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 <linux/uaccess.h>
  16
  17 #include <asm/traps.h>
  18
  19 #include "patch.h"
  20
  21 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
  22 {
  23         { "r0", 4, offsetof(struct pt_regs, ARM_r0)},
  24         { "r1", 4, offsetof(struct pt_regs, ARM_r1)},
  25         { "r2", 4, offsetof(struct pt_regs, ARM_r2)},
  26         { "r3", 4, offsetof(struct pt_regs, ARM_r3)},
  27         { "r4", 4, offsetof(struct pt_regs, ARM_r4)},
  28         { "r5", 4, offsetof(struct pt_regs, ARM_r5)},
  29         { "r6", 4, offsetof(struct pt_regs, ARM_r6)},
  30         { "r7", 4, offsetof(struct pt_regs, ARM_r7)},
  31         { "r8", 4, offsetof(struct pt_regs, ARM_r8)},
  32         { "r9", 4, offsetof(struct pt_regs, ARM_r9)},
  33         { "r10", 4, offsetof(struct pt_regs, ARM_r10)},
  34         { "fp", 4, offsetof(struct pt_regs, ARM_fp)},
  35         { "ip", 4, offsetof(struct pt_regs, ARM_ip)},
  36         { "sp", 4, offsetof(struct pt_regs, ARM_sp)},
  37         { "lr", 4, offsetof(struct pt_regs, ARM_lr)},
  38         { "pc", 4, offsetof(struct pt_regs, ARM_pc)},
  39         { "f0", 12, -1 },
  40         { "f1", 12, -1 },
  41         { "f2", 12, -1 },
  42         { "f3", 12, -1 },
  43         { "f4", 12, -1 },
  44         { "f5", 12, -1 },
  45         { "f6", 12, -1 },
  46         { "f7", 12, -1 },
  47         { "fps", 4, -1 },
  48         { "cpsr", 4, offsetof(struct pt_regs, ARM_cpsr)},
  49 };
  50
  51 char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
  52 {
  53         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  54                 return NULL;
  55
  56         if (dbg_reg_def[regno].offset != -1)
  57                 memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
  58                        dbg_reg_def[regno].size);
  59         else
  60                 memset(mem, 0, dbg_reg_def[regno].size);
  61         return dbg_reg_def[regno].name;
  62 }
  63
  64 int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
  65 {
  66         if (regno >= DBG_MAX_REG_NUM || regno < 0)
  67                 return -EINVAL;
  68
  69         if (dbg_reg_def[regno].offset != -1)
  70                 memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
  71                        dbg_reg_def[regno].size);
  72         return 0;
  73 }
  74
  75 void
  76 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
  77 {
  78         struct pt_regs *thread_regs;
  79         int regno;
  80
  81         /* Just making sure... */
  82         if (task == NULL)
  83                 return;
  84
  85         /* Initialize to zero */
  86         for (regno = 0; regno < GDB_MAX_REGS; regno++)
  87                 gdb_regs[regno] = 0;
  88
  89         /* Otherwise, we have only some registers from switch_to() */
  90         thread_regs             = task_pt_regs(task);
  91         gdb_regs[_R0]           = thread_regs->ARM_r0;
  92         gdb_regs[_R1]           = thread_regs->ARM_r1;
  93         gdb_regs[_R2]           = thread_regs->ARM_r2;
  94         gdb_regs[_R3]           = thread_regs->ARM_r3;
  95         gdb_regs[_R4]           = thread_regs->ARM_r4;
  96         gdb_regs[_R5]           = thread_regs->ARM_r5;
  97         gdb_regs[_R6]           = thread_regs->ARM_r6;
  98         gdb_regs[_R7]           = thread_regs->ARM_r7;
  99         gdb_regs[_R8]           = thread_regs->ARM_r8;
 100         gdb_regs[_R9]           = thread_regs->ARM_r9;
 101         gdb_regs[_R10]          = thread_regs->ARM_r10;
 102         gdb_regs[_FP]           = thread_regs->ARM_fp;
 103         gdb_regs[_IP]           = thread_regs->ARM_ip;
 104         gdb_regs[_SPT]          = thread_regs->ARM_sp;
 105         gdb_regs[_LR]           = thread_regs->ARM_lr;
 106         gdb_regs[_PC]           = thread_regs->ARM_pc;
 107         gdb_regs[_CPSR]         = thread_regs->ARM_cpsr;
 108 }
 109
 110 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 111 {
 112         regs->ARM_pc = pc;
 113 }
 114
 115 static int compiled_break;
 116
 117 int kgdb_arch_handle_exception(int exception_vector, int signo,
 118                                int err_code, char *remcom_in_buffer,
 119                                char *remcom_out_buffer,
 120                                struct pt_regs *linux_regs)
 121 {
 122         unsigned long addr;
 123         char *ptr;
 124
 125         switch (remcom_in_buffer[0]) {
 126         case 'D':
 127         case 'k':
 128         case 'c':
 129                 /*
 130                  * Try to read optional parameter, pc unchanged if no parm.
