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: stable/12/sys/arm/arm/undefined.c 372763 2022-11-18 10:03:21Z cognet $");
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) & 0xe000) == 0xe000) && \
98 (((insn) & 0x1800) != 0))
99 /*
100 * Coprocessor, Advanced SIMD, and
101 * Floating-point instructions on page A6-251
102 * OP1 == 01 OR 11
103 * OP2 == 1xxxxxx
104 */
105 #define THUMB_COPROC_INSN(insn) (((insn) & (3 << 26)) == (3 << 26))
106 /*
107 * Advanced SIMD element or structure
108 * load/store instructions on page A7-275
109 * OP1 == 11
110 * OP2 == 001xxx0
111 */
112 #define THUMB_VFP_INSN(insn) (((insn) & (0x1F1 << 20)) == (0x190 << 20))
113 #define THUMB_COPROC(insn) (((insn) >> 8) & 0xf)
114
115 #define COPROC_VFP 10
116
117 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
118
119 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
120
121
122 void *
install_coproc_handler(int coproc,undef_handler_t handler)123 install_coproc_handler(int coproc, undef_handler_t handler)
124 {
125 struct undefined_handler *uh;
126
127 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
128 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
129
130 /* XXX: M_TEMP??? */
131 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
132 uh->uh_handler = handler;
133 install_coproc_handler_static(coproc, uh);
134 return uh;
135 }
136
137 void
install_coproc_handler_static(int coproc,struct undefined_handler * uh)138 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
139 {
140
141 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
142 }
143
144 void
remove_coproc_handler(void * cookie)145 remove_coproc_handler(void *cookie)
146 {
147 struct undefined_handler *uh = cookie;
148
149 LIST_REMOVE(uh, uh_link);
150 free(uh, M_TEMP);
151 }
152
153
154 static int
gdb_trapper(u_int addr,u_int insn,struct trapframe * frame,int code)155 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
156 {
157 struct thread *td;
158 ksiginfo_t ksi;
159 int error;
160
161 td = (curthread == NULL) ? &thread0 : curthread;
162
163 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
164 if (code == FAULT_USER) {
165 ksiginfo_init_trap(&ksi);
166 ksi.ksi_signo = SIGTRAP;
167 ksi.ksi_code = TRAP_BRKPT;
168 ksi.ksi_addr = (u_int32_t *)addr;
169 trapsignal(td, &ksi);
170 return 0;
171 }
172 #if 0
173 #ifdef KGDB
174 return !kgdb_trap(T_BREAKPOINT, frame);
175 #endif
176 #endif
177 }
178
179 if (code == FAULT_USER) {
180 /* TODO: No support for ptrace from Thumb-2 */
181 if ((frame->tf_spsr & PSR_T) == 0 &&
182 insn == PTRACE_BREAKPOINT) {
183 PROC_LOCK(td->td_proc);
184 _PHOLD(td->td_proc);
185 error = ptrace_clear_single_step(td);
186 _PRELE(td->td_proc);
187 PROC_UNLOCK(td->td_proc);
188 if (error == 0) {
189 ksiginfo_init_trap(&ksi);
190 ksi.ksi_signo = SIGTRAP;
191 ksi.ksi_code = TRAP_TRACE;
192 ksi.ksi_addr = (u_int32_t *)addr;
193 trapsignal(td, &ksi);
194 return (0);
195 }
196 }
197 }
198
199 return 1;
200 }
201
202 static struct undefined_handler gdb_uh;
203
204 void
undefined_init(void)205 undefined_init(void)
206 {
207 int loop;
208
209 /* Not actually necessary -- the initialiser is just NULL */
210 for (loop = 0; loop < MAX_COPROCS; ++loop)
211 LIST_INIT(&undefined_handlers[loop]);
212
213 /* Install handler for GDB breakpoints */
214 gdb_uh.uh_handler = gdb_trapper;
215 install_coproc_handler_static(0, &gdb_uh);
216 }
217
218
219 void
undefinedinstruction(struct trapframe * frame)220 undefinedinstruction(struct trapframe *frame)
221 {
222 struct thread *td;
223 u_int fault_pc;
224 int fault_instruction;
225 int fault_code;
226 int coprocessor;
227 struct undefined_handler *uh;
228 #ifdef VERBOSE_ARM32
229 int s;
230 #endif
231 ksiginfo_t ksi;
232
233 /* Enable interrupts if they were enabled before the exception. */
234 if (__predict_true(frame->tf_spsr & PSR_I) == 0)
235 enable_interrupts(PSR_I);
236 if (__predict_true(frame->tf_spsr & PSR_F) == 0)
237 enable_interrupts(PSR_F);
238
239 VM_CNT_INC(v_trap);
240
241 fault_pc = frame->tf_pc;
242
243 /*
244 * Get the current thread/proc structure or thread0/proc0 if there is
245 * none.
