arch/arm/kernel/kgdb.c

   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 <asm/traps.h>
  16
  17 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
  18 {
  19         { "r0", 4, offsetof(struct pt_regs, ARM_r0)},
  20         { "r1", 4, offsetof(struct pt_regs, ARM_r1)},
  21         { "r2", 4, offsetof(struct pt_regs, ARM_r2)},
  22         { "r3", 4, offsetof(struct pt_regs, ARM_r3)},
  23         { "r4", 4, offsetof(struct pt_regs, ARM_r4)},
  24         { "r5", 4, offsetof(struct pt_regs, ARM_r5)},
  25         { "r6", 4, offsetof(struct pt_regs, ARM_r6)},
  26         { "r7", 4, offsetof(struct pt_regs, ARM_r7)},
  27         { "r8", 4, offsetof(struct pt_regs, ARM_r8)},
  28         { "r9", 4, offsetof(struct pt_regs, ARM_r9)},
  29         { "r10", 4, offsetof(struct pt_regs, ARM_r10)},
  30         { "fp", 4, offsetof(struct pt_regs, ARM_fp)},
  31         { "ip", 4, offsetof(struct pt_regs, ARM_ip)},
  32         { "sp", 4, offsetof(struct pt_regs, ARM_sp)},
  33         { "lr", 4, offsetof(struct pt_regs, ARM_lr)},
  34         { "pc", 4, offsetof(struct pt_regs, ARM_pc)},
  35         { "f0", 12, -1 },
  36         { "f1", 12, -1 },
  37         { "f2", 12, -1 },
  38         { "f3", 12, -1 },
  39         { "f4", 12, -1 },
  40         { "f5", 12, -1 },
  41         { "f6", 12, -1 },
  42         { "f7", 12, -1 },
  43         { "fps", 4, -1 },
  44         { "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)},
  45 };
  46
  47 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  48 {
  49         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  50                 return NULL;
  51
  52         if (dbg_reg_def[regno].offset != -1)
  53                 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
  54                        dbg_reg_def[regno].size);
  55         else
  56                 memset(mem, 0, dbg_reg_def[regno].size);
  57         return dbg_reg_def[regno].name;
  58 }
  59
  60 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
  61 {
  62         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  63                 return -EINVAL;
  64
  65         if (dbg_reg_def[regno].offset != -1)
  66                 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
  67                        dbg_reg_def[regno].size);
  68         return 0;
  69 }
  70
  71 void
  72 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
  73 {
  74         struct pt_regs *thread_regs;
  75         int regno;
  76
  77         /* Just making sure... */
  78         if (task == NULL)
  79                 return;
  80
  81         /* Initialize to zero */
  82         for (regno = 0; regno < GDB_MAX_REGS; regno++)
  83                 gdb_regs[regno] = 0;
  84
  85         /* Otherwise, we have only some registers from switch_to() */
  86         thread_regs             = task_pt_regs(task);
  87         gdb_regs[_R0]           = thread_regs->ARM_r0;
  88         gdb_regs[_R1]           = thread_regs->ARM_r1;
  89         gdb_regs[_R2]           = thread_regs->ARM_r2;
  90         gdb_regs[_R3]           = thread_regs->ARM_r3;
  91         gdb_regs[_R4]           = thread_regs->ARM_r4;
  92         gdb_regs[_R5]           = thread_regs->ARM_r5;
  93         gdb_regs[_R6]           = thread_regs->ARM_r6;
  94         gdb_regs[_R7]           = thread_regs->ARM_r7;
  95         gdb_regs[_R8]           = thread_regs->ARM_r8;
  96         gdb_regs[_R9]           = thread_regs->ARM_r9;
  97         gdb_regs[_R10]          = thread_regs->ARM_r10;
  98         gdb_regs[_FP]           = thread_regs->ARM_fp;
  99         gdb_regs[_IP]           = thread_regs->ARM_ip;
 100         gdb_regs[_SPT]          = thread_regs->ARM_sp;
 101         gdb_regs[_LR]           = thread_regs->ARM_lr;
 102         gdb_regs[_PC]           = thread_regs->ARM_pc;
 103         gdb_regs[_CPSR]         = thread_regs->ARM_cpsr;
 104 }
 105
 106 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 107 {
 108         regs->ARM_pc = pc;
 109 }
 110
 111 static int compiled_break;
 112
 113 int kgdb_arch_handle_exception(int exception_vector, int signo,
 114                                int err_code, char *remcom_in_buffer,
 115                                char *remcom_out_buffer,
 116                                struct pt_regs *linux_regs)
 117 {
 118         unsigned long addr;
 119         char *ptr;
 120
 121         switch (remcom_in_buffer[0]) {
 122         case 'D':
 123         case 'k':
 124         case 'c':
 125                 /*
 126                  * Try to read optional parameter, pc unchanged if no parm.
