4 * Based on arch/arm/kernel/kgdb.c
6 * Copyright (C) 2013 Cavium Inc.
7 * Author: Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>
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.
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.
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/>.
22 #include <linux/bug.h>
23 #include <linux/irq.h>
24 #include <linux/kdebug.h>
25 #include <linux/kgdb.h>
26 #include <linux/kprobes.h>
27 #include <linux/sched/task_stack.h>
29 #include <asm/debug-monitors.h>
31 #include <asm/traps.h>
33 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
34 { "x0", 8, offsetof(struct pt_regs, regs[0])},
35 { "x1", 8, offsetof(struct pt_regs, regs[1])},
36 { "x2", 8, offsetof(struct pt_regs, regs[2])},
37 { "x3", 8, offsetof(struct pt_regs, regs[3])},
38 { "x4", 8, offsetof(struct pt_regs, regs[4])},
39 { "x5", 8, offsetof(struct pt_regs, regs[5])},
40 { "x6", 8, offsetof(struct pt_regs, regs[6])},
41 { "x7", 8, offsetof(struct pt_regs, regs[7])},
42 { "x8", 8, offsetof(struct pt_regs, regs[8])},
43 { "x9", 8, offsetof(struct pt_regs, regs[9])},
44 { "x10", 8, offsetof(struct pt_regs, regs[10])},
45 { "x11", 8, offsetof(struct pt_regs, regs[11])},
46 { "x12", 8, offsetof(struct pt_regs, regs[12])},
47 { "x13", 8, offsetof(struct pt_regs, regs[13])},
48 { "x14", 8, offsetof(struct pt_regs, regs[14])},
49 { "x15", 8, offsetof(struct pt_regs, regs[15])},
50 { "x16", 8, offsetof(struct pt_regs, regs[16])},
51 { "x17", 8, offsetof(struct pt_regs, regs[17])},
52 { "x18", 8, offsetof(struct pt_regs, regs[18])},
53 { "x19", 8, offsetof(struct pt_regs, regs[19])},
54 { "x20", 8, offsetof(struct pt_regs, regs[20])},
55 { "x21", 8, offsetof(struct pt_regs, regs[21])},
56 { "x22", 8, offsetof(struct pt_regs, regs[22])},
57 { "x23", 8, offsetof(struct pt_regs, regs[23])},
58 { "x24", 8, offsetof(struct pt_regs, regs[24])},
59 { "x25", 8, offsetof(struct pt_regs, regs[25])},
60 { "x26", 8, offsetof(struct pt_regs, regs[26])},
61 { "x27", 8, offsetof(struct pt_regs, regs[27])},
62 { "x28", 8, offsetof(struct pt_regs, regs[28])},
63 { "x29", 8, offsetof(struct pt_regs, regs[29])},
64 { "x30", 8, offsetof(struct pt_regs, regs[30])},
65 { "sp", 8, offsetof(struct pt_regs, sp)},
66 { "pc", 8, offsetof(struct pt_regs, pc)},
68 * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote
69 * protocol disagrees. Therefore we must extract only the lower
70 * 32-bits. Look for the big comment in asm/kgdb.h for more
73 { "pstate", 4, offsetof(struct pt_regs, pstate)
74 #ifdef CONFIG_CPU_BIG_ENDIAN
114 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
116 if (regno >= DBG_MAX_REG_NUM || regno < 0)
119 if (dbg_reg_def[regno].offset != -1)
120 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
121 dbg_reg_def[regno].size);
123 memset(mem, 0, dbg_reg_def[regno].size);
124 return dbg_reg_def[regno].name;
127 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
129 if (regno >= DBG_MAX_REG_NUM || regno < 0)
132 if (dbg_reg_def[regno].offset != -1)
133 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
134 dbg_reg_def[regno].size);
139 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
141 struct cpu_context *cpu_context = &task->thread.cpu_context;
143 /* Initialize to zero */
144 memset((char *)gdb_regs, 0, NUMREGBYTES);
146 gdb_regs[19] = cpu_context->x19;
147 gdb_regs[20] = cpu_context->x20;
148 gdb_regs[21] = cpu_context->x21;
149 gdb_regs[22] = cpu_context->x22;
150 gdb_regs[23] = cpu_context->x23;
151 gdb_regs[24] = cpu_context->x24;
152 gdb_regs[25] = cpu_context->x25;
153 gdb_regs[26] = cpu_context->x26;
154 gdb_regs[27] = cpu_context->x27;
155 gdb_regs[28] = cpu_context->x28;
156 gdb_regs[29] = cpu_context->fp;
158 gdb_regs[31] = cpu_context->sp;
159 gdb_regs[32] = cpu_context->pc;
162 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
167 static int compiled_break;
169 static void kgdb_arch_update_addr(struct pt_regs *regs,
170 char *remcom_in_buffer)
175 ptr = &remcom_in_buffer[1];
176 if (kgdb_hex2long(&ptr, &addr))
177 kgdb_arch_set_pc(regs, addr);
178 else if (compiled_break == 1)
179 kgdb_arch_set_pc(regs, regs->pc + 4);
184 int kgdb_arch_handle_exception(int exception_vector, int signo,
185 int err_code, char *remcom_in_buffer,
186 char *remcom_out_buffer,
187 struct pt_regs *linux_regs)
191 switch (remcom_in_buffer[0]) {
195 * Packet D (Detach), k (kill). No special handling
196 * is required here. Handle same as c packet.
