summaryrefslogtreecommitdiffstats
path: root/arch/xtensa/kernel/ptrace.c
blob: 145742d70a9f21d4d02cb2884b3b79367dca5723 (plain)
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
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
/*
 * 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.
 *
 * Copyright (C) 2001 - 2007  Tensilica Inc.
 *
 * Joe Taylor	<joe@tensilica.com, joetylr@yahoo.com>
 * Chris Zankel <chris@zankel.net>
 * Scott Foehner<sfoehner@yahoo.com>,
 * Kevin Chea
 * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
 */

#include <linux/errno.h>
#include <linux/hw_breakpoint.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/perf_event.h>
#include <linux/ptrace.h>
#include <linux/regset.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>

#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

#include <asm/coprocessor.h>
#include <asm/elf.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/ptrace.h>

static int gpr_get(struct task_struct *target,
		   const struct user_regset *regset,
		   unsigned int pos, unsigned int count,
		   void *kbuf, void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	struct user_pt_regs newregs = {
		.pc = regs->pc,
		.ps = regs->ps & ~(1 << PS_EXCM_BIT),
		.lbeg = regs->lbeg,
		.lend = regs->lend,
		.lcount = regs->lcount,
		.sar = regs->sar,
		.threadptr = regs->threadptr,
		.windowbase = regs->windowbase,
		.windowstart = regs->windowstart,
	};

	memcpy(newregs.a,
	       regs->areg + XCHAL_NUM_AREGS - regs->windowbase * 4,
	       regs->windowbase * 16);
	memcpy(newregs.a + regs->windowbase * 4,
	       regs->areg,
	       (WSBITS - regs->windowbase) * 16);

	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				   &newregs, 0, -1);
}

static int gpr_set(struct task_struct *target,
		   const struct user_regset *regset,
		   unsigned int pos, unsigned int count,
		   const void *kbuf, const void __user *ubuf)
{
	int ret;
	struct user_pt_regs newregs = {0};
	struct pt_regs *regs;
	const u32 ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
	if (ret)
		return ret;

	if (newregs.windowbase >= XCHAL_NUM_AREGS / 4)
		return -EINVAL;

	regs = task_pt_regs(target);
	regs->pc = newregs.pc;
	regs->ps = (regs->ps & ~ps_mask) | (newregs.ps & ps_mask);
	regs->lbeg = newregs.lbeg;
	regs->lend = newregs.lend;
	regs->lcount = newregs.lcount;
	regs->sar = newregs.sar;
	regs->threadptr = newregs.threadptr;

	if (newregs.windowbase != regs->windowbase ||
	    newregs.windowstart != regs->windowstart) {
		u32 rotws, wmask;

		rotws = (((newregs.windowstart |
			   (newregs.windowstart << WSBITS)) >>
			  newregs.windowbase) &
			 ((1 << WSBITS) - 1)) & ~1;
		wmask = ((rotws ? WSBITS + 1 - ffs(rotws) : 0) << 4) |
			(rotws & 0xF) | 1;
		regs->windowbase = newregs.windowbase;
		regs->windowstart = newregs.windowstart;
		regs->wmask = wmask;
	}

	memcpy(regs->areg + XCHAL_NUM_AREGS - newregs.windowbase * 4,
	       newregs.a, newregs.windowbase * 16);
	memcpy(regs->areg, newregs.a + newregs.windowbase * 4,
	       (WSBITS - newregs.windowbase) * 16);

	return 0;
}

static int tie_get(struct task_struct *target,
		   const struct user_regset *regset,
		   unsigned int pos, unsigned int count,
		   void *kbuf, void __user *ubuf)
{
	int ret;
	struct pt_regs *regs = task_pt_regs(target);
	struct thread_info *ti = task_thread_info(target);
	elf_xtregs_t *newregs = kzalloc(sizeof(elf_xtregs_t), GFP_KERNEL);

	if (!newregs)
		return -ENOMEM;

	newregs->opt = regs->xtregs_opt;
	newregs->user = ti->xtregs_user;

