Loading...
1/*
2 * arch/arm/kernel/kgdb.c
3 *
4 * ARM KGDB support
5 *
6 * Copyright (c) 2002-2004 MontaVista Software, Inc
7 * Copyright (c) 2008 Wind River Systems, Inc.
8 *
9 * Authors: George Davis <davis_g@mvista.com>
10 * Deepak Saxena <dsaxena@plexity.net>
11 */
12#include <linux/irq.h>
13#include <linux/kdebug.h>
14#include <linux/kgdb.h>
15#include <linux/uaccess.h>
16
17#include <asm/patch.h>
18#include <asm/traps.h>
19
20struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
21{
22 { "r0", 4, offsetof(struct pt_regs, ARM_r0)},
23 { "r1", 4, offsetof(struct pt_regs, ARM_r1)},
24 { "r2", 4, offsetof(struct pt_regs, ARM_r2)},
25 { "r3", 4, offsetof(struct pt_regs, ARM_r3)},
26 { "r4", 4, offsetof(struct pt_regs, ARM_r4)},
27 { "r5", 4, offsetof(struct pt_regs, ARM_r5)},
28 { "r6", 4, offsetof(struct pt_regs, ARM_r6)},
29 { "r7", 4, offsetof(struct pt_regs, ARM_r7)},
30 { "r8", 4, offsetof(struct pt_regs, ARM_r8)},
31 { "r9", 4, offsetof(struct pt_regs, ARM_r9)},
32 { "r10", 4, offsetof(struct pt_regs, ARM_r10)},
33 { "fp", 4, offsetof(struct pt_regs, ARM_fp)},
34 { "ip", 4, offsetof(struct pt_regs, ARM_ip)},
35 { "sp", 4, offsetof(struct pt_regs, ARM_sp)},
36 { "lr", 4, offsetof(struct pt_regs, ARM_lr)},
37 { "pc", 4, offsetof(struct pt_regs, ARM_pc)},
38 { "f0", 12, -1 },
39 { "f1", 12, -1 },
40 { "f2", 12, -1 },
41 { "f3", 12, -1 },
42 { "f4", 12, -1 },
43 { "f5", 12, -1 },
44 { "f6", 12, -1 },
45 { "f7", 12, -1 },
46 { "fps", 4, -1 },
47 { "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)},
48};
49
50char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
51{
52 if (regno >= DBG_MAX_REG_NUM || regno < 0)
53 return NULL;
54
55 if (dbg_reg_def[regno].offset != -1)
56 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
57 dbg_reg_def[regno].size);
58 else
59 memset(mem, 0, dbg_reg_def[regno].size);
60 return dbg_reg_def[regno].name;
61}
62
63int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
64{
65 if (regno >= DBG_MAX_REG_NUM || regno < 0)
66 return -EINVAL;
67
68 if (dbg_reg_def[regno].offset != -1)
69 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
70 dbg_reg_def[regno].size);
71 return 0;
72}
73
74void
75sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
76{
77 struct thread_info *ti;
78 int regno;
79
80 /* Just making sure... */
81 if (task == NULL)
82 return;
83
84 /* Initialize to zero */
85 for (regno = 0; regno < GDB_MAX_REGS; regno++)
86 gdb_regs[regno] = 0;
87
88 /* Otherwise, we have only some registers from switch_to() */
89 ti = task_thread_info(task);
90 gdb_regs[_R4] = ti->cpu_context.r4;
91 gdb_regs[_R5] = ti->cpu_context.r5;
92 gdb_regs[_R6] = ti->cpu_context.r6;
93 gdb_regs[_R7] = ti->cpu_context.r7;
94 gdb_regs[_R8] = ti->cpu_context.r8;
95 gdb_regs[_R9] = ti->cpu_context.r9;
96 gdb_regs[_R10] = ti->cpu_context.sl;
97 gdb_regs[_FP] = ti->cpu_context.fp;
98 gdb_regs[_SPT] = ti->cpu_context.sp;
99 gdb_regs[_PC] = ti->cpu_context.pc;
100}
101
102void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
103{
104 regs->ARM_pc = pc;
105}
106
107static int compiled_break;
108
109int kgdb_arch_handle_exception(int exception_vector, int signo,
110 int err_code, char *remcom_in_buffer,
111 char *remcom_out_buffer,
112 struct pt_regs *linux_regs)
113{
114 unsigned long addr;
115 char *ptr;
116
117 switch (remcom_in_buffer[0]) {
118 case 'D':
119 case 'k':
120 case 'c':
121 /*
122 * Try to read optional parameter, pc unchanged if no parm.
