summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/kgdb.c
blob: 9b78ff6e9b846fadcb135413b1f1ba7aa3c04fe4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
/*
 *  Originally written by Glenn Engel, Lake Stevens Instrument Division
 *
 *  Contributed by HP Systems
 *
 *  Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
 *  Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
 *
 *  Copyright (C) 1995 Andreas Busse
 *
 *  Copyright (C) 2003 MontaVista Software Inc.
 *  Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
 *
 *  Copyright (C) 2004-2005 MontaVista Software Inc.
 *  Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
 *
 *  Copyright (C) 2007-2008 Wind River Systems, Inc.
 *  Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
 *
 *  This file is licensed under the terms of the GNU General Public License
 *  version 2. This program is licensed "as is" without any warranty of any
 *  kind, whether express or implied.
 */

#include <linux/ptrace.h>		/* for linux pt_regs struct */
#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <asm/inst.h>
#include <asm/fpu.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/sigcontext.h>

static struct hard_trap_info {
	unsigned char tt;	/* Trap type code for MIPS R3xxx and R4xxx */
	unsigned char signo;	/* Signal that we map this trap into */
} hard_trap_info[] = {
	{ 6, SIGBUS },		/* instruction bus error */
	{ 7, SIGBUS },		/* data bus error */
	{ 9, SIGTRAP },		/* break */
/*	{ 11, SIGILL },	*/	/* CPU unusable */
	{ 12, SIGFPE },		/* overflow */
	{ 13, SIGTRAP },	/* trap */
	{ 14, SIGSEGV },	/* virtual instruction cache coherency */
	{ 15, SIGFPE },		/* floating point exception */
	{ 23, SIGSEGV },	/* watch */
	{ 31, SIGSEGV },	/* virtual data cache coherency */
	{ 0, 0}			/* Must be last */
};

void arch_kgdb_breakpoint(void)
{
	__asm__ __volatile__(
		".globl breakinst\n\t"
		".set\tnoreorder\n\t"
		"nop\n"
		"breakinst:\tbreak\n\t"
		"nop\n\t"
		".set\treorder");
}

static void kgdb_call_nmi_hook(void *ignored)
{
	kgdb_nmicallback(raw_smp_processor_id(), NULL);
}

void kgdb_roundup_cpus(unsigned long flags)
{
	local_irq_enable();
	smp_call_function(kgdb_call_nmi_hook, NULL, 0);
	local_irq_disable();
}

static int compute_signal(int tt)
{
	struct hard_trap_info *ht;

	for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
		if (ht->tt == tt)
			return ht->signo;

	return SIGHUP;		/* default for things we don't know about */
}

void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
	int reg;

#if (KGDB_GDB_REG_SIZE == 32)
	u32 *ptr = (u32 *)gdb_regs;
#else
	u64 *ptr = (u64 *)gdb_regs;
#endif

	for (reg = 0; reg < 32; reg++)
		*(ptr++) = regs->regs[reg];

	*(ptr++) = regs->cp0_status;
	*(ptr++) = regs->lo;
	*(ptr++) = regs->hi;
	*(ptr++) = regs->cp0_badvaddr;
	*(ptr++) = regs->cp0_cause;
	*(ptr++) = regs->cp0_epc;

	/* FP REGS */
	if (!(current && (regs->cp0_status & ST0_CU1)))
		return;

	save_fp(current);
	for (reg = 0; reg < 32; reg++)
		*(ptr++) = current->thread.fpu.fpr[reg];
}

void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
	int reg;

#if (KGDB_GDB_REG_SIZE == 32)
	const u32 *ptr = (u32 *)gdb_regs;
#else
	const u64 *ptr = (u64 *)gdb_regs;
#endif

	for (reg = 0; reg < 32; reg++)
		regs->regs[reg] = *(ptr++);

	regs->cp0_status = *(ptr++);
	regs->lo = *(ptr++);
	regs->hi = *(ptr++);
	regs->cp0_badvaddr = *(ptr++);
	regs->cp0_cause = *(ptr++);
	regs->cp0_epc = *(ptr++);

	/* FP REGS from current */
	if (!(current && (regs->cp0_status & ST0_CU1)))
		return;

	for (reg = 0; reg < 32; reg++)
		current->thread.fpu.fpr[reg] = *(ptr++);
	restore_fp(current);
}

