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/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
88static int gdb_trapper(u_int, u_int, struct trapframe *, int);
89
90LIST_HEAD(, undefined_handler) undefined_handlers[MAX_COPROCS];
91
92
93void *
94install_coproc_handler(int coproc, undef_handler_t handler)
95{
96	struct undefined_handler *uh;
97
98	KASSERT(coproc >= 0 && coproc < MAX_COPROCS, ("bad coproc"));
99	KASSERT(handler != NULL, ("handler is NULL")); /* Used to be legal. */
100
101	/* XXX: M_TEMP??? */
102	uh = malloc(sizeof(*uh), M_TEMP, M_WAITOK);
103	uh->uh_handler = handler;
104	install_coproc_handler_static(coproc, uh);
105	return uh;
106}
107
108void
109install_coproc_handler_static(int coproc, struct undefined_handler *uh)
110{
111
112	LIST_INSERT_HEAD(&undefined_handlers[coproc], uh, uh_link);
113}
114
115void
116remove_coproc_handler(void *cookie)
117{
118	struct undefined_handler *uh = cookie;
119
120	LIST_REMOVE(uh, uh_link);
121	free(uh, M_TEMP);
122}
123
124
125static int
126gdb_trapper(u_int addr, u_int insn, struct trapframe *frame, int code)
127{
128	struct thread *td;
129	ksiginfo_t ksi;
130
131	td = (curthread == NULL) ? &thread0 : curthread;
132
133	if (insn == GDB_BREAKPOINT || insn == GDB5_BREAKPOINT) {
134		if (code == FAULT_USER) {
135			ksiginfo_init_trap(&ksi);
136			ksi.ksi_signo = SIGTRAP;
137			ksi.ksi_code = TRAP_BRKPT;
138			ksi.ksi_addr = (u_int32_t *)addr;
139			trapsignal(td, &ksi);
140			return 0;
141		}
142#if 0
143#ifdef KGDB
144		return !kgdb_trap(T_BREAKPOINT, frame);
145#endif
146#endif
147	}
148	return 1;
149}
150
151static struct undefined_handler gdb_uh;
152
153void
154undefined_init()
155{
156	int loop;
157
158	/* Not actually necessary -- the initialiser is just NULL */
159	for (loop = 0; loop < MAX_COPROCS; ++loop)
160		LIST_INIT(&undefined_handlers[loop]);
161
162	/* Install handler for GDB breakpoints */
163	gdb_uh.uh_handler = gdb_trapper;
164	install_coproc_handler_static(0, &gdb_uh);
165}
166
167
168void
169undefinedinstruction(trapframe_t *frame)
170{
171	struct thread *td;
172	u_int fault_pc;
173	int fault_instruction;
174	int fault_code;
175	int coprocessor;
176	struct undefined_handler *uh;
177#ifdef VERBOSE_ARM32
178	int s;
179#endif
180	ksiginfo_t ksi;
181
182	/* Enable interrupts if they were enabled before the exception. */
183	if (!(frame->tf_spsr & I32_bit))
184		enable_interrupts(I32_bit|F32_bit);
185
186	frame->tf_pc -= INSN_SIZE;
187	PCPU_INC(cnt.v_trap);
188
189	fault_pc = frame->tf_pc;
190
191	/*
192	 * Get the current thread/proc structure or thread0/proc0 if there is
193	 * none.
194	 */
195	td = curthread == NULL ? &thread0 : curthread;
196
197	/*
198	 * Make sure the program counter is correctly aligned so we
199	 * don't take an alignment fault trying to read the opcode.
200	 */
201	if (__predict_false((fault_pc & 3) != 0)) {
202		ksiginfo_init_trap(&ksi);
203		ksi.ksi_signo = SIGILL;
204		ksi.ksi_code = ILL_ILLADR;
205		ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
206		trapsignal(td, &ksi);
207		userret(td, frame);
208		return;
209	}
210
211	/*
212	 * Should use fuword() here .. but in the interests of squeezing every
213	 * bit of speed we will just use ReadWord(). We know the instruction
214	 * can be read as was just executed so this will never fail unless the
215	 * kernel is screwed up in which case it does not really matter does
216	 * it ?
217	 */
218
219	fault_instruction = *(u_int32_t *)fault_pc;
220
221	/* Update vmmeter statistics */
222#if 0
223	uvmexp.traps++;
224#endif
225	/* Check for coprocessor instruction */
226
227	/*
228	 * According to the datasheets you only need to look at bit 27 of the
229	 * instruction to tell the difference between and undefined
230	 * instruction and a coprocessor instruction following an undefined
231	 * instruction trap.
232	 */
233
234	coprocessor = 0;
235	if ((fault_instruction & (1 << 27)) != 0)
236		coprocessor = (fault_instruction >> 8) & 0x0f;
237#ifdef VFP
238	else {          /* check for special instructions */
239		if (((fault_instruction & 0xfe000000) == 0xf2000000) ||
240		    ((fault_instruction & 0xff100000) == 0xf4000000))
241			coprocessor = 10;       /* vfp / simd */
242	}
243#endif	/* VFP */
244
245	if ((frame->tf_spsr & PSR_MODE) == PSR_USR32_MODE) {
246		/*
247		 * Modify the fault_code to reflect the USR/SVC state at
248		 * time of fault.
249		 */
250		fault_code = FAULT_USER;
251		td->td_frame = frame;
252	} else
253		fault_code = 0;
254
255	/* OK this is were we do something about the instruction. */
256	LIST_FOREACH(uh, &undefined_handlers[coprocessor], uh_link)
257	    if (uh->uh_handler(fault_pc, fault_instruction, frame,
258			       fault_code) == 0)
259		    break;
260
261	if (fault_code & FAULT_USER && fault_instruction == PTRACE_BREAKPOINT) {
262		PROC_LOCK(td->td_proc);
263		_PHOLD(td->td_proc);
264		ptrace_clear_single_step(td);
265		_PRELE(td->td_proc);
266		PROC_UNLOCK(td->td_proc);
267		return;
268	}
269
270	if (uh == NULL && (fault_code & FAULT_USER)) {
271		/* Fault has not been handled */
272		ksiginfo_init_trap(&ksi);
273		ksi.ksi_signo = SIGILL;
274		ksi.ksi_code = ILL_ILLOPC;
275		ksi.ksi_addr = (u_int32_t *)(intptr_t) fault_pc;
276		trapsignal(td, &ksi);
277	}
278
279	if ((fault_code & FAULT_USER) == 0) {
280		if (fault_instruction == KERNEL_BREAKPOINT) {
281#ifdef KDB
282			kdb_trap(T_BREAKPOINT, 0, frame);
283#else
284			printf("No debugger in kernel.\n");
285#endif
286			return;
287		} else
288			panic("Undefined instruction in kernel.\n");
289	}
290
291	userret(td, frame);
292}
293