aboutsummaryrefslogtreecommitdiff
path: root/arch/um/sys-i386/ptrace.c
blob: 8032a105949a02155945d52e00e1123f29039a1e (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
/* 
 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include <linux/config.h>
#include <linux/compiler.h>
#include "linux/sched.h"
#include "linux/mm.h"
#include "asm/elf.h"
#include "asm/ptrace.h"
#include "asm/uaccess.h"
#include "asm/unistd.h"
#include "sysdep/ptrace.h"
#include "sysdep/sigcontext.h"
#include "sysdep/sc.h"

void arch_switch(void)
{
	update_debugregs(current->thread.arch.debugregs_seq);
}

int is_syscall(unsigned long addr)
{
	unsigned short instr;
	int n;

	n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
	if(n){
		/* access_process_vm() grants access to vsyscall and stub,
		 * while copy_from_user doesn't. Maybe access_process_vm is
		 * slow, but that doesn't matter, since it will be called only
		 * in case of singlestepping, if copy_from_user failed.
		 */
		n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
		if(n != sizeof(instr)) {
			printk("is_syscall : failed to read instruction from "
			       "0x%lx\n", addr);
			return(1);
		}
	}
	/* int 0x80 or sysenter */
	return((instr == 0x80cd) || (instr == 0x340f));
}

/* determines which flags the user has access to. */
/* 1 = access 0 = no access */
#define FLAG_MASK 0x00044dd5

int putreg(struct task_struct *child, int regno, unsigned long value)
{
	regno >>= 2;
	switch (regno) {
	case FS:
		if (value && (value & 3) != 3)
			return -EIO;
		PT_REGS_FS(&child->thread.regs) = value;
		return 0;
	case GS:
		if (value && (value & 3) != 3)
			return -EIO;
		PT_REGS_GS(&child->thread.regs) = value;
		return 0;
	case DS:
	case ES:
		if (value && (value & 3) != 3)
			return -EIO;
		value &= 0xffff;
		break;
	case SS:
	case CS:
		if ((value & 3) != 3)
			return -EIO;
		value &= 0xffff;
		break;
	case EFL:
		value &= FLAG_MASK;
		value |= PT_REGS_EFLAGS(&child->thread.regs);
		break;
	}
	PT_REGS_SET(&child->thread.regs, regno, value);
	return 0;
}

int poke_user(struct task_struct *child, long addr, long data)
{
        if ((addr & 3) || addr < 0)
                return -EIO;

        if (addr < MAX_REG_OFFSET)
                return putreg(child, addr, data);

        else if((addr >= offsetof(struct user, u_debugreg[0])) &&
                (addr <= offsetof(struct user, u_debugreg[7]))){
                addr -= offsetof(struct user, u_debugreg[0]);
                addr = addr >> 2;
                if((addr == 4) || (addr == 5)) return -EIO;
                child->thread.arch.debugregs[addr] = data;
                return 0;
        }
        return -EIO;
}

unsigned long getreg(struct task_struct *child, int regno)
{
	unsigned long retval = ~0UL;

	regno >>= 2;
	switch (regno) {
	case FS:
	case GS:
	case DS:
	case ES:
	case SS:
	case CS:
		retval = 0xffff;
		/* fall through */
	default:
		retval &= PT_REG(&child->thread.regs, regno);
	}
	return retval;
}

int peek_user(struct task_struct *child, long addr, long data)
{
/* read the word at location addr in the USER area. */
        unsigned long tmp;

        if ((addr & 3) || addr < 0)
                return -EIO;

        tmp = 0;  /* Default return condition */
        if(addr < MAX_REG_OFFSET){
                tmp = getreg(child, addr);
        }
        else if((addr >= offsetof(struct user, u_debugreg[0])) &&
                (addr <= offsetof(struct user, u_debugreg[7]))){
                addr -= offsetof(struct user, u_debugreg[0]);
                addr = addr >> 2;
                tmp = child->thread.arch.debugregs[addr];
        }
        return put_user(tmp, (unsigned long *) data);
}

struct i387_fxsave_struct {
	unsigned short	cwd;
	unsigned short	swd;
	unsigned short	twd;
	unsigned short	fop;
	long	fip;
	long	fcs;
	long	foo;
	long	fos;
	long	mxcsr;
	long	reserved;
	long	st_space[32];	/* 8*16 bytes for each FP-reg = 128 bytes */
	long	xmm_space[32];	/* 8*16 bytes for each XMM-reg = 128 bytes */
	long	padding[56];
};

