1 /*
2 * Copyright 2003 PathScale, Inc.
3 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 *
5 * Licensed under the GPL
6 */
7
8 #include <linux/mm.h>
9 #include <linux/sched.h>
10 #include <linux/errno.h>
11 #define __FRAME_OFFSETS
12 #include <asm/ptrace.h>
13 #include <asm/uaccess.h>
14
15 /*
16 * determines which flags the user has access to.
17 * 1 = access 0 = no access
18 */
19 #define FLAG_MASK 0x44dd5UL
20
21 int putreg(struct task_struct *child, int regno, unsigned long value)
22 {
23 unsigned long tmp;
24
25 #ifdef TIF_IA32
26 /*
27 * Some code in the 64bit emulation may not be 64bit clean.
28 * Don't take any chances.
29 */
30 if (test_tsk_thread_flag(child, TIF_IA32))
31 value &= 0xffffffff;
32 #endif
33 switch (regno) {
34 case FS:
35 case GS:
36 case DS:
37 case ES:
38 case SS:
39 case CS:
40 if (value && (value & 3) != 3)
41 return -EIO;
42 value &= 0xffff;
43 break;
44
45 case FS_BASE:
46 case GS_BASE:
47 if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
48 return -EIO;
49 break;
50
51 case EFLAGS:
52 value &= FLAG_MASK;
53 tmp = PT_REGS_EFLAGS(&child->thread.regs) & ~FLAG_MASK;
54 value |= tmp;
55 break;
56 }
57
58 PT_REGS_SET(&child->thread.regs, regno, value);
59 return 0;
60 }
61
62 int poke_user(struct task_struct *child, long addr, long data)
63 {
64 if ((addr & 3) || addr < 0)
65 return -EIO;
66
67 if (addr < MAX_REG_OFFSET)
68 return putreg(child, addr, data);
69 else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
70 (addr <= offsetof(struct user, u_debugreg[7]))) {
71 addr -= offsetof(struct user, u_debugreg[0]);
72 addr = addr >> 2;
73 if ((addr == 4) || (addr == 5))
74 return -EIO;
75 child->thread.arch.debugregs[addr] = data;
76 return 0;
77 }
78 return -EIO;
79 }
80
81 unsigned long getreg(struct task_struct *child, int regno)
82 {
83 unsigned long retval = ~0UL;
84 switch (regno) {
85 case FS:
86 case GS:
87 case DS:
88 case ES:
89 case SS:
90 case CS:
91 retval = 0xffff;
92 /* fall through */
93 default:
94 retval &= PT_REG(&child->thread.regs, regno);
95 #ifdef TIF_IA32
96 if (test_tsk_thread_flag(child, TIF_IA32))
97 retval &= 0xffffffff;
98 #endif
99 }
100 return retval;
101 }
102
103 int peek_user(struct task_struct *child, long addr, long data)
104 {
105 /* read the word at location addr in the USER area. */
106 unsigned long tmp;
107
108 if ((addr & 3) || addr < 0)
109 return -EIO;
110
111 tmp = 0; /* Default return condition */
112 if (addr < MAX_REG_OFFSET)
113 tmp = getreg(child, addr);
114 else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
115 (addr <= offsetof(struct user, u_debugreg[7]))) {
116 addr -= offsetof(struct user, u_debugreg[0]);
117 addr = addr >> 2;
118 tmp = child->thread.arch.debugregs[addr];
119 }
120 return put_user(tmp, (unsigned long *) data);
121 }
122
123 /* XXX Mostly copied from sys-i386 */
124 int is_syscall(unsigned long addr)
125 {
126 unsigned short instr;
127 int n;
128
129 n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
130 if (n) {
131 /*
132 * access_process_vm() grants access to vsyscall and stub,
133 * while copy_from_user doesn't. Maybe access_process_vm is
134 * slow, but that doesn't matter, since it will be called only
135 * in case of singlestepping, if copy_from_user failed.
136 */
137 n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
138 if (n != sizeof(instr)) {
139 printk("is_syscall : failed to read instruction from "
140 "0x%lx\n", addr);
141 return 1;
142 }
143 }
144 /* sysenter */
145 return instr == 0x050f;
146 }
147
148 int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
149 {
150 int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
151 long fpregs[HOST_FP_SIZE];
152
153 BUG_ON(sizeof(*buf) != sizeof(fpregs));
154 err = save_fp_registers(userspace_pid[cpu], fpregs);
155 if (err)
156 return err;
157
158 n = copy_to_user(buf, fpregs, sizeof(fpregs));
159 if (n > 0)
160 return -EFAULT;
161
162 return n;
163 }
164
165 int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
166 {
167 int n, cpu = ((struct thread_info *) child->stack)->cpu;
168 long fpregs[HOST_FP_SIZE];
169
170 BUG_ON(sizeof(*buf) != sizeof(fpregs));
171 n = copy_from_user(fpregs, buf, sizeof(fpregs));
172 if (n > 0)
173 return -EFAULT;
174
175 return restore_fp_registers(userspace_pid[cpu], fpregs);
176 }
177
178 long subarch_ptrace(struct task_struct *child, long request, long addr,
179 long data)
180 {
181 int ret = -EIO;
182
183 switch (request) {
184 case PTRACE_GETFPXREGS: /* Get the child FPU state. */
185 ret = get_fpregs((struct user_i387_struct __user *) data,
186 child);
187 break;
188 case PTRACE_SETFPXREGS: /* Set the child FPU state. */
189 ret = set_fpregs((struct user_i387_struct __user *) data,
190 child);
191 break;
192 }
193
194 return ret;
195 }
196
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