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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm26/kernel/ptrace.c | |
3 | * | |
4 | * By Ross Biro 1/23/92 | |
5 | * edited by Linus Torvalds | |
6 | * ARM modifications Copyright (C) 2000 Russell King | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #include <linux/config.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/mm.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/smp_lock.h> | |
18 | #include <linux/ptrace.h> | |
19 | #include <linux/user.h> | |
20 | #include <linux/security.h> | |
7ed20e1a | 21 | #include <linux/signal.h> |
1da177e4 LT |
22 | |
23 | #include <asm/uaccess.h> | |
24 | #include <asm/pgtable.h> | |
25 | #include <asm/system.h> | |
26 | //#include <asm/processor.h> | |
27 | ||
28 | #include "ptrace.h" | |
29 | ||
30 | #define REG_PC 15 | |
31 | #define REG_PSR 15 | |
32 | /* | |
33 | * does not yet catch signals sent when the child dies. | |
34 | * in exit.c or in signal.c. | |
35 | */ | |
36 | ||
37 | /* | |
38 | * Breakpoint SWI instruction: SWI &9F0001 | |
39 | */ | |
40 | #define BREAKINST_ARM 0xef9f0001 | |
41 | ||
42 | /* | |
43 | * Get the address of the live pt_regs for the specified task. | |
44 | * These are saved onto the top kernel stack when the process | |
45 | * is not running. | |
46 | * | |
47 | * Note: if a user thread is execve'd from kernel space, the | |
48 | * kernel stack will not be empty on entry to the kernel, so | |
49 | * ptracing these tasks will fail. | |
50 | */ | |
51 | static inline struct pt_regs * | |
52 | get_user_regs(struct task_struct *task) | |
53 | { | |
54 | return __get_user_regs(task->thread_info); | |
55 | } | |
56 | ||
57 | /* | |
58 | * this routine will get a word off of the processes privileged stack. | |
59 | * the offset is how far from the base addr as stored in the THREAD. | |
60 | * this routine assumes that all the privileged stacks are in our | |
61 | * data space. | |
62 | */ | |
63 | static inline long get_user_reg(struct task_struct *task, int offset) | |
64 | { | |
65 | return get_user_regs(task)->uregs[offset]; | |
66 | } | |
67 | ||
68 | /* | |
69 | * this routine will put a word on the processes privileged stack. | |
70 | * the offset is how far from the base addr as stored in the THREAD. | |
71 | * this routine assumes that all the privileged stacks are in our | |
72 | * data space. | |
73 | */ | |
74 | static inline int | |
75 | put_user_reg(struct task_struct *task, int offset, long data) | |
76 | { | |
77 | struct pt_regs newregs, *regs = get_user_regs(task); | |
78 | int ret = -EINVAL; | |
79 | ||
80 | newregs = *regs; | |
81 | newregs.uregs[offset] = data; | |
82 | ||
83 | if (valid_user_regs(&newregs)) { | |
84 | regs->uregs[offset] = data; | |
85 | ret = 0; | |
86 | } | |
87 | ||
88 | return ret; | |
89 | } | |
90 | ||
91 | static inline int | |
92 | read_u32(struct task_struct *task, unsigned long addr, u32 *res) | |
93 | { | |
94 | int ret; | |
95 | ||
96 | ret = access_process_vm(task, addr, res, sizeof(*res), 0); | |
97 | ||
98 | return ret == sizeof(*res) ? 0 : -EIO; | |
99 | } | |
100 | ||
101 | static inline int | |
102 | read_instr(struct task_struct *task, unsigned long addr, u32 *res) | |
103 | { | |
104 | int ret; | |
