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 static int compiled_break;
 102
 103 int kgdb_arch_handle_exception(int exception_vector, int signo,
 104                                int err_code, char *remcom_in_buffer,
 105                                char *remcom_out_buffer,
 106                                struct pt_regs *linux_regs)
 107 {
 108         unsigned long addr;
 109         char *ptr;
 110
 111         switch (remcom_in_buffer[0]) {
 112         case 'D':
 113         case 'k':
 114         case 'c':
 115                 /*
 116                  * Try to read optional parameter, pc unchanged if no parm.
 117                  * If this was a compiled breakpoint, we need to move
 118                  * to the next instruction or we will just breakpoint
 119                  * over and over again.
 120                  */
 121                 ptr = &remcom_in_buffer[1];
 122                 if (kgdb_hex2long(&ptr, &addr))
 123                         linux_regs->ARM_pc = addr;
 124                 else if (compiled_break == 1)
 125                         linux_regs->ARM_pc += 4;
 126
 127                 compiled_break = 0;
 128
 129                 return 0;
 130         }
 131
 132         return -1;
 133 }
 134
 135 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
 136 {
 137         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 138
 139         return 0;
 140 }
 141
 142 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
 143 {
 144         compiled_break = 1;
 145         kgdb_handle_exception(1, SIGTRAP, 0, regs);
 146
 147         return 0;
 148 }
 149
 150 static struct undef_hook kgdb_brkpt_hook = {
 151         .instr_mask             = 0xffffffff,
 152         .instr_val              = KGDB_BREAKINST,
 153         .fn                     = kgdb_brk_fn
 154 };
 155
 156 static struct undef_hook kgdb_compiled_brkpt_hook = {
 157         .instr_mask             = 0xffffffff,
 158         .instr_val              = KGDB_COMPILED_BREAK,
 159         .fn                     = kgdb_compiled_brk_fn
 160 };
 161
 162 static void kgdb_call_nmi_hook(void *ignored)
 163 {
 164        kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
 165 }
 166
 167 void kgdb_roundup_cpus(unsigned long flags)
 168 {
 169        local_irq_enable();
 170        smp_call_function(kgdb_call_nmi_hook, NULL, 0);
 171        local_irq_disable();
 172 }
 173
 174 /**
 175  *      kgdb_arch_init - Perform any architecture specific initalization.
 176  *
 177  *      This function will handle the initalization of any architecture
 178  *      specific callbacks.
 179  */
 180 int kgdb_arch_init(void)
 181 {
 182         register_undef_hook(&kgdb_brkpt_hook);
 183         register_undef_hook(&kgdb_compiled_brkpt_hook);
 184
 185         return 0;
 186 }
 187
 188 /**
 189  *      kgdb_arch_exit - Perform any architecture specific uninitalization.
 190  *
 191  *      This function will handle the uninitalization of any architecture
 192  *      specific callbacks, for dynamic registration and unregistration.
 193  */
 194 void kgdb_arch_exit(void)
 195 {
 196         unregister_undef_hook(&kgdb_brkpt_hook);
 197         unregister_undef_hook(&kgdb_compiled_brkpt_hook);
 198 }
 199
 200 /*
 201  * Register our undef instruction hooks with ARM undef core.
 202  * We regsiter a hook specifically looking for the KGB break inst
 203  * and we handle the normal undef case within the do_undefinstr
 204  * handler.
 205  */
 206 struct kgdb_arch arch_kgdb_ops = {
 207 #ifndef __ARMEB__
 208         .gdb_bpt_instr          = {0xfe, 0xde, 0xff, 0xe7}
 209 #else /* ! __ARMEB__ */
 210         .gdb_bpt_instr          = {0xe7, 0xff, 0xde, 0xfe}
 211 #endif
 212 };