xref: /freebsd/sys/arm/arm/undefined.c (revision 7bd6fde3)
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 #ifdef FAST_FPE
69 #include <sys/acct.h>
70 #endif
71 
72 #include <vm/vm.h>
73 #include <vm/vm_extern.h>
74 
75 #include <machine/asm.h>
76 #include <machine/cpu.h>
77 #include <machine/frame.h>
78 #include <machine/undefined.h>
79 #include <machine/trap.h>
80 
81 #include <machine/disassem.h>
82 
83 #ifdef DDB
84 #include <ddb/db_output.h>
85 #include <machine/db_machdep.h>
86 #endif
87 
88 #ifdef acorn26
89 #include <machine/machdep.h>
90 #endif
91 
92 static int gdb_trapper(u_int, u_int, struct trapframe *, int);
93 #ifdef FAST_FPE
94 extern int want_resched;
95 #endif
96 
97 LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
98 
99 
100 void *
101 install_coproc_handler(int coproc, undef_handler_t handler)
102 {
103 	struct undefined_handler *uh;
104 
105 	KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
106 	KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
107 
108 	/* XXX: M_TEMP??? */
109 	MALLOC(uh, struct undefined_handler *, sizeof(*uh), M_TEMP, M_WAITOK);
110 	uh->uh_handler = handler;
111 	install_coproc_handler_static(coproc, uh);
112 	return uh;
113 }
114 
115 void
116 install_coproc_handler_static(int coproc, struct undefined_handler *uh)
117 {
118 
119 	LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
120 }
121 
122 void
123 remove_coproc_handler(void *cookie)
124 {
125 	struct undefined_handler *uh = cookie;
126 
127 	LIST_REMOVE(uh, uh_link);
128 	FREE(uh, M_TEMP);
129 }
130 
131 
132 static int
133 gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
134 {
135 	struct thread *td;
136 	ksiginfo_t ksi;
137 
138 	td = (curthread == NULL) ? &thread0 : curthread;
139 
140 	if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
141 		if (code == FAULT_USER) {
142 			ksiginfo_init_trap(&ksi);
143 			ksi.ksi_signo = SIGTRAP;
144 			ksi.ksi_code = TRAP_BRKPT;
145 			ksi.ksi_addr = (u_int32_t *)addr;
146 			trapsignal(td, &ksi);
147 			return 0;
148 		}
149 #if 0
150 #ifdef KGDB
151 		return !kgdb_trap(T_BREAKPOINT, frame);
152 #endif
153 #endif
154 	}
155 	return 1;
156 }
157 
158 static struct undefined_handler gdb_uh;
159 
160 void
161 undefined_init()
162 {
163 	int loop;
164 
165 	/* Not actually necessary -- the initialiser is just NULL */
166 	for (loop = 0; loop < MAX_COPROCS; ++loop)
167 		LIST_INIT(&undefined_handlers[loop]);
168 
169 	/* Install handler for GDB breakpoints */
170 	gdb_uh.uh_handler = gdb_trapper;
171 	install_coproc_handler_static(0, &gdb_uh);
172 }
173 
174 
175 void
176 undefinedinstruction(trapframe_t *frame)
177 {
178 	struct thread *td;
179 	u_int fault_pc;
180 	int fault_instruction;
181 	int fault_code;
182 	int coprocessor;
183 	struct undefined_handler *uh;
184 #ifdef VERBOSE_ARM32
185 	int s;
186 #endif
187 	ksiginfo_t ksi;
188 
189 	/* Enable interrupts if they were enabled before the exception. */
190 	if (!(frame->tf_spsr & I32_bit))
191 		enable_interrupts(I32_bit|F32_bit);
192 
193 	frame->tf_pc -= INSN_SIZE;
194 	PCPU_LAZY_INC(cnt.v_trap);
195 
196 	fault_pc = frame->tf_pc;
197 
198 	/*
199 	 * Get the current thread/proc structure or thread0/proc0 if there is
200 	 * none.
