summaryrefslogtreecommitdiffstats
path: root/arch/blackfin/kernel/ptrace.c
blob: d76618db50df8c4e3f4c06cb44d09906e5b41147 (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
/*
 * File:         arch/blackfin/kernel/ptrace.c
 * Based on:     Taken from linux/kernel/ptrace.c
 * Author:       linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 *
 * Created:      1/23/92
 * Description:
 *
 * Modified:
 *               Copyright 2004-2006 Analog Devices Inc.
 *
 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
#include <linux/uaccess.h>

#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/asm-offsets.h>
#include <asm/dma.h>
#include <asm/fixed_code.h>
#include <asm/cacheflush.h>
#include <asm/mem_map.h>

#define TEXT_OFFSET 0
/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

/* determines which bits in the SYSCFG reg the user has access to. */
/* 1 = access 0 = no access */
#define SYSCFG_MASK 0x0007	/* SYSCFG reg */
/* sets the trace bits. */
#define TRACE_BITS 0x0001

/* Find the stack offset for a register, relative to thread.esp0. */
#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)

/*
 * Get the address of the live pt_regs for the specified task.
 * These are saved onto the top kernel stack when the process
 * is not running.
 *
 * Note: if a user thread is execve'd from kernel space, the
 * kernel stack will not be empty on entry to the kernel, so
 * ptracing these tasks will fail.
 */
static inline struct pt_regs *get_user_regs(struct task_struct *task)
{
	return (struct pt_regs *)
	    ((unsigned long)task_stack_page(task) +
	     (THREAD_SIZE - sizeof(struct pt_regs)));
}

/*
 * Get all user integer registers.
 */
static inline int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
{
	struct pt_regs regs;
	memcpy(&regs, get_user_regs(tsk), sizeof(regs));
	regs.usp = tsk->thread.usp;
	return copy_to_user(uregs, &regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
}

/* Mapping from PT_xxx to the stack offset at which the register is
 * saved.  Notice that usp has no stack-slot and needs to be treated
 * specially (see get_reg/put_reg below).
 */

/*
 * Get contents of register REGNO in task TASK.
 */
static inline long get_reg(struct task_struct *task, int regno)
{
	unsigned char *reg_ptr;

	struct pt_regs *regs =
	    (struct pt_regs *)((unsigned long)task_stack_page(task) +
			       (THREAD_SIZE - sizeof(struct pt_regs)));
	reg_ptr = (char *)regs;

	switch (regno) {
	case PT_USP:
		return task->thread.usp;
	default:
		if (regno <= 216)
			return *(long *)(reg_ptr + regno);
	}
	/* slight mystery ... never seems to come here but kernel misbehaves without this code! */

	printk(KERN_WARNING "Request to get for unknown register %d\n", regno);
	return 0;
}

/*
 * Write contents of register REGNO in task TASK.
 */
static inline int
put_reg(struct task_struct *task, int regno, unsigned long data)
{
	char *reg_ptr;

	struct pt_regs *regs =
	    (struct pt_regs *)((unsigned long)task_stack_page(task) +
			       (THREAD_SIZE - sizeof(struct pt_regs)));
	reg_ptr = (char *)regs;

	switch (regno) {
	case PT_PC:
		/*********************************************************************/
		/* At this point the kernel is most likely in exception.             */
		/* The RETX register will be used to populate the pc of the process. */
		/*********************************************************************/
		regs->retx = data;
		regs->pc = data;
		break;
	case PT_RETX:
		break;		/* regs->retx = data; break; */
	case PT_USP:
		regs->usp = data;
		task->thread.usp = data;
		break;
	default:
		if (regno <= 216)
			*(long *)(reg_ptr + regno) = data;
	}
	return 0;
}

/*
 * check that an address falls within the bounds of the target process's memory mappings
 */
static inline int is_user_addr_valid(struct task_struct *child,
				     unsigned long start, unsigned long len)
{
	struct vm_area_struct *vma;
	struct sram_list_struct *sraml;

