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bcf5763b VK |
1 | /* |
2 | * AArch64 KGDB support | |
3 | * | |
4 | * Based on arch/arm/kernel/kgdb.c | |
5 | * | |
6 | * Copyright (C) 2013 Cavium Inc. | |
7 | * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License version 2 as | |
11 | * published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
20 | */ | |
21 | ||
22 | #include <linux/irq.h> | |
23 | #include <linux/kdebug.h> | |
24 | #include <linux/kgdb.h> | |
44b53f67 | 25 | #include <linux/kprobes.h> |
bcf5763b VK |
26 | #include <asm/traps.h> |
27 | ||
28 | struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = { | |
29 | { "x0", 8, offsetof(struct pt_regs, regs[0])}, | |
30 | { "x1", 8, offsetof(struct pt_regs, regs[1])}, | |
31 | { "x2", 8, offsetof(struct pt_regs, regs[2])}, | |
32 | { "x3", 8, offsetof(struct pt_regs, regs[3])}, | |
33 | { "x4", 8, offsetof(struct pt_regs, regs[4])}, | |
34 | { "x5", 8, offsetof(struct pt_regs, regs[5])}, | |
35 | { "x6", 8, offsetof(struct pt_regs, regs[6])}, | |
36 | { "x7", 8, offsetof(struct pt_regs, regs[7])}, | |
37 | { "x8", 8, offsetof(struct pt_regs, regs[8])}, | |
38 | { "x9", 8, offsetof(struct pt_regs, regs[9])}, | |
39 | { "x10", 8, offsetof(struct pt_regs, regs[10])}, | |
40 | { "x11", 8, offsetof(struct pt_regs, regs[11])}, | |
41 | { "x12", 8, offsetof(struct pt_regs, regs[12])}, | |
42 | { "x13", 8, offsetof(struct pt_regs, regs[13])}, | |
43 | { "x14", 8, offsetof(struct pt_regs, regs[14])}, | |
44 | { "x15", 8, offsetof(struct pt_regs, regs[15])}, | |
45 | { "x16", 8, offsetof(struct pt_regs, regs[16])}, | |
46 | { "x17", 8, offsetof(struct pt_regs, regs[17])}, | |
47 | { "x18", 8, offsetof(struct pt_regs, regs[18])}, | |
48 | { "x19", 8, offsetof(struct pt_regs, regs[19])}, | |
49 | { "x20", 8, offsetof(struct pt_regs, regs[20])}, | |
50 | { "x21", 8, offsetof(struct pt_regs, regs[21])}, | |
51 | { "x22", 8, offsetof(struct pt_regs, regs[22])}, | |
52 | { "x23", 8, offsetof(struct pt_regs, regs[23])}, | |
53 | { "x24", 8, offsetof(struct pt_regs, regs[24])}, | |
54 | { "x25", 8, offsetof(struct pt_regs, regs[25])}, | |
55 | { "x26", 8, offsetof(struct pt_regs, regs[26])}, | |
56 | { "x27", 8, offsetof(struct pt_regs, regs[27])}, | |
57 | { "x28", 8, offsetof(struct pt_regs, regs[28])}, | |
58 | { "x29", 8, offsetof(struct pt_regs, regs[29])}, | |
59 | { "x30", 8, offsetof(struct pt_regs, regs[30])}, | |
60 | { "sp", 8, offsetof(struct pt_regs, sp)}, | |
61 | { "pc", 8, offsetof(struct pt_regs, pc)}, | |
0d15ef67 DT |
62 | /* |
63 | * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote | |
64 | * protocol disagrees. Therefore we must extract only the lower | |
65 | * 32-bits. Look for the big comment in asm/kgdb.h for more | |
66 | * detail. | |
67 | */ | |
68 | { "pstate", 4, offsetof(struct pt_regs, pstate) | |
69 | #ifdef CONFIG_CPU_BIG_ENDIAN | |
70 | + 4 | |
71 | #endif | |
72 | }, | |
bcf5763b VK |
73 | { "v0", 16, -1 }, |
74 | { "v1", 16, -1 }, | |
75 | { "v2", 16, -1 }, | |
