linux/arch/arm/kernel/kgdb.c
<<
>>
Prefs 
   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
  20struct 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
  50char *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
  63int 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
  74void
  75sleeping_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
 109void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 110{
 111        regs->ARM_pc = pc;
 112}
 113
 114static int compiled_break;
 115
 116int 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
 148static 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
 155static 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
 163static 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
 171static 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
 179static void kgdb_call_nmi_hook(void *ignored)
 180{
 181       kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 182}
 183
 184void 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
 191static 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}
 199static int
 200kgdb_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
 212static 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 */
 224int 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 */
 243void 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
 250int 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        /* Machine is already stopped, so we can use __patch_text() directly */
 263        __patch_text((void *)bpt->bpt_addr,
 264                     *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
 265
 266        return err;
 267}
 268
 269int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
 270{
 271        /* Machine is already stopped, so we can use __patch_text() directly */
 272        __patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
 273
 274        return 0;
 275}
 276
 277/*
 278 * Register our undef instruction hooks with ARM undef core.
 279 * We regsiter a hook specifically looking for the KGB break inst
 280 * and we handle the normal undef case within the do_undefinstr
 281 * handler.
 282 */
 283struct kgdb_arch arch_kgdb_ops = {
 284#ifndef __ARMEB__
 285        .gdb_bpt_instr          = {0xfe, 0xde, 0xff, 0xe7}
 286#else /* ! __ARMEB__ */
 287        .gdb_bpt_instr          = {0xe7, 0xff, 0xde, 0xfe}
 288#endif
 289};
 290
Hosted by Missing Link Electronics. The original LXR software by the LXR community, this experimental version by lxr@linux.no.