 131                  * If this was a compiled breakpoint, we need to move
 132                  * to the next instruction or we will just breakpoint
 133                  * over and over again.
 134                  */
 135                 ptr = &remcom_in_buffer[1];
 136                 if (kgdb_hex2long(&ptr, &addr))
 137                         linux_regs->ARM_pc = addr;
 138                 else if (compiled_break == 1)
 139                         linux_regs->ARM_pc += 4;
 140
 141                 compiled_break = 0;
 142
 143                 return 0;
 144         }
 145
 146         return -1;
 147 }
 148
 149 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
 150 {
 151         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 152
 153         return 0;
 154 }
 155
 156 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
 157 {
 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         .cpsr_mask              = MODE_MASK,
 168         .cpsr_val               = SVC_MODE,
 169         .fn                     = kgdb_brk_fn
 170 };
 171
 172 static struct undef_hook kgdb_compiled_brkpt_hook = {
 173         .instr_mask             = 0xffffffff,
 174         .instr_val              = KGDB_COMPILED_BREAK,
 175         .cpsr_mask              = MODE_MASK,
 176         .cpsr_val               = SVC_MODE,
 177         .fn                     = kgdb_compiled_brk_fn
 178 };
 179
 180 static void kgdb_call_nmi_hook(void *ignored)
 181 {
 182        kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 183 }
 184
 185 void kgdb_roundup_cpus(unsigned long flags)
 186 {
 187        local_irq_enable();
 188        smp_call_function(kgdb_call_nmi_hook, NULL, 0);
 189        local_irq_disable();
 190 }
 191
 192 static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 193 {
 194         struct pt_regs *regs = args->regs;
 195
 196         if (kgdb_handle_exception(1, args->signr, cmd, regs))
 197                 return NOTIFY_DONE;
 198         return NOTIFY_STOP;
 199 }
 200 static int
 201 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
 202 {
 203         unsigned long flags;
 204         int ret;
 205
 206         local_irq_save(flags);
 207         ret = __kgdb_notify(ptr, cmd);
 208         local_irq_restore(flags);
 209
 210         return ret;
 211 }
 212
 213 static struct notifier_block kgdb_notifier = {
 214         .notifier_call  = kgdb_notify,
 215         .priority       = -INT_MAX,
 216 };
 217
 218
 219 /**
 220  *      kgdb_arch_init - Perform any architecture specific initalization.
 221  *
 222  *      This function will handle the initalization of any architecture
 223  *      specific callbacks.
 224  */
 225 int kgdb_arch_init(void)
 226 {
 227         int ret = register_die_notifier(&kgdb_notifier);
 228
 229         if (ret != 0)
 230                 return ret;
 231
 232         register_undef_hook(&kgdb_brkpt_hook);
 233         register_undef_hook(&kgdb_compiled_brkpt_hook);
 234
 235         return 0;
 236 }
 237
 238 /**
 239  *      kgdb_arch_exit - Perform any architecture specific uninitalization.
 240  *
 241  *      This function will handle the uninitalization of any architecture
 242  *      specific callbacks, for dynamic registration and unregistration.
 243  */
 244 void kgdb_arch_exit(void)
 245 {
 246         unregister_undef_hook(&kgdb_brkpt_hook);
 247         unregister_undef_hook(&kgdb_compiled_brkpt_hook);
 248         unregister_die_notifier(&kgdb_notifier);
 249 }
 250
 251 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
 252 {
 253         int err;
 254
 255         /* patch_text() only supports int-sized breakpoints */
 256         BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
 257
 258         err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
 259                                 BREAK_INSTR_SIZE);
 260         if (err)
 261                 return err;
 262
 263         patch_text((void *)bpt->bpt_addr,
 264                    *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
 265
 266         return err;
 267 }
 268
 269 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
 270 {
 271         patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
 272
 273         return 0;
 274 }
 275
 276 /*
 277  * Register our undef instruction hooks with ARM undef core.
 278  * We regsiter a hook specifically looking for the KGB break inst
 279  * and we handle the normal undef case within the do_undefinstr
 280  * handler.
 281  */
 282 struct kgdb_arch arch_kgdb_ops = {
 283 #ifndef __ARMEB__
 284         .gdb_bpt_instr          = {0xfe, 0xde, 0xff, 0xe7}
 285 #else /* ! __ARMEB__ */
 286         .gdb_bpt_instr          = {0xe7, 0xff, 0xde, 0xfe}
 287 #endif
 288 };