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caab277b | 1 | // SPDX-License-Identifier: GPL-2.0-only |
bcf5763b VK |
2 | /* |
3 | * AArch64 KGDB support | |
4 | * | |
5 | * Based on arch/arm/kernel/kgdb.c | |
6 | * | |
7 | * Copyright (C) 2013 Cavium Inc. | |
8 | * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com> | |
bcf5763b VK |
9 | */ |
10 | ||
67787b68 | 11 | #include <linux/bug.h> |
bcf5763b VK |
12 | #include <linux/irq.h> |
13 | #include <linux/kdebug.h> | |
14 | #include <linux/kgdb.h> | |
44b53f67 | 15 | #include <linux/kprobes.h> |
68db0cf1 IM |
16 | #include <linux/sched/task_stack.h> |
17 | ||
67787b68 AT |
18 | #include <asm/debug-monitors.h> |
19 | #include <asm/insn.h> | |
bcf5763b VK |
20 | #include <asm/traps.h> |
21 | ||
22 | struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { | |
23 | { "x0", 8, offsetof(struct pt_regs, regs[0])}, | |
24 | { "x1", 8, offsetof(struct pt_regs, regs[1])}, | |
25 | { "x2", 8, offsetof(struct pt_regs, regs[2])}, | |
26 | { "x3", 8, offsetof(struct pt_regs, regs[3])}, | |
27 | { "x4", 8, offsetof(struct pt_regs, regs[4])}, | |
28 | { "x5", 8, offsetof(struct pt_regs, regs[5])}, | |
29 | { "x6", 8, offsetof(struct pt_regs, regs[6])}, | |
30 | { "x7", 8, offsetof(struct pt_regs, regs[7])}, | |
31 | { "x8", 8, offsetof(struct pt_regs, regs[8])}, | |
32 | { "x9", 8, offsetof(struct pt_regs, regs[9])}, | |
33 | { "x10", 8, offsetof(struct pt_regs, regs[10])}, | |
34 | { "x11", 8, offsetof(struct pt_regs, regs[11])}, | |
35 | { "x12", 8, offsetof(struct pt_regs, regs[12])}, | |
36 | { "x13", 8, offsetof(struct pt_regs, regs[13])}, | |
37 | { "x14", 8, offsetof(struct pt_regs, regs[14])}, | |
38 | { "x15", 8, offsetof(struct pt_regs, regs[15])}, | |
39 | { "x16", 8, offsetof(struct pt_regs, regs[16])}, | |
40 | { "x17", 8, offsetof(struct pt_regs, regs[17])}, | |
41 | { "x18", 8, offsetof(struct pt_regs, regs[18])}, | |
42 | { "x19", 8, offsetof(struct pt_regs, regs[19])}, | |
43 | { "x20", 8, offsetof(struct pt_regs, regs[20])}, | |
44 | { "x21", 8, offsetof(struct pt_regs, regs[21])}, | |
45 | { "x22", 8, offsetof(struct pt_regs, regs[22])}, | |
46 | { "x23", 8, offsetof(struct pt_regs, regs[23])}, | |
47 | { "x24", 8, offsetof(struct pt_regs, regs[24])}, | |
48 | { "x25", 8, offsetof(struct pt_regs, regs[25])}, | |
49 | { "x26", 8, offsetof(struct pt_regs, regs[26])}, | |
50 | { "x27", 8, offsetof(struct pt_regs, regs[27])}, | |
51 | { "x28", 8, offsetof(struct pt_regs, regs[28])}, | |
52 | { "x29", 8, offsetof(struct pt_regs, regs[29])}, | |
53 | { "x30", 8, offsetof(struct pt_regs, regs[30])}, | |
54 | { "sp", 8, offsetof(struct pt_regs, sp)}, | |
55 | { "pc", 8, offsetof(struct pt_regs, pc)}, | |
0d15ef67 DT |
56 | /* |
57 | * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote | |
58 | * protocol disagrees. Therefore we must extract only the lower | |
59 | * 32-bits. Look for the big comment in asm/kgdb.h for more | |
60 | * detail. | |
61 | */ | |
62 | { "pstate", 4, offsetof(struct pt_regs, pstate) | |
63 | #ifdef CONFIG_CPU_BIG_ENDIAN | |
64 | + 4 | |
65 | #endif | |
66 | }, | |
bcf5763b VK |
67 | { "v0", 16, -1 }, |
68 | { "v1", 16, -1 }, | |