123 * If this was a compiled breakpoint, we need to move
124 * to the next instruction or we will just breakpoint
125 * over and over again.
126 */
127 ptr = &remcom_in_buffer[1];
128 if (kgdb_hex2long(&ptr, &addr))
129 linux_regs->ARM_pc = addr;
130 else if (compiled_break == 1)
131 linux_regs->ARM_pc += 4;
132
133 compiled_break = 0;
134
135 return 0;
136 }
137
138 return -1;
139}
140
141static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
142{
143 kgdb_handle_exception(1, SIGTRAP, 0, regs);
144
145 return 0;
146}
147
148static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
149{
150 compiled_break = 1;
151 kgdb_handle_exception(1, SIGTRAP, 0, regs);
152
153 return 0;
154}
155
156static struct undef_hook kgdb_brkpt_hook = {
157 .instr_mask = 0xffffffff,
158 .instr_val = KGDB_BREAKINST,
159 .cpsr_mask = MODE_MASK,
160 .cpsr_val = SVC_MODE,
161 .fn = kgdb_brk_fn
162};
163
164static struct undef_hook kgdb_compiled_brkpt_hook = {
165 .instr_mask = 0xffffffff,
166 .instr_val = KGDB_COMPILED_BREAK,
167 .cpsr_mask = MODE_MASK,
168 .cpsr_val = SVC_MODE,
169 .fn = kgdb_compiled_brk_fn
170};
171
172static void kgdb_call_nmi_hook(void *ignored)
173{
174 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
175}
176
177void kgdb_roundup_cpus(unsigned long flags)
178{
179 local_irq_enable();
180 smp_call_function(kgdb_call_nmi_hook, NULL, 0);
181 local_irq_disable();
182}
183
184static int __kgdb_notify(struct die_args *args, unsigned long cmd)
185{
186 struct pt_regs *regs = args->regs;
187
188 if (kgdb_handle_exception(1, args->signr, cmd, regs))
189 return NOTIFY_DONE;
190 return NOTIFY_STOP;
191}
192static int
193kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
194{
195 unsigned long flags;
196 int ret;
197
198 local_irq_save(flags);
199 ret = __kgdb_notify(ptr, cmd);
200 local_irq_restore(flags);
201
202 return ret;
203}
204
205static struct notifier_block kgdb_notifier = {
206 .notifier_call = kgdb_notify,
207 .priority = -INT_MAX,
208};
209
210
211/**
212 * kgdb_arch_init - Perform any architecture specific initalization.
213 *
214 * This function will handle the initalization of any architecture
215 * specific callbacks.
216 */
217int kgdb_arch_init(void)
218{
219 int ret = register_die_notifier(&kgdb_notifier);
220
221 if (ret != 0)
222 return ret;
223
224 register_undef_hook(&kgdb_brkpt_hook);
225 register_undef_hook(&kgdb_compiled_brkpt_hook);
226
227 return 0;
228}
229
230/**
231 * kgdb_arch_exit - Perform any architecture specific uninitalization.
232 *
233 * This function will handle the uninitalization of any architecture
234 * specific callbacks, for dynamic registration and unregistration.
235 */
236void kgdb_arch_exit(void)
237{
238 unregister_undef_hook(&kgdb_brkpt_hook);
239 unregister_undef_hook(&kgdb_compiled_brkpt_hook);
240 unregister_die_notifier(&kgdb_notifier);
241}
242
243int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
244{
245 int err;
246
247 /* patch_text() only supports int-sized breakpoints */
248 BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
249
250 err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
251 BREAK_INSTR_SIZE);
252 if (err)
253 return err;
254
255 /* Machine is already stopped, so we can use __patch_text() directly */
256 __patch_text((void *)bpt->bpt_addr,
257 *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
258
259 return err;
260}
261
262int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
263{
264 /* Machine is already stopped, so we can use __patch_text() directly */
265 __patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
266
267 return 0;
268}
269
270/*
271 * Register our undef instruction hooks with ARM undef core.
272 * We regsiter a hook specifically looking for the KGB break inst
273 * and we handle the normal undef case within the do_undefinstr
274 * handler.
