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
21static const int reg_offsets[] =
22{
23	[R8 >> 3] = HOST_R8,
24	[R9 >> 3] = HOST_R9,
25	[R10 >> 3] = HOST_R10,
26	[R11 >> 3] = HOST_R11,
27	[R12 >> 3] = HOST_R12,
28	[R13 >> 3] = HOST_R13,
29	[R14 >> 3] = HOST_R14,
30	[R15 >> 3] = HOST_R15,
31	[RIP >> 3] = HOST_IP,
32	[RSP >> 3] = HOST_SP,
33	[RAX >> 3] = HOST_AX,
34	[RBX >> 3] = HOST_BX,
35	[RCX >> 3] = HOST_CX,
36	[RDX >> 3] = HOST_DX,
37	[RSI >> 3] = HOST_SI,
38	[RDI >> 3] = HOST_DI,
39	[RBP >> 3] = HOST_BP,
40	[CS >> 3] = HOST_CS,
41	[SS >> 3] = HOST_SS,
42	[FS_BASE >> 3] = HOST_FS_BASE,
43	[GS_BASE >> 3] = HOST_GS_BASE,
44	[DS >> 3] = HOST_DS,
45	[ES >> 3] = HOST_ES,
46	[FS >> 3] = HOST_FS,
47	[GS >> 3] = HOST_GS,
48	[EFLAGS >> 3] = HOST_EFLAGS,
49	[ORIG_RAX >> 3] = HOST_ORIG_AX,
50};
51
52int putreg(struct task_struct *child, int regno, unsigned long value)
53{
54#ifdef TIF_IA32
55	/*
56	 * Some code in the 64bit emulation may not be 64bit clean.
57	 * Don't take any chances.
58	 */
59	if (test_tsk_thread_flag(child, TIF_IA32))
60		value &= 0xffffffff;
61#endif
62	switch (regno) {
63	case R8:
64	case R9:
65	case R10:
66	case R11:
67	case R12:
68	case R13:
69	case R14:
70	case R15:
71	case RIP:
72	case RSP:
73	case RAX:
74	case RBX:
75	case RCX:
76	case RDX:
77	case RSI:
78	case RDI:
79	case RBP:
80	case ORIG_RAX:
81		break;
82
83	case FS:
84	case GS:
85	case DS:
86	case ES:
87	case SS:
88	case CS:
89		if (value && (value & 3) != 3)
90			return -EIO;
91		value &= 0xffff;
92		break;
93
94	case FS_BASE:
95	case GS_BASE:
96		if (!((value >> 48) == 0 || (value >> 48) == 0xffff))
97			return -EIO;
98		break;
99
100	case EFLAGS:
101		value &= FLAG_MASK;
102		child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
103		return 0;
104
105	default:
106		panic("Bad register in putreg(): %d\n", regno);
107	}
108
109	child->thread.regs.regs.gp[reg_offsets[regno >> 3]] = value;
110	return 0;
111}
112
113int poke_user(struct task_struct *child, long addr, long data)
114{
115	if ((addr & 3) || addr < 0)
116		return -EIO;
117
118	if (addr < MAX_REG_OFFSET)
119		return putreg(child, addr, data);
120	else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
121		(addr <= offsetof(struct user, u_debugreg[7]))) {
122		addr -= offsetof(struct user, u_debugreg[0]);
123		addr = addr >> 2;
124		if ((addr == 4) || (addr == 5))
125			return -EIO;
126		child->thread.arch.debugregs[addr] = data;
127		return 0;
128	}
129	return -EIO;
130}
131
132unsigned long getreg(struct task_struct *child, int regno)
133{
134	unsigned long mask = ~0UL;
135#ifdef TIF_IA32
136	if (test_tsk_thread_flag(child, TIF_IA32))
137		mask = 0xffffffff;
138#endif
139	switch (regno) {
140	case R8:
141	case R9:
142	case R10:
143	case R11:
144	case R12:
145	case R13:
146	case R14:
147	case R15:
148	case RIP:
149	case RSP:
150	case RAX:
151	case RBX:
152	case RCX:
153	case RDX:
154	case RSI:
155	case RDI:
156	case RBP:
157	case ORIG_RAX:
158	case EFLAGS:
159	case FS_BASE:
160	case GS_BASE:
161		break;
162	case FS:
163	case GS:
164	case DS:
165	case ES:
166	case SS:
167	case CS:
168		mask = 0xffff;
169		break;
170	default:
171		panic("Bad register in getreg: %d\n", regno);
172	}
173	return mask & child->thread.regs.regs.gp[reg_offsets[regno >> 3]];
174}
175
176int peek_user(struct task_struct *child, long addr, long data)
177{
178	/* read the word at location addr in the USER area. */
179	unsigned long tmp;
180
181	if ((addr & 3) || addr < 0)
182		return -EIO;
183
184	tmp = 0;  /* Default return condition */
185	if (addr < MAX_REG_OFFSET)
186		tmp = getreg(child, addr);
187	else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
188		(addr <= offsetof(struct user, u_debugreg[7]))) {
189		addr -= offsetof(struct user, u_debugreg[0]);
190		addr = addr >> 2;
191		tmp = child->thread.arch.debugregs[addr];
192	}
193	return put_user(tmp, (unsigned long *) data);
194}
195
196/* XXX Mostly copied from sys-i386 */
197int is_syscall(unsigned long addr)
198{
199	unsigned short instr;
200	int n;
201
202	n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
203	if (n) {
204		/*
205		 * access_process_vm() grants access to vsyscall and stub,
206		 * while copy_from_user doesn't. Maybe access_process_vm is
207		 * slow, but that doesn't matter, since it will be called only
208		 * in case of singlestepping, if copy_from_user failed.
209		 */
210		n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
211		if (n != sizeof(instr)) {
212			printk("is_syscall : failed to read instruction from "
213			       "0x%lx\n", addr);
214			return 1;
215		}
216	}
217	/* sysenter */
218	return instr == 0x050f;
219}
220
221static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
222{
223	int err, n, cpu = ((struct thread_info *) child->stack)->cpu;
224	long fpregs[HOST_FP_SIZE];
225
226	BUG_ON(sizeof(*buf) != sizeof(fpregs));
227	err = save_fp_registers(userspace_pid[cpu], fpregs);
228	if (err)
229		return err;
230
231	n = copy_to_user(buf, fpregs, sizeof(fpregs));
232	if (n > 0)
233		return -EFAULT;
234
235	return n;
236}
237
238static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
239{
240	int n, cpu = ((struct thread_info *) child->stack)->cpu;
241	long fpregs[HOST_FP_SIZE];
242
243	BUG_ON(sizeof(*buf) != sizeof(fpregs));
244	n = copy_from_user(fpregs, buf, sizeof(fpregs));
245	if (n > 0)
246		return -EFAULT;
247
248	return restore_fp_registers(userspace_pid[cpu], fpregs);
249}
250
251long subarch_ptrace(struct task_struct *child, long request,
252		    unsigned long addr, unsigned long data)
253{
254	int ret = -EIO;
255	void __user *datap = (void __user *) data;
256
257	switch (request) {
258	case PTRACE_GETFPREGS: /* Get the child FPU state. */
259		ret = get_fpregs(datap, child);
260		break;
261	case PTRACE_SETFPREGS: /* Set the child FPU state. */
262		ret = set_fpregs(datap, child);
263		break;
264	case PTRACE_ARCH_PRCTL:
265		/* XXX Calls ptrace on the host - needs some SMP thinking */
266		ret = arch_prctl(child, data, (void __user *) addr);
267		break;
268	}
269
270	return ret;
271}
272