#if XTENSA_HAVE_COPROCESSORS
	/* Flush all coprocessor registers to memory. */
	coprocessor_flush_all(ti);
	newregs->cp0 = ti->xtregs_cp.cp0;
	newregs->cp1 = ti->xtregs_cp.cp1;
	newregs->cp2 = ti->xtregs_cp.cp2;
	newregs->cp3 = ti->xtregs_cp.cp3;
	newregs->cp4 = ti->xtregs_cp.cp4;
	newregs->cp5 = ti->xtregs_cp.cp5;
	newregs->cp6 = ti->xtregs_cp.cp6;
	newregs->cp7 = ti->xtregs_cp.cp7;
#endif
	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				  newregs, 0, -1);
	kfree(newregs);
	return ret;
}

static int tie_set(struct task_struct *target,
		   const struct user_regset *regset,
		   unsigned int pos, unsigned int count,
		   const void *kbuf, const void __user *ubuf)
{
	int ret;
	struct pt_regs *regs = task_pt_regs(target);
	struct thread_info *ti = task_thread_info(target);
	elf_xtregs_t *newregs = kzalloc(sizeof(elf_xtregs_t), GFP_KERNEL);

	if (!newregs)
		return -ENOMEM;

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 newregs, 0, -1);

	if (ret)
		goto exit;
	regs->xtregs_opt = newregs->opt;
	ti->xtregs_user = newregs->user;

#if XTENSA_HAVE_COPROCESSORS
	/* Flush all coprocessors before we overwrite them. */
	coprocessor_flush_all(ti);
	coprocessor_release_all(ti);
	ti->xtregs_cp.cp0 = newregs->cp0;
	ti->xtregs_cp.cp1 = newregs->cp1;
	ti->xtregs_cp.cp2 = newregs->cp2;
	ti->xtregs_cp.cp3 = newregs->cp3;
	ti->xtregs_cp.cp4 = newregs->cp4;
	ti->xtregs_cp.cp5 = newregs->cp5;
	ti->xtregs_cp.cp6 = newregs->cp6;
	ti->xtregs_cp.cp7 = newregs->cp7;
#endif
exit:
	kfree(newregs);
	return ret;
}

enum xtensa_regset {
	REGSET_GPR,
	REGSET_TIE,
};

static const struct user_regset xtensa_regsets[] = {
	[REGSET_GPR] = {
		.core_note_type = NT_PRSTATUS,
		.n = sizeof(struct user_pt_regs) / sizeof(u32),
		.size = sizeof(u32),
		.align = sizeof(u32),
		.get = gpr_get,
		.set = gpr_set,
	},
	[REGSET_TIE] = {
		.core_note_type = NT_PRFPREG,
		.n = sizeof(elf_xtregs_t) / sizeof(u32),
		.size = sizeof(u32),
		.align = sizeof(u32),
		.get = tie_get,
		.set = tie_set,
	},
};

static const struct user_regset_view user_xtensa_view = {
	.name = "xtensa",
	.e_machine = EM_XTENSA,
	.regsets = xtensa_regsets,
	.n = ARRAY_SIZE(xtensa_regsets)
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
	return &user_xtensa_view;
}

void user_enable_single_step(struct task_struct *child)
{
	child->ptrace |= PT_SINGLESTEP;
}

void user_disable_single_step(struct task_struct *child)
{
	child->ptrace &= ~PT_SINGLESTEP;
}

/*
 * Called by kernel/ptrace.c when detaching to disable single stepping.
 */

void ptrace_disable(struct task_struct *child)
{
	/* Nothing to do.. */
}

static int ptrace_getregs(struct task_struct *child, void __user *uregs)
{
	return copy_regset_to_user(child, &user_xtensa_view, REGSET_GPR,
				   0, sizeof(xtensa_gregset_t), uregs);
}

static int ptrace_setregs(struct task_struct *child, void __user *uregs)
{
	return copy_regset_from_user(child, &user_xtensa_view, REGSET_GPR,
				     0, sizeof(xtensa_gregset_t), uregs);
}

static int ptrace_getxregs(struct task_struct *child, void __user *uregs)
{
	return copy_regset_to_user(child, &user_xtensa_view, REGSET_TIE,
				   0, sizeof(elf_xtregs_t), uregs);
}

static int ptrace_setxregs(struct task_struct *child, void __user *uregs)
{
	return copy_regset_from_user(child, &user_xtensa_view, REGSET_TIE,
				     0, sizeof(elf_xtregs_t), uregs);
}

