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
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
|
// SPDX-License-Identifier: GPL-2.0
/*
* Kernel probes (kprobes) for SuperH
*
* Copyright (C) 2007 Chris Smith <chris.smith@st.com>
* Copyright (C) 2006 Lineo Solutions, Inc.
*/
#include <linux/kprobes.h>
#include <linux/extable.h>
#include <linux/ptrace.h>
#include <linux/preempt.h>
#include <linux/kdebug.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <linux/uaccess.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static DEFINE_PER_CPU(struct kprobe, saved_current_opcode);
static DEFINE_PER_CPU(struct kprobe, saved_next_opcode);
static DEFINE_PER_CPU(struct kprobe, saved_next_opcode2);
#define OPCODE_JMP(x) (((x) & 0xF0FF) == 0x402b)
#define OPCODE_JSR(x) (((x) & 0xF0FF) == 0x400b)
#define OPCODE_BRA(x) (((x) & 0xF000) == 0xa000)
#define OPCODE_BRAF(x) (((x) & 0xF0FF) == 0x0023)
#define OPCODE_BSR(x) (((x) & 0xF000) == 0xb000)
#define OPCODE_BSRF(x) (((x) & 0xF0FF) == 0x0003)
#define OPCODE_BF_S(x) (((x) & 0xFF00) == 0x8f00)
#define OPCODE_BT_S(x) (((x) & 0xFF00) == 0x8d00)
#define OPCODE_BF(x) (((x) & 0xFF00) == 0x8b00)
#define OPCODE_BT(x) (((x) & 0xFF00) == 0x8900)
#define OPCODE_RTS(x) (((x) & 0x000F) == 0x000b)
#define OPCODE_RTE(x) (((x) & 0xFFFF) == 0x002b)
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
kprobe_opcode_t opcode = *(kprobe_opcode_t *) (p->addr);
if (OPCODE_RTE(opcode))
return -EFAULT; /* Bad breakpoint */
p->opcode = opcode;
return 0;
}
void __kprobes arch_copy_kprobe(struct kprobe *p)
{
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
p->opcode = *p->addr;
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
*p->addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long)p->addr,
(unsigned long)p->addr + sizeof(kprobe_opcode_t));
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
*p->addr = p->opcode;
flush_icache_range((unsigned long)p->addr,
(unsigned long)p->addr + sizeof(kprobe_opcode_t));
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
if (*p->addr == BREAKPOINT_INSTRUCTION)
return 1;
return 0;
}
/**
* If an illegal slot instruction exception occurs for an address
* containing a kprobe, remove the probe.
*
* Returns 0 if the exception was handled successfully, 1 otherwise.
*/
int __kprobes kprobe_handle_illslot(unsigned long pc)
{
struct kprobe *p = get_kprobe((kprobe_opcode_t *) pc + 1);
if (p != NULL) {
printk("Warning: removing kprobe from delay slot: 0x%.8x\n",
(unsigned int)pc + 2);
unregister_kprobe(p);
return 0;
}
return 1;
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
struct kprobe *saved = this_cpu_ptr(&saved_next_opcode);
if (saved->addr) {
arch_disarm_kprobe(p);
arch_disarm_kprobe(saved);
saved->addr = NULL;
saved->opcode = 0;
saved = this_cpu_ptr(&saved_next_opcode2);
if (saved->addr) {
arch_disarm_kprobe(saved);
saved->addr = NULL;
saved->opcode = 0;
}
}
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
}
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
kcb->kprobe_status = kcb->prev_kprobe.status;
}
static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, p);
}
/*
* Singlestep is implemented by disabling the current kprobe and setting one
* on the next instruction, following branches. Two probes are set if the
* branch is conditional.
*/
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
{
__this_cpu_write(saved_current_opcode.addr, (kprobe_opcode_t *)regs->pc);
if (p != NULL) {
struct kprobe *op1, *op2;
arch_disarm_kprobe(p);
op1 = this_cpu_ptr(&saved_next_opcode);
op2 = this_cpu_ptr(&saved_next_opcode2);
if (OPCODE_JSR(p->opcode) || OPCODE_JMP(p->opcode)) {
unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
op1->addr = (kprobe_opcode_t *) regs->regs[reg_nr];
} else if (OPCODE_BRA(p->opcode) || OPCODE_BSR(p->opcode)) {
unsigned long disp = (p->opcode & 0x0FFF);
op1->addr =
(kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
} else if (OPCODE_BRAF(p->opcode) || OPCODE_BSRF(p->opcode)) {
unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
op1->addr =
(kprobe_opcode_t *) (regs->pc + 4 +
regs->regs[reg_nr]);
} else if (OPCODE_RTS(p->opcode)) {
op1->addr = (kprobe_opcode_t *) regs->pr;
} else if (OPCODE_BF(p->opcode) || OPCODE_BT(p->opcode)) {
unsigned long disp = (p->opcode & 0x00FF);
/* case 1 */
op1->addr = p->addr + 1;
/* case 2 */
op2->addr =
(kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
op2->opcode = *(op2->addr);
arch_arm_kprobe(op2);
} else if (OPCODE_BF_S(p->opcode) || OPCODE_BT_S(p->opcode)) {
unsigned long disp = (p->opcode & 0x00FF);
/* case 1 */
op1->addr = p->addr + 2;
/* case 2 */
op2->addr =
(kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
op2->opcode = *(op2->addr);
arch_arm_kprobe(op2);
} else {
op1->addr = p->addr + 1;
}
op1->opcode = *(op1->addr);
arch_arm_kprobe(op1);
}
}
/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *) regs->pr;
ri->fp = NULL;
/* Replace the return addr with trampoline addr */
regs->pr = (unsigned long)kretprobe_trampoline;
}
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr = NULL;
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
addr = (kprobe_opcode_t *) (regs->pc);
/* Check we're not actually recursing */
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if (kcb->kprobe_status == KPROBE_HIT_SS &&
*p->ainsn.insn ==
|