aboutsummaryrefslogtreecommitdiffstats
path: root/arch/blackfin/kernel/ptrace.c
blob: 75089f80855d0ca590dc6b9c7e9a2d30011c82ad (plain) (blame)
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
/*
 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 * these modifications are Copyright 2004-2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/regset.h>
#include <linux/signal.h>
#include <linux/tracehook.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>
#include <asm/mmu_context.h>

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

/*
 * Get contents of register REGNO in task TASK.
 */
static inline long
get_reg(struct task_struct *task, unsigned long regno,
	unsigned long __user *datap)
{
	long tmp;
	struct pt_regs *regs = task_pt_regs(task);

	if (regno & 3 || regno > PT_LAST_PSEUDO)
		return -EIO;

	switch (regno) {
	case PT_TEXT_ADDR:
		tmp = task->mm->start_code;
		break;
	case PT_TEXT_END_ADDR:
		tmp = task->mm->end_code;
		break;
	case PT_DATA_ADDR:
		tmp = task->mm->start_data;
		break;
	case PT_USP:
		tmp = task->thread.usp;
		break;
	default:
		if (regno < sizeof(*regs)) {
			void *reg_ptr = regs;
			tmp = *(long *)(reg_ptr + regno);
		} else
			return -EIO;
	}

	return put_user(tmp, datap);
}

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

	if (regno & 3 || regno > PT_LAST_PSEUDO)
		return -EIO;

	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;
	case PT_SYSCFG:	/* don't let userspace screw with this */
		if ((data & ~1) != 0x6)
			pr_warning("ptrace: ignore syscfg write of %#lx\n", data);
		break;		/* regs->syscfg = data; break; */
	default:
		if (regno < sizeof(*regs)) {
			void *reg_offset = regs;
			*(long *)(reg_offset + regno) = data;
		}
		/* Ignore writes to pseudo registers */
	}

	return 0;
}

/*
 * check that an address falls within the bounds of the target process's memory mappings
 */
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;

#ifdef CONFIG_APP_STACK_L1
	if (child->mm->context.l1_stack_save)
		if (start >= (unsigned long)l1_stack_base &&
			start + len < (unsigned long)l1_stack_base + l1_stack_len)
			return 0;
#endif

	return -EIO;
}

/*
 * retrieve the contents of Blackfin userspace general registers
 */
static int genregs_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);
	int ret;

	/* This sucks ... */
	regs->usp = target->thread.usp;

	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
				  regs, 0, sizeof(*regs));
	if (ret < 0)
		return ret;

	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
					sizeof(*regs), -1);
}

/*
 * update the contents of the Blackfin userspace general registers
 */
static int genregs_set(struct task_struct *target,
		       const struct user_regset *regset,
		       unsigned int pos, unsigned int count,
		       const void *kbuf, const void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	int ret;

	/* Don't let people set SYSCFG (it's at the end of pt_regs) */
	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 regs, 0, PT_SYSCFG);
	if (ret < 0)
		return ret;

	/* This sucks ... */
	target->thread.usp = regs->usp;
	/* regs->retx = regs->pc; */

	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
					PT_SYSCFG, -1);
}

/*
 * Define the register sets available on the Blackfin under Linux
 */
enum bfin_regset {
	REGSET_GENERAL,
};

static const struct user_regset bfin_regsets[] = {
	[REGSET_GENERAL] = {
		.core_note_type = NT_PRSTATUS,
		.n              = sizeof(struct pt_regs) / sizeof(long),
		.size           = sizeof(long),
		.align          = sizeof(long),
		.get            = genregs_get,
		.set            = genregs_set,
	},
};

static const struct user_regset_view user_bfin_native_view = {
	.name      = "Blackfin",
	.e_machine = EM_BLACKFIN,
	.regsets   = bfin_regsets,
	.n         = ARRAY_SIZE(bfin_regsets),
};