246 */
247 td = curthread == NULL ? &thread0 : curthread;
248
249 coprocessor = 0;
250 if ((frame->tf_spsr & PSR_T) == 0) {
251 /*
252 * Make sure the program counter is correctly aligned so we
253 * don't take an alignment fault trying to read the opcode.
254 */
255 if (__predict_false((fault_pc & 3) != 0)) {
256 ksiginfo_init_trap(&ksi);
257 ksi.ksi_signo = SIGILL;
258 ksi.ksi_code = ILL_ILLADR;
259 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
260 trapsignal(td, &ksi);
261 userret(td, frame);
262 return;
263 }
264
265 /*
266 * Should use fuword() here .. but in the interests of
267 * squeezing every bit of speed we will just use ReadWord().
268 * We know the instruction can be read as was just executed
269 * so this will never fail unless the kernel is screwed up
270 * in which case it does not really matter does it ?
271 */
272
273 fault_instruction = *(u_int32_t *)fault_pc;
274
275 /* Check for coprocessor instruction */
276
277 /*
278 * According to the datasheets you only need to look at bit
279 * 27 of the instruction to tell the difference between and
280 * undefined instruction and a coprocessor instruction
281 * following an undefined instruction trap.
282 */
283
284 if (ARM_COPROC_INSN(fault_instruction))
285 coprocessor = ARM_COPROC(fault_instruction);
286 else { /* check for special instructions */
287 if (ARM_VFP_INSN(fault_instruction))
288 coprocessor = COPROC_VFP; /* vfp / simd */
289 }
290 } else {
291 #if __ARM_ARCH >= 7
292 fault_instruction = *(uint16_t *)fault_pc;
293 if (THUMB_32BIT_INSN(fault_instruction)) {
294 fault_instruction <<= 16;
295 fault_instruction |= *(uint16_t *)(fault_pc + 2);
296
297 /* Coprocessor, Advanced SIMD and Floating-point */
298 if (THUMB_COPROC_INSN(fault_instruction))
299 coprocessor = THUMB_COPROC(fault_instruction);
300 else {
301 /* Advanced SIMD load/store */
302 if (THUMB_VFP_INSN(fault_instruction))
303 coprocessor = COPROC_VFP; /* SIMD */
304 }
305 }
306 #else
307 /*
308 * No support for Thumb-2 on this cpu
309 */
310 ksiginfo_init_trap(&ksi);
311 ksi.ksi_signo = SIGILL;
312 ksi.ksi_code = ILL_ILLADR;
313 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
314 trapsignal(td, &ksi);
315 userret(td, frame);
316 return;
317 #endif
318 }
319
320 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
321 /*
322 * Modify the fault_code to reflect the USR/SVC state at
323 * time of fault.
324 */
325 fault_code = FAULT_USER;
326 td->td_frame = frame;
327 } else
328 fault_code = 0;
329
330 /* OK this is were we do something about the instruction. */
331 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
332 if (uh->uh_handler(fault_pc, fault_instruction, frame,
333 fault_code) == 0)
334 break;
335
336 if (uh == NULL && (fault_code & FAULT_USER)) {
337 /* Fault has not been handled */
338 ksiginfo_init_trap(&ksi);
339 ksi.ksi_signo = SIGILL;
340 ksi.ksi_code = ILL_ILLOPC;
341 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
342 trapsignal(td, &ksi);
343 }
344
345 if ((fault_code & FAULT_USER) == 0) {
346 if (fault_instruction == KERNEL_BREAKPOINT) {
347 #ifdef KDB
348 kdb_trap(T_BREAKPOINT, 0, frame);
349 #else
350 printf("No debugger in kernel.\n");
351 #endif
352 return;
353 }
354 else
355 panic("Undefined instruction in kernel.\n");
356 }
357
358 userret(td, frame);
359 }
360