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#include <asm/ptrace-abi.h>
15
16/*
17 * determines which flags the user has access to.
18 * 1 = access 0 = no access
19 */
20#define FLAG_MASK 0x44dd5UL
21
22static const int reg_offsets[] =
23{
24	[R8 >> 3] = HOST_R8,
25	[R9 >> 3] = HOST_R9,
26	[R10 >> 3] = HOST_R10,
27	[R11 >> 3] = HOST_R11,
28	[R12 >> 3] = HOST_R12,
29	[R13 >> 3] = HOST_R13,
30	[R14 >> 3] = HOST_R14,
31	[R15 >> 3] = HOST_R15,
32	[RIP >> 3] = HOST_IP,
33	[RSP >> 3] = HOST_SP,
34	[RAX >> 3] = HOST_AX,
35	[RBX >> 3] = HOST_BX,
36	[RCX >> 3] = HOST_CX,
37	[RDX >> 3] = HOST_DX,
38	[RSI >> 3] = HOST_SI,
39	[RDI >> 3] = HOST_DI,
40	[RBP >> 3] = HOST_BP,
41	[CS >> 3] = HOST_CS,
42	[SS >> 3] = HOST_SS,
43	[FS_BASE >> 3] = HOST_FS_BASE,
44	[GS_BASE >> 3] = HOST_GS_BASE,
45	[DS >> 3] = HOST_DS,
46	[ES >> 3] = HOST_ES,
47	[FS >> 3] = HOST_FS,
48	[GS >> 3] = HOST_GS,
49	[EFLAGS >> 3] = HOST_EFLAGS,
50	[ORIG_RAX >> 3] = HOST_ORIG_AX,
51};
52
53int putreg(struct task_struct *child, int regno, unsigned long value)
54{
55#ifdef TIF_IA32
56	/*
57	 * Some code in the 64bit emulation may not be 64bit clean.
58	 * Don't take any chances.
59	 */
60	if (test_tsk_thread_flag(child, TIF_IA32))
61		value &= 0xffffffff;
62#endif
63	switch (regno) {
64	case R8:
65	case R9:
66	case R10:
67	case R11:
68	case R12:
69	case R13:
70	case R14:
71	case R15:
72	case RIP:
73	case RSP:
74	case RAX:
75	case RBX:
76	case RCX:
77	case RDX:
78	case RSI:
79	case RDI:
80	case RBP:
81	case ORIG_RAX:
82		break;
83
84	case FS:
85	case GS:
86	case DS:
87	case ES:
88	case SS:
89	case CS:
90		if (value && (value & 3) != 3)
91			return -EIO;
92		value &= 0xffff;
93		break;
94
95	case FS_BASE:
96	case GS_BASE:
97		if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
98			return -EIO;
99		break;
100
101	case EFLAGS:
102		value &= FLAG_MASK;
103		child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
104		return 0;
105
106	default:
107		panic("Bad register in putreg(): %d\n", regno);
108	}
109
110	child->thread.regs.regs.gp[reg_offsets[regno >> 3]] = value;
111	return 0;
112}
113
114int poke_user(struct task_struct *child, long addr, long data)
115{
116	if ((addr & 3) || addr < 0)
117		return -EIO;
118
119	if (addr < MAX_REG_OFFSET)
120		return putreg(child, addr, data);
121	else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
122		(addr <= offsetof(struct user, u_debugreg[7]))) {
123		addr -= offsetof(struct user, u_debugreg[0]);
124		addr = addr >> 2;
125		if ((addr == 4) || (addr == 5))
126			return -EIO;
127		child->thread.arch.debugregs[addr] = data;
128		return 0;
129	}
130	return -EIO;
131}
132
133unsigned long getreg(struct task_struct *child, int regno)
134{
135	unsigned long mask = ~0UL;
136#ifdef TIF_IA32
137	if (test_tsk_thread_flag(child, TIF_IA32))
138		mask = 0xffffffff;
139#endif
140	switch (regno) {
141	case R8:
142	case R9:
143	case R10:
144	case R11:
145	case R12:
146	case R13:
147	case R14:
148	case R15:
149	case RIP:
150	case RSP:
151	case RAX:
152	case RBX:
153	case RCX:
154	case RDX:
155	case RSI:
156	case RDI:
157	case RBP:
158	case ORIG_RAX:
