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