summaryrefslogtreecommitdiff
path: root/arch/m68knommu/kernel/ptrace.c
blob: 621d7b91ccfe5147833dc47f1de8e8c6de79c1b7 (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
/*
 *  linux/arch/m68knommu/kernel/ptrace.c
 *
 *  Copyright (C) 1994 by Hamish Macdonald
 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 *
 * 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.
 */

#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/config.h>
#include <linux/signal.h>

#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>

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

/* determines which bits in the SR the user has access to. */
/* 1 = access 0 = no access */
#define SR_MASK 0x001f

/* sets the trace bits. */
#define TRACE_BITS 0x8000

/* Find the stack offset for a register, relative to thread.esp0. */
#define PT_REG(reg)	((long)&((struct pt_regs *)0)->reg)
#define SW_REG(reg)	((long)&((struct switch_stack *)0)->reg \
			 - sizeof(struct switch_stack))
/* 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). */
static int regoff[] = {
	PT_REG(d1), PT_REG(d2), PT_REG(d3), PT_REG(d4),
	PT_REG(d5), SW_REG(d6), SW_REG(d7), PT_REG(a0),
	PT_REG(a1), PT_REG(a2), SW_REG(a3), SW_REG(a4),
	SW_REG(a5), SW_REG(a6), PT_REG(d0), -1,
	PT_REG(orig_d0), PT_REG(sr), PT_REG(pc),
};

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

	if (regno == PT_USP)
		addr = &task->thread.usp;
	else if (regno < sizeof(regoff)/sizeof(regoff[0]))
		addr = (unsigned long *)(task->thread.esp0 + regoff[regno]);
	else
		return 0;
	return *addr;
}

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

	if (regno == PT_USP)
		addr = &task->thread.usp;
	else if (regno < sizeof(regoff)/sizeof(regoff[0]))
		addr = (unsigned long *) (task->thread.esp0 + regoff[regno]);
	else
		return -1;
	*addr = data;
	return 0;
}

/*
 * 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_SR) & ~(TRACE_BITS << 16);
	put_reg(child, PT_SR, tmp);
}

asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
{
	struct task_struct *child;
	int ret;

	lock_kernel();
	ret = -EPERM;
	if (request == PTRACE_TRACEME) {
		/* are we already being traced? */
		if (current->ptrace & PT_PTRACED)
			goto out;
		/* set the ptrace bit in the process flags. */
		current->ptrace |= PT_PTRACED;
		ret = 0;
		goto out;
	}
	ret = -ESRCH;
	read_lock(&tasklist_lock);
	child = find_task_by_pid(pid);
	if (child)
		get_task_struct(child);
	read_unlock(&tasklist_lock);
	if (!child)
		goto out;

	ret = -EPERM;
	if (pid == 1)		/* you may not mess with init */
		goto out_tsk;

	if (request == PTRACE_ATTACH) {
		ret = ptrace_attach(child);
		goto out_tsk;
	}
	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	if (ret < 0)
		goto out_tsk;

	switch (request) {
		/* when I and D space are separate, these will need to be fixed. */
		case PTRACE_PEEKTEXT: /* read word at location addr. */ 
		case PTRACE_PEEKDATA: {
			unsigned long tmp;
			int copied;

			copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
			ret = -EIO;
			if (copied != sizeof(tmp))
				break;
			ret = put_user(tmp,(unsigned long *) data);
			break;
		}

		/* read the word at location addr in the USER area. */
		case PTRACE_PEEKUSR: {
			unsigned long tmp;
			
			ret = -EIO;
			if ((addr & 3) || addr < 0 ||
			    addr > sizeof(struct user) - 3)
				break;
			
			tmp = 0;  /* Default return condition */
			addr = addr >> 2; /* temporary hack. */
			ret = -EIO;
			if (addr < 19) {
				tmp = get_reg(child, addr);
				if (addr == PT_SR)
					tmp >>= 16;
			} else if (addr >= 21 && addr < 49) {
				tmp = child->thread.fp[addr - 21];
#ifdef CONFIG_M68KFPU_EMU
				/* Convert internal fpu reg representation
				 * into long double format
				 */
				if (FPU_IS_EMU && (addr < 45) && !(addr % 3))
					tmp = ((tmp & 0xffff0000) << 15) |
					      ((tmp & 0x0000ffff) << 16);
#endif
			} else if (addr == 49) {
				tmp = child->mm->start_code;
			} else if (addr == 50) {
				tmp = child->mm->start_data;
			} else if (addr == 51) {
				tmp = child->mm->end_code;
			} else
				break;
			ret = put_user(tmp,(unsigned long *) data);
			break;
		}

