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/irq.h>
23 #include <linux/kdebug.h>
24 #include <linux/kgdb.h>
25 #include <asm/traps.h>
27 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
28 { "x0", 8, offsetof(struct pt_regs, regs[0])},
29 { "x1", 8, offsetof(struct pt_regs, regs[1])},
30 { "x2", 8, offsetof(struct pt_regs, regs[2])},
31 { "x3", 8, offsetof(struct pt_regs, regs[3])},
32 { "x4", 8, offsetof(struct pt_regs, regs[4])},
33 { "x5", 8, offsetof(struct pt_regs, regs[5])},
34 { "x6", 8, offsetof(struct pt_regs, regs[6])},
35 { "x7", 8, offsetof(struct pt_regs, regs[7])},
36 { "x8", 8, offsetof(struct pt_regs, regs[8])},
37 { "x9", 8, offsetof(struct pt_regs, regs[9])},
38 { "x10", 8, offsetof(struct pt_regs, regs[10])},
39 { "x11", 8, offsetof(struct pt_regs, regs[11])},
40 { "x12", 8, offsetof(struct pt_regs, regs[12])},
41 { "x13", 8, offsetof(struct pt_regs, regs[13])},
42 { "x14", 8, offsetof(struct pt_regs, regs[14])},
43 { "x15", 8, offsetof(struct pt_regs, regs[15])},
44 { "x16", 8, offsetof(struct pt_regs, regs[16])},
45 { "x17", 8, offsetof(struct pt_regs, regs[17])},
46 { "x18", 8, offsetof(struct pt_regs, regs[18])},
47 { "x19", 8, offsetof(struct pt_regs, regs[19])},
48 { "x20", 8, offsetof(struct pt_regs, regs[20])},
49 { "x21", 8, offsetof(struct pt_regs, regs[21])},
50 { "x22", 8, offsetof(struct pt_regs, regs[22])},
51 { "x23", 8, offsetof(struct pt_regs, regs[23])},
52 { "x24", 8, offsetof(struct pt_regs, regs[24])},
53 { "x25", 8, offsetof(struct pt_regs, regs[25])},
54 { "x26", 8, offsetof(struct pt_regs, regs[26])},
55 { "x27", 8, offsetof(struct pt_regs, regs[27])},
56 { "x28", 8, offsetof(struct pt_regs, regs[28])},
57 { "x29", 8, offsetof(struct pt_regs, regs[29])},
58 { "x30", 8, offsetof(struct pt_regs, regs[30])},
59 { "sp", 8, offsetof(struct pt_regs, sp)},
60 { "pc", 8, offsetof(struct pt_regs, pc)},
62 * struct pt_regs thinks PSTATE is 64-bits wide but gdb remote
63 * protocol disagrees. Therefore we must extract only the lower
64 * 32-bits. Look for the big comment in asm/kgdb.h for more
67 { "pstate", 4, offsetof(struct pt_regs, pstate)
68 #ifdef CONFIG_CPU_BIG_ENDIAN
108 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
110 if (regno >= DBG_MAX_REG_NUM || regno < 0)
113 if (dbg_reg_def[regno].offset != -1)
114 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
115 dbg_reg_def[regno].size);
117 memset(mem, 0, dbg_reg_def[regno].size);
118 return dbg_reg_def[regno].name;
121 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
123 if (regno >= DBG_MAX_REG_NUM || regno < 0)
126 if (dbg_reg_def[regno].offset != -1)
127 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
128 dbg_reg_def[regno].size);
133 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
135 struct pt_regs *thread_regs;
137 /* Initialize to zero */
138 memset((char *)gdb_regs, 0, NUMREGBYTES);
139 thread_regs = task_pt_regs(task);
140 memcpy((void *)gdb_regs, (void *)thread_regs->regs, GP_REG_BYTES);
141 /* Special case for PSTATE (check comments in asm/kgdb.h for details) */
142 dbg_get_reg(33, gdb_regs + GP_REG_BYTES, thread_regs);
145 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
150 static int compiled_break;
152 static void kgdb_arch_update_addr(struct pt_regs *regs,
153 char *remcom_in_buffer)
158 ptr = &remcom_in_buffer[1];
159 if (kgdb_hex2long(&ptr, &addr))
160 kgdb_arch_set_pc(regs, addr);
161 else if (compiled_break == 1)
162 kgdb_arch_set_pc(regs, regs->pc + 4);
167 int kgdb_arch_handle_exception(int exception_vector, int signo,
168 int err_code, char *remcom_in_buffer,
169 char *remcom_out_buffer,
170 struct pt_regs *linux_regs)
174 switch (remcom_in_buffer[0]) {
178 * Packet D (Detach), k (kill). No special handling
179 * is required here. Handle same as c packet.