201 	 */
202 	td = curthread == NULL ? &thread0 : curthread;
203 
204 	/*
205 	 * Make sure the program counter is correctly aligned so we
206 	 * don't take an alignment fault trying to read the opcode.
207 	 */
208 	if (__predict_false((fault_pc & 3) != 0)) {
209 		ksiginfo_init_trap(&ksi);
210 		ksi.ksi_signo = SIGILL;
211 		ksi.ksi_code = ILL_ILLADR;
212 		ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
213 		trapsignal(td, &ksi);
214 		userret(td, frame);
215 		return;
216 	}
217 
218 	/*
219 	 * Should use fuword() here .. but in the interests of squeezing every
220 	 * bit of speed we will just use ReadWord(). We know the instruction
221 	 * can be read as was just executed so this will never fail unless the
222 	 * kernel is screwed up in which case it does not really matter does
223 	 * it ?
224 	 */
225 
226 	fault_instruction = *(u_int32_t *)fault_pc;
227 
228 	/* Update vmmeter statistics */
229 #if 0
230 	uvmexp.traps++;
231 #endif
232 	/* Check for coprocessor instruction */
233 
234 	/*
235 	 * According to the datasheets you only need to look at bit 27 of the
236 	 * instruction to tell the difference between and undefined
237 	 * instruction and a coprocessor instruction following an undefined
238 	 * instruction trap.
239 	 */
240 
241 	if ((fault_instruction & (1 << 27)) != 0)
242 		coprocessor = (fault_instruction >> 8) & 0x0f;
243 	else
244 		coprocessor = 0;
245 
246 	if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
247 		/*
248 		 * Modify the fault_code to reflect the USR/SVC state at
249 		 * time of fault.
250 		 */
251 		fault_code = FAULT_USER;
252 		td->td_frame = frame;
253 	} else
254 		fault_code = 0;
255 
256 	/* OK this is were we do something about the instruction. */
257 	LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
258 	    if (uh->uh_handler(fault_pc, fault_instruction, frame,
259 			       fault_code) == 0)
260 		    break;
261 
262 	if (fault_code & FAULT_USER && fault_instruction == PTRACE_BREAKPOINT) {
263 		PROC_LOCK(td->td_proc);
264 		_PHOLD(td->td_proc);
265 		ptrace_clear_single_step(td);
266 		_PRELE(td->td_proc);
267 		PROC_UNLOCK(td->td_proc);
268 		return;
269 	}
270 
271 	if (uh == NULL && (fault_code & FAULT_USER)) {
272 		/* Fault has not been handled */
273 		ksiginfo_init_trap(&ksi);
274 		ksi.ksi_signo = SIGILL;
275 		ksi.ksi_code = ILL_ILLOPC;
276 		ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
277 		trapsignal(td, &ksi);
278 	}
279 
280 	if ((fault_code & FAULT_USER) == 0) {
281 		if (fault_instruction == KERNEL_BREAKPOINT) {
282 #ifdef KDB
283 			kdb_trap(T_BREAKPOINT, 0, frame);
284 #else
285 			printf("No debugger in kernel.\n");
286 #endif
287 			return;
288 		} else
289 			panic("Undefined instruction in kernel.\n");
290 	}
291 
292 #ifdef FAST_FPE
293 	/* Optimised exit code */
294 	{
295 
296 		/*
297 		 * Check for reschedule request, at the moment there is only
298 		 * 1 ast so this code should always be run
299 		 */
300 
301 		if (want_resched) {
302 			/*
303 			 * We are being preempted.
304 			 */
305 			preempt(0);
306 		}
307 
308 		/* Invoke MI userret code */
309 		mi_userret(td);
310 
311 #if 0
312 		l->l_priority = l->l_usrpri;
313 
314 		curcpu()->ci_schedstate.spc_curpriority = l->l_priority;
315 #endif
316 	}
317 
318 #else
319 	userret(td, frame);
320 #endif
321 }
322