	/* overflow */
	if (start + len < start)
		return -EIO;

	vma = find_vma(child->mm, start);
	if (vma && start >= vma->vm_start && start + len <= vma->vm_end)
			return 0;

	for (sraml = child->mm->context.sram_list; sraml; sraml = sraml->next)
		if (start >= (unsigned long)sraml->addr
		    && start + len < (unsigned long)sraml->addr + sraml->length)
			return 0;

	if (start >= FIXED_CODE_START && start + len < FIXED_CODE_END)
		return 0;

	return -EIO;
}

void ptrace_enable(struct task_struct *child)
{
	unsigned long tmp;
	tmp = get_reg(child, PT_SYSCFG) | (TRACE_BITS);
	put_reg(child, PT_SYSCFG, tmp);
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure the single step bit is not set.
 */
void ptrace_disable(struct task_struct *child)
{
	unsigned long tmp;
	/* make sure the single step bit is not set. */
	tmp = get_reg(child, PT_SYSCFG) & ~TRACE_BITS;
	put_reg(child, PT_SYSCFG, tmp);
}

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

	switch (request) {
		/* when I and D space are separate, these will need to be fixed. */
	case PTRACE_PEEKDATA:
		pr_debug("ptrace: PEEKDATA\n");
		/* fall through */
	case PTRACE_PEEKTEXT:	/* read word at location addr. */
		{
			unsigned long tmp = 0;
			int copied;

			ret = -EIO;
			pr_debug("ptrace: PEEKTEXT at addr 0x%08lx + %ld\n", addr, sizeof(data));
			if (is_user_addr_valid(child, addr, sizeof(tmp)) < 0)
				break;
			pr_debug("ptrace: user address is valid\n");

			if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
			    && addr + sizeof(tmp) <= get_l1_code_start() + L1_CODE_LENGTH) {
				safe_dma_memcpy (&tmp, (const void *)(addr), sizeof(tmp));
				copied = sizeof(tmp);

			} else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
			    && addr + sizeof(tmp) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
				memcpy(&tmp, (const void *)(addr), sizeof(tmp));
				copied = sizeof(tmp);

			} else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
			    && addr + sizeof(tmp) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
				memcpy(&tmp, (const void *)(addr), sizeof(tmp));
				copied = sizeof(tmp);

			} else if (addr >= FIXED_CODE_START
			    && addr + sizeof(tmp) <= FIXED_CODE_END) {
				copy_from_user_page(0, 0, 0, &tmp, (const void *)(addr), sizeof(tmp));
				copied = sizeof(tmp);

			} else
				copied = access_process_vm(child, addr, &tmp,
							   sizeof(tmp), 0);

			pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
			if (copied != sizeof(tmp))
				break;
			ret = put_user(tmp, datap);
			break;
		}

		/* read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR:
		{
			unsigned long tmp;
			ret = -EIO;
			tmp = 0;
			if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
				printk(KERN_WARNING "ptrace error : PEEKUSR : temporarily returning "
				                    "0 - %x sizeof(pt_regs) is %lx\n",
				     (int)addr, sizeof(struct pt_regs));
				break;
			}
			if (addr == sizeof(struct pt_regs)) {
				/* PT_TEXT_ADDR */
				tmp = child->mm->start_code + TEXT_OFFSET;
			} else if (addr == (sizeof(struct pt_regs) + 4)) {
				/* PT_TEXT_END_ADDR */
				tmp = child->mm->end_code;
			} else if (addr == (sizeof(struct pt_regs) + 8)) {
				/* PT_DATA_ADDR */
				tmp = child->mm->start_data;
#ifdef CONFIG_BINFMT_ELF_FDPIC
			} else if (addr == (sizeof(struct pt_regs) + 12)) {
				tmp = child->mm->context.exec_fdpic_loadmap;
			} else if (addr == (sizeof(struct pt_regs) + 16)) {
				tmp = child->mm->context.interp_fdpic_loadmap;
#endif
			} else {
				tmp = get_reg(child, addr);
			}
			ret = put_user(tmp, datap);
			break;
		}

		/* when I and D space are separate, this will have to be fixed. */
	case PTRACE_POKEDATA:
		pr_debug("ptrace: PTRACE_PEEKDATA\n");
		/* fall through */
	case PTRACE_POKETEXT:	/* write the word at location addr. */
		{
			int copied;

			ret = -EIO;
			pr_debug("ptrace: POKETEXT at addr 0x%08lx + %ld bytes %lx\n",
			         addr, sizeof(data), data);
			if (is_user_addr_valid(child, addr, sizeof(data)) < 0)
				break;
			pr_debug("ptrace: user address is valid\n");

			if (L1_CODE_LENGTH != 0 && addr >= get_l1_code_start()
			    && addr + sizeof(data) <= get_l1_code_start() + L1_CODE_LENGTH) {
				safe_dma_memcpy ((void *)(addr), &data, sizeof(data));
				copied = sizeof(data);

			} else if (L1_DATA_A_LENGTH != 0 && addr >= L1_DATA_A_START
			    && addr + sizeof(data) <= L1_DATA_A_START + L1_DATA_A_LENGTH) {
				memcpy((void *)(addr), &data, sizeof(data));
				copied = sizeof(data);

			} else if (L1_DATA_B_LENGTH != 0 && addr >= L1_DATA_B_START
			    && addr + sizeof(data) <= L1_DATA_B_START + L1_DATA_B_LENGTH) {
				memcpy((void *)(addr), &data, sizeof(data));
				copied = sizeof(data);

			} else if (addr >= FIXED_CODE_START
			    && addr + sizeof(data) <= FIXED_CODE_END) {
				copy_to_user_page(0, 0, 0, (void *)(addr), &data, sizeof(data));
				copied = sizeof(data);

			} else
				copied = access_process_vm(child, addr, &data,
							   sizeof(data), 1);

			pr_debug("ptrace: copied size %d\n", copied);
			if (copied != sizeof(data))
				break;
			ret = 0;
			break;
		}

	case PTRACE_POKEUSR:	/* write the word at location addr in the USER area */
		ret = -EIO;
		if ((addr & 3) || (addr > (sizeof(struct pt_regs) + 16))) {
			printk(KERN_WARNING "ptrace error : POKEUSR: temporarily returning 0\n");
			break;
		}

		if (addr >= (sizeof(struct pt_regs))) {
			ret = 0;
			break;
		}
		if (addr == PT_SYSCFG) {
			data &= SYSCFG_MASK;
			data |= get_reg(child, PT_SYSCFG);
		}
		ret = put_reg(child, addr, data);
		break;

	case PTRACE_SYSCALL:	/* continue and stop at next (return from) syscall */
	case PTRACE_CONT:	/* restart after signal. */
		pr_debug("ptrace: syscall/cont\n");

		ret = -EIO;
		if (!valid_signal(data))
			break;
		if (request == PTRACE_SYSCALL)
			set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		else
			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->exit_code = data;
		ptrace_disable(child);
		pr_debug("ptrace: before wake_up_process\n");
		wake_up_process(child);
		ret = 0;
		break;

	/*
	 * make the child exit.  Best I can do is send it a sigkill.
	 * perhaps it should be put in the status that it wants to
	 * exit.
	 */
	case PTRACE_KILL:
		ret = 0;
		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
			break;
		child->exit_code = SIGKILL;
		ptrace_disable(child);
		wake_up_process(child);
		break;

	case PTRACE_SINGLESTEP:	/* set the trap flag. */
		pr_debug("ptrace: single step\n");
		ret = -EIO;
		if (!valid_signal(data))
			break;
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		ptrace_enable(child);
		child->exit_code = data;
		wake_up_process(child);
		ret = 0;
		break;

	case PTRACE_GETREGS:
		/* Get all gp regs from the child. */
		ret = ptrace_getregs(child, datap);
		break;

	case PTRACE_SETREGS:
		printk(KERN_WARNING "ptrace: SETREGS: **** NOT IMPLEMENTED ***\n");
		/* Set all gp regs in the child. */
		ret = 0;
		break;

	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}

asmlinkage void 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.  strace only continues with a signal if the
	 * stopping signal is not SIGTRAP.  -brl
	 */
	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}
}