76 | { "v3", 16, -1 }, | |
77 | { "v4", 16, -1 }, | |
78 | { "v5", 16, -1 }, | |
79 | { "v6", 16, -1 }, | |
80 | { "v7", 16, -1 }, | |
81 | { "v8", 16, -1 }, | |
82 | { "v9", 16, -1 }, | |
83 | { "v10", 16, -1 }, | |
84 | { "v11", 16, -1 }, | |
85 | { "v12", 16, -1 }, | |
86 | { "v13", 16, -1 }, | |
87 | { "v14", 16, -1 }, | |
88 | { "v15", 16, -1 }, | |
89 | { "v16", 16, -1 }, | |
90 | { "v17", 16, -1 }, | |
91 | { "v18", 16, -1 }, | |
92 | { "v19", 16, -1 }, | |
93 | { "v20", 16, -1 }, | |
94 | { "v21", 16, -1 }, | |
95 | { "v22", 16, -1 }, | |
96 | { "v23", 16, -1 }, | |
97 | { "v24", 16, -1 }, | |
98 | { "v25", 16, -1 }, | |
99 | { "v26", 16, -1 }, | |
100 | { "v27", 16, -1 }, | |
101 | { "v28", 16, -1 }, | |
102 | { "v29", 16, -1 }, | |
103 | { "v30", 16, -1 }, | |
104 | { "v31", 16, -1 }, | |
105 | { "fpsr", 4, -1 }, | |
106 | { "fpcr", 4, -1 }, | |
107 | }; | |
108 | ||
109 | char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs) | |
110 | { | |
111 | if (regno >= DBG_MAX_REG_NUM || regno < 0) | |
112 | return NULL; | |
113 | ||
114 | if (dbg_reg_def[regno].offset != -1) | |
115 | memcpy(mem, (void *)regs + dbg_reg_def[regno].offset, | |
116 | dbg_reg_def[regno].size); | |
117 | else | |
118 | memset(mem, 0, dbg_reg_def[regno].size); | |
119 | return dbg_reg_def[regno].name; | |
120 | } | |
121 | ||
122 | int dbg_set_reg(int regno, void *mem, struct pt_regs *regs) | |
123 | { | |
124 | if (regno >= DBG_MAX_REG_NUM || regno < 0) | |
125 | return -EINVAL; | |
126 | ||
127 | if (dbg_reg_def[regno].offset != -1) | |
128 | memcpy((void *)regs + dbg_reg_def[regno].offset, mem, | |
129 | dbg_reg_def[regno].size); | |
130 | return 0; | |
131 | } | |
132 | ||
133 | void | |
134 | sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) | |
135 | { | |
136 | struct pt_regs *thread_regs; | |
137 | ||
138 | /* Initialize to zero */ | |
139 | memset((char *)gdb_regs, 0, NUMREGBYTES); | |
140 | thread_regs = task_pt_regs(task); | |
141 | memcpy((void *)gdb_regs, (void *)thread_regs->regs, GP_REG_BYTES); | |
0d15ef67 DT |
142 | /* Special case for PSTATE (check comments in asm/kgdb.h for details) */ |
143 | dbg_get_reg(33, gdb_regs + GP_REG_BYTES, thread_regs); | |
bcf5763b VK |
144 | } |
145 | ||
146 | void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) | |
147 | { | |
148 | regs->pc = pc; | |
149 | } | |
150 | ||
151 | static int compiled_break; | |
152 | ||
44679a4f VK |
153 | static void kgdb_arch_update_addr(struct pt_regs *regs, |
154 | char *remcom_in_buffer) | |
155 | { | |
156 | unsigned long addr; | |
157 | char *ptr; | |
158 | ||
159 | ptr = &remcom_in_buffer[1]; | |
160 | if (kgdb_hex2long(&ptr, &addr)) | |
161 | kgdb_arch_set_pc(regs, addr); | |
162 | else if (compiled_break == 1) | |
163 | kgdb_arch_set_pc(regs, regs->pc + 4); | |
164 | ||
165 | compiled_break = 0; | |
166 | } | |
167 | ||
bcf5763b VK |
168 | int kgdb_arch_handle_exception(int exception_vector, int signo, |
169 | int err_code, char *remcom_in_buffer, | |
170 | char *remcom_out_buffer, | |
