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 #include "opt_ddb.h"
50
51 #include <sys/cdefs.h>
52 #include <sys/param.h>
53 #include <sys/malloc.h>
54 #include <sys/queue.h>
55 #include <sys/signal.h>
56 #include <sys/systm.h>
57 #include <sys/proc.h>
58 #include <sys/syslog.h>
59 #include <sys/vmmeter.h>
60 #include <sys/lock.h>
61 #include <sys/mutex.h>
62 #include <sys/signalvar.h>
63 #include <sys/ptrace.h>
64 #include <sys/vmmeter.h>
65 #ifdef KDB
66 #include <sys/kdb.h>
67 #endif
68
69 #include <vm/vm.h>
70 #include <vm/vm_extern.h>
71
72 #include <machine/armreg.h>
73 #include <machine/asm.h>
74 #include <machine/cpu.h>
75 #include <machine/frame.h>
76 #include <machine/undefined.h>
77 #include <machine/trap.h>
78
79 #include <machine/disassem.h>
80
81 #ifdef DDB
82 #include <ddb/db_output.h>
83 #endif
84
85 #ifdef KDB
86 #include <machine/db_machdep.h>
87 #endif
88
89 #define ARM_COPROC_INSN(insn) (((insn) & (1 << 27)) != 0)
90 #define ARM_VFP_INSN(insn) ((((insn) & 0xfe000000) == 0xf2000000) || \
91 (((insn) & 0xff100000) == 0xf4000000))
92 #define ARM_COPROC(insn) (((insn) >> 8) & 0xf)
93
94 #define THUMB_32BIT_INSN(insn) ((((insn) & 0xe000) == 0xe000) && \
95 (((insn) & 0x1800) != 0))
96 /*
97 * Coprocessor, Advanced SIMD, and
98 * Floating-point instructions on page A6-251
99 * OP1 == 01 OR 11
100 * OP2 == 1xxxxxx
101 */
102 #define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26))
103 /*
104 * Advanced SIMD element or structure
105 * load/store instructions on page A7-275
106 * OP1 == 11
107 * OP2 == 001xxx0
108 */
109 #define THUMB_VFP_INSN(insn) (((insn) & (0x1F1 << 20)) == (0x190 << 20))
110 #define THUMB_COPROC(insn) (((insn) >> 8) & 0xf)
111
112 #define COPROC_VFP 10
113
114 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
115
116 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
117
118 void *
install_coproc_handler(int coproc,undef_handler_t handler)119 install_coproc_handler(int coproc, undef_handler_t handler)
120 {
121 struct undefined_handler *uh;
122
123 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
124 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
125
126 /* XXX: M_TEMP??? */
127 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
128 uh->uh_handler = handler;
129 install_coproc_handler_static(coproc, uh);
130 return uh;
131 }
132
133 void
install_coproc_handler_static(int coproc,struct undefined_handler * uh)134 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
135 {
136
137 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
138 }
139
140 void
remove_coproc_handler(void * cookie)141 remove_coproc_handler(void *cookie)
142 {
143 struct undefined_handler *uh = cookie;
144
145 LIST_REMOVE(uh, uh_link);
146 free(uh, M_TEMP);
147 }
148
149 static int
gdb_trapper(u_int addr,u_int insn,struct trapframe * frame,int code)150 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
151 {
152 struct thread *td;
153 ksiginfo_t ksi;
154 int error;
155
156 td = (curthread == NULL) ? &thread0 : curthread;
157
158 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
159 if (code == FAULT_USER) {
160 ksiginfo_init_trap(&ksi);
161 ksi.ksi_signo = SIGTRAP;
162 ksi.ksi_code = TRAP_BRKPT;
163 ksi.ksi_addr = (u_int32_t *)addr;
164 trapsignal(td, &ksi);
165 return 0;
166 }
167 #if 0
168 #ifdef KGDB
169 return !kgdb_trap(T_BREAKPOINT, frame);
170 #endif
171 #endif
172 }
173
174 if (code == FAULT_USER) {
175 /* TODO: No support for ptrace from Thumb-2 */
176 if ((frame->tf_spsr & PSR_T) == 0 &&
177 insn == PTRACE_BREAKPOINT) {
178 PROC_LOCK(td->td_proc);
179 _PHOLD(td->td_proc);
180 error = ptrace_clear_single_step(td);
181 _PRELE(td->td_proc);
182 PROC_UNLOCK(td->td_proc);
183 if (error == 0) {
184 ksiginfo_init_trap(&ksi);
185 ksi.ksi_signo = SIGTRAP;
186 ksi.ksi_code = TRAP_TRACE;
187 ksi.ksi_addr = (u_int32_t *)addr;
188 trapsignal(td, &ksi);
189 return (0);
190 }
191 }
192 }
193
194 return 1;
195 }
196
197 static struct undefined_handler gdb_uh;
198
199 void
undefined_init(void)200 undefined_init(void)
201 {
202 int loop;
203
204 /* Not actually necessary -- the initialiser is just NULL */
205 for (loop = 0; loop < MAX_COPROCS; ++loop)
206 LIST_INIT(&undefined_handlers[loop]);
207
208 /* Install handler for GDB breakpoints */
209 gdb_uh.uh_handler = gdb_trapper;
210 install_coproc_handler_static(0, &gdb_uh);
211 }
212
213 void
undefinedinstruction(struct trapframe * frame)214 undefinedinstruction(struct trapframe *frame)
215 {
216 struct thread *td;
217 u_int fault_pc;
218 int fault_instruction;
219 int fault_code;
220 int coprocessor;
221 struct undefined_handler *uh;
222 #ifdef VERBOSE_ARM32
223 int s;
224 #endif
225 ksiginfo_t ksi;
226
227 /* Enable interrupts if they were enabled before the exception. */
228 if (__predict_true(frame->tf_spsr & PSR_I) == 0)
229 enable_interrupts(PSR_I);
230 if (__predict_true(frame->tf_spsr & PSR_F) == 0)
231 enable_interrupts(PSR_F);
232
233 VM_CNT_INC(v_trap);
234
235 fault_pc = frame->tf_pc;
236
237 /*
238 * Get the current thread/proc structure or thread0/proc0 if there is
239 * none.