159	case EFLAGS:
160	case FS_BASE:
161	case GS_BASE:
162		break;
163	case FS:
164	case GS:
165	case DS:
166	case ES:
167	case SS:
168	case CS:
169		mask = 0xffff;
170		break;
171	default:
172		panic("Bad register in getreg: %d\n", regno);
173	}
174	return mask & child->thread.regs.regs.gp[reg_offsets[regno >> 3]];
175}
176
177int peek_user(struct task_struct *child, long addr, long data)
178{
179	/* read the word at location addr in the USER area. */
180	unsigned long tmp;
181
182	if ((addr & 3) || addr < 0)
183		return -EIO;
184
185	tmp = 0;  /* Default return condition */
186	if (addr < MAX_REG_OFFSET)
187		tmp = getreg(child, addr);
188	else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
189		(addr <= offsetof(struct user, u_debugreg[7]))) {
190		addr -= offsetof(struct user, u_debugreg[0]);
191		addr = addr >> 2;
192		tmp = child->thread.arch.debugregs[addr];
193	}
194	return put_user(tmp, (unsigned long *) data);
195}
196
197/* XXX Mostly copied from sys-i386 */
198int is_syscall(unsigned long addr)
199{
200	unsigned short instr;
201	int n;
202
203	n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
204	if (n) {
205		/*
206		 * access_process_vm() grants access to vsyscall and stub,
207		 * while copy_from_user doesn't. Maybe access_process_vm is
208		 * slow, but that doesn't matter, since it will be called only
209		 * in case of singlestepping, if copy_from_user failed.
210		 */
211		n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
212		if (n != sizeof(instr)) {
213			printk("is_syscall : failed to read instruction from "
214			       "0x%lx\n", addr);
215			return 1;
216		}
217	}
218	/* sysenter */
219	return instr == 0x050f;
220}
221
222static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
223{
224	int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
225	long fpregs[HOST_FP_SIZE];
226
227	BUG_ON(sizeof(*buf) != sizeof(fpregs));
228	err = save_fp_registers(userspace_pid[cpu], fpregs);
229	if (err)
230		return err;
231
232	n = copy_to_user(buf, fpregs, sizeof(fpregs));
233	if (n > 0)
234		return -EFAULT;
235
236	return n;
237}
238
239static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
240{
241	int n, cpu = ((struct thread_info *) child->stack)->cpu;
242	long fpregs[HOST_FP_SIZE];
243
244	BUG_ON(sizeof(*buf) != sizeof(fpregs));
245	n = copy_from_user(fpregs, buf, sizeof(fpregs));
246	if (n > 0)
247		return -EFAULT;
248
249	return restore_fp_registers(userspace_pid[cpu], fpregs);
250}
251
252long subarch_ptrace(struct task_struct *child, long request,
253		    unsigned long addr, unsigned long data)
254{
255	int ret = -EIO;
256	void __user *datap = (void __user *) data;
257
258	switch (request) {
259	case PTRACE_GETFPREGS: /* Get the child FPU state. */
260		ret = get_fpregs(datap, child);
261		break;
262	case PTRACE_SETFPREGS: /* Set the child FPU state. */
263		ret = set_fpregs(datap, child);
264		break;
265	case PTRACE_ARCH_PRCTL:
266		/* XXX Calls ptrace on the host - needs some SMP thinking */
267		ret = arch_prctl(child, data, (void __user *) addr);
268		break;
269	}
270
271	return ret;
272}
273