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