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 <registers.h>
 11#include <skas.h>
 12
 13extern int arch_switch_tls(struct task_struct *to);
 14
 15void arch_switch_to(struct task_struct *to)
 16{
 17	int err = arch_switch_tls(to);
 18	if (!err)
 19		return;
 20
 21	if (err != -EINVAL)
 22		printk(KERN_WARNING "arch_switch_tls failed, errno %d, "
 23		       "not EINVAL\n", -err);
 24	else
 25		printk(KERN_WARNING "arch_switch_tls failed, errno = EINVAL\n");
 26}
 27
 28int is_syscall(unsigned long addr)
 29{
 30	unsigned short instr;
 31	int n;
 32
 33	n = copy_from_user(&instr, (void __user *) addr, sizeof(instr));
 34	if (n) {
 35		/* access_process_vm() grants access to vsyscall and stub,
 36		 * while copy_from_user doesn't. Maybe access_process_vm is
 37		 * slow, but that doesn't matter, since it will be called only
 38		 * in case of singlestepping, if copy_from_user failed.
 39		 */
 40		n = access_process_vm(current, addr, &instr, sizeof(instr),
 41				FOLL_FORCE);
 42		if (n != sizeof(instr)) {
 43			printk(KERN_ERR "is_syscall : failed to read "
 44			       "instruction from 0x%lx\n", addr);
 45			return 1;
 46		}
 47	}
 48	/* int 0x80 or sysenter */
 49	return (instr == 0x80cd) || (instr == 0x340f);
 50}
 51
 52/* determines which flags the user has access to. */
 53/* 1 = access 0 = no access */
 54#define FLAG_MASK 0x00044dd5
 55
 56static const int reg_offsets[] = {
 57	[EBX] = HOST_BX,
 58	[ECX] = HOST_CX,
 59	[EDX] = HOST_DX,
 60	[ESI] = HOST_SI,
 61	[EDI] = HOST_DI,
 62	[EBP] = HOST_BP,
 63	[EAX] = HOST_AX,
 64	[DS] = HOST_DS,
 65	[ES] = HOST_ES,
 66	[FS] = HOST_FS,
 67	[GS] = HOST_GS,
 68	[EIP] = HOST_IP,
 69	[CS] = HOST_CS,
 70	[EFL] = HOST_EFLAGS,
 71	[UESP] = HOST_SP,
 72	[SS] = HOST_SS,
 73	[ORIG_EAX] = HOST_ORIG_AX,
 74};
 75
 76int putreg(struct task_struct *child, int regno, unsigned long value)
 77{
 78	regno >>= 2;
 79	switch (regno) {
 80	case EBX:
 81	case ECX:
 82	case EDX:
 83	case ESI:
 84	case EDI:
 85	case EBP:
 86	case EAX:
 87	case EIP:
 88	case UESP:
 89		break;
 90	case ORIG_EAX:
 91		/* Update the syscall number. */
 92		UPT_SYSCALL_NR(&child->thread.regs.regs) = value;
 93		break;
 94	case FS:
 95		if (value && (value & 3) != 3)
 96			return -EIO;
 97		break;
 98	case GS:
 99		if (value && (value & 3) != 3)
100			return -EIO;
101		break;
102	case DS:
103	case ES:
104		if (value && (value & 3) != 3)
105			return -EIO;
106		value &= 0xffff;
107		break;
108	case SS:
109	case CS:
110		if ((value & 3) != 3)
111			return -EIO;
112		value &= 0xffff;
113		break;
114	case EFL:
115		value &= FLAG_MASK;
116		child->thread.regs.regs.gp[HOST_EFLAGS] |= value;
117		return 0;
118	default :
119		panic("Bad register in putreg() : %d\n", regno);
120	}
121	child->thread.regs.regs.gp[reg_offsets[regno]] = value;
122	return 0;
123}
124
125int poke_user(struct task_struct *child, long addr, long data)
126{
127	if ((addr & 3) || addr < 0)
128		return -EIO;
129
130	if (addr < MAX_REG_OFFSET)
131		return putreg(child, addr, data);
132	else if ((addr >= offsetof(struct user, u_debugreg[0])) &&
133		 (addr <= offsetof(struct user, u_debugreg[7]))) {
134		addr -= offsetof(struct user, u_debugreg[0]);
135		addr = addr >> 2;
136		if ((addr == 4) || (addr == 5))
137			return -EIO;
138		child->thread.arch.debugregs[addr] = data;
139		return 0;
140	}
141	return -EIO;
142}
143
144unsigned long getreg(struct task_struct *child, int regno)
145{
146	unsigned long mask = ~0UL;
147
148	regno >>= 2;
149	switch (regno) {
150	case FS:
151	case GS:
152	case DS:
153	case ES:
154	case SS:
155	case CS:
156		mask = 0xffff;
157		break;
158	case EIP:
159	case UESP:
160	case EAX:
161	case EBX:
162	case ECX:
163	case EDX:
164	case ESI:
165	case EDI:
166	case EBP:
167	case EFL:
168	case ORIG_EAX:
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]];
174}
175
176/* read the word at location addr in the USER area. */
177int peek_user(struct task_struct *child, long addr, long data)
178{
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	}
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 __user *) data);
195}
196
197static int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
198{
199	int err, n, cpu = task_cpu(child);
200	struct user_i387_struct fpregs;
201
202	err = save_i387_registers(userspace_pid[cpu],
203				  (unsigned long *) &fpregs);
204	if (err)
205		return err;
206
207	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
208	if(n > 0)
209		return -EFAULT;
210
211	return n;
212}
213
214static int set_fpregs(struct user_i387_struct __user *buf, struct task_struct *child)
215{
216	int n, cpu = task_cpu(child);
217	struct user_i387_struct fpregs;
218
219	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
220	if (n > 0)
221		return -EFAULT;
222
223	return restore_i387_registers(userspace_pid[cpu],
224				    (unsigned long *) &fpregs);
225}
226
227static int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
228{
229	int err, n, cpu = task_cpu(child);
230	struct user_fxsr_struct fpregs;
231
232	err = save_fpx_registers(userspace_pid[cpu], (unsigned long *) &fpregs);
233	if (err)
234		return err;
235
236	n = copy_to_user(buf, &fpregs, sizeof(fpregs));
237	if(n > 0)
238		return -EFAULT;
239
240	return n;
241}
242
243static int set_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *child)
244{
245	int n, cpu = task_cpu(child);
246	struct user_fxsr_struct fpregs;
247
248	n = copy_from_user(&fpregs, buf, sizeof(fpregs));
249	if (n > 0)
250		return -EFAULT;
251
252	return restore_fpx_registers(userspace_pid[cpu],
253				     (unsigned long *) &fpregs);
254}
255
256long subarch_ptrace(struct task_struct *child, long request,
257		    unsigned long addr, unsigned long data)
258{
259	int ret = -EIO;
260	void __user *datap = (void __user *) data;
261	switch (request) {
262	case PTRACE_GETFPREGS: /* Get the child FPU state. */
263		ret = get_fpregs(datap, child);
264		break;
265	case PTRACE_SETFPREGS: /* Set the child FPU state. */
266		ret = set_fpregs(datap, child);
267		break;
268	case PTRACE_GETFPXREGS: /* Get the child FPU state. */
269		ret = get_fpxregs(datap, child);
270		break;
271	case PTRACE_SETFPXREGS: /* Set the child FPU state. */
272		ret = set_fpxregs(datap, child);
273		break;
274	default:
275		ret = -EIO;
276	}
277	return ret;
278}