/*
 * FPU tag word conversions.
 */

static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
{
	unsigned int tmp; /* to avoid 16 bit prefixes in the code */
 
	/* Transform each pair of bits into 01 (valid) or 00 (empty) */
        tmp = ~twd;
        tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
        /* and move the valid bits to the lower byte. */
        tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
        tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
        tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
        return tmp;
}

static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
{
	struct _fpxreg *st = NULL;
	unsigned long twd = (unsigned long) fxsave->twd;
	unsigned long tag;
	unsigned long ret = 0xffff0000;
	int i;

#define FPREG_ADDR(f, n)	((char *)&(f)->st_space + (n) * 16);

	for ( i = 0 ; i < 8 ; i++ ) {
		if ( twd & 0x1 ) {
			st = (struct _fpxreg *) FPREG_ADDR( fxsave, i );

			switch ( st->exponent & 0x7fff ) {
			case 0x7fff:
				tag = 2;		/* Special */
				break;
			case 0x0000:
				if ( !st->significand[0] &&
				     !st->significand[1] &&
				     !st->significand[2] &&
				     !st->significand[3] ) {
					tag = 1;	/* Zero */
				} else {
					tag = 2;	/* Special */
				}
				break;
			default:
				if ( st->significand[3] & 0x8000 ) {
					tag = 0;	/* Valid */
				} else {
					tag = 2;	/* Special */
				}
				break;
			}
		} else {
			tag = 3;			/* Empty */
		}
		ret |= (tag << (2 * i));
		twd = twd >> 1;
	}
	return ret;
}

/*
 * FXSR floating point environment conversions.
 */

#ifdef CONFIG_MODE_TT
static inline int convert_fxsr_to_user_tt(struct _fpstate __user *buf,
					  struct pt_regs *regs)
{
	struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
	unsigned long env[7];
	struct _fpreg __user *to;
	struct _fpxreg *from;
	int i;

	env[0] = (unsigned long)fxsave->cwd | 0xffff0000;
	env[1] = (unsigned long)fxsave->swd | 0xffff0000;
	env[2] = twd_fxsr_to_i387(fxsave);
	env[3] = fxsave->fip;
	env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
	env[5] = fxsave->foo;
	env[6] = fxsave->fos;

	if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) )
		return 1;

	to = &buf->_st[0];
	from = (struct _fpxreg *) &fxsave->st_space[0];
	for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
		if ( __copy_to_user( to, from, sizeof(*to) ) )
			return 1;
	}
	return 0;
}
#endif

static inline int convert_fxsr_to_user(struct _fpstate __user *buf,
				       struct pt_regs *regs)
{
	return(CHOOSE_MODE(convert_fxsr_to_user_tt(buf, regs), 0));
}

#ifdef CONFIG_MODE_TT
static inline int convert_fxsr_from_user_tt(struct pt_regs *regs,
					    struct _fpstate __user *buf)
{
	struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
	unsigned long env[7];
	struct _fpxreg *to;
	struct _fpreg __user *from;
	int i;

	if ( __copy_from_user( env, buf, 7 * sizeof(long) ) )
		return 1;

	fxsave->cwd = (unsigned short)(env[0] & 0xffff);
	fxsave->swd = (unsigned short)(env[1] & 0xffff);
	fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
	fxsave->fip = env[3];
	fxsave->fop = (unsigned short)((env[4] & 0xffff0000) >> 16);
	fxsave->fcs = (env[4] & 0xffff);
	fxsave->foo = env[5];
	fxsave->fos = env[6];