275 */
276struct kgdb_arch arch_kgdb_ops = {
277#ifndef __ARMEB__
278 .gdb_bpt_instr = {0xfe, 0xde, 0xff, 0xe7}
279#else /* ! __ARMEB__ */
280 .gdb_bpt_instr = {0xe7, 0xff, 0xde, 0xfe}
281#endif
282};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/arm/kernel/kgdb.c
4 *
5 * ARM KGDB support
6 *
7 * Copyright (c) 2002-2004 MontaVista Software, Inc
8 * Copyright (c) 2008 Wind River Systems, Inc.
9 *
10 * Authors: George Davis <davis_g@mvista.com>
11 * Deepak Saxena <dsaxena@plexity.net>
12 */
13#include <linux/irq.h>
14#include <linux/kdebug.h>
15#include <linux/kgdb.h>
16#include <linux/uaccess.h>
17
18#include <asm/patch.h>
19#include <asm/traps.h>
20
21struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
22{
23 { "r0", 4, offsetof(struct pt_regs, ARM_r0)},
24 { "r1", 4, offsetof(struct pt_regs, ARM_r1)},
25 { "r2", 4, offsetof(struct pt_regs, ARM_r2)},
26 { "r3", 4, offsetof(struct pt_regs, ARM_r3)},
27 { "r4", 4, offsetof(struct pt_regs, ARM_r4)},
28 { "r5", 4, offsetof(struct pt_regs, ARM_r5)},
29 { "r6", 4, offsetof(struct pt_regs, ARM_r6)},
30 { "r7", 4, offsetof(struct pt_regs, ARM_r7)},
31 { "r8", 4, offsetof(struct pt_regs, ARM_r8)},
32 { "r9", 4, offsetof(struct pt_regs, ARM_r9)},
33 { "r10", 4, offsetof(struct pt_regs, ARM_r10)},
34 { "fp", 4, offsetof(struct pt_regs, ARM_fp)},
35 { "ip", 4, offsetof(struct pt_regs, ARM_ip)},
36 { "sp", 4, offsetof(struct pt_regs, ARM_sp)},
37 { "lr", 4, offsetof(struct pt_regs, ARM_lr)},
38 { "pc", 4, offsetof(struct pt_regs, ARM_pc)},
39 { "f0", 12, -1 },
40 { "f1", 12, -1 },
41 { "f2", 12, -1 },
42 { "f3", 12, -1 },
43 { "f4", 12, -1 },
44 { "f5", 12, -1 },
45 { "f6", 12, -1 },
46 { "f7", 12, -1 },
47 { "fps", 4, -1 },
48 { "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)},
49};
50
51char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
52{
53 if (regno >= DBG_MAX_REG_NUM || regno < 0)
54 return NULL;
55
56 if (dbg_reg_def[regno].offset != -1)
57 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
58 dbg_reg_def[regno].size);
59 else
60 memset(mem, 0, dbg_reg_def[regno].size);
61 return dbg_reg_def[regno].name;
62}
63
64int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
65{
66 if (regno >= DBG_MAX_REG_NUM || regno < 0)
67 return -EINVAL;
68
69 if (dbg_reg_def[regno].offset != -1)
70 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
71 dbg_reg_def[regno].size);
72 return 0;
73}
74
75void
76sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
77{
78 struct thread_info *ti;
79 int regno;
80
81 /* Just making sure... */
82 if (task == NULL)
83 return;
84
85 /* Initialize to zero */
86 for (regno = 0; regno < GDB_MAX_REGS; regno++)
87 gdb_regs[regno] = 0;
88
89 /* Otherwise, we have only some registers from switch_to() */
90 ti = task_thread_info(task);
91 gdb_regs[_R4] = ti->cpu_context.r4;
92 gdb_regs[_R5] = ti->cpu_context.r5;
93 gdb_regs[_R6] = ti->cpu_context.r6;
94 gdb_regs[_R7] = ti->cpu_context.r7;
95 gdb_regs[_R8] = ti->cpu_context.r8;
96 gdb_regs[_R9] = ti->cpu_context.r9;
97 gdb_regs[_R10] = ti->cpu_context.sl;
98 gdb_regs[_FP] = ti->cpu_context.fp;
99 gdb_regs[_SPT] = ti->cpu_context.sp;
100 gdb_regs[_PC] = ti->cpu_context.pc;
101}
102
103void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
104{
105 regs->ARM_pc = pc;
106}
107
108static int compiled_break;
109
110int kgdb_arch_handle_exception(int exception_vector, int signo,
111 int err_code, char *remcom_in_buffer,
112 char *remcom_out_buffer,
113 struct pt_regs *linux_regs)
114{
115 unsigned long addr;
116 char *ptr;
117
118 switch (remcom_in_buffer[0]) {
119 case 'D':
120 case 'k':
121 case 'c':
122 /*
123 * Try to read optional parameter, pc unchanged if no parm.