240 */
241 td = curthread == NULL ? &thread0 : curthread;
242
243 coprocessor = 0;
244 if ((frame->tf_spsr & PSR_T) == 0) {
245 /*
246 * Make sure the program counter is correctly aligned so we
247 * don't take an alignment fault trying to read the opcode.
248 */
249 if (__predict_false((fault_pc & 3) != 0)) {
250 ksiginfo_init_trap(&ksi);
251 ksi.ksi_signo = SIGILL;
252 ksi.ksi_code = ILL_ILLADR;
253 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
254 trapsignal(td, &ksi);
255 userret(td, frame);
256 return;
257 }
258
259 /*
260 * Should use fuword() here .. but in the interests of
261 * squeezing every bit of speed we will just use ReadWord().
262 * We know the instruction can be read as was just executed
263 * so this will never fail unless the kernel is screwed up
264 * in which case it does not really matter does it ?
265 */
266
267 fault_instruction = *(u_int32_t *)fault_pc;
268
269 /* Check for coprocessor instruction */
270
271 /*
272 * According to the datasheets you only need to look at bit
273 * 27 of the instruction to tell the difference between and
274 * undefined instruction and a coprocessor instruction
275 * following an undefined instruction trap.
276 */
277
278 if (ARM_COPROC_INSN(fault_instruction))
279 coprocessor = ARM_COPROC(fault_instruction);
280 else { /* check for special instructions */
281 if (ARM_VFP_INSN(fault_instruction))
282 coprocessor = COPROC_VFP; /* vfp / simd */
283 }
284 } else {
285 #if __ARM_ARCH >= 7
286 fault_instruction = *(uint16_t *)fault_pc;
287 if (THUMB_32BIT_INSN(fault_instruction)) {
288 fault_instruction <<= 16;
289 fault_instruction |= *(uint16_t *)(fault_pc + 2);
290
291 /* Coprocessor, Advanced SIMD and Floating-point */
292 if (THUMB_COPROC_INSN(fault_instruction))
293 coprocessor = THUMB_COPROC(fault_instruction);
294 else {
295 /* Advanced SIMD load/store */
296 if (THUMB_VFP_INSN(fault_instruction))
297 coprocessor = COPROC_VFP; /* SIMD */
298 }
299 }
300 #else
301 /*
302 * No support for Thumb-2 on this cpu
303 */
304 ksiginfo_init_trap(&ksi);
305 ksi.ksi_signo = SIGILL;
306 ksi.ksi_code = ILL_ILLADR;
307 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
308 trapsignal(td, &ksi);
309 userret(td, frame);
310 return;
311 #endif
312 }
313
314 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
315 /*
316 * Modify the fault_code to reflect the USR/SVC state at
317 * time of fault.
318 */
319 fault_code = FAULT_USER;
320 td->td_frame = frame;
321 } else
322 fault_code = 0;
323
324 /* OK this is were we do something about the instruction. */
325 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
326 if (uh->uh_handler(fault_pc, fault_instruction, frame,
327 fault_code) == 0)
328 break;
329
330 if (uh == NULL && (fault_code & FAULT_USER)) {
331 /* Fault has not been handled */
332 ksiginfo_init_trap(&ksi);
333 ksi.ksi_signo = SIGILL;
334 ksi.ksi_code = ILL_ILLOPC;
335 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
336 trapsignal(td, &ksi);
337 }
338
339 if ((fault_code & FAULT_USER) == 0) {
340 if (fault_instruction == KERNEL_BREAKPOINT) {
341 #ifdef KDB
342 kdb_trap(T_BREAKPOINT, 0, frame);
343 #else
344 printf("No debugger in kernel.\n");
345 #endif
346 } else if (uh == NULL) {
347 panic("Undefined instruction in kernel (0x%08x)",
348 fault_instruction);
349 }
350 return;
351 }
352
353 userret(td, frame);
354 }
355