1 /*
2 * linux/arch/ppc/kernel/ptrace.c
3 *
4 * PowerPC version
5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 *
7 * Derived from "arch/m68k/kernel/ptrace.c"
8 * Copyright (C) 1994 by Hamish Macdonald
9 * Taken from linux/kernel/ptrace.c and modified for M680x0.
10 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
11 *
12 * Modified by Cort Dougan (cort@hq.fsmlabs.com)
13 * and Paul Mackerras (paulus@linuxcare.com.au).
14 *
15 * This file is subject to the terms and conditions of the GNU General
16 * Public License. Please read the COPYING file for all license details.
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/mm.h>
22 #include <linux/smp.h>
23 #include <linux/smp_lock.h>
24 #include <linux/errno.h>
25 #include <linux/ptrace.h>
26 #include <linux/user.h>
27
28 #include <asm/uaccess.h>
29 #include <asm/page.h>
30 #include <asm/pgtable.h>
31 #include <asm/system.h>
32
33 /*
34 * Set of msr bits that gdb can change on behalf of a process.
35 */
36 #if defined(CONFIG_4xx)
37 #define MSR_DEBUGCHANGE (0)
38 #else
39 #define MSR_DEBUGCHANGE (MSR_FE0 | MSR_SE | MSR_BE | MSR_FE1)
40 #endif
41
42 /*
43 * does not yet catch signals sent when the child dies.
44 * in exit.c or in signal.c.
45 */
46
47 /*
48 * Get contents of register REGNO in task TASK.
49 */
get_reg(struct task_struct * task,int regno)50 static inline unsigned long get_reg(struct task_struct *task, int regno)
51 {
52 if (regno < sizeof(struct pt_regs) / sizeof(unsigned long)
53 && task->thread.regs != NULL)
54 return ((unsigned long *)task->thread.regs)[regno];
55 return (0);
56 }
57
58 /*
59 * Write contents of register REGNO in task TASK.
60 */
put_reg(struct task_struct * task,int regno,unsigned long data)61 static inline int put_reg(struct task_struct *task, int regno,
62 unsigned long data)
63 {
64 if (regno <= PT_MQ && task->thread.regs != NULL) {
65 if (regno == PT_MSR)
66 data = (data & MSR_DEBUGCHANGE)
67 | (task->thread.regs->msr & ~MSR_DEBUGCHANGE);
68 ((unsigned long *)task->thread.regs)[regno] = data;
69 return 0;
70 }
71 return -EIO;
72 }
73
74 #ifdef CONFIG_ALTIVEC
75 /*
76 * Get contents of AltiVec register state in task TASK
77 */
get_vrregs(unsigned long * data,struct task_struct * task)78 static inline int get_vrregs(unsigned long *data, struct task_struct *task)
79 {
80 int i, j;
81
82 if (!access_ok(VERIFY_WRITE, data, 133 * sizeof(unsigned long)))
83 return -EFAULT;
84
85 /* copy AltiVec registers VR[0] .. VR[31] */
86 for (i = 0; i < 32; i++)
87 for (j = 0; j < 4; j++, data++)
88 if (__put_user(task->thread.vr[i].u[j], data))
89 return -EFAULT;
90
91 /* copy VSCR */
92 for (i = 0; i < 4; i++, data++)
93 if (__put_user(task->thread.vscr.u[i], data))
94 return -EFAULT;
95
96 /* copy VRSAVE */
97 if (__put_user(task->thread.vrsave, data))
98 return -EFAULT;
99
100 return 0;
101 }
102
103 /*
104 * Write contents of AltiVec register state into task TASK.
