1 /* $NetBSD: undefined.c,v 1.22 2003/11/29 22:21:29 bjh21 Exp $ */
2
3 /*-
4 * Copyright (c) 2001 Ben Harris.
5 * Copyright (c) 1995 Mark Brinicombe.
6 * Copyright (c) 1995 Brini.
7 * All rights reserved.
8 *
9 * This code is derived from software written for Brini by Mark Brinicombe
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by Brini.
22 * 4. The name of the company nor the name of the author may be used to
23 * endorse or promote products derived from this software without specific
24 * prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
27 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
28 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
30 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
31 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
32 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * RiscBSD kernel project
39 *
40 * undefined.c
41 *
42 * Fault handler
43 *
44 * Created : 06/01/95
45 */
46
47
48 #include "opt_ddb.h"
49
50 #include <sys/cdefs.h>
51 __FBSDID("$FreeBSD$");
52
53 #include <sys/param.h>
54 #include <sys/malloc.h>
55 #include <sys/queue.h>
56 #include <sys/signal.h>
57 #include <sys/systm.h>
58 #include <sys/proc.h>
59 #include <sys/syslog.h>
60 #include <sys/vmmeter.h>
61 #include <sys/lock.h>
62 #include <sys/mutex.h>
63 #include <sys/signalvar.h>
64 #include <sys/ptrace.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 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
90
91 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
92
93
94 void *
install_coproc_handler(int coproc,undef_handler_t handler)95 install_coproc_handler(int coproc, undef_handler_t handler)
96 {
97 struct undefined_handler *uh;
98
99 KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
100 KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
101
102 /* XXX: M_TEMP??? */
103 uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
104 uh->uh_handler = handler;
105 install_coproc_handler_static(coproc, uh);
106 return uh;
107 }
108
109 void
install_coproc_handler_static(int coproc,struct undefined_handler * uh)110 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
111 {
112
113 LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
114 }
115
116 void
remove_coproc_handler(void * cookie)117 remove_coproc_handler(void *cookie)
118 {
119 struct undefined_handler *uh = cookie;
120
121 LIST_REMOVE(uh, uh_link);
122 free(uh, M_TEMP);
123 }
124
125
126 static int
gdb_trapper(u_int addr,u_int insn,struct trapframe * frame,int code)127 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
128 {
129 struct thread *td;
130 ksiginfo_t ksi;
131
132 td = (curthread == NULL) ? &thread0 : curthread;
133
134 if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
135 if (code == FAULT_USER) {
136 ksiginfo_init_trap(&ksi);
137 ksi.ksi_signo = SIGTRAP;
138 ksi.ksi_code = TRAP_BRKPT;
139 ksi.ksi_addr = (u_int32_t *)addr;
140 trapsignal(td, &ksi);
141 return 0;
142 }
143 #if 0
144 #ifdef KGDB
145 return !kgdb_trap(T_BREAKPOINT, frame);
146 #endif
147 #endif
148 }
149 return 1;
150 }
151
152 static struct undefined_handler gdb_uh;
153
154 void
undefined_init()155 undefined_init()
156 {
157 int loop;
158
159 /* Not actually necessary -- the initialiser is just NULL */
160 for (loop = 0; loop < MAX_COPROCS; ++loop)
161 LIST_INIT(&undefined_handlers[loop]);
162
163 /* Install handler for GDB breakpoints */
164 gdb_uh.uh_handler = gdb_trapper;
165 install_coproc_handler_static(0, &gdb_uh);
166 }
167
168
169 void
undefinedinstruction(struct trapframe * frame)170 undefinedinstruction(struct trapframe *frame)
171 {
172 struct thread *td;
173 u_int fault_pc;
174 int fault_instruction;
175 int fault_code;
176 int coprocessor;
177 struct undefined_handler *uh;
178 #ifdef VERBOSE_ARM32
179 int s;
180 #endif
181 ksiginfo_t ksi;
182
183 /* Enable interrupts if they were enabled before the exception. */
184 if (__predict_true(frame->tf_spsr & PSR_I) == 0)
185 enable_interrupts(PSR_I);
186 if (__predict_true(frame->tf_spsr & PSR_F) == 0)
187 enable_interrupts(PSR_F);
188
189 PCPU_INC(cnt.v_trap);
190
191 fault_pc = frame->tf_pc;
192
193 /*
194 * Get the current thread/proc structure or thread0/proc0 if there is
195 * none.
196 */
197 td = curthread == NULL ? &thread0 : curthread;
198
199 /*
200 * Make sure the program counter is correctly aligned so we
201 * don't take an alignment fault trying to read the opcode.
202 */
203 if (__predict_false((fault_pc & 3) != 0)) {
204 ksiginfo_init_trap(&ksi);
205 ksi.ksi_signo = SIGILL;
206 ksi.ksi_code = ILL_ILLADR;
207 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
208 trapsignal(td, &ksi);
209 userret(td, frame);
210 return;
211 }
212
213 /*
214 * Should use fuword() here .. but in the interests of squeezing every
215 * bit of speed we will just use ReadWord(). We know the instruction
216 * can be read as was just executed so this will never fail unless the
217 * kernel is screwed up in which case it does not really matter does
218 * it ?
219 */
220
221 fault_instruction = *(u_int32_t *)fault_pc;
222
223 /* Update vmmeter statistics */
224 #if 0
225 uvmexp.traps++;
226 #endif
227 /* Check for coprocessor instruction */
228
229 /*
230 * According to the datasheets you only need to look at bit 27 of the
231 * instruction to tell the difference between and undefined
232 * instruction and a coprocessor instruction following an undefined
233 * instruction trap.
234 */
235
236 coprocessor = 0;
237 if ((fault_instruction & (1 << 27)) != 0)
238 coprocessor = (fault_instruction >> 8) & 0x0f;
239 #ifdef VFP
240 else { /* check for special instructions */
241 if (((fault_instruction & 0xfe000000) == 0xf2000000) ||
242 ((fault_instruction & 0xff100000) == 0xf4000000))
243 coprocessor = 10; /* vfp / simd */
244 }
245 #endif /* VFP */
246
247 if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
248 /*
249 * Modify the fault_code to reflect the USR/SVC state at
250 * time of fault.
251 */
252 fault_code = FAULT_USER;
253 td->td_frame = frame;
254 } else
255 fault_code = 0;
256
257 /* OK this is were we do something about the instruction. */
258 LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
259 if (uh->uh_handler(fault_pc, fault_instruction, frame,
260 fault_code) == 0)
261 break;
262
263 if (fault_code & FAULT_USER && fault_instruction == PTRACE_BREAKPOINT) {
264 PROC_LOCK(td->td_proc);
265 _PHOLD(td->td_proc);
266 ptrace_clear_single_step(td);
267 _PRELE(td->td_proc);
268 PROC_UNLOCK(td->td_proc);
269 return;
270 }
271
272 if (uh == NULL && (fault_code & FAULT_USER)) {
273 /* Fault has not been handled */
274 ksiginfo_init_trap(&ksi);
275 ksi.ksi_signo = SIGILL;
276 ksi.ksi_code = ILL_ILLOPC;
277 ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
278 trapsignal(td, &ksi);
279 }
280
281 if ((fault_code & FAULT_USER) == 0) {
282 if (fault_instruction == KERNEL_BREAKPOINT) {
283 #ifdef KDB
284 kdb_trap(T_BREAKPOINT, 0, frame);
285 #else
286 printf("No debugger in kernel.\n");
287 #endif
288 return;
289 } else
290 panic("Undefined instruction in kernel.\n");
291 }
292
293 userret(td, frame);
294 }
295