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) */
pt_regs_to_gdb_regs(unsigned long * gdb_regs,struct pt_regs * kernel_regs)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 */
gdb_regs_to_pt_regs(unsigned long * gdb_regs,struct pt_regs * kernel_regs)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
sleeping_thread_to_gdb_regs(unsigned long * gdb_regs,struct task_struct * task)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
kgdb_arch_handle_exception(int exception_vector,int signo,int err_code,char * remcom_in_buffer,char * remcom_out_buffer,struct pt_regs * linux_regs)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
kgdb_brk_fn(struct pt_regs * regs,unsigned int instr)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
kgdb_compiled_brk_fn(struct pt_regs * regs,unsigned int instr)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 */
kgdb_arch_init(void)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 */
kgdb_arch_exit(void)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