105 */
set_vrregs(struct task_struct * task,unsigned long * data)106 static inline int set_vrregs(struct task_struct *task, unsigned long *data)
107 {
108 int i, j;
109
110 if (!access_ok(VERIFY_READ, data, 133 * sizeof(unsigned long)))
111 return -EFAULT;
112
113 /* copy AltiVec registers VR[0] .. VR[31] */
114 for (i = 0; i < 32; i++)
115 for (j = 0; j < 4; j++, data++)
116 if (__get_user(task->thread.vr[i].u[j], data))
117 return -EFAULT;
118
119 /* copy VSCR */
120 for (i = 0; i < 4; i++, data++)
121 if (__get_user(task->thread.vscr.u[i], data))
122 return -EFAULT;
123
124 /* copy VRSAVE */
125 if (__get_user(task->thread.vrsave, data))
126 return -EFAULT;
127
128 return 0;
129 }
130 #endif
131
132 static inline void
set_single_step(struct task_struct * task)133 set_single_step(struct task_struct *task)
134 {
135 struct pt_regs *regs = task->thread.regs;
136 #if defined(CONFIG_4xx)
137 regs->msr |= MSR_DE;
138 task->thread.dbcr0 |= (DBCR0_IDM | DBCR0_IC);
139 #else
140 if (regs != NULL)
141 regs->msr |= MSR_SE;
142 #endif
143
144 }
145
146 static inline void
clear_single_step(struct task_struct * task)147 clear_single_step(struct task_struct *task)
148 {
149 struct pt_regs *regs = task->thread.regs;
150 #if defined(CONFIG_4xx)
151 regs->msr &= ~MSR_DE;
152 task->thread.dbcr0 &= ~DBCR0_IC;
153 #else
154 if (regs != NULL)
155 regs->msr &= ~MSR_SE;
156 #endif
157 }
158
159 /*
160 * Called by kernel/ptrace.c when detaching..
161 *
162 * Make sure single step bits etc are not set.
163 */
ptrace_disable(struct task_struct * child)164 void ptrace_disable(struct task_struct *child)
165 {
166 /* make sure the single step bit is not set. */
167 clear_single_step(child);
168 }
169
sys_ptrace(long request,long pid,long addr,long data)170 int sys_ptrace(long request, long pid, long addr, long data)
171 {
172 struct task_struct *child;
173 int ret = -EPERM;
174
175 lock_kernel();
176 if (request == PTRACE_TRACEME) {
177 /* are we already being traced? */
178 if (current->ptrace & PT_PTRACED)
179 goto out;
180 /* set the ptrace bit in the process flags. */
181 current->ptrace |= PT_PTRACED;
182 ret = 0;
183 goto out;
184 }
185 ret = -ESRCH;
186 read_lock(&tasklist_lock);
187 child = find_task_by_pid(pid);
188 if (child)
189 get_task_struct(child);
190 read_unlock(&tasklist_lock);
191 if (!child)
192 goto out;
193
194 ret = -EPERM;
195 if (pid == 1) /* you may not mess with init */
196 goto out_tsk;
197
198 if (request == PTRACE_ATTACH) {
199 ret = ptrace_attach(child);
200 goto out_tsk;
201 }
202
203 ret = ptrace_check_attach(child, request == PTRACE_KILL);
204 if (ret < 0)
205 goto out_tsk;
206
207 switch (request) {
208 /* when I and D space are separate, these will need to be fixed. */
209 case PTRACE_PEEKTEXT: /* read word at location addr. */
210 case PTRACE_PEEKDATA: {
211 unsigned long tmp;
212 int copied;
213
214 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
215 ret = -EIO;
216 if (copied != sizeof(tmp))
217 break;
218 ret = put_user(tmp,(unsigned long *) data);
219 break;
220 }
221
222 /* read the word at location addr in the USER area. */
223 /* XXX this will need fixing for 64-bit */
224 case PTRACE_PEEKUSR: {
225 unsigned long index, tmp;
226
227 ret = -EIO;
228 /* convert to index and check */
229 index = (unsigned long) addr >> 2;
230 if ((addr & 3) || index > PT_FPSCR)
231 break;
232
233 if (index < PT_FPR0) {
234 tmp = get_reg(child, (int) index);
235 } else {
236 if (child->thread.regs != NULL
237 && child->thread.regs->msr & MSR_FP)
238 giveup_fpu(child);
239 tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
240 }
241 ret = put_user(tmp,(unsigned long *) data);
242 break;