124 * If this was a compiled breakpoint, we need to move
125 * to the next instruction or we will just breakpoint
126 * over and over again.
127 */
128 ptr = &remcom_in_buffer[1];
129 if (kgdb_hex2long(&ptr, &addr))
130 linux_regs->ARM_pc = addr;
131 else if (compiled_break == 1)
132 linux_regs->ARM_pc += 4;
133
134 compiled_break = 0;
135
136 return 0;
137 }
138
139 return -1;
140}
141
142static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
143{
144 kgdb_handle_exception(1, SIGTRAP, 0, regs);
145
146 return 0;
147}
148
149static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
150{
151 compiled_break = 1;
152 kgdb_handle_exception(1, SIGTRAP, 0, regs);
153
154 return 0;
155}
156
157static struct undef_hook kgdb_brkpt_hook = {
158 .instr_mask = 0xffffffff,
159 .instr_val = KGDB_BREAKINST,
160 .cpsr_mask = MODE_MASK,
161 .cpsr_val = SVC_MODE,
162 .fn = kgdb_brk_fn
163};
164
165static struct undef_hook kgdb_compiled_brkpt_hook = {
166 .instr_mask = 0xffffffff,
167 .instr_val = KGDB_COMPILED_BREAK,
168 .cpsr_mask = MODE_MASK,
169 .cpsr_val = SVC_MODE,
170 .fn = kgdb_compiled_brk_fn
171};
172
173static int __kgdb_notify(struct die_args *args, unsigned long cmd)
174{
175 struct pt_regs *regs = args->regs;
176
177 if (kgdb_handle_exception(1, args->signr, cmd, regs))
178 return NOTIFY_DONE;
179 return NOTIFY_STOP;
180}
181static int
182kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
183{
184 unsigned long flags;
185 int ret;
186
187 local_irq_save(flags);
188 ret = __kgdb_notify(ptr, cmd);
189 local_irq_restore(flags);
190
191 return ret;
192}
193
194static struct notifier_block kgdb_notifier = {
195 .notifier_call = kgdb_notify,
196 .priority = -INT_MAX,
197};
198
199
200/**
201 * kgdb_arch_init - Perform any architecture specific initalization.
202 *
203 * This function will handle the initalization of any architecture
204 * specific callbacks.
205 */
206int kgdb_arch_init(void)
207{
208 int ret = register_die_notifier(&kgdb_notifier);
209
210 if (ret != 0)
211 return ret;
212
213 register_undef_hook(&kgdb_brkpt_hook);
214 register_undef_hook(&kgdb_compiled_brkpt_hook);
215
216 return 0;
217}
218
219/**
220 * kgdb_arch_exit - Perform any architecture specific uninitalization.
221 *
222 * This function will handle the uninitalization of any architecture
223 * specific callbacks, for dynamic registration and unregistration.
224 */
225void kgdb_arch_exit(void)
226{
227 unregister_undef_hook(&kgdb_brkpt_hook);
228 unregister_undef_hook(&kgdb_compiled_brkpt_hook);
229 unregister_die_notifier(&kgdb_notifier);
230}
231
232int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
233{
234 int err;
235
236 /* patch_text() only supports int-sized breakpoints */
237 BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
238
239 err = copy_from_kernel_nofault(bpt->saved_instr, (char *)bpt->bpt_addr,
240 BREAK_INSTR_SIZE);
241 if (err)
242 return err;
243
244 /* Machine is already stopped, so we can use __patch_text() directly */
245 __patch_text((void *)bpt->bpt_addr,
246 *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
247
248 return err;
249}
250
251int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
252{
253 /* Machine is already stopped, so we can use __patch_text() directly */
254 __patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
255
256 return 0;
257}
258
259/*
260 * Register our undef instruction hooks with ARM undef core.
261 * We register a hook specifically looking for the KGB break inst
262 * and we handle the normal undef case within the do_undefinstr
263 * handler.
264 */
265const struct kgdb_arch arch_kgdb_ops = {
266#ifndef __ARMEB__
267 .gdb_bpt_instr = {0xfe, 0xde, 0xff, 0xe7}
268#else /* ! __ARMEB__ */
269 .gdb_bpt_instr = {0xe7, 0xff, 0xde, 0xfe}
270#endif
271};