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 thread_info *ti; 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 ti = task_thread_info(task); 90 gdb_regs[_R4] = ti->cpu_context.r4; 91 gdb_regs[_R5] = ti->cpu_context.r5; 92 gdb_regs[_R6] = ti->cpu_context.r6; 93 gdb_regs[_R7] = ti->cpu_context.r7; 94 gdb_regs[_R8] = ti->cpu_context.r8; 95 gdb_regs[_R9] = ti->cpu_context.r9; 96 gdb_regs[_R10] = ti->cpu_context.sl; 97 gdb_regs[_FP] = ti->cpu_context.fp; 98 gdb_regs[_SPT] = ti->cpu_context.sp; 99 gdb_regs[_PC] = ti->cpu_context.pc; 100 } 101 102 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc) 103 { 104 regs->ARM_pc = pc; 105 } 106 107 static int compiled_break; 108 109 int kgdb_arch_handle_exception(int exception_vector, int signo, 110 int err_code, char *remcom_in_buffer, 111 char *remcom_out_buffer, 112 struct pt_regs *linux_regs) 113 { 114 unsigned long addr; 115 char *ptr; 116 117 switch (remcom_in_buffer[0]) { 118 case 'D': 119 case 'k': 120 case 'c': 121 /* 122 * Try to read optional parameter, pc unchanged if no parm. 123 * If this was a compiled breakpoint, we need to move 124 * to the next instruction or we will just breakpoint 125 * over and over again. 126 */ 127 ptr = &remcom_in_buffer[1]; 128 if (kgdb_hex2long(&ptr, &addr)) 129 linux_regs->ARM_pc = addr; 130 else if (compiled_break == 1) 131 linux_regs->ARM_pc += 4; 132 133 compiled_break = 0; 134 135 return 0; 136 } 137 138 return -1; 139 } 140 141 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr) 142 { 143 kgdb_handle_exception(1, SIGTRAP, 0, regs); 144 145 return 0; 146 } 147 148 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr) 149 { 150 compiled_break = 1; 151 kgdb_handle_exception(1, SIGTRAP, 0, regs); 152 153 return 0; 154 } 155 156 static struct undef_hook kgdb_brkpt_hook = { 157 .instr_mask = 0xffffffff, 158 .instr_val = KGDB_BREAKINST, 159 .cpsr_mask = MODE_MASK, 160 .cpsr_val = SVC_MODE, 161 .fn = kgdb_brk_fn 162 }; 163 164 static struct undef_hook kgdb_compiled_brkpt_hook = { 165 .instr_mask = 0xffffffff, 166 .instr_val = KGDB_COMPILED_BREAK, 167 .cpsr_mask = MODE_MASK, 168 .cpsr_val = SVC_MODE, 169 .fn = kgdb_compiled_brk_fn 170 }; 171 172 static void kgdb_call_nmi_hook(void *ignored) 173 { 174 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs()); 175 } 176 177 void kgdb_roundup_cpus(unsigned long flags) 178 { 179 local_irq_enable(); 180 smp_call_function(kgdb_call_nmi_hook, NULL, 0); 181 local_irq_disable(); 182 } 183 184 static int __kgdb_notify(struct die_args *args, unsigned long cmd) 185 { 186 struct pt_regs *regs = args->regs; 187 188 if (kgdb_handle_exception(1, args->signr, cmd, regs)) 189 return NOTIFY_DONE; 190 return NOTIFY_STOP; 191 } 192 static int 193 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) 194 { 195 unsigned long flags; 196 int ret; 197 198 local_irq_save(flags); 199 ret = __kgdb_notify(ptr, cmd); 200 local_irq_restore(flags); 201 202 return ret; 203 } 204 205 static struct notifier_block kgdb_notifier = { 206 .notifier_call = kgdb_notify, 207 .priority = -INT_MAX, 208 }; 209 210 211 /** 212 * kgdb_arch_init - Perform any architecture specific initalization. 213 * 214 * This function will handle the initalization of any architecture 215 * specific callbacks. 216 */ 217 int kgdb_arch_init(void) 218 { 219 int ret = register_die_notifier(&kgdb_notifier); 220 221 if (ret != 0) 222 return ret; 223 224 register_undef_hook(&kgdb_brkpt_hook); 225 register_undef_hook(&kgdb_compiled_brkpt_hook); 226 227 return 0; 228 } 229 230 /** 231 * kgdb_arch_exit - Perform any architecture specific uninitalization. 232 * 233 * This function will handle the uninitalization of any architecture 234 * specific callbacks, for dynamic registration and unregistration. 235 */ 236 void kgdb_arch_exit(void) 237 { 238 unregister_undef_hook(&kgdb_brkpt_hook); 239 unregister_undef_hook(&kgdb_compiled_brkpt_hook); 240 unregister_die_notifier(&kgdb_notifier); 241 } 242 243 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) 244 { 245 int err; 246 247 /* patch_text() only supports int-sized breakpoints */ 248 BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE); 249 250 err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, 251 BREAK_INSTR_SIZE); 252 if (err) 253 return err; 254 255 /* Machine is already stopped, so we can use __patch_text() directly */ 256 __patch_text((void *)bpt->bpt_addr, 257 *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr); 258 259 return err; 260 } 261 262 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) 263 { 264 /* Machine is already stopped, so we can use __patch_text() directly */ 265 __patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr); 266 267 return 0; 268 } 269 270 /* 271 * Register our undef instruction hooks with ARM undef core. 272 * We regsiter a hook specifically looking for the KGB break inst 273 * and we handle the normal undef case within the do_undefinstr 274 * handler. 275 */ 276 struct kgdb_arch arch_kgdb_ops = { 277 #ifndef __ARMEB__ 278 .gdb_bpt_instr = {0xfe, 0xde, 0xff, 0xe7} 279 #else /* ! __ARMEB__ */ 280 .gdb_bpt_instr = {0xe7, 0xff, 0xde, 0xfe} 281 #endif 282 }; 283