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/kgdb.h>
  14 #include <asm/traps.h>
  15
  16 /* Make a local copy of the registers passed into the handler (bletch) */
  17 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
  18 {
  19         int regno;
  20
  21         /* Initialize all to zero. */
  22         for (regno = 0; regno < GDB_MAX_REGS; regno++)
  23                 gdb_regs[regno] = 0;
  24
  25         gdb_regs[_R0]           = kernel_regs->ARM_r0;
  26         gdb_regs[_R1]           = kernel_regs->ARM_r1;
  27         gdb_regs[_R2]           = kernel_regs->ARM_r2;
  28         gdb_regs[_R3]           = kernel_regs->ARM_r3;
  29         gdb_regs[_R4]           = kernel_regs->ARM_r4;
  30         gdb_regs[_R5]           = kernel_regs->ARM_r5;
  31         gdb_regs[_R6]           = kernel_regs->ARM_r6;
  32         gdb_regs[_R7]           = kernel_regs->ARM_r7;
  33         gdb_regs[_R8]           = kernel_regs->ARM_r8;
  34         gdb_regs[_R9]           = kernel_regs->ARM_r9;
  35         gdb_regs[_R10]          = kernel_regs->ARM_r10;
  36         gdb_regs[_FP]           = kernel_regs->ARM_fp;
  37         gdb_regs[_IP]           = kernel_regs->ARM_ip;
  38         gdb_regs[_SPT]          = kernel_regs->ARM_sp;
  39         gdb_regs[_LR]           = kernel_regs->ARM_lr;
  40         gdb_regs[_PC]           = kernel_regs->ARM_pc;
  41         gdb_regs[_CPSR]         = kernel_regs->ARM_cpsr;
  42 }
  43
  44 /* Copy local gdb registers back to kgdb regs, for later copy to kernel */
  45 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *kernel_regs)
  46 {
  47         kernel_regs->ARM_r0     = gdb_regs[_R0];
  48         kernel_regs->ARM_r1     = gdb_regs[_R1];
  49         kernel_regs->ARM_r2     = gdb_regs[_R2];
  50         kernel_regs->ARM_r3     = gdb_regs[_R3];
  51         kernel_regs->ARM_r4     = gdb_regs[_R4];
  52         kernel_regs->ARM_r5     = gdb_regs[_R5];
  53         kernel_regs->ARM_r6     = gdb_regs[_R6];
  54         kernel_regs->ARM_r7     = gdb_regs[_R7];
  55         kernel_regs->ARM_r8     = gdb_regs[_R8];
  56         kernel_regs->ARM_r9     = gdb_regs[_R9];
  57         kernel_regs->ARM_r10    = gdb_regs[_R10];
  58         kernel_regs->ARM_fp     = gdb_regs[_FP];
  59         kernel_regs->ARM_ip     = gdb_regs[_IP];
  60         kernel_regs->ARM_sp     = gdb_regs[_SPT];
  61         kernel_regs->ARM_lr     = gdb_regs[_LR];
  62         kernel_regs->ARM_pc     = gdb_regs[_PC];
  63         kernel_regs->ARM_cpsr   = gdb_regs[_CPSR];
  64 }
  65
  66 void
  67 sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
  68 {
  69         struct pt_regs *thread_regs;
  70         int regno;
  71
  72         /* Just making sure... */
  73         if (task == NULL)
  74                 return;
  75
  76         /* Initialize to zero */
  77         for (regno = 0; regno < GDB_MAX_REGS; regno++)
  78                 gdb_regs[regno] = 0;
  79
  80         /* Otherwise, we have only some registers from switch_to() */
  81         thread_regs             = task_pt_regs(task);
  82         gdb_regs[_R0]           = thread_regs->ARM_r0;
  83         gdb_regs[_R1]           = thread_regs->ARM_r1;
  84         gdb_regs[_R2]           = thread_regs->ARM_r2;
  85         gdb_regs[_R3]           = thread_regs->ARM_r3;
  86         gdb_regs[_R4]           = thread_regs->ARM_r4;
  87         gdb_regs[_R5]           = thread_regs->ARM_r5;
  88         gdb_regs[_R6]           = thread_regs->ARM_r6;
  89         gdb_regs[_R7]           = thread_regs->ARM_r7;
  90         gdb_regs[_R8]           = thread_regs->ARM_r8;
  91         gdb_regs[_R9]           = thread_regs->ARM_r9;
  92         gdb_regs[_R10]          = thread_regs->ARM_r10;
  93         gdb_regs[_FP]           = thread_regs->ARM_fp;
  94         gdb_regs[_IP]           = thread_regs->ARM_ip;
  95         gdb_regs[_SPT]          = thread_regs->ARM_sp;
  96         gdb_regs[_LR]           = thread_regs->ARM_lr;
  97         gdb_regs[_PC]           = thread_regs->ARM_pc;
  98         gdb_regs[_CPSR]         = thread_regs->ARM_cpsr;
  99 }
 100
 101 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 102 {
 103         regs->ARM_pc = pc;
 104 }
 105
 106 static int compiled_break;
 107
 108 int kgdb_arch_handle_exception(int exception_vector, int signo,
 109                                int err_code, char *remcom_in_buffer,
 110                                char *remcom_out_buffer,
 111                                struct pt_regs *linux_regs)
 112 {
 113         unsigned long addr;
 114         char *ptr;
 115
 116         switch (remcom_in_buffer[0]) {
 117         case 'D':
 118         case 'k':
 119         case 'c':
 120                 /*
 121                  * Try to read optional parameter, pc unchanged if no parm.
 122                  * If this was a compiled breakpoint, we need to move
 123                  * to the next instruction or we will just breakpoint
 124                  * over and over again.
 125                  */
 126                 ptr = &remcom_in_buffer[1];
 127                 if (kgdb_hex2long(&ptr, &addr))
 128                         linux_regs->ARM_pc = addr;
 129                 else if (compiled_break == 1)
 130                         linux_regs->ARM_pc += 4;
 131
 132                 compiled_break = 0;
 133
 134                 return 0;
 135         }
 136
 137         return -1;
 138 }
 139
 140 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
 141 {
 142         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 143
 144         return 0;
 145 }
 146
 147 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
 148 {
 149         compiled_break = 1;
 150         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 151
 152         return 0;
 153 }
 154
 155 static struct undef_hook kgdb_brkpt_hook = {
 156         .instr_mask             = 0xffffffff,
 157         .instr_val              = KGDB_BREAKINST,
 158         .fn                     = kgdb_brk_fn
 159 };
 160
 161 static struct undef_hook kgdb_compiled_brkpt_hook = {
 162         .instr_mask             = 0xffffffff,
 163         .instr_val              = KGDB_COMPILED_BREAK,
 164         .fn                     = kgdb_compiled_brk_fn
 165 };
 166
 167 static void kgdb_call_nmi_hook(void *ignored)
 168 {
 169        kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 170 }
 171
 172 void kgdb_roundup_cpus(unsigned long flags)
 173 {
 174        local_irq_enable();
 175        smp_call_function(kgdb_call_nmi_hook, NULL, 0);
 176        local_irq_disable();
 177 }
 178
 179 /**
 180  *      kgdb_arch_init - Perform any architecture specific initalization.
 181  *
 182  *      This function will handle the initalization of any architecture
 183  *      specific callbacks.
 184  */
 185 int kgdb_arch_init(void)
 186 {
 187         register_undef_hook(&kgdb_brkpt_hook);
 188         register_undef_hook(&kgdb_compiled_brkpt_hook);
 189
 190         return 0;
 191 }
 192
 193 /**
 194  *      kgdb_arch_exit - Perform any architecture specific uninitalization.
 195  *
 196  *      This function will handle the uninitalization of any architecture
 197  *      specific callbacks, for dynamic registration and unregistration.
 198  */
 199 void kgdb_arch_exit(void)
 200 {
 201         unregister_undef_hook(&kgdb_brkpt_hook);
 202         unregister_undef_hook(&kgdb_compiled_brkpt_hook);
 203 }
 204
 205 /*
 206  * Register our undef instruction hooks with ARM undef core.
 207  * We regsiter a hook specifically looking for the KGB break inst
 208  * and we handle the normal undef case within the do_undefinstr
 209  * handler.
 210  */
 211 struct kgdb_arch arch_kgdb_ops = {
 212 #ifndef __ARMEB__
 213         .gdb_bpt_instr          = {0xfe, 0xde, 0xff, 0xe7}
 214 #else /* ! __ARMEB__ */
 215         .gdb_bpt_instr          = {0xe7, 0xff, 0xde, 0xfe}
 216 #endif
 217 };