200 * Packet c (Continue) to continue executing.
201 * Set pc to required address.
202 * Try to read optional parameter and set pc.
203 * If this was a compiled breakpoint, we need to move
204 * to the next instruction else we will just breakpoint
205 * over and over again.
207 kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
208 atomic_set(&kgdb_cpu_doing_single_step, -1);
209 kgdb_single_step = 0;
212 * Received continue command, disable single step
214 if (kernel_active_single_step())
215 kernel_disable_single_step();
221 * Update step address value with address passed
223 * On debug exception return PC is copied to ELR
225 * If no step address is passed, resume from the address
226 * pointed by PC. Do not update PC
228 kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
229 atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
230 kgdb_single_step = 1;
233 * Enable single step handling
235 if (!kernel_active_single_step())
236 kernel_enable_single_step(linux_regs);
245 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr)
248 return DBG_HOOK_ERROR;
250 kgdb_handle_exception(1, SIGTRAP, 0, regs);
251 return DBG_HOOK_HANDLED;
253 NOKPROBE_SYMBOL(kgdb_brk_fn)
255 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr)
258 return DBG_HOOK_ERROR;
261 kgdb_handle_exception(1, SIGTRAP, 0, regs);
263 return DBG_HOOK_HANDLED;
265 NOKPROBE_SYMBOL(kgdb_compiled_brk_fn);
267 static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)
269 if (user_mode(regs) || !kgdb_single_step)
270 return DBG_HOOK_ERROR;
272 kgdb_handle_exception(1, SIGTRAP, 0, regs);
273 return DBG_HOOK_HANDLED;
275 NOKPROBE_SYMBOL(kgdb_step_brk_fn);
277 static struct break_hook kgdb_brkpt_hook = {
278 .esr_mask = 0xffffffff,
279 .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_DYN_DBG_BRK_IMM),
283 static struct break_hook kgdb_compiled_brkpt_hook = {
284 .esr_mask = 0xffffffff,
285 .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_COMPILED_DBG_BRK_IMM),
286 .fn = kgdb_compiled_brk_fn
289 static struct step_hook kgdb_step_hook = {
290 .fn = kgdb_step_brk_fn
293 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
295 struct pt_regs *regs = args->regs;
297 if (kgdb_handle_exception(1, args->signr, cmd, regs))
303 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
308 local_irq_save(flags);
309 ret = __kgdb_notify(ptr, cmd);
310 local_irq_restore(flags);
315 static struct notifier_block kgdb_notifier = {
316 .notifier_call = kgdb_notify,
318 * Want to be lowest priority
320 .priority = -INT_MAX,
324 * kgdb_arch_init - Perform any architecture specific initialization.
325 * This function will handle the initialization of any architecture
326 * specific callbacks.
328 int kgdb_arch_init(void)
330 int ret = register_die_notifier(&kgdb_notifier);
335 register_break_hook(&kgdb_brkpt_hook);
336 register_break_hook(&kgdb_compiled_brkpt_hook);
337 register_step_hook(&kgdb_step_hook);
342 * kgdb_arch_exit - Perform any architecture specific uninitalization.
343 * This function will handle the uninitalization of any architecture
344 * specific callbacks, for dynamic registration and unregistration.
346 void kgdb_arch_exit(void)
348 unregister_break_hook(&kgdb_brkpt_hook);
349 unregister_break_hook(&kgdb_compiled_brkpt_hook);
350 unregister_step_hook(&kgdb_step_hook);
351 unregister_die_notifier(&kgdb_notifier);
354 const struct kgdb_arch arch_kgdb_ops;
356 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
360 BUILD_BUG_ON(AARCH64_INSN_SIZE != BREAK_INSTR_SIZE);
362 err = aarch64_insn_read((void *)bpt->bpt_addr, (u32 *)bpt->saved_instr);
366 return aarch64_insn_write((void *)bpt->bpt_addr,
367 (u32)AARCH64_BREAK_KGDB_DYN_DBG);
370 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
372 return aarch64_insn_write((void *)bpt->bpt_addr,
373 *(u32 *)bpt->saved_instr);