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 20 struct 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 50 char *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 63 int 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 74 void 75 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task) 76 { 77 struct pt_regs *thread_regs; 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 thread_regs = task_pt_regs(task); 90 gdb_regs[_R0] = thread_regs->ARM_r0; 91 gdb_regs[_R1] = thread_regs->ARM_r1; 92 gdb_regs[_R2] = thread_regs->ARM_r2; 93 gdb_regs[_R3] = thread_regs->ARM_r3; 94 gdb_regs[_R4] = thread_regs->ARM_r4; 95 gdb_regs[_R5] = thread_regs->ARM_r5; 96 gdb_regs[_R6] = thread_regs->ARM_r6; 97 gdb_regs[_R7] = thread_regs->ARM_r7; 98 gdb_regs[_R8] = thread_regs->ARM_r8; 99 gdb_regs[_R9] = thread_regs->ARM_r9; 100 gdb_regs[_R10] = thread_regs->ARM_r10; 101 gdb_regs[_FP] = thread_regs->ARM_fp; 102 gdb_regs[_IP] = thread_regs->ARM_ip; 103 gdb_regs[_SPT] = thread_regs->ARM_sp; 104 gdb_regs[_LR] = thread_regs->ARM_lr; 105 gdb_regs[_PC] = thread_regs->ARM_pc; 106 gdb_regs[_CPSR] = thread_regs->ARM_cpsr; 107 } 108 109 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 110 { 111 regs->ARM_pc = pc; 112 } 113 114 static int compiled_break; 115 116 int kgdb_arch_handle_exception(int exception_vector, int signo, 117 int err_code, char *remcom_in_buffer, 118 char *remcom_out_buffer, 119 struct pt_regs *linux_regs) 120 { 121 unsigned long addr; 122 char *ptr; 123 124 switch (remcom_in_buffer[0]) { 125 case 'D': 126 case 'k': 127 case 'c': 128 /* 129 * Try to read optional parameter, pc unchanged if no parm. 130 * If this was a compiled breakpoint, we need to move 131 * to the next instruction or we will just breakpoint 132 * over and over again. 133 */ 134 ptr = &remcom_in_buffer[1]; 135 if (kgdb_hex2long(&ptr, &addr)) 136 linux_regs->ARM_pc = addr; 137 else if (compiled_break == 1) 138 linux_regs->ARM_pc += 4; 139 140 compiled_break = 0; 141 142 return 0; 143 } 144 145 return -1; 146 } 147 148 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr) 149 { 150 kgdb_handle_exception(1, SIGTRAP, 0, regs); 151 152 return 0; 153 } 154 155 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr) 156 { 157 compiled_break = 1; 158 kgdb_handle_exception(1, SIGTRAP, 0, regs); 159 160 return 0; 161 } 162 163 static struct undef_hook kgdb_brkpt_hook = { 164 .instr_mask = 0xffffffff, 165 .instr_val = KGDB_BREAKINST, 166 .cpsr_mask = MODE_MASK, 167 .cpsr_val = SVC_MODE, 168 .fn = kgdb_brk_fn 169 }; 170 171 static struct undef_hook kgdb_compiled_brkpt_hook = { 172 .instr_mask = 0xffffffff, 173 .instr_val = KGDB_COMPILED_BREAK, 174 .cpsr_mask = MODE_MASK, 175 .cpsr_val = SVC_MODE, 176 .fn = kgdb_compiled_brk_fn 177 }; 178 179 static void kgdb_call_nmi_hook(void *ignored) 180 { 181 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); 182 } 183 184 void kgdb_roundup_cpus(unsigned long flags) 185 { 186 local_irq_enable(); 187 smp_call_function(kgdb_call_nmi_hook, NULL, 0); 188 local_irq_disable(); 189 } 190 191 static int __kgdb_notify(struct die_args *args, unsigned long cmd) 192 { 193 struct pt_regs *regs = args->regs; 194 195 if (kgdb_handle_exception(1, args->signr, cmd, regs)) 196 return NOTIFY_DONE; 197 return NOTIFY_STOP; 198 } 199 static int 200 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) 201 { 202 unsigned long flags; 203 int ret; 204 205 local_irq_save(flags); 206 ret = __kgdb_notify(ptr, cmd); 207 local_irq_restore(flags); 208 209 return ret; 210 } 211 212 static struct notifier_block kgdb_notifier = { 213 .notifier_call = kgdb_notify, 214 .priority = -INT_MAX, 215 }; 216 217 218 /** 219 * kgdb_arch_init - Perform any architecture specific initalization. 220 * 221 * This function will handle the initalization of any architecture 222 * specific callbacks. 223 */ 224 int kgdb_arch_init(void) 225 { 226 int ret = register_die_notifier(&kgdb_notifier); 227 228 if (ret != 0) 229 return ret; 230 231 register_undef_hook(&kgdb_brkpt_hook); 232 register_undef_hook(&kgdb_compiled_brkpt_hook); 233 234 return 0; 235 } 236 237 /** 238 * kgdb_arch_exit - Perform any architecture specific uninitalization. 239 * 240 * This function will handle the uninitalization of any architecture 241 * specific callbacks, for dynamic registration and unregistration. 242 */ 243 void kgdb_arch_exit(void) 244 { 245 unregister_undef_hook(&kgdb_brkpt_hook); 246 unregister_undef_hook(&kgdb_compiled_brkpt_hook); 247 unregister_die_notifier(&kgdb_notifier); 248 } 249 250 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 251 { 252 int err; 253 254 /* patch_text() only supports int-sized breakpoints */ 255 BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE); 256 257 err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, 258 BREAK_INSTR_SIZE); 259 if (err) 260 return err; 261 262 patch_text((void *)bpt->bpt_addr, 263 *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr); 264 265 return err; 266 } 267 268 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) 269 { 270 patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr); 271 272 return 0; 273 } 274 275 /* 276 * Register our undef instruction hooks with ARM undef core. 277 * We regsiter a hook specifically looking for the KGB break inst 278 * and we handle the normal undef case within the do_undefinstr 279 * handler. 280 */ 281 struct kgdb_arch arch_kgdb_ops = { 282 #ifndef __ARMEB__ 283 .gdb_bpt_instr = {0xfe, 0xde, 0xff, 0xe7} 284 #else /* ! __ARMEB__ */ 285 .gdb_bpt_instr = {0xe7, 0xff, 0xde, 0xfe} 286 #endif 287 }; 288