69 | { "v2", 16, -1 }, | |
70 | { "v3", 16, -1 }, | |
71 | { "v4", 16, -1 }, | |
72 | { "v5", 16, -1 }, | |
73 | { "v6", 16, -1 }, | |
74 | { "v7", 16, -1 }, | |
75 | { "v8", 16, -1 }, | |
76 | { "v9", 16, -1 }, | |
77 | { "v10", 16, -1 }, | |
78 | { "v11", 16, -1 }, | |
79 | { "v12", 16, -1 }, | |
80 | { "v13", 16, -1 }, | |
81 | { "v14", 16, -1 }, | |
82 | { "v15", 16, -1 }, | |
83 | { "v16", 16, -1 }, | |
84 | { "v17", 16, -1 }, | |
85 | { "v18", 16, -1 }, | |
86 | { "v19", 16, -1 }, | |
87 | { "v20", 16, -1 }, | |
88 | { "v21", 16, -1 }, | |
89 | { "v22", 16, -1 }, | |
90 | { "v23", 16, -1 }, | |
91 | { "v24", 16, -1 }, | |
92 | { "v25", 16, -1 }, | |
93 | { "v26", 16, -1 }, | |
94 | { "v27", 16, -1 }, | |
95 | { "v28", 16, -1 }, | |
96 | { "v29", 16, -1 }, | |
97 | { "v30", 16, -1 }, | |
98 | { "v31", 16, -1 }, | |
99 | { "fpsr", 4, -1 }, | |
100 | { "fpcr", 4, -1 }, | |
101 | }; | |
102 | ||
103 | char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) | |
104 | { | |
105 | if (regno >= DBG_MAX_REG_NUM || regno < 0) | |
106 | return NULL; | |
107 | ||
108 | if (dbg_reg_def[regno].offset != -1) | |
109 | memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, | |
110 | dbg_reg_def[regno].size); | |
111 | else | |
112 | memset(mem, 0, dbg_reg_def[regno].size); | |
113 | return dbg_reg_def[regno].name; | |
114 | } | |
115 | ||
116 | int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) | |
117 | { | |
118 | if (regno >= DBG_MAX_REG_NUM || regno < 0) | |
119 | return -EINVAL; | |
120 | ||
121 | if (dbg_reg_def[regno].offset != -1) | |
122 | memcpy((void *)regs + dbg_reg_def[regno].offset, mem, | |
123 | dbg_reg_def[regno].size); | |
124 | return 0; | |
125 | } | |
126 | ||
127 | void | |
128 | sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) | |
129 | { | |
24153c03 | 130 | struct cpu_context *cpu_context = &task->thread.cpu_context; |
bcf5763b VK |
131 | |
132 | /* Initialize to zero */ | |
133 | memset((char *)gdb_regs, 0, NUMREGBYTES); | |
24153c03 DA |
134 | |
135 | gdb_regs[19] = cpu_context->x19; | |
136 | gdb_regs[20] = cpu_context->x20; | |
137 | gdb_regs[21] = cpu_context->x21; | |
138 | gdb_regs[22] = cpu_context->x22; | |
139 | gdb_regs[23] = cpu_context->x23; | |
140 | gdb_regs[24] = cpu_context->x24; | |
141 | gdb_regs[25] = cpu_context->x25; | |
142 | gdb_regs[26] = cpu_context->x26; | |
143 | gdb_regs[27] = cpu_context->x27; | |
144 | gdb_regs[28] = cpu_context->x28; | |
145 | gdb_regs[29] = cpu_context->fp; | |
146 | ||
147 | gdb_regs[31] = cpu_context->sp; | |
148 | gdb_regs[32] = cpu_context->pc; | |
bcf5763b VK |
149 | } |
150 | ||
151 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) | |
152 | { | |
153 | regs->pc = pc; | |
154 | } | |
155 | ||
156 | static int compiled_break; | |
157 | ||
44679a4f VK |
158 | static void kgdb_arch_update_addr(struct pt_regs *regs, |
159 | char *remcom_in_buffer) | |
160 | { | |
161 | unsigned long addr; | |
162 | char *ptr; | |
163 | ||
164 | ptr = &remcom_in_buffer[1]; | |
165 | if (kgdb_hex2long(&ptr, &addr)) | |
166 | kgdb_arch_set_pc(regs, addr); | |
167 | else if (compiled_break == 1) | |
168 | kgdb_arch_set_pc(regs, regs->pc + 4); | |