static int ptrace_peekusr(struct task_struct *child, long regno,
			  long __user *ret)
{
	struct pt_regs *regs;
	unsigned long tmp;

	regs = task_pt_regs(child);
	tmp = 0;  /* Default return value. */

	switch(regno) {
	case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
		tmp = regs->areg[regno - REG_AR_BASE];
		break;

	case REG_A_BASE ... REG_A_BASE + 15:
		tmp = regs->areg[regno - REG_A_BASE];
		break;

	case REG_PC:
		tmp = regs->pc;
		break;

	case REG_PS:
		/* Note: PS.EXCM is not set while user task is running;
		 * its being set in regs is for exception handling
		 * convenience.
		 */
		tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
		break;

	case REG_WB:
		break;		/* tmp = 0 */

	case REG_WS:
		{
			unsigned long wb = regs->windowbase;
			unsigned long ws = regs->windowstart;
			tmp = ((ws >> wb) | (ws << (WSBITS - wb))) &
				((1 << WSBITS) - 1);
			break;
		}
	case REG_LBEG:
		tmp = regs->lbeg;
		break;

	case REG_LEND:
		tmp = regs->lend;
		break;

	case REG_LCOUNT:
		tmp = regs->lcount;
		break;

	case REG_SAR:
		tmp = regs->sar;
		break;

	case SYSCALL_NR:
		tmp = regs->syscall;
		break;

	default:
		return -EIO;
	}
	return put_user(tmp, ret);
}

static int ptrace_pokeusr(struct task_struct *child, long regno, long val)
{
	struct pt_regs *regs;
	regs = task_pt_regs(child);

	switch (regno) {
	case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
		regs->areg[regno - REG_AR_BASE] = val;
		break;

	case REG_A_BASE ... REG_A_BASE + 15:
		regs->areg[regno - REG_A_BASE] = val;
		break;

	case REG_PC:
		regs->pc = val;
		break;

	case SYSCALL_NR:
		regs->syscall = val;
		break;

	default:
		return -EIO;
	}
	return 0;
}

#ifdef CONFIG_HAVE_HW_BREAKPOINT
static void ptrace_hbptriggered(struct perf_event *bp,
				struct perf_sample_data *data,
				struct pt_regs *regs)
{
	int i;
	struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);

	if (bp->attr.bp_type & HW_BREAKPOINT_X) {
		for (i = 0; i < XCHAL_NUM_IBREAK; ++i)
			if (current->thread.ptrace_bp[i] == bp)
				break;
		i <<= 1;
	} else {
		for (i = 0; i < XCHAL_NUM_DBREAK; ++i)
			if (current->thread.ptrace_wp[i] == bp)
				break;
		i = (i << 1) | 1;
	}

	force_sig_ptrace_errno_trap(i, (void __user *)bkpt->address);
}

static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
{
	struct perf_event_attr attr;

	ptrace_breakpoint_init(&attr);

	/* Initialise fields to sane defaults. */
	attr.bp_addr	= 0;
	attr.bp_len	= 1;
	attr.bp_type	= type;
	attr.disabled	= 1;

	return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
					   tsk);
}

/*
 * Address bit 0 choose instruction (0) or data (1) break register, bits
 * 31..1 are the register number.
 * Both PTRACE_GETHBPREGS and PTRACE_SETHBPREGS transfer two 32-bit words:
 * address (0) and control (1).
 * Instruction breakpoint contorl word is 0 to clear breakpoint, 1 to set.
 * Data breakpoint control word bit 31 is 'trigger on store', bit 30 is
 * 'trigger on load, bits 29..0 are length. Length 0 is used to clear a
 * breakpoint. To set a breakpoint length must be a power of 2 in the range
 * 1..64 and the address must be length-aligned.
 */

static long ptrace_gethbpregs(struct task_struct *child, long addr,
			      long __user *datap)
{
	struct perf_event *bp;
	u32 user_data[2] = {0};
	bool dbreak = addr & 1;
	unsigned idx = addr >> 1;

	if ((!dbreak && idx >= XCHAL_NUM_IBREAK) ||
	    (dbreak && idx >= XCHAL_NUM_DBREAK))
		return -EINVAL;

	if (dbreak)
		bp = child->thread.ptrace_wp[idx];
	else
		bp = child->thread.ptrace_bp[idx];

