aboutsummaryrefslogtreecommitdiffstats
path: root/arch/parisc/kernel/ptrace.c
blob: 3f28de974556c838894ab5d12f40227d2c39c23e (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
/*
 * Kernel support for the ptrace() and syscall tracing interfaces.
 *
 * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
 * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
 */

#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/personality.h>
#include <linux/security.h>
#include <linux/compat.h>
#include <linux/signal.h>

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

/* PSW bits we allow the debugger to modify */
#define USER_PSW_BITS	(PSW_N | PSW_V | PSW_CB)

#undef DEBUG_PTRACE

#ifdef DEBUG_PTRACE
#define DBG(x...)	printk(x)
#else
#define DBG(x...)
#endif

#ifdef __LP64__

/* This function is needed to translate 32 bit pt_regs offsets in to
 * 64 bit pt_regs offsets.  For example, a 32 bit gdb under a 64 bit kernel
 * will request offset 12 if it wants gr3, but the lower 32 bits of
 * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
 * This code relies on a 32 bit pt_regs being comprised of 32 bit values
 * except for the fp registers which (a) are 64 bits, and (b) follow
 * the gr registers at the start of pt_regs.  The 32 bit pt_regs should
 * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
 * being 64 bit in both cases.
 */

static long translate_usr_offset(long offset)
{
	if (offset < 0)
		return -1;
	else if (offset <= 32*4)	/* gr[0..31] */
		return offset * 2 + 4;
	else if (offset <= 32*4+32*8)	/* gr[0..31] + fr[0..31] */
		return offset + 32*4;
	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
		return offset * 2 + 4 - 32*8;
	else
		return -1;
}
#endif

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* make sure the trap bits are not set */
	pa_psw(child)->r = 0;
	pa_psw(child)->t = 0;
	pa_psw(child)->h = 0;
	pa_psw(child)->l = 0;
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
	long ret;
#ifdef DEBUG_PTRACE
	long oaddr=addr, odata=data;
#endif

	switch (request) {
	case PTRACE_PEEKTEXT: /* read word at location addr. */ 
	case PTRACE_PEEKDATA: {
		int copied;

#ifdef __LP64__
		if (__is_compat_task(child)) {
			unsigned int tmp;

			addr &= 0xffffffffL;
			copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
			ret = -EIO;
			if (copied != sizeof(tmp))
				goto out_tsk;
			ret = put_user(tmp,(unsigned int *) data);
			DBG("sys_ptrace(PEEK%s, %d, %lx, %lx) returning %ld, data %x\n",
				request == PTRACE_PEEKTEXT ? "TEXT" : "DATA",
				pid, oaddr, odata, ret, tmp);
		}
		else
#endif
		{
			unsigned long tmp;

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

	/* 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;
#ifdef __LP64__
		if (__is_compat_task(child)) {
			unsigned int tmp = (unsigned int)data;
			DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n",
				request == PTRACE_POKETEXT ? "TEXT" : "DATA",
				pid, oaddr, odata);
			addr &= 0xffffffffL;
			if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1) == sizeof(tmp))
				goto out_tsk;
		}
		else
#endif
		{
			if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
				goto out_tsk;
		}
		ret = -EIO;
		goto out_tsk;

	/* Read the word at location addr in the USER area.  For ptraced
	   processes, the kernel saves all regs on a syscall. */
	case PTRACE_PEEKUSR: {
		ret = -EIO;
#ifdef __LP64__
		if (__is_compat_task(child)) {
			unsigned int tmp;

			if (addr & (sizeof(int)-1))
				goto out_tsk;
			if ((addr = translate_usr_offset(addr)) < 0)
				goto out_tsk;

			tmp = *(unsigned int *) ((char *) task_regs(child) + addr);
			ret = put_user(tmp, (unsigned int *) data);
			DBG("sys_ptrace(PEEKUSR, %d, %lx, %lx) returning %ld, addr %lx, data %x\n",
				pid, oaddr, odata, ret, addr, tmp);
		}
		else
#endif
		{
			unsigned long tmp;

			if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs))
				goto out_tsk;
			tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
			ret = put_user(tmp, (unsigned long *) data);
		}
		goto out_tsk;
	}

