summaryrefslogtreecommitdiffstats
path: root/arch/x86/um/ptrace_64.c
blob: 0b5c184dd5b3b80894c3db60ead6432ad20dca57 (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
/*
 * Copyright 2003 PathScale, Inc.
 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 *
 * Licensed under the GPL
 */

#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/errno.h>
#define __FRAME_OFFSETS
#include <asm/ptrace.h>
#include <asm/uaccess.h>
#include <asm/ptrace-abi.h>

/*
 * determines which flags the user has access to.
 * 1 = access 0 = no access
 */
#define FLAG_MASK 0x44dd5UL

static const int reg_offsets[] =
{
	[R8 >> 3] = HOST_R8,
	[R9 >> 3] = HOST_R9,
	[R10 >> 3] = HOST_R10,
	[R11 >> 3] = HOST_R11,
	[R12 >> 3] = HOST_R12,
	[R13 >> 3] = HOST_R13,
	[R14 >> 3] = HOST_R14,
	[R15 >> 3] = HOST_R15,
	[RIP >> 3] = HOST_IP,
	[RSP >> 3] = HOST_SP,
	[RAX >> 3] = HOST_AX,
	[RBX >> 3] = HOST_BX,
	[RCX >> 3] = HOST_CX,
	[RDX >> 3] = HOST_DX,
	[RSI >> 3] = HOST_SI,
	[RDI >> 3] = HOST_DI,
	[RBP >> 3] = HOST_BP,
	[CS >> 3] = HOST_CS,
	[SS >> 3] = HOST_SS,
	[FS_BASE >> 3] = HOST_FS_BASE,
	[GS_BASE >> 3] = HOST_GS_BASE,
	[DS >> 3] = HOST_DS,
	[ES >> 3] = HOST_ES,
	[FS >> 3] = HOST_FS,
	[GS >> 3] = HOST_GS,
	[EFLAGS >> 3] = HOST_EFLAGS,
	[ORIG_RAX >> 3] = HOST_ORIG_AX,
};

int putreg(struct task_struct *child, int regno, unsigned long value)
{
#ifdef TIF_IA32
	/*
	 * Some code in the 64bit emulation may not be 64bit clean.
	 * Don't take any chances.
	 */
	if (test_tsk_thread_flag(child, TIF_IA32))
		value &= 0xffffffff;
#endif
	switch (regno) {
	case R8:
	case R9:
	case R10:
	case R11:
	case R12:
	case R13:
	case R14:
	case R15:
	case RIP:
	case RSP:
	case RAX:
	case RBX:
	case RCX:
	case RDX:
	case RSI:
	case RDI:
	case RBP:
		break;

	case ORIG_RAX:
		/* Update the syscall number. */
		UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
		break;

	case FS:
	case GS:
	case DS:
	case ES:
	case SS:
	case CS:
		if (value && (value & 3) != 3)
			return -EIO;
		value &= 0xffff;
		break;

	case FS_BASE:
	case GS_BASE:
		if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
			return -EIO;
		break;

	case EFLAGS:
		value &= FLAG_MASK;
		child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
		return 0;

	default:
		panic("Bad register in putreg(): %d\n", regno);
	}

	child->thread.regs.regs.gp[reg_offsets[regno >> 3]] = 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 mask = ~0UL;
#ifdef TIF_IA32
	if (test_tsk_thread_flag(child, TIF_IA32))
		mask = 0xffffffff;
#endif
	switch (regno) {
	case R8:
	case R9:
	case R10:
	case R11:
	case R12:
	case R13:
	case R14:
	case R15:
	case RIP:
	case RSP:
	case RAX:
	case RBX:
	case RCX:
	case RDX:
	case RSI:
	case RDI:
	case RBP:
	case ORIG_RAX:
	case EFLAGS:
	case FS_BASE:
	case GS_BASE:
		break;
	case FS:
	case GS:
	case DS:
	case ES:
	case SS:
	case CS:
		mask = 0xffff;
		break;
	default:
		panic("Bad register in getreg: %d\n", regno);
	}
	return mask & child->thread.regs.regs.gp[reg_offsets[regno >> 3]];
}

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);
}

/* XXX Mostly copied from sys-i386 */
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;
		}
	}
	/* sysenter */
	return instr == 0x050f;
}

static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
{
	int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
	struct user_i387_struct fpregs;

	err = save_i387_registers(userspace_pid[cpu],
				  (unsigned long *) &fpregs);
	if (err)
		return err;

	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
	if (n > 0)
		return -EFAULT;

	return n;
}

static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
{
	int n, cpu = ((struct thread_info *) child->stack)->cpu;
	struct user_i387_struct fpregs;

	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
	if (n > 0)
		return -EFAULT;

	return restore_i387_registers(userspace_pid[cpu],
				      (unsigned long *) &fpregs);
}

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

	switch (request) {
	case PTRACE_GETFPREGS: /* Get the child FPU state. */
		ret = get_fpregs(datap, child);
		break;
	case PTRACE_SETFPREGS: /* Set the child FPU state. */
		ret = set_fpregs(datap, child);
		break;
	case PTRACE_ARCH_PRCTL:
		/* XXX Calls ptrace on the host - needs some SMP thinking */
		ret = arch_prctl(child, data, (void __user *) addr);
		break;
	}

	return ret;
}