1 /* $NetBSD: undefined.c,v 1.22 2003/11/29 22:21:29 bjh21 Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-4-Clause
5 *
6 * Copyright (c) 2001 Ben Harris.
7 * Copyright (c) 1995 Mark Brinicombe.
8 * Copyright (c) 1995 Brini.
9 * All rights reserved.
10 *
11 * This code is derived from software written for Brini by Mark Brinicombe
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 * must display the following acknowledgement:
23 * This product includes software developed by Brini.
24 * 4. The name of the company nor the name of the author may be used to
25 * endorse or promote products derived from this software without specific
26 * prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
29 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
30 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
32 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
33 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
34 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 * SUCH DAMAGE.
39 *
40 * RiscBSD kernel project
41 *
42 * undefined.c
43 *
44 * Fault handler
45 *
46 * Created : 06/01/95
47 */
48
49
50 #include "opt_ddb.h"
51
52 #include <sys/cdefs.h>
53 __FBSDID("$FreeBSD$");
54
55 #include <sys/param.h>
56 #include <sys/malloc.h>
57 #include <sys/queue.h>
58 #include <sys/signal.h>
59 #include <sys/systm.h>
60 #include <sys/proc.h>
61 #include <sys/syslog.h>
62 #include <sys/vmmeter.h>
63 #include <sys/lock.h>
64 #include <sys/mutex.h>
65 #include <sys/signalvar.h>
66 #include <sys/ptrace.h>
67 #include <sys/vmmeter.h>
68 #ifdef KDB
69 #include <sys/kdb.h>
70 #endif
71
72 #include <vm/vm.h>
73 #include <vm/vm_extern.h>
74
75 #include <machine/armreg.h>
76 #include <machine/asm.h>
77 #include <machine/cpu.h>
78 #include <machine/frame.h>
79 #include <machine/undefined.h>
80 #include <machine/trap.h>
81
82 #include <machine/disassem.h>
83
84 #ifdef DDB
85 #include <ddb/db_output.h>
86 #endif
87
88 #ifdef KDB
89 #include <machine/db_machdep.h>
90 #endif
91
92 #define ARM_COPROC_INSN(insn) (((insn) & (1 << 27)) != 0)
93 #define ARM_VFP_INSN(insn) ((((insn) & 0xfe000000) == 0xf2000000) || \
94 (((insn) & 0xff100000) == 0xf4000000))
95 #define ARM_COPROC(insn) (((insn) >> 8) & 0xf)
96
97 #define THUMB_32BIT_INSN(insn) ((insn) >= 0xe800)
98 #define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26))
99 #define THUMB_COPROC_UNDEFINED(insn) (((insn) & 0x3e << 20) == 0)
100 #define THUMB_VFP_INSN(insn) (((insn) & (3 << 24)) == (3 << 24))
101 #define THUMB_COPROC(insn) (((insn) >> 8) & 0xf)
102
103 #define COPROC_VFP 10
104
105 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
106
107 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
108
109
110 void *
install_coproc_handler(int coproc,undef_handler_t handler)111 install_coproc_handler(int coproc, undef_handler_t handler)
112 {
113 struct undefined_handler *uh;
114
115 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
116 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
117
118 /* XXX: M_TEMP??? */
119 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
120 uh->uh_handler = handler;
121 install_coproc_handler_static(coproc, uh);
122 return uh;
123 }
124
125 void
install_coproc_handler_static(int coproc,struct undefined_handler * uh)126 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
127 {
128
129 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
130 }
131
132 void
remove_coproc_handler(void * cookie)133 remove_coproc_handler(void *cookie)
134 {
135 struct undefined_handler *uh = cookie;
136
137 LIST_REMOVE(uh, uh_link);
138 free(uh, M_TEMP);
139 }
140
141
142 static int
gdb_trapper(u_int addr,u_int insn,struct trapframe * frame,int code)143 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
144 {
145 struct thread *td;
146 ksiginfo_t ksi;
147 int error;
148
149 td = (curthread == NULL) ? &thread0 : curthread;
150
151 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
152 if (code == FAULT_USER) {
153 ksiginfo_init_trap(&ksi);
154 ksi.ksi_signo = SIGTRAP;
155 ksi.ksi_code = TRAP_BRKPT;
156 ksi.ksi_addr = (u_int32_t *)addr;
157 trapsignal(td, &ksi);
158 return 0;
159 }
160 #if 0
161 #ifdef KGDB
162 return !kgdb_trap(T_BREAKPOINT, frame);
163 #endif
164 #endif
165 }
166
167 if (code == FAULT_USER) {
168 /* TODO: No support for ptrace from Thumb-2 */
169 if ((frame->tf_spsr & PSR_T) == 0 &&
170 insn == PTRACE_BREAKPOINT) {
171 PROC_LOCK(td->td_proc);
172 _PHOLD(td->td_proc);
173 error = ptrace_clear_single_step(td);
174 _PRELE(td->td_proc);
175 PROC_UNLOCK(td->td_proc);
176 if (error == 0) {
177 ksiginfo_init_trap(&ksi);
178 ksi.ksi_signo = SIGTRAP;
179 ksi.ksi_code = TRAP_TRACE;
180 ksi.ksi_addr = (u_int32_t *)addr;
181 trapsignal(td, &ksi);
182 return (0);
183 }
184 }
185 }
186
187 return 1;
188 }
189
190 static struct undefined_handler gdb_uh;
191
192 void
undefined_init(void)193 undefined_init(void)
194 {
195 int loop;
196
197 /* Not actually necessary -- the initialiser is just NULL */
198 for (loop = 0; loop < MAX_COPROCS; ++loop)
199 LIST_INIT(&undefined_handlers[loop]);
200
201 /* Install handler for GDB breakpoints */
202 gdb_uh.uh_handler = gdb_trapper;
203 install_coproc_handler_static(0, &gdb_uh);
204 }
205
206
207 void
undefinedinstruction(struct trapframe * frame)208 undefinedinstruction(struct trapframe *frame)
209 {
210 struct thread *td;
211 u_int fault_pc;
212 int fault_instruction;
213 int fault_code;
214 int coprocessor;
215 struct undefined_handler *uh;
216 #ifdef VERBOSE_ARM32
217 int s;
218 #endif
219 ksiginfo_t ksi;
220
221 /* Enable interrupts if they were enabled before the exception. */
222 if (__predict_true(frame->tf_spsr & PSR_I) == 0)
223 enable_interrupts(PSR_I);
224 if (__predict_true(frame->tf_spsr & PSR_F) == 0)
225 enable_interrupts(PSR_F);
226
227 VM_CNT_INC(v_trap);
228
229 fault_pc = frame->tf_pc;
230
231 /*
232 * Get the current thread/proc structure or thread0/proc0 if there is
233 * none.
234 */
235 td = curthread == NULL ? &thread0 : curthread;
236
237 coprocessor = 0;
238 if ((frame->tf_spsr & PSR_T) == 0) {
239 /*
240 * Make sure the program counter is correctly aligned so we
241 * don't take an alignment fault trying to read the opcode.
242 */
243 if (__predict_false((fault_pc & 3) != 0)) {
244 ksiginfo_init_trap(&ksi);
245 ksi.ksi_signo = SIGILL;
246 ksi.ksi_code = ILL_ILLADR;
247 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
248 trapsignal(td, &ksi);
249 userret(td, frame);
250 return;
251 }
252
253 /*
254 * Should use fuword() here .. but in the interests of
255 * squeezing every bit of speed we will just use ReadWord().
256 * We know the instruction can be read as was just executed
257 * so this will never fail unless the kernel is screwed up
258 * in which case it does not really matter does it ?
259 */
260
261 fault_instruction = *(u_int32_t *)fault_pc;
262
263 /* Check for coprocessor instruction */
264
265 /*
266 * According to the datasheets you only need to look at bit
267 * 27 of the instruction to tell the difference between and
268 * undefined instruction and a coprocessor instruction
269 * following an undefined instruction trap.
270 */
271
272 if (ARM_COPROC_INSN(fault_instruction))
273 coprocessor = ARM_COPROC(fault_instruction);
274 else { /* check for special instructions */
275 if (ARM_VFP_INSN(fault_instruction))
276 coprocessor = COPROC_VFP; /* vfp / simd */
277 }
278 } else {
279 #if __ARM_ARCH >= 7
280 fault_instruction = *(uint16_t *)fault_pc;
281 if (THUMB_32BIT_INSN(fault_instruction)) {
282 fault_instruction <<= 16;
283 fault_instruction |= *(uint16_t *)(fault_pc + 2);
284
285 /*
286 * Is it a Coprocessor, Advanced SIMD, or
287 * Floating-point instruction.
288 */
289 if (THUMB_COPROC_INSN(fault_instruction)) {
290 if (THUMB_COPROC_UNDEFINED(fault_instruction)) {
291 /* undefined insn */
292 } else if (THUMB_VFP_INSN(fault_instruction))
293 coprocessor = COPROC_VFP;
294 else
295 coprocessor =
296 THUMB_COPROC(fault_instruction);
297 }
298 }
299 #else
300 /*
301 * No support for Thumb-2 on this cpu
302 */
303 ksiginfo_init_trap(&ksi);
304 ksi.ksi_signo = SIGILL;
305 ksi.ksi_code = ILL_ILLADR;
306 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
307 trapsignal(td, &ksi);
308 userret(td, frame);
309 return;
310 #endif
311 }
312
313 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
314 /*
315 * Modify the fault_code to reflect the USR/SVC state at
316 * time of fault.
317 */
318 fault_code = FAULT_USER;
319 td->td_frame = frame;
320 } else
321 fault_code = 0;
322
323 /* OK this is were we do something about the instruction. */
324 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
325 if (uh->uh_handler(fault_pc, fault_instruction, frame,
326 fault_code) == 0)
327 break;
328
329 if (uh == NULL && (fault_code & FAULT_USER)) {
330 /* Fault has not been handled */
331 ksiginfo_init_trap(&ksi);
332 ksi.ksi_signo = SIGILL;
333 ksi.ksi_code = ILL_ILLOPC;
334 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
335 trapsignal(td, &ksi);
336 }
337
338 if ((fault_code & FAULT_USER) == 0) {
339 if (fault_instruction == KERNEL_BREAKPOINT) {
340 #ifdef KDB
341 kdb_trap(T_BREAKPOINT, 0, frame);
342 #else
343 printf("No debugger in kernel.\n");
344 #endif
345 return;
346 }
347 else
348 panic("Undefined instruction in kernel.\n");
349 }
350
351 userret(td, frame);
352 }
353