105 | u32 val; | |
106 | ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0); | |
107 | ret = ret == sizeof(val) ? 0 : -EIO; | |
108 | *res = val; | |
109 | return ret; | |
110 | } | |
111 | ||
112 | /* | |
113 | * Get value of register `rn' (in the instruction) | |
114 | */ | |
115 | static unsigned long | |
116 | ptrace_getrn(struct task_struct *child, unsigned long insn) | |
117 | { | |
118 | unsigned int reg = (insn >> 16) & 15; | |
119 | unsigned long val; | |
120 | ||
121 | val = get_user_reg(child, reg); | |
122 | if (reg == 15) | |
123 | val = pc_pointer(val + 8); //FIXME - correct for arm26? | |
124 | ||
125 | return val; | |
126 | } | |
127 | ||
128 | /* | |
129 | * Get value of operand 2 (in an ALU instruction) | |
130 | */ | |
131 | static unsigned long | |
132 | ptrace_getaluop2(struct task_struct *child, unsigned long insn) | |
133 | { | |
134 | unsigned long val; | |
135 | int shift; | |
136 | int type; | |
137 | ||
138 | if (insn & 1 << 25) { | |
139 | val = insn & 255; | |
140 | shift = (insn >> 8) & 15; | |
141 | type = 3; | |
142 | } else { | |
143 | val = get_user_reg (child, insn & 15); | |
144 | ||
145 | if (insn & (1 << 4)) | |
146 | shift = (int)get_user_reg (child, (insn >> 8) & 15); | |
147 | else | |
148 | shift = (insn >> 7) & 31; | |
149 | ||
150 | type = (insn >> 5) & 3; | |
151 | } | |
152 | ||
153 | switch (type) { | |
154 | case 0: val <<= shift; break; | |
155 | case 1: val >>= shift; break; | |
156 | case 2: | |
157 | val = (((signed long)val) >> shift); | |
158 | break; | |
159 | case 3: | |
160 | val = (val >> shift) | (val << (32 - shift)); | |
161 | break; | |
162 | } | |
163 | return val; | |
164 | } | |
165 | ||
166 | /* | |
167 | * Get value of operand 2 (in a LDR instruction) | |
168 | */ | |
169 | static unsigned long | |
170 | ptrace_getldrop2(struct task_struct *child, unsigned long insn) | |
171 | { | |
172 | unsigned long val; | |
173 | int shift; | |
174 | int type; | |
175 | ||
176 | val = get_user_reg(child, insn & 15); | |
177 | shift = (insn >> 7) & 31; | |
178 | type = (insn >> 5) & 3; | |
179 | ||
180 | switch (type) { | |
181 | case 0: val <<= shift; break; | |
182 | case 1: val >>= shift; break; | |
183 | case 2: | |
184 | val = (((signed long)val) >> shift); | |
185 | break; | |
186 | case 3: | |
187 | val = (val >> shift) | (val << (32 - shift)); | |
188 | break; | |
189 | } | |
190 | return val; | |
191 | } | |
192 | ||
193 | #define OP_MASK 0x01e00000 | |
194 | #define OP_AND 0x00000000 | |
195 | #define OP_EOR 0x00200000 | |
196 | #define OP_SUB 0x00400000 | |
197 | #define OP_RSB 0x00600000 | |
198 | #define OP_ADD 0x00800000 | |
199 | #define OP_ADC 0x00a00000 | |
200 | #define OP_SBC 0x00c00000 | |
201 | #define OP_RSC 0x00e00000 | |
202 | #define OP_ORR 0x01800000 | |
203 | #define OP_MOV 0x01a00000 | |
204 | #define OP_BIC 0x01c00000 | |
205 | #define OP_MVN 0x01e00000 | |
206 | ||
207 | static unsigned long | |
208 | get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn) | |
209 | { | |
210 | u32 alt = 0; | |
211 | ||
212 | switch (insn & 0x0e000000) { | |
213 | case 0x00000000: | |
214 | case 0x02000000: { | |
215 | /* | |
216 | * data processing | |
217 | */ | |
218 | long aluop1, aluop2, ccbit; | |
219 | ||
220 | if ((insn