183 * Packet c (Continue) to continue executing.
184 * Set pc to required address.
185 * Try to read optional parameter and set pc.
186 * If this was a compiled breakpoint, we need to move
187 * to the next instruction else we will just breakpoint
188 * over and over again.
190 kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
191 atomic_set(&kgdb_cpu_doing_single_step, -1);
192 kgdb_single_step = 0;
195 * Received continue command, disable single step
197 if (kernel_active_single_step())
198 kernel_disable_single_step();
204 * Update step address value with address passed
206 * On debug exception return PC is copied to ELR
208 * If no step address is passed, resume from the address
209 * pointed by PC. Do not update PC
211 kgdb_arch_update_addr(linux_regs, remcom_in_buffer);
212 atomic_set(&kgdb_cpu_doing_single_step, raw_smp_processor_id());
213 kgdb_single_step = 1;
216 * Enable single step handling
218 if (!kernel_active_single_step())
219 kernel_enable_single_step(linux_regs);
228 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int esr)
230 kgdb_handle_exception(1, SIGTRAP, 0, regs);
234 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int esr)
237 kgdb_handle_exception(1, SIGTRAP, 0, regs);
242 static int kgdb_step_brk_fn(struct pt_regs *regs, unsigned int esr)
244 kgdb_handle_exception(1, SIGTRAP, 0, regs);
248 static struct break_hook kgdb_brkpt_hook = {
249 .esr_mask = 0xffffffff,
250 .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_DYN_DBG_BRK_IMM),
254 static struct break_hook kgdb_compiled_brkpt_hook = {
255 .esr_mask = 0xffffffff,
256 .esr_val = (u32)ESR_ELx_VAL_BRK64(KGDB_COMPILED_DBG_BRK_IMM),
257 .fn = kgdb_compiled_brk_fn
260 static struct step_hook kgdb_step_hook = {
261 .fn = kgdb_step_brk_fn
264 static void kgdb_call_nmi_hook(void *ignored)
266 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
269 void kgdb_roundup_cpus(unsigned long flags)
272 smp_call_function(kgdb_call_nmi_hook, NULL, 0);
276 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
278 struct pt_regs *regs = args->regs;
280 if (kgdb_handle_exception(1, args->signr, cmd, regs))
286 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
291 local_irq_save(flags);
292 ret = __kgdb_notify(ptr, cmd);
293 local_irq_restore(flags);
298 static struct notifier_block kgdb_notifier = {
299 .notifier_call = kgdb_notify,
301 * Want to be lowest priority
303 .priority = -INT_MAX,
307 * kgdb_arch_init - Perform any architecture specific initialization.
308 * This function will handle the initialization of any architecture
309 * specific callbacks.
311 int kgdb_arch_init(void)
313 int ret = register_die_notifier(&kgdb_notifier);
318 register_break_hook(&kgdb_brkpt_hook);
319 register_break_hook(&kgdb_compiled_brkpt_hook);
320 register_step_hook(&kgdb_step_hook);
325 * kgdb_arch_exit - Perform any architecture specific uninitalization.
326 * This function will handle the uninitalization of any architecture
327 * specific callbacks, for dynamic registration and unregistration.
329 void kgdb_arch_exit(void)
331 unregister_break_hook(&kgdb_brkpt_hook);
332 unregister_break_hook(&kgdb_compiled_brkpt_hook);
333 unregister_step_hook(&kgdb_step_hook);
334 unregister_die_notifier(&kgdb_notifier);
338 * ARM instructions are always in LE.
339 * Break instruction is encoded in LE format
341 struct kgdb_arch arch_kgdb_ops = {
343 KGDB_DYN_BRK_INS_BYTE(0),
344 KGDB_DYN_BRK_INS_BYTE(1),
345 KGDB_DYN_BRK_INS_BYTE(2),
346 KGDB_DYN_BRK_INS_BYTE(3),