1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
|
/*
* SuperH KGDB support
*
* Copyright (C) 2008 Paul Mundt
*
* Single stepping taken from the old stub by Henry Bell and Jeremy Siegel.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
char in_nmi = 0; /* Set during NMI to prevent re-entry */
/* Macros for single step instruction identification */
#define OPCODE_BT(op) (((op) & 0xff00) == 0x8900)
#define OPCODE_BF(op) (((op) & 0xff00) == 0x8b00)
#define OPCODE_BTF_DISP(op) (((op) & 0x80) ? (((op) | 0xffffff80) << 1) : \
(((op) & 0x7f ) << 1))
#define OPCODE_BFS(op) (((op) & 0xff00) == 0x8f00)
#define OPCODE_BTS(op) (((op) & 0xff00) == 0x8d00)
#define OPCODE_BRA(op) (((op) & 0xf000) == 0xa000)
#define OPCODE_BRA_DISP(op) (((op) & 0x800) ? (((op) | 0xfffff800) << 1) : \
(((op) & 0x7ff) << 1))
#define OPCODE_BRAF(op) (((op) & 0xf0ff) == 0x0023)
#define OPCODE_BRAF_REG(op) (((op) & 0x0f00) >> 8)
#define OPCODE_BSR(op) (((op) & 0xf000) == 0xb000)
#define OPCODE_BSR_DISP(op) (((op) & 0x800) ? (((op) | 0xfffff800) << 1) : \
(((op) & 0x7ff) << 1))
#define OPCODE_BSRF(op) (((op) & 0xf0ff) == 0x0003)
#define OPCODE_BSRF_REG(op) (((op) >> 8) & 0xf)
#define OPCODE_JMP(op) (((op) & 0xf0ff) == 0x402b)
#define OPCODE_JMP_REG(op) (((op) >> 8) & 0xf)
#define OPCODE_JSR(op) (((op) & 0xf0ff) == 0x400b)
#define OPCODE_JSR_REG(op) (((op) >> 8) & 0xf)
#define OPCODE_RTS(op) ((op) == 0xb)
#define OPCODE_RTE(op) ((op) == 0x2b)
#define SR_T_BIT_MASK 0x1
#define STEP_OPCODE 0xc33d
/* Calculate the new address for after a step */
static short *get_step_address(struct pt_regs *linux_regs)
{
opcode_t op = __raw_readw(linux_regs->pc);
long addr;
/* BT */
if (OPCODE_BT(op)) {
if (linux_regs->sr & SR_T_BIT_MASK)
addr = linux_regs->pc + 4 + OPCODE_BTF_DISP(op);
else
addr = linux_regs->pc + 2;
}
/* BTS */
else if (OPCODE_BTS(op)) {
if (linux_regs->sr & SR_T_BIT_MASK)
addr = linux_regs->pc + 4 + OPCODE_BTF_DISP(op);
else
addr = linux_regs->pc + 4; /* Not in delay slot */
}
/* BF */
else if (OPCODE_BF(op)) {
if (!(linux_regs->sr & SR_T_BIT_MASK))
addr = linux_regs->pc + 4 + OPCODE_BTF_DISP(op);
else
addr = linux_regs->pc + 2;
}
/* BFS */
else if (OPCODE_BFS(op)) {
if (!(linux_regs->sr & SR_T_BIT_MASK))
addr = linux_regs->pc + 4 + OPCODE_BTF_DISP(op);
else
addr = linux_regs->pc + 4; /* Not in delay slot */
}
/* BRA */
else if (OPCODE_BRA(op))
addr = linux_regs->pc + 4 + OPCODE_BRA_DISP(op);
/* BRAF */
else if (OPCODE_BRAF(op))
addr = linux_regs->pc + 4
+ linux_regs->regs[OPCODE_BRAF_REG(op)];
/* BSR */
else if (OPCODE_BSR(op))
addr = linux_regs->pc + 4 + OPCODE_BSR_DISP(op);
/* BSRF */
else if (OPCODE_BSRF(op))
addr = linux_regs->pc + 4
+ linux_regs->regs[OPCODE_BSRF_REG(op)];
/* JMP */
else if (OPCODE_JMP(op))
addr = linux_regs->regs[OPCODE_JMP_REG(op)];
/* JSR */
else if (OPCODE_JSR(op))
addr = linux_regs->regs[OPCODE_JSR_REG(op)];
/* RTS */
else if (OPCODE_RTS(op))
addr = linux_regs->pr;
/* RTE */
else if (OPCODE_RTE(op))
addr = linux_regs->regs[15];
/* Other */
else
addr = linux_regs->pc + instruction_size(op);
flush_icache_range(addr, addr + instruction_size(op));
return (short *)addr;
}
/*
* Replace the instruction immediately after the current instruction
* (i.e. next in the expected flow of control) with a trap instruction,
* so that returning will cause only a single instruction to be executed.