171 | struct pt_regs *linux_regs) | |
172 | { | |
bcf5763b VK |
173 | int err; |
174 | ||
175 | switch (remcom_in_buffer[0]) { | |
176 | case 'D': | |
177 | case 'k': | |
178 | /* | |
179 | * Packet D (Detach), k (kill). No special handling | |
180 | * is required here. Handle same as c packet. | |
181 | */ | |
182 | case 'c': | |
183 | /* | |
184 | * Packet c (Continue) to continue executing. | |
185 | * Set pc to required address. | |
186 | * Try to read optional parameter and set pc. | |
187 | * If this was a compiled breakpoint, we need to move | |
188 | * to the next instruction else we will just breakpoint | |
189 | * over and over again. | |
190 | */ | |
44679a4f VK |
191 | kgdb_arch_update_addr(linux_regs, remcom_in_buffer); |
192 | atomic_set(&kgdb_cpu_doing_single_step, -1); | |
193 | kgdb_single_step = 0; | |
194 | ||
195 | /* | |
196 | * Received continue command, disable single step | |
197 | */ | |
198 | if (kernel_active_single_step()) | |
199 | kernel_disable_single_step(); | |
200 | ||
201 | err = 0; | |
202 | break; | |
203 | case 's': | |
204 | /* | |
205 | * Update step address value with address passed | |
206 | * with step packet. | |
207 | * On debug exception return PC is copied to ELR | |
208 | * So just update PC. | |
209 | * If no step address is passed, resume from the address | |
210 | * pointed by PC. Do not update PC | |
211 | */ | |
212 | kgdb_arch_update_addr(linux_regs, remcom_in_buffer); | |
213 | atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id()); | |
214 | kgdb_single_step = 1; | |
bcf5763b | 215 | |
44679a4f VK |
216 | /* |
217 | * Enable single step handling | |
218 | */ | |
219 | if (!kernel_active_single_step()) | |
220 | kernel_enable_single_step(linux_regs); | |
bcf5763b VK |
221 | err = 0; |
222 | break; | |
223 | default: | |
224 | err = -1; | |
225 | } | |
226 | return err; | |
227 | } | |
228 | ||
229 | static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr) | |
230 | { | |
231 | kgdb_handle_exception(1, SIGTRAP, 0, regs); | |
232 | return 0; | |
233 | } | |
44b53f67 | 234 | NOKPROBE_SYMBOL(kgdb_brk_fn) |
bcf5763b VK |
235 | |
236 | static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr) | |
237 | { | |
238 | compiled_break = 1; | |
239 | kgdb_handle_exception(1, SIGTRAP, 0, regs); | |
240 | ||
241 | return 0; | |
242 | } | |
44b53f67 | 243 | NOKPROBE_SYMBOL(kgdb_compiled_brk_fn); |
bcf5763b | 244 | |
44679a4f VK |
245 | static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr) |
246 | { | |
247 | kgdb_handle_exception(1, SIGTRAP, 0, regs); | |
248 | return 0; | |
249 | } | |
44b53f67 | 250 | NOKPROBE_SYMBOL(kgdb_step_brk_fn); |
44679a4f | 251 | |
bcf5763b VK |
252 | static struct break_hook kgdb_brkpt_hook = { |
253 | .esr_mask = 0xffffffff, | |
c696b934 | 254 | .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_DYN_DBG_BRK_IMM), |
bcf5763b VK |
255 | .fn = kgdb_brk_fn |
256 | }; | |
257 | ||
258 | static struct break_hook kgdb_compiled_brkpt_hook = { | |
259 | .esr_mask = 0xffffffff, | |