/*
 * Similar to regs_to_gdb_regs() except that process is sleeping and so
 * we may not be able to get all the info.
 */
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
	int reg;
	struct thread_info *ti = task_thread_info(p);
	unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
	struct pt_regs *regs = (struct pt_regs *)ksp - 1;
#if (KGDB_GDB_REG_SIZE == 32)
	u32 *ptr = (u32 *)gdb_regs;
#else
	u64 *ptr = (u64 *)gdb_regs;
#endif

	for (reg = 0; reg < 16; reg++)
		*(ptr++) = regs->regs[reg];

	/* S0 - S7 */
	for (reg = 16; reg < 24; reg++)
		*(ptr++) = regs->regs[reg];

	for (reg = 24; reg < 28; reg++)
		*(ptr++) = 0;

	/* GP, SP, FP, RA */
	for (reg = 28; reg < 32; reg++)
		*(ptr++) = regs->regs[reg];

	*(ptr++) = regs->cp0_status;
	*(ptr++) = regs->lo;
	*(ptr++) = regs->hi;
	*(ptr++) = regs->cp0_badvaddr;
	*(ptr++) = regs->cp0_cause;
	*(ptr++) = regs->cp0_epc;
}

void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
	regs->cp0_epc = pc;
}

/*
 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
 * then try to fall into the debugger
 */
static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
			    void *ptr)
{
	struct die_args *args = (struct die_args *)ptr;
	struct pt_regs *regs = args->regs;
	int trap = (regs->cp0_cause & 0x7c) >> 2;

	/* Userpace events, ignore. */
	if (user_mode(regs))
		return NOTIFY_DONE;

	if (atomic_read(&kgdb_active) != -1)
		kgdb_nmicallback(smp_processor_id(), regs);

	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
		return NOTIFY_DONE;

	if (atomic_read(&kgdb_setting_breakpoint))
		if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
			regs->cp0_epc += 4;

	/* In SMP mode, __flush_cache_all does IPI */
	local_irq_enable();
	__flush_cache_all();

	return NOTIFY_STOP;
}

#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
int kgdb_ll_trap(int cmd, const char *str,
		 struct pt_regs *regs, long err, int trap, int sig)
{
	struct die_args args = {
		.regs	= regs,
		.str	= str,
		.err	= err,
		.trapnr	= trap,
		.signr	= sig,

	};

	if (!kgdb_io_module_registered)
		return NOTIFY_DONE;

	return kgdb_mips_notify(NULL, cmd, &args);
}
#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */

static struct notifier_block kgdb_notifier = {
	.notifier_call = kgdb_mips_notify,
};

/*
 * Handle the 's' and 'c' commands
 */
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
			       char *remcom_in_buffer, char *remcom_out_buffer,
			       struct pt_regs *regs)
{
	char *ptr;
	unsigned long address;
	int cpu = smp_processor_id();

	switch (remcom_in_buffer[0]) {
	case 's':
	case 'c':
		/* handle the optional parameter */
		ptr = &remcom_in_buffer[1];
		if (kgdb_hex2long(&ptr, &address))
			regs->cp0_epc = address;

		atomic_set(&kgdb_cpu_doing_single_step, -1);
		if (remcom_in_buffer[0] == 's')
			atomic_set(&kgdb_cpu_doing_single_step, cpu);

		return 0;
	}

	return -1;
}

struct kgdb_arch arch_kgdb_ops;

/*
 * We use kgdb_early_setup so that functions we need to call now don't
 * cause trouble when called again later.
 */
int kgdb_arch_init(void)
{
	union mips_instruction insn = {
		.r_format = {
			.opcode = spec_op,
			.func   = break_op,
		}
	};
	memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);

	register_die_notifier(&kgdb_notifier);

	return 0;
}

/*
 *	kgdb_arch_exit - Perform any architecture specific uninitalization.
 *
 *	This function will handle the uninitalization of any architecture
 *	specific callbacks, for dynamic registration and unregistration.
 */
void kgdb_arch_exit(void)
{
	unregister_die_notifier(&kgdb_notifier);
}
OpenPOWER on IntegriCloud