* Note that this model is slightly broken for instructions with delay
* slots (e.g. B[TF]S, BSR, BRA etc), where both the branch and the
* instruction in the delay slot will be executed.
*/
static unsigned long stepped_address;
static opcode_t stepped_opcode;
static void do_single_step(struct pt_regs *linux_regs)
{
/* Determine where the target instruction will send us to */
unsigned short *addr = get_step_address(linux_regs);
stepped_address = (int)addr;
/* Replace it */
stepped_opcode = __raw_readw((long)addr);
*addr = STEP_OPCODE;
/* Flush and return */
flush_icache_range((long)addr, (long)addr +
instruction_size(stepped_opcode));
}
/* Undo a single step */
static void undo_single_step(struct pt_regs *linux_regs)
{
/* If we have stepped, put back the old instruction */
/* Use stepped_address in case we stopped elsewhere */
if (stepped_opcode != 0) {
__raw_writew(stepped_opcode, stepped_address);
flush_icache_range(stepped_address, stepped_address + 2);
}
stepped_opcode = 0;
}
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
int i;
for (i = 0; i < 16; i++)
gdb_regs[GDB_R0 + i] = regs->regs[i];
gdb_regs[GDB_PC] = regs->pc;
gdb_regs[GDB_PR] = regs->pr;
gdb_regs[GDB_SR] = regs->sr;
gdb_regs[GDB_GBR] = regs->gbr;
gdb_regs[GDB_MACH] = regs->mach;
gdb_regs[GDB_MACL] = regs->macl;
__asm__ __volatile__ ("stc vbr, %0" : "=r" (gdb_regs[GDB_VBR]));
}
void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
{
int i;
for (i = 0; i < 16; i++)
regs->regs[GDB_R0 + i] = gdb_regs[GDB_R0 + i];
regs->pc = gdb_regs[GDB_PC];
regs->pr = gdb_regs[GDB_PR];
regs->sr = gdb_regs[GDB_SR];
regs->gbr = gdb_regs[GDB_GBR];
regs->mach = gdb_regs[GDB_MACH];
regs->macl = gdb_regs[GDB_MACL];
__asm__ __volatile__ ("ldc %0, vbr" : : "r" (gdb_regs[GDB_VBR]));
}
void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
{
gdb_regs[GDB_R15] = p->thread.sp;
gdb_regs[GDB_PC] = p->thread.pc;
}
int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
char *remcomInBuffer, char *remcomOutBuffer,
struct pt_regs *linux_regs)
{
unsigned long addr;
char *ptr;
/* Undo any stepping we may have done */
undo_single_step(linux_regs);
switch (remcomInBuffer[0]) {
case 'c':
case 's':
/* try to read optional parameter, pc unchanged if no parm */
ptr = &remcomInBuffer[1];
if (kgdb_hex2long(&ptr, &addr))
linux_regs->pc = addr;
case 'D':
case 'k':
atomic_set(&kgdb_cpu_doing_single_step, -1);
if (remcomInBuffer[0] == 's') {
do_single_step(linux_regs);
kgdb_single_step = 1;
atomic_set(&kgdb_cpu_doing_single_step,
raw_smp_processor_id());
}
return 0;
}
/* this means that we do not want to exit from the handler: */
return -1;
}
/*
* The primary entry points for the kgdb debug trap table entries.
*/
BUILD_TRAP_HANDLER(singlestep)
{
unsigned long flags;
TRAP_HANDLER_DECL;
local_irq_save(flags);
regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
kgdb_handle_exception(vec >> 2, SIGTRAP, 0, regs);
local_irq_restore(flags);
}
BUILD_TRAP_HANDLER(breakpoint)
{
unsigned long flags;
TRAP_HANDLER_DECL;
local_irq_save(flags);
kgdb_handle_exception(vec >> 2, SIGTRAP, 0, regs);
local_irq_restore(flags);
}
int kgdb_arch_init(void)
{
return 0;
}
void kgdb_arch_exit(void)
{
}
struct kgdb_arch arch_kgdb_ops = {
/* Breakpoint instruction: trapa #0x3c */
#ifdef CONFIG_CPU_LITTLE_ENDIAN
.gdb_bpt_instr = { 0x3c, 0xc3 },
#else
.gdb_bpt_instr = { 0xc3, 0x3c },
#endif
};
|