c696b934 | 260 | .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_COMPILED_DBG_BRK_IMM), |
bcf5763b VK |
261 | .fn = kgdb_compiled_brk_fn |
262 | }; | |
263 | ||
44679a4f VK |
264 | static struct step_hook kgdb_step_hook = { |
265 | .fn = kgdb_step_brk_fn | |
266 | }; | |
267 | ||
bcf5763b VK |
268 | static void kgdb_call_nmi_hook(void *ignored) |
269 | { | |
270 | kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); | |
271 | } | |
272 | ||
273 | void kgdb_roundup_cpus(unsigned long flags) | |
274 | { | |
275 | local_irq_enable(); | |
276 | smp_call_function(kgdb_call_nmi_hook, NULL, 0); | |
277 | local_irq_disable(); | |
278 | } | |
279 | ||
280 | static int __kgdb_notify(struct die_args *args, unsigned long cmd) | |
281 | { | |
282 | struct pt_regs *regs = args->regs; | |
283 | ||
284 | if (kgdb_handle_exception(1, args->signr, cmd, regs)) | |
285 | return NOTIFY_DONE; | |
286 | return NOTIFY_STOP; | |
287 | } | |
288 | ||
289 | static int | |
290 | kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) | |
291 | { | |
292 | unsigned long flags; | |
293 | int ret; | |
294 | ||
295 | local_irq_save(flags); | |
296 | ret = __kgdb_notify(ptr, cmd); | |
297 | local_irq_restore(flags); | |
298 | ||
299 | return ret; | |
300 | } | |
301 | ||
302 | static struct notifier_block kgdb_notifier = { | |
303 | .notifier_call = kgdb_notify, | |
304 | /* | |
305 | * Want to be lowest priority | |
306 | */ | |
307 | .priority = -INT_MAX, | |
308 | }; | |
309 | ||
310 | /* | |
ef769e32 AB |
311 | * kgdb_arch_init - Perform any architecture specific initialization. |
312 | * This function will handle the initialization of any architecture | |
bcf5763b VK |
313 | * specific callbacks. |
314 | */ | |
315 | int kgdb_arch_init(void) | |
316 | { | |
317 | int ret = register_die_notifier(&kgdb_notifier); | |
318 | ||
319 | if (ret != 0) | |
320 | return ret; | |
321 | ||
322 | register_break_hook(&kgdb_brkpt_hook); | |
323 | register_break_hook(&kgdb_compiled_brkpt_hook); | |
44679a4f | 324 | register_step_hook(&kgdb_step_hook); |
bcf5763b VK |
325 | return 0; |
326 | } | |
327 | ||
328 | /* | |
329 | * kgdb_arch_exit - Perform any architecture specific uninitalization. | |
330 | * This function will handle the uninitalization of any architecture | |
331 | * specific callbacks, for dynamic registration and unregistration. | |
332 | */ | |
333 | void kgdb_arch_exit(void) | |
334 | { | |
335 | unregister_break_hook(&kgdb_brkpt_hook); | |
336 | unregister_break_hook(&kgdb_compiled_brkpt_hook); | |
44679a4f | 337 | unregister_step_hook(&kgdb_step_hook); |
bcf5763b VK |
338 | unregister_die_notifier(&kgdb_notifier); |
339 | } | |
340 | ||
341 | /* | |
342 | * ARM instructions are always in LE. | |
343 | * Break instruction is encoded in LE format | |
344 | */ | |
345 | struct kgdb_arch arch_kgdb_ops = { | |
346 | .gdb_bpt_instr = { | |
c696b934 DM |
347 | KGDB_DYN_BRK_INS_BYTE(0), |
348 | KGDB_DYN_BRK_INS_BYTE(1), | |
349 | KGDB_DYN_BRK_INS_BYTE(2), | |
350 | KGDB_DYN_BRK_INS_BYTE(3), | |
bcf5763b VK |
351 | } |
352 | }; |