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