summaryrefslogtreecommitdiffstats
path: root/arch/um/sys-x86_64/ptrace.c
blob: 67e63680df288de1140ed7861f4468973a8ad5c5 (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
/*
 * 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>

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

int putreg(struct task_struct *child, int regno, unsigned long value)
{
	unsigned long tmp;

#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 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;
		tmp = PT_REGS_EFLAGS(&child->thread.regs) & ~FLAG_MASK;
		value |= tmp;
		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;
	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);
#ifdef TIF_IA32
		if (test_tsk_thread_flag(child, TIF_IA32))
			retval &= 0xffffffff;
#endif
	}
	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);
}

/* 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;
}

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

	BUG_ON(sizeof(*buf) != sizeof(fpregs));
	err = save_fp_registers(userspace_pid[cpu], fpregs);
	if (err)
		return err;

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

	return n;
}

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

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

	return restore_fp_registers(userspace_pid[cpu], fpregs);
}

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

	switch (request) {
	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
		ret = get_fpregs((struct user_i387_struct __user *) data,
				 child);
		break;
	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
		ret = set_fpregs((struct user_i387_struct __user *) data,
				 child);
		break;
	}

	return ret;
}
OpenPOWER on IntegriCloud