	if (bp) {
		user_data[0] = bp->attr.bp_addr;
		user_data[1] = bp->attr.disabled ? 0 : bp->attr.bp_len;
		if (dbreak) {
			if (bp->attr.bp_type & HW_BREAKPOINT_R)
				user_data[1] |= DBREAKC_LOAD_MASK;
			if (bp->attr.bp_type & HW_BREAKPOINT_W)
				user_data[1] |= DBREAKC_STOR_MASK;
		}
	}

	if (copy_to_user(datap, user_data, sizeof(user_data)))
		return -EFAULT;

	return 0;
}

static long ptrace_sethbpregs(struct task_struct *child, long addr,
			      long __user *datap)
{
	struct perf_event *bp;
	struct perf_event_attr attr;
	u32 user_data[2];
	bool dbreak = addr & 1;
	unsigned idx = addr >> 1;
	int bp_type = 0;

	if ((!dbreak && idx >= XCHAL_NUM_IBREAK) ||
	    (dbreak && idx >= XCHAL_NUM_DBREAK))
		return -EINVAL;

	if (copy_from_user(user_data, datap, sizeof(user_data)))
		return -EFAULT;

	if (dbreak) {
		bp = child->thread.ptrace_wp[idx];
		if (user_data[1] & DBREAKC_LOAD_MASK)
			bp_type |= HW_BREAKPOINT_R;
		if (user_data[1] & DBREAKC_STOR_MASK)
			bp_type |= HW_BREAKPOINT_W;
	} else {
		bp = child->thread.ptrace_bp[idx];
		bp_type = HW_BREAKPOINT_X;
	}

	if (!bp) {
		bp = ptrace_hbp_create(child,
				       bp_type ? bp_type : HW_BREAKPOINT_RW);
		if (IS_ERR(bp))
			return PTR_ERR(bp);
		if (dbreak)
			child->thread.ptrace_wp[idx] = bp;
		else
			child->thread.ptrace_bp[idx] = bp;
	}

	attr = bp->attr;
	attr.bp_addr = user_data[0];
	attr.bp_len = user_data[1] & ~(DBREAKC_LOAD_MASK | DBREAKC_STOR_MASK);
	attr.bp_type = bp_type;
	attr.disabled = !attr.bp_len;

	return modify_user_hw_breakpoint(bp, &attr);
}
#endif

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	int ret = -EPERM;
	void __user *datap = (void __user *) data;

	switch (request) {
	case PTRACE_PEEKUSR:	/* read register specified by addr. */
		ret = ptrace_peekusr(child, addr, datap);
		break;

	case PTRACE_POKEUSR:	/* write register specified by addr. */
		ret = ptrace_pokeusr(child, addr, data);
		break;

	case PTRACE_GETREGS:
		ret = ptrace_getregs(child, datap);
		break;

	case PTRACE_SETREGS:
		ret = ptrace_setregs(child, datap);
		break;

	case PTRACE_GETXTREGS:
		ret = ptrace_getxregs(child, datap);
		break;

	case PTRACE_SETXTREGS:
		ret = ptrace_setxregs(child, datap);
		break;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
	case PTRACE_GETHBPREGS:
		ret = ptrace_gethbpregs(child, addr, datap);
		break;

	case PTRACE_SETHBPREGS:
		ret = ptrace_sethbpregs(child, addr, datap);
		break;
#endif
	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}

void do_syscall_trace_leave(struct pt_regs *regs);
int do_syscall_trace_enter(struct pt_regs *regs)
{
	if (regs->syscall == NO_SYSCALL)
		regs->areg[2] = -ENOSYS;

	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
	    tracehook_report_syscall_entry(regs)) {
		regs->areg[2] = -ENOSYS;
		regs->syscall = NO_SYSCALL;
		return 0;
	}

	if (regs->syscall == NO_SYSCALL) {
		do_syscall_trace_leave(regs);
		return 0;
	}

	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
		trace_sys_enter(regs, syscall_get_nr(current, regs));

	return 1;
}

void do_syscall_trace_leave(struct pt_regs *regs)
{
	int step;

	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
		trace_sys_exit(regs, regs_return_value(regs));

	step = test_thread_flag(TIF_SINGLESTEP);

	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
		tracehook_report_syscall_exit(regs, step);
}