1/*
  2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include <linux/mm.h>
  7#include <linux/sched.h>
  8#include <linux/uaccess.h>
  9#include <asm/ptrace-abi.h>
 10#include <skas.h>
 11
 12extern int arch_switch_tls(struct task_struct *to);
 13
 14void arch_switch_to(struct task_struct *to)
 15{
 16	int err = arch_switch_tls(to);
 17	if (!err)
 18		return;
 19
 20	if (err != -EINVAL)
 21		printk(KERN_WARNING "arch_switch_tls failed, errno %d, "
 22		       "not EINVAL\n", -err);
 23	else
 24		printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n");
 25}
 26
 27int is_syscall(unsigned long addr)
 28{
 29	unsigned short instr;
 30	int n;
 31
 32	n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
 33	if (n) {
 34		/* access_process_vm() grants access to vsyscall and stub,
 35		 * while copy_from_user doesn't. Maybe access_process_vm is
 36		 * slow, but that doesn't matter, since it will be called only
 37		 * in case of singlestepping, if copy_from_user failed.
 38		 */
 39		n = access_process_vm(current, addr, &instr, sizeof(instr),
 40				FOLL_FORCE);
 41		if (n != sizeof(instr)) {
 42			printk(KERN_ERR "is_syscall : failed to read "
 43			       "instruction from 0x%lx\n", addr);
 44			return 1;
 45		}
 46	}
 47	/* int 0x80 or sysenter */
 48	return (instr == 0x80cd) || (instr == 0x340f);
 49}
 50
 51/* determines which flags the user has access to. */
 52/* 1 = access 0 = no access */
 53#define FLAG_MASK 0x00044dd5
 54
 55static const int reg_offsets[] = {
 56	[EBX] = HOST_BX,
 57	[ECX] = HOST_CX,
 58	[EDX] = HOST_DX,
 59	[ESI] = HOST_SI,
 60	[EDI] = HOST_DI,
 61	[EBP] = HOST_BP,
 62	[EAX] = HOST_AX,
 63	[DS] = HOST_DS,
 64	[ES] = HOST_ES,
 65	[FS] = HOST_FS,
 66	[GS] = HOST_GS,
 67	[EIP] = HOST_IP,
 68	[CS] = HOST_CS,
 69	[EFL] = HOST_EFLAGS,
 70	[UESP] = HOST_SP,
 71	[SS] = HOST_SS,
 72	[ORIG_EAX] = HOST_ORIG_AX,
 73};
 74
 75int putreg(struct task_struct *child, int regno, unsigned long value)
 76{
 77	regno >>= 2;
 78	switch (regno) {
 79	case EBX:
 80	case ECX:
 81	case EDX:
 82	case ESI:
 83	case EDI:
 84	case EBP:
 85	case EAX:
 86	case EIP:
 87	case UESP:
 88		break;
 89	case ORIG_EAX:
 90		/* Update the syscall number. */
 91		UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
 92		break;
 93	case FS:
 94		if (value && (value & 3) != 3)
 95			return -EIO;
 96		break;
 97	case GS:
 98		if (value && (value & 3) != 3)
 99			return -EIO;
100		break;
101	case DS:
102	case ES:
103		if (value && (value & 3) != 3)
104			return -EIO;
105		value &= 0xffff;
106		break;
107	case SS:
108	case CS:
109		if ((value & 3) != 3)
110			return -EIO;
111		value &= 0xffff;
112		break;
113	case EFL:
114		value &= FLAG_MASK;
115		child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
116		return 0;
117	default :
118		panic("Bad register in putreg() : %d\n", regno);
119	}
120	child->thread.regs.regs.gp[reg_offsets[regno]] = value;
121	return 0;
122}
123
124int poke_user(struct task_struct *child, long addr, long data)
125{
126	if ((addr & 3) || addr < 0)
127		return -EIO;
128
129	if (addr < MAX_REG_OFFSET)
130		return putreg(child, addr, data);
131	else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
132		 (addr <= offsetof(struct user, u_debugreg[7]))) {
133		addr -= offsetof(struct user, u_debugreg[0]);
134		addr = addr >> 2;
135		if ((addr == 4) || (addr == 5))
136			return -EIO;
137		child->thread.arch.debugregs[addr] = data;
138		return 0;
139	}
140	return -EIO;
141}
142
143unsigned long getreg(struct task_struct *child, int regno)
144{
145	unsigned long mask = ~0UL;
146
147	regno >>= 2;
148	switch (regno) {
149	case FS:
150	case GS:
151	case DS:
152	case ES:
153	case SS:
154	case CS:
155		mask = 0xffff;
156		break;
157	case EIP:
158	case UESP:
159	case EAX:
160	case EBX:
161	case ECX:
162	case EDX:
163	case ESI:
164	case EDI:
165	case EBP:
166	case EFL:
167	case ORIG_EAX:
168		break;
169	default:
170		panic("Bad register in getreg() : %d\n", regno);
171	}
172	return mask & child->thread.regs.regs.gp[reg_offsets[regno]];
173}
174
175/* read the word at location addr in the USER area. */
176int peek_user(struct task_struct *child, long addr, long data)
177{
178	unsigned long tmp;
179
180	if ((addr & 3) || addr < 0)
181		return -EIO;
182
183	tmp = 0;  /* Default return condition */
184	if (addr < MAX_REG_OFFSET) {
185		tmp = getreg(child, addr);
186	}
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 __user *) data);
194}
195
196static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
197{
198	int err, n, cpu = task_cpu(child);
199	struct user_i387_struct fpregs;
200
201	err = save_i387_registers(userspace_pid[cpu],
202				  (unsigned long *) &fpregs);
203	if (err)
204		return err;
205
206	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
207	if(n > 0)
208		return -EFAULT;
209
210	return n;
211}
212
213static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
214{
215	int n, cpu = task_cpu(child);
216	struct user_i387_struct fpregs;
217
218	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
219	if (n > 0)
220		return -EFAULT;
221
222	return restore_i387_registers(userspace_pid[cpu],
223				    (unsigned long *) &fpregs);
224}
225
226static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
227{
228	int err, n, cpu = task_cpu(child);
229	struct user_fxsr_struct fpregs;
230
231	err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
232	if (err)
233		return err;
234
235	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
236	if(n > 0)
237		return -EFAULT;
238
239	return n;
240}
241
242static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
243{
244	int n, cpu = task_cpu(child);
245	struct user_fxsr_struct fpregs;
246
247	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
248	if (n > 0)
249		return -EFAULT;
250
251	return restore_fpx_registers(userspace_pid[cpu],
252				     (unsigned long *) &fpregs);
253}
254
255long subarch_ptrace(struct task_struct *child, long request,
256		    unsigned long addr, unsigned long data)
257{
258	int ret = -EIO;
259	void __user *datap = (void __user *) data;
260	switch (request) {
261	case PTRACE_GETFPREGS: /* Get the child FPU state. */
262		ret = get_fpregs(datap, child);
263		break;
264	case PTRACE_SETFPREGS: /* Set the child FPU state. */
265		ret = set_fpregs(datap, child);
266		break;
267	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
268		ret = get_fpxregs(datap, child);
269		break;
270	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
271		ret = set_fpxregs(datap, child);
272		break;
273	default:
274		ret = -EIO;
275	}
276	return ret;
277}