xref: /openbmc/linux/arch/x86/um/ptrace_32.c (revision dbba7f70)
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 
13 extern int arch_switch_tls(struct task_struct *to);
14 
arch_switch_to(struct task_struct * to)15 void 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 
is_syscall(unsigned long addr)28 int 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 
56 static 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 
putreg(struct task_struct * child,int regno,unsigned long value)76 int 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 
poke_user(struct task_struct * child,long addr,long data)125 int 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 
getreg(struct task_struct * child,int regno)144 unsigned 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. */
peek_user(struct task_struct * child,long addr,long data)177 int 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 
get_fpregs(struct user_i387_struct __user * buf,struct task_struct * child)197 static 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 
set_fpregs(struct user_i387_struct __user * buf,struct task_struct * child)214 static 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 
get_fpxregs(struct user_fxsr_struct __user * buf,struct task_struct * child)227 static 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 
set_fpxregs(struct user_fxsr_struct __user * buf,struct task_struct * child)243 static 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 
subarch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)256 long 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 }
279