	/* Write the word at location addr in the USER area.  This will need
	   to change when the kernel no longer saves all regs on a syscall.
	   FIXME.  There is a problem at the moment in that r3-r18 are only
	   saved if the process is ptraced on syscall entry, and even then
	   those values are overwritten by actual register values on syscall
	   exit. */
	case PTRACE_POKEUSR:
		ret = -EIO;
		/* Some register values written here may be ignored in
		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
		 * r31/r31+4, and not with the values in pt_regs.
		 */
		 /* PT_PSW=0, so this is valid for 32 bit processes under 64
		 * bit kernels.
		 */
		if (addr == PT_PSW) {
			/* PT_PSW=0, so this is valid for 32 bit processes
			 * under 64 bit kernels.
			 *
			 * Allow writing to Nullify, Divide-step-correction,
			 * and carry/borrow bits.
			 * BEWARE, if you set N, and then single step, it won't
			 * stop on the nullified instruction.
			 */
			DBG("sys_ptrace(POKEUSR, %d, %lx, %lx)\n",
				pid, oaddr, odata);
			data &= USER_PSW_BITS;
			task_regs(child)->gr[0] &= ~USER_PSW_BITS;
			task_regs(child)->gr[0] |= data;
			ret = 0;
			goto out_tsk;
		}
#ifdef __LP64__
		if (__is_compat_task(child)) {
			if (addr & (sizeof(int)-1))
				goto out_tsk;
			if ((addr = translate_usr_offset(addr)) < 0)
				goto out_tsk;
			DBG("sys_ptrace(POKEUSR, %d, %lx, %lx) addr %lx\n",
				pid, oaddr, odata, addr);
			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
				/* Special case, fp regs are 64 bits anyway */
				*(unsigned int *) ((char *) task_regs(child) + addr) = data;
				ret = 0;
			}
			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
					addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
					addr == PT_SAR+4) {
				/* Zero the top 32 bits */
				*(unsigned int *) ((char *) task_regs(child) + addr - 4) = 0;
				*(unsigned int *) ((char *) task_regs(child) + addr) = data;
				ret = 0;
			}
			goto out_tsk;
		}
		else
#endif
		{
			if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs))
				goto out_tsk;
			if ((addr >= PT_GR1 && addr <= PT_GR31) ||
					addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
					(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
					addr == PT_SAR) {
				*(unsigned long *) ((char *) task_regs(child) + addr) = data;
				ret = 0;
			}
			goto out_tsk;
		}

	case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
	case PTRACE_CONT:
		ret = -EIO;
		DBG("sys_ptrace(%s)\n",
			request == PTRACE_SYSCALL ? "SYSCALL" : "CONT");
		if (!valid_signal(data))
			goto out_tsk;
		child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP);
		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;
		goto out_wake_notrap;

	case PTRACE_KILL:
		/*
		 * 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.
		 */
		ret = 0;
		DBG("sys_ptrace(KILL)\n");
		if (child->exit_state == EXIT_ZOMBIE)	/* already dead */
			goto out_tsk;
		child->exit_code = SIGKILL;
		goto out_wake_notrap;

	case PTRACE_SINGLEBLOCK:
		DBG("sys_ptrace(SINGLEBLOCK)\n");
		ret = -EIO;
		if (!valid_signal(data))
			goto out_tsk;
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->ptrace &= ~PT_SINGLESTEP;
		child->ptrace |= PT_BLOCKSTEP;
		child->exit_code = data;

		/* Enable taken branch trap. */
		pa_psw(child)->r = 0;
		pa_psw(child)->t = 1;
		pa_psw(child)->h = 0;
		pa_psw(child)->l = 0;
		goto out_wake;

	case PTRACE_SINGLESTEP:
		DBG("sys_ptrace(SINGLESTEP)\n");
		ret = -EIO;
		if (!valid_signal(data))
			goto out_tsk;

		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->ptrace &= ~PT_BLOCKSTEP;
		child->ptrace |= PT_SINGLESTEP;
		child->exit_code = data;

		if (pa_psw(child)->n) {
			struct siginfo si;

			/* Nullified, just crank over the queue. */
			task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1];
			task_regs(child)->iasq[0] = task_regs(child)->iasq[1];
			task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4;
			pa_psw(child)->n = 0;
			pa_psw(child)->x = 0;
			pa_psw(child)->y = 0;
			pa_psw(child)->z = 0;
			pa_psw(child)->b = 0;
			ptrace_disable(child);
			/* Don't wake up the child, but let the
			   parent know something happened. */
			si.si_code = TRAP_TRACE;
			si.si_addr = (void __user *) (task_regs(child)->iaoq[0] & ~3);
			si.si_signo = SIGTRAP;
			si.si_errno = 0;
			force_sig_info(SIGTRAP, &si, child);
			//notify_parent(child, SIGCHLD);
			//ret = 0;
			goto out_wake;
		}

		/* Enable recovery counter traps.  The recovery counter
		 * itself will be set to zero on a task switch.  If the
		 * task is suspended on a syscall then the syscall return
		 * path will overwrite the recovery counter with a suitable
		 * value such that it traps once back in user space.  We
		 * disable interrupts in the childs PSW here also, to avoid
		 * interrupts while the recovery counter is decrementing.
		 */
		pa_psw(child)->r = 1;
		pa_psw(child)->t = 0;
		pa_psw(child)->h = 0;
		pa_psw(child)->l = 0;
		/* give it a chance to run. */
		goto out_wake;

	case PTRACE_DETACH:
		ret = ptrace_detach(child, data);
		goto out_tsk;

	case PTRACE_GETEVENTMSG:
                ret = put_user(child->ptrace_message, (unsigned int __user *) data);
		goto out_tsk;

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

out_wake_notrap:
	ptrace_disable(child);
out_wake:
	wake_up_process(child);
	ret = 0;
out_tsk:
	DBG("arch_ptrace(%ld, %d, %lx, %lx) returning %ld\n",
		request, pid, oaddr, odata, ret);
	return ret;
}

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;
	}
}