169 | ||
170 | compiled_break = 0; | |
171 | } | |
172 | ||
bcf5763b VK |
173 | int kgdb_arch_handle_exception(int exception_vector, int signo, |
174 | int err_code, char *remcom_in_buffer, | |
175 | char *remcom_out_buffer, | |
176 | struct pt_regs *linux_regs) | |
177 | { | |
bcf5763b VK |
178 | int err; |
179 | ||
180 | switch (remcom_in_buffer[0]) { | |
181 | case 'D': | |
182 | case 'k': | |
183 | /* | |
184 | * Packet D (Detach), k (kill). No special handling | |
185 | * is required here. Handle same as c packet. | |
186 | */ | |
187 | case 'c': | |
188 | /* | |
189 | * Packet c (Continue) to continue executing. | |
190 | * Set pc to required address. | |
191 | * Try to read optional parameter and set pc. | |
192 | * If this was a compiled breakpoint, we need to move | |
193 | * to the next instruction else we will just breakpoint | |
194 | * over and over again. | |
195 | */ | |
44679a4f VK |
196 | kgdb_arch_update_addr(linux_regs, remcom_in_buffer); |
197 | atomic_set(&kgdb_cpu_doing_single_step, -1); | |
198 | kgdb_single_step = 0; | |
199 | ||
200 | /* | |
201 | * Received continue command, disable single step | |
202 | */ | |
203 | if (kernel_active_single_step()) | |
204 | kernel_disable_single_step(); | |
205 | ||
206 | err = 0; | |
207 | break; | |
208 | case 's': | |
209 | /* | |
210 | * Update step address value with address passed | |
211 | * with step packet. | |
212 | * On debug exception return PC is copied to ELR | |
213 | * So just update PC. | |
214 | * If no step address is passed, resume from the address | |
215 | * pointed by PC. Do not update PC | |
216 | */ | |
217 | kgdb_arch_update_addr(linux_regs, remcom_in_buffer); | |
218 | atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id()); | |
219 | kgdb_single_step = 1; | |
bcf5763b | 220 | |
44679a4f VK |
221 | /* |
222 | * Enable single step handling | |
223 | */ | |
224 | if (!kernel_active_single_step()) | |
225 | kernel_enable_single_step(linux_regs); | |
bcf5763b VK |
226 | err = 0; |
227 | break; | |
228 | default: | |
229 | err = -1; | |
230 | } | |
231 | return err; | |
232 | } | |
233 | ||
234 | static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr) | |
235 | { | |
236 | kgdb_handle_exception(1, SIGTRAP, 0, regs); | |
6bd28856 | 237 | return DBG_HOOK_HANDLED; |
bcf5763b | 238 | } |
44b53f67 | 239 | NOKPROBE_SYMBOL(kgdb_brk_fn) |
bcf5763b VK |
240 | |
241 | static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr) | |
242 | { | |
243 | compiled_break = 1; | |
244 | kgdb_handle_exception(1, SIGTRAP, 0, regs); | |
245 | ||
6bd28856 | 246 | return DBG_HOOK_HANDLED; |
bcf5763b | 247 | } |
44b53f67 | 248 | NOKPROBE_SYMBOL(kgdb_compiled_brk_fn); |
bcf5763b | 249 | |
44679a4f VK |
250 | static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr) |
251 | { | |
fb610f2a | 252 | if (!kgdb_single_step) |
b66c9870 PA |
253 | return DBG_HOOK_ERROR; |
254 | ||
8523c006 | 255 | kgdb_handle_exception(0, SIGTRAP, 0, regs); |
6bd28856 | 256 | return DBG_HOOK_HANDLED; |
44679a4f | 257 | } |
44b53f67 | 258 | NOKPROBE_SYMBOL(kgdb_step_brk_fn); |
44679a4f | 259 | |
bcf5763b | 260 | static struct break_hook kgdb_brkpt_hook = { |
26a04d84 WD |
261 | .fn = kgdb_brk_fn, |
262 | .imm = KGDB_DYN_DBG_BRK_IMM, | |
bcf5763b VK |
263 | }; |
264 | ||
265 | static struct break_hook kgdb_compiled_brkpt_hook = { | |
26a04d84 WD |
266 | .fn = kgdb_compiled_brk_fn, |
267 | .imm = KGDB_COMPILED_DBG_BRK_IMM, | |
bcf5763b VK |
268 | }; |
269 | ||
44679a4f VK |
270 | static struct step_hook kgdb_step_hook = { |
271 | .fn = kgdb_step_brk_fn | |
272 | }; | |
273 | ||
bcf5763b VK |
274 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) |
275 | { | |
276 | struct pt_regs *regs = args->regs; | |
277 | ||
278 | if (kgdb_handle_exception(1, args->signr, cmd, regs)) | |
279 | return NOTIFY_DONE; | |
280 | return NOTIFY_STOP; | |
281 | } | |
282 | ||
283 | static int | |
284 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
285 | { | |
286 | unsigned long flags; | |
287 | int ret; | |
288 | ||
289 | local_irq_save(flags); | |
290 | ret = __kgdb_notify(ptr, cmd); | |
291 | local_irq_restore(flags); | |
292 | ||
293 | return ret; | |
294 | } | |
295 | ||
296 | static struct notifier_block kgdb_notifier = { | |
297 | .notifier_call = kgdb_notify, | |
298 | /* | |
299 | * Want to be lowest priority | |
300 | */ | |
301 | .priority = -INT_MAX, | |
302 | }; | |
303 | ||
304 | /* | |
ef769e32 AB |
305 | * kgdb_arch_init - Perform any architecture specific initialization. |
306 | * This function will handle the initialization of any architecture | |
bcf5763b VK |
307 | * specific callbacks. |
308 | */ | |
309 | int kgdb_arch_init(void) | |
310 | { | |
311 | int ret = register_die_notifier(&kgdb_notifier); | |
312 | ||
313 | if (ret != 0) | |
314 | return ret; | |
315 | ||
26a04d84 WD |
316 | register_kernel_break_hook(&kgdb_brkpt_hook); |
317 | register_kernel_break_hook(&kgdb_compiled_brkpt_hook); | |
318 | register_kernel_step_hook(&kgdb_step_hook); | |
bcf5763b VK |
319 | return 0; |
320 | } | |
321 | ||
322 | /* | |
323 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
324 | * This function will handle the uninitalization of any architecture | |
325 | * specific callbacks, for dynamic registration and unregistration. | |
326 | */ | |
327 | void kgdb_arch_exit(void) | |
328 | { | |
26a04d84 WD |
329 | unregister_kernel_break_hook(&kgdb_brkpt_hook); |
330 | unregister_kernel_break_hook(&kgdb_compiled_brkpt_hook); | |
331 | unregister_kernel_step_hook(&kgdb_step_hook); | |
bcf5763b VK |
332 | unregister_die_notifier(&kgdb_notifier); |
333 | } | |
334 | ||
cc028297 | 335 | const struct kgdb_arch arch_kgdb_ops; |
67787b68 AT |
336 | |
337 | int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) | |
338 | { | |
339 | int err; | |
340 | ||
341 | BUILD_BUG_ON(AARCH64_INSN_SIZE != BREAK_INSTR_SIZE); | |
342 | ||
343 | err = aarch64_insn_read((void *)bpt->bpt_addr, (u32 *)bpt->saved_instr); | |
344 | if (err) | |
345 | return err; | |
346 | ||
347 | return aarch64_insn_write((void *)bpt->bpt_addr, | |
348 | (u32)AARCH64_BREAK_KGDB_DYN_DBG); | |
349 | } | |
350 | ||
351 | int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) | |
352 | { | |
353 | return aarch64_insn_write((void *)bpt->bpt_addr, | |
354 | *(u32 *)bpt->saved_instr); | |
355 | } |