243 }
244
245 /* If I and D space are separate, this will have to be fixed. */
246 case PTRACE_POKETEXT: /* write the word at location addr. */
247 case PTRACE_POKEDATA:
248 ret = 0;
249 if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
250 break;
251 ret = -EIO;
252 break;
253
254 /* write the word at location addr in the USER area */
255 /* XXX this will need fixing for 64-bit */
256 case PTRACE_POKEUSR: {
257 unsigned long index;
258
259 ret = -EIO;
260 /* convert to index and check */
261 index = (unsigned long) addr >> 2;
262 if ((addr & 3) || index > PT_FPSCR)
263 break;
264
265 if (index == PT_ORIG_R3)
266 break;
267 if (index < PT_FPR0) {
268 ret = put_reg(child, index, data);
269 } else {
270 if (child->thread.regs != NULL
271 && child->thread.regs->msr & MSR_FP)
272 giveup_fpu(child);
273 ((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
274 ret = 0;
275 }
276 break;
277 }
278
279 case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
280 case PTRACE_CONT: { /* restart after signal. */
281 ret = -EIO;
282 if ((unsigned long) data > _NSIG)
283 break;
284 if (request == PTRACE_SYSCALL)
285 child->ptrace |= PT_TRACESYS;
286 else
287 child->ptrace &= ~PT_TRACESYS;
288 child->exit_code = data;
289 /* make sure the single step bit is not set. */
290 clear_single_step(child);
291 #ifdef CONFIG_4xx
292 /* ...but traps may be set, so catch those....
293 */
294 child->thread.regs->msr |= MSR_DE;
295 child->thread.dbcr0 |= (DBCR0_IDM | DBCR0_TDE);
296 #endif
297 wake_up_process(child);
298 ret = 0;
299 break;
300 }
301
302 /*
303 * make the child exit. Best I can do is send it a sigkill.
304 * perhaps it should be put in the status that it wants to
305 * exit.
306 */
307 case PTRACE_KILL: {
308 ret = 0;
309 if (child->state == TASK_ZOMBIE) /* already dead */
310 break;
311 child->exit_code = SIGKILL;
312 /* make sure the single step bit is not set. */
313 clear_single_step(child);
314 wake_up_process(child);
315 break;
316 }
317
318 case PTRACE_SINGLESTEP: { /* set the trap flag. */
319 ret = -EIO;
320 if ((unsigned long) data > _NSIG)
321 break;
322 child->ptrace &= ~PT_TRACESYS;
323 set_single_step(child);
324 child->exit_code = data;
325 /* give it a chance to run. */
326 wake_up_process(child);
327 ret = 0;
328 break;
329 }
330
331 case PTRACE_DETACH:
332 ret = ptrace_detach(child, data);
333 break;
334
335 #ifdef CONFIG_ALTIVEC
336 case PTRACE_GETVRREGS:
337 /* Get the child altivec register state. */
338 if (child->thread.regs->msr & MSR_VEC)
339 giveup_altivec(child);
340 ret = get_vrregs((unsigned long *)data, child);
341 break;
342
343 case PTRACE_SETVRREGS:
344 /* Set the child altivec register state. */
345 /* this is to clear the MSR_VEC bit to force a reload
346 * of register state from memory */
347 if (child->thread.regs->msr & MSR_VEC)
348 giveup_altivec(child);
349 ret = set_vrregs(child, (unsigned long *)data);
350 break;
351 #endif
352
353 default:
354 ret = -EIO;
355 break;
356 }
357 out_tsk:
358 free_task_struct(child);
359 out:
360 unlock_kernel();
361 return ret;
362 }
363
syscall_trace(void)364 void syscall_trace(void)
365 {
366 if ((current->ptrace & (PT_PTRACED|PT_TRACESYS))
367 != (PT_PTRACED|PT_TRACESYS))
368 return;
369 current->exit_code = SIGTRAP;
370 current->state = TASK_STOPPED;
371 notify_parent(current, SIGCHLD);
372 schedule();
373 /*
374 * this isn't the same as continuing with a signal, but it will do
375 * for normal use. strace only continues with a signal if the
376 * stopping signal is not SIGTRAP. -brl
377 */
378 if (current->exit_code) {
379 send_sig(current->exit_code, current, 1);
380 current->exit_code = 0;
381 }
382 }
383