		/* when I and D space are separate, this will have to be fixed. */
		case PTRACE_POKETEXT: /* write the word at location addr. */
		case PTRACE_POKEDATA:
			ret = 0;
			if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
				break;
			ret = -EIO;
			break;

		case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
			ret = -EIO;
			if ((addr & 3) || addr < 0 ||
			    addr > sizeof(struct user) - 3)
				break;

			addr = addr >> 2; /* temporary hack. */
			    
			if (addr == PT_SR) {
				data &= SR_MASK;
				data <<= 16;
				data |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
			}
			if (addr < 19) {
				if (put_reg(child, addr, data))
					break;
				ret = 0;
				break;
			}
			if (addr >= 21 && addr < 48)
			{
#ifdef CONFIG_M68KFPU_EMU
				/* Convert long double format
				 * into internal fpu reg representation
				 */
				if (FPU_IS_EMU && (addr < 45) && !(addr % 3)) {
					data = (unsigned long)data << 15;
					data = (data & 0xffff0000) |
					       ((data & 0x0000ffff) >> 1);
				}
#endif
				child->thread.fp[addr - 21] = data;
				ret = 0;
			}
			break;

		case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
		case PTRACE_CONT: { /* restart after signal. */
			long tmp;

			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;
			/* make sure the single step bit is not set. */
			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
			put_reg(child, PT_SR, tmp);
			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: {
			long tmp;

			ret = 0;
			if (child->exit_state == EXIT_ZOMBIE) /* already dead */
				break;
			child->exit_code = SIGKILL;
			/* make sure the single step bit is not set. */
			tmp = get_reg(child, PT_SR) & ~(TRACE_BITS << 16);
			put_reg(child, PT_SR, tmp);
			wake_up_process(child);
			break;
		}

		case PTRACE_SINGLESTEP: {  /* set the trap flag. */
			long tmp;

			ret = -EIO;
			if (!valid_signal(data))
				break;
			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
			tmp = get_reg(child, PT_SR) | (TRACE_BITS << 16);
			put_reg(child, PT_SR, tmp);

			child->exit_code = data;
			/* give it a chance to run. */
			wake_up_process(child);
			ret = 0;
			break;
		}

		case PTRACE_DETACH:	/* detach a process that was attached. */
			ret = ptrace_detach(child, data);
			break;

		case PTRACE_GETREGS: { /* Get all gp regs from the child. */
		  	int i;
			unsigned long tmp;
			for (i = 0; i < 19; i++) {
			    tmp = get_reg(child, i);
			    if (i == PT_SR)
				tmp >>= 16;
			    if (put_user(tmp, (unsigned long *) data)) {
				ret = -EFAULT;
				break;
			    }
			    data += sizeof(long);
			}
			ret = 0;
			break;
		}

		case PTRACE_SETREGS: { /* Set all gp regs in the child. */
			int i;
			unsigned long tmp;
			for (i = 0; i < 19; i++) {
			    if (get_user(tmp, (unsigned long *) data)) {
				ret = -EFAULT;
				break;
			    }
			    if (i == PT_SR) {
				tmp &= SR_MASK;
				tmp <<= 16;
				tmp |= get_reg(child, PT_SR) & ~(SR_MASK << 16);
			    }
			    put_reg(child, i, tmp);
			    data += sizeof(long);
			}
			ret = 0;
			break;
		}

#ifdef PTRACE_GETFPREGS
		case PTRACE_GETFPREGS: { /* Get the child FPU state. */
			ret = 0;
			if (copy_to_user((void *)data, &child->thread.fp,
					 sizeof(struct user_m68kfp_struct)))
				ret = -EFAULT;
			break;
		}
#endif

#ifdef PTRACE_SETFPREGS
		case PTRACE_SETFPREGS: { /* Set the child FPU state. */
			ret = 0;
			if (copy_from_user(&child->thread.fp, (void *)data,
					   sizeof(struct user_m68kfp_struct)))
				ret = -EFAULT;
			break;
		}
#endif

		default:
			ret = -EIO;
			break;
	}
out_tsk:
	put_task_struct(child);
out:
	unlock_kernel();
	return ret;
}

asmlinkage void syscall_trace(void)
{
	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;
	if (!(current->ptrace & PT_PTRACED))
		return;
	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;
	}
}