 127                  * If this was a compiled breakpoint, we need to move
 128                  * to the next instruction or we will just breakpoint
 129                  * over and over again.
 130                  */
 131                 ptr = &remcom_in_buffer[1];
 132                 if (kgdb_hex2long(&ptr, &addr))
 133                         linux_regs->ARM_pc = addr;
 134                 else if (compiled_break == 1)
 135                         linux_regs->ARM_pc += 4;
 136
 137                 compiled_break = 0;
 138
 139                 return 0;
 140         }
 141
 142         return -1;
 143 }
 144
 145 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
 146 {
 147         if (user_mode(regs))
 148                 return -1;
 149         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 150
 151         return 0;
 152 }
 153
 154 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
 155 {
 156         if (user_mode(regs))
 157                 return -1;
 158         compiled_break = 1;
 159         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 160
 161         return 0;
 162 }
 163
 164 static struct undef_hook kgdb_brkpt_hook = {
 165         .instr_mask             = 0xffffffff,
 166         .instr_val              = KGDB_BREAKINST,
 167         .fn                     = kgdb_brk_fn
 168 };
 169
 170 static struct undef_hook kgdb_compiled_brkpt_hook = {
 171         .instr_mask             = 0xffffffff,
 172         .instr_val              = KGDB_COMPILED_BREAK,
 173         .fn                     = kgdb_compiled_brk_fn
 174 };
 175
 176 static void kgdb_call_nmi_hook(void *ignored)
 177 {
 178        kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 179 }
 180
 181 void kgdb_roundup_cpus(unsigned long flags)
 182 {
 183        local_irq_enable();
 184        smp_call_function(kgdb_call_nmi_hook, NULL, 0);
 185        local_irq_disable();
 186 }
 187
 188 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 189 {
 190         struct pt_regs *regs = args->regs;
 191
 192         if (kgdb_handle_exception(1, args->signr, cmd, regs))
 193                 return NOTIFY_DONE;
 194         return NOTIFY_STOP;
 195 }
 196 static int
 197 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
 198 {
 199         unsigned long flags;
 200         int ret;
 201
 202         local_irq_save(flags);
 203         ret = __kgdb_notify(ptr, cmd);
 204         local_irq_restore(flags);
 205
 206         return ret;
 207 }
 208
 209 static struct notifier_block kgdb_notifier = {
 210         .notifier_call  = kgdb_notify,
 211         .priority       = -INT_MAX,
 212 };
 213
 214
 215 /**
 216  *      kgdb_arch_init - Perform any architecture specific initalization.
 217  *
 218  *      This function will handle the initalization of any architecture
 219  *      specific callbacks.
 220  */
 221 int kgdb_arch_init(void)
 222 {
 223         int ret = register_die_notifier(&kgdb_notifier);
 224
 225         if (ret != 0)
 226                 return ret;
 227
 228         register_undef_hook(&kgdb_brkpt_hook);
 229         register_undef_hook(&kgdb_compiled_brkpt_hook);
 230
 231         return 0;
 232 }
 233
 234 /**
 235  *      kgdb_arch_exit - Perform any architecture specific uninitalization.
 236  *
 237  *      This function will handle the uninitalization of any architecture
 238  *      specific callbacks, for dynamic registration and unregistration.
 239  */
 240 void kgdb_arch_exit(void)
 241 {
 242         unregister_undef_hook(&kgdb_brkpt_hook);
 243         unregister_undef_hook(&kgdb_compiled_brkpt_hook);
 244         unregister_die_notifier(&kgdb_notifier);
 245 }
 246
 247 /*
 248  * Register our undef instruction hooks with ARM undef core.
 249  * We regsiter a hook specifically looking for the KGB break inst
 250  * and we handle the normal undef case within the do_undefinstr
 251  * handler.
 252  */
 253 struct kgdb_arch arch_kgdb_ops = {
 254 #ifndef __ARMEB__
 255         .gdb_bpt_instr          = {0xfe, 0xde, 0xff, 0xe7}
 256 #else /* ! __ARMEB__ */
 257         .gdb_bpt_instr          = {0xe7, 0xff, 0xde, 0xfe}
 258 #endif
 259 };