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
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
|
/*
* Copyright (C) 2000-2007, Axis Communications AB.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/security.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <arch/hwregs/supp_reg.h>
/*
* Determines which bits in CCS the user has access to.
* 1 = access, 0 = no access.
*/
#define CCS_MASK 0x00087c00 /* SXNZVC */
#define SBIT_USER (1 << (S_CCS_BITNR + CCS_SHIFT))
static int put_debugreg(long pid, unsigned int regno, long data);
static long get_debugreg(long pid, unsigned int regno);
static unsigned long get_pseudo_pc(struct task_struct *child);
void deconfigure_bp(long pid);
extern unsigned long cris_signal_return_page;
/*
* Get contents of register REGNO in task TASK.
*/
long get_reg(struct task_struct *task, unsigned int regno)
{
/* USP is a special case, it's not in the pt_regs struct but
* in the tasks thread struct
*/
unsigned long ret;
if (regno <= PT_EDA)
ret = ((unsigned long *)task_pt_regs(task))[regno];
else if (regno == PT_USP)
ret = task->thread.usp;
else if (regno == PT_PPC)
ret = get_pseudo_pc(task);
else if (regno <= PT_MAX)
ret = get_debugreg(task->pid, regno);
else
ret = 0;
return ret;
}
/*
* Write contents of register REGNO in task TASK.
*/
int put_reg(struct task_struct *task, unsigned int regno, unsigned long data)
{
if (regno <= PT_EDA)
((unsigned long *)task_pt_regs(task))[regno] = data;
else if (regno == PT_USP)
task->thread.usp = data;
else if (regno == PT_PPC) {
/* Write pseudo-PC to ERP only if changed. */
if (data != get_pseudo_pc(task))
task_pt_regs(task)->erp = data;
} else if (regno <= PT_MAX)
return put_debugreg(task->pid, regno, data);
else
return -1;
return 0;
}
void user_enable_single_step(struct task_struct *child)
{
unsigned long tmp;
/*
* Set up SPC if not set already (in which case we have no other
* choice but to trust it).
*/
if (!get_reg(child, PT_SPC)) {
/* In case we're stopped in a delay slot. */
tmp = get_reg(child, PT_ERP) & ~1;
put_reg(child, PT_SPC, tmp);
}
tmp = get_reg(child, PT_CCS) | SBIT_USER;
put_reg(child, PT_CCS, tmp);
}
void user_disable_single_step(struct task_struct *child)
{
put_reg(child, PT_SPC, 0);
if (!get_debugreg(child->pid, PT_BP_CTRL)) {
unsigned long tmp;
/* If no h/w bp configured, disable S bit. */
tmp = get_reg(child, PT_CCS) & ~SBIT_USER;
put_reg(child, PT_CCS, tmp);
}
}
/*
* Called by kernel/ptrace.c when detaching.
*
* Make sure the single step bit is not set.
*/
void
ptrace_disable(struct task_struct *child)
{
/* Deconfigure SPC and S-bit. */
user_disable_single_step(child);
put_reg(child, PT_SPC, 0);
/* Deconfigure any watchpoints associated with the child. */
deconfigure_bp(child->pid);
}
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int ret;
unsigned int regno = addr >> 2;
unsigned long __user *datap = (unsigned long __user *)data;
switch (request) {
/* Read word at location address. */
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA: {
unsigned long tmp;
int copied;
ret = -EIO;
/* The signal trampoline page is outside the normal user-addressable
* space but still accessible. This is hack to make it possible to
* access the signal handler code in GDB.
*/
if ((addr & PAGE_MASK) == cris_signal_return_page) {
/* The trampoline page is globally mapped, no page table to traverse.*/
tmp = *(unsigned long*)addr;
} else {
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), FOLL_FORCE);
if (copied != sizeof(tmp))
break;
}
ret = put_user(tmp,datap);
break;
}
/* Read the word at location address in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 3) || regno > PT_MAX)
break;
tmp = get_reg(child, regno);
ret = put_user(tmp, datap);
break;
}
/* Write the word at location address. */
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
ret = generic_ptrace_pokedata(child, addr, data);
break;
/* Write the word at location address in the USER area. */
case PTRACE_POKEUSR:
ret = -EIO;
if ((addr & 3) || regno > PT_MAX)
break;
if (regno == PT_CCS) {
/* don't allow the tracing process to change stuff like
* interrupt enable, kernel/user bit, dma enables etc.
*/
data &= CCS_MASK;
data |= get_reg(child, PT_CCS) & ~CCS_MASK;
}
if (put_reg(child, regno, data))
break;
ret = 0;
break;
/* Get all GP registers from the child. */
case PTRACE_GETREGS: {
int i;
unsigned long tmp;
for (i = 0; i <= PT_MAX; i++) {
tmp = get_reg(child, i);
if (put_user(tmp, datap)) {
ret = -EFAULT;
goto out_tsk;
}
datap++;
}
ret = 0;
break;
}
/* Set all GP registers in the child. */
case PTRACE_SETREGS: {
int i;
unsigned long tmp;
for (i = 0; i <= PT_MAX; i++) {
if (get_user(tmp, datap)) {
ret = -EFAULT;
goto out_tsk;
}
if (i == PT_CCS) {
tmp &= CCS_MASK;
tmp |= get_reg(child, PT_CCS) & ~CCS_MASK;
}
put_reg(child, i, tmp);
datap++;
}
ret = 0;
break;
}
default:
ret = ptrace_request(child, request, addr, data);
break;
}
out_tsk:
return ret;
}
void do_syscall_trace(void)
{
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
if (!(current->ptrace & PT_PTRACED))
return;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
? 0x80 : 0));
/*
* This isn't the same as continuing with a signal, but it will do for
* normal use.
*/
if (current->exit_code) {
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
|