	to = (struct _fpxreg *) &fxsave->st_space[0];
	from = &buf->_st[0];
	for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
		if ( __copy_from_user( to, from, sizeof(*from) ) )
			return 1;
	}
	return 0;
}
#endif

static inline int convert_fxsr_from_user(struct pt_regs *regs, 
					 struct _fpstate __user *buf)
{
	return(CHOOSE_MODE(convert_fxsr_from_user_tt(regs, buf), 0));
}

int get_fpregs(unsigned long buf, struct task_struct *child)
{
	int err;

	err = convert_fxsr_to_user((struct _fpstate __user *) buf,
				   &child->thread.regs);
	if(err) return(-EFAULT);
	else return(0);
}

int set_fpregs(unsigned long buf, struct task_struct *child)
{
	int err;

	err = convert_fxsr_from_user(&child->thread.regs, 
				     (struct _fpstate __user *) buf);
	if(err) return(-EFAULT);
	else return(0);
}

#ifdef CONFIG_MODE_TT
int get_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
{
	struct pt_regs *regs = &tsk->thread.regs;
	struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
	int err;

	err = __copy_to_user((void __user *) buf, fxsave,
			     sizeof(struct user_fxsr_struct));
	if(err) return -EFAULT;
	else return 0;
}
#endif

int get_fpxregs(unsigned long buf, struct task_struct *tsk)
{
	return(CHOOSE_MODE(get_fpxregs_tt(buf, tsk), 0));
}

#ifdef CONFIG_MODE_TT
int set_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
{
	struct pt_regs *regs = &tsk->thread.regs;
	struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
	int err;

	err = __copy_from_user(fxsave, (void __user *) buf,
			       sizeof(struct user_fxsr_struct) );
	if(err) return -EFAULT;
	else return 0;
}
#endif

int set_fpxregs(unsigned long buf, struct task_struct *tsk)
{
	return(CHOOSE_MODE(set_fpxregs_tt(buf, tsk), 0));
}

#ifdef notdef
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
{
	fpu->cwd = (((SC_FP_CW(PT_REGS_SC(regs)) & 0xffff) << 16) |
		    (SC_FP_SW(PT_REGS_SC(regs)) & 0xffff));
	fpu->swd = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
	fpu->twd = SC_FP_IPOFF(PT_REGS_SC(regs));
	fpu->fip = SC_FP_CSSEL(PT_REGS_SC(regs)) & 0xffff;
	fpu->fcs = SC_FP_DATAOFF(PT_REGS_SC(regs));
	fpu->foo = SC_FP_DATASEL(PT_REGS_SC(regs));
	fpu->fos = 0;
	memcpy(fpu->st_space, (void *) SC_FP_ST(PT_REGS_SC(regs)),
	       sizeof(fpu->st_space));
	return(1);
}
#endif

#ifdef CONFIG_MODE_TT
static inline void copy_fpu_fxsave_tt(struct pt_regs *regs,
				      struct user_i387_struct *buf)
{
	struct i387_fxsave_struct *fpu = SC_FXSR_ENV(PT_REGS_SC(regs));
	unsigned short *to;
	unsigned short *from;
	int i;

	memcpy( buf, fpu, 7 * sizeof(long) );

	to = (unsigned short *) &buf->st_space[0];
	from = (unsigned short *) &fpu->st_space[0];
	for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) {
		memcpy( to, from, 5 * sizeof(unsigned short) );
	}
}
#endif

static inline void copy_fpu_fxsave(struct pt_regs *regs,
				   struct user_i387_struct *buf)
{
	(void) CHOOSE_MODE(copy_fpu_fxsave_tt(regs, buf), 0);
}

int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu )
{
	copy_fpu_fxsave(regs, (struct user_i387_struct *) fpu);
	return(1);
}

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */