __arch64__
247 /* For 64-bit, fpu_fr.fpu_dregs contains 32 instead of 16 doubles. */
248 for (i = 32; i < 64; i++)
249 {
250 if (i > 32 && (i & 1))
251 continue;
252
253 fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
254 fs->regs.reg[i + 32].loc.offset
255 = (long)&mctx->fpregs.fpu_fr.fpu_dregs[i/2] - new_cfa;
256 }
257 #endif
258 }
259
260 /* State the rules to find the kernel's code "return address", which is
261 the address of the active instruction when the signal was caught.
262 On the SPARC, since RETURN_ADDR_OFFSET (essentially 8) is defined, we
263 need to preventively subtract it from the purported return address. */
264 ra_location = &mctx->gregs[REG_PC];
265 shifted_ra_location = &mctx->gregs[REG_Y];
266 *(void **)shifted_ra_location = *(void **)ra_location - 8;
267 fs->retaddr_column = 0;
268 fs->regs.reg[0].how = REG_SAVED_OFFSET;
269 fs->regs.reg[0].loc.offset = (long)shifted_ra_location - new_cfa;
270
271 /* SIGFPE for IEEE-754 exceptions is delivered after the faulting insn
272 rather than before it, so don't set fs->signal_frame in that case.
273 We test whether the cexc field of the FSR is zero. */
274 if ((mctx->fpregs.fpu_fsr & 0x1f) == 0)
275 fs->signal_frame = 1;
276
277 return _URC_NO_REASON;
278 }
279