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

void user_enable_single_step(struct task_struct *child)
{
	struct pt_regs *regs = task_pt_regs(child);
	regs->syscfg |= SYSCFG_SSSTEP;

	set_tsk_thread_flag(child, TIF_SINGLESTEP);
}

void user_disable_single_step(struct task_struct *child)
{
	struct pt_regs *regs = task_pt_regs(child);
	regs->syscfg &= ~SYSCFG_SSSTEP;

	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
}

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

	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 = 0, to_copy = sizeof(tmp);

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

			switch (bfin_mem_access_type(addr, to_copy)) {
			case BFIN_MEM_ACCESS_CORE:
			case BFIN_MEM_ACCESS_CORE_ONLY:
				copied = access_process_vm(child, addr, &tmp,
				                           to_copy, 0);
				if (copied)
					break;

				/* hrm, why didn't that work ... maybe no mapping */
				if (addr >= FIXED_CODE_START &&
				    addr + to_copy <= FIXED_CODE_END) {
					copy_from_user_page(0, 0, 0, &tmp, paddr, to_copy);
					copied = to_copy;
				} else if (addr >= BOOT_ROM_START) {
					memcpy(&tmp, paddr, to_copy);
					copied = to_copy;
				}

				break;
			case BFIN_MEM_ACCESS_DMA:
				if (safe_dma_memcpy(&tmp, paddr, to_copy))
					copied = to_copy;
				break;
			case BFIN_MEM_ACCESS_ITEST:
				if (isram_memcpy(&tmp, paddr, to_copy))
					copied = to_copy;
				break;
			default:
				copied = 0;
				break;
			}

			pr_debug("ptrace: copied size %d [0x%08lx]\n", copied, tmp);
			if (copied == to_copy)
				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 = 0, to_copy = sizeof(data);

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

			switch (bfin_mem_access_type(addr, to_copy)) {
			case BFIN_MEM_ACCESS_CORE:
			case BFIN_MEM_ACCESS_CORE_ONLY:
				copied = access_process_vm(child, addr, &data,
				                           to_copy, 1);
				break;
			case BFIN_MEM_ACCESS_DMA:
				if (safe_dma_memcpy(paddr, &data, to_copy))
					copied = to_copy;
				break;
			case BFIN_MEM_ACCESS_ITEST:
				if (isram_memcpy(paddr, &data, to_copy))
					copied = to_copy;
				break;
			default:
				copied = 0;
				break;
			}

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

	case PTRACE_PEEKUSR:
		switch (addr) {
#ifdef CONFIG_BINFMT_ELF_FDPIC	/* backwards compat */
		case PT_FDPIC_EXEC:
			request = PTRACE_GETFDPIC;
			addr = PTRACE_GETFDPIC_EXEC;
			goto case_default;
		case PT_FDPIC_INTERP:
			request = PTRACE_GETFDPIC;
			addr = PTRACE_GETFDPIC_INTERP;
			goto case_default;
#endif
		default:
			ret = get_reg(child, addr, datap);
		}
		pr_debug("ptrace: PEEKUSR reg %li with %#lx = %i\n", addr, data, ret);
		break;

	case PTRACE_POKEUSR:
		ret = put_reg(child, addr, data);
		pr_debug("ptrace: POKEUSR reg %li with %li = %i\n", addr, data, ret);
		break;

	case PTRACE_GETREGS:
		pr_debug("ptrace: PTRACE_GETREGS\n");
		return copy_regset_to_user(child, &user_bfin_native_view,
					   REGSET_GENERAL,
					   0, sizeof(struct pt_regs),
					   datap);

	case PTRACE_SETREGS:
		pr_debug("ptrace: PTRACE_SETREGS\n");
		return copy_regset_from_user(child, &user_bfin_native_view,
					     REGSET_GENERAL,
					     0, sizeof(struct pt_regs),
					     datap);

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

	return ret;
}

asmlinkage int syscall_trace_enter(struct pt_regs *regs)
{
	int ret = 0;

	if (test_thread_flag(TIF_SYSCALL_TRACE))
		ret = tracehook_report_syscall_entry(regs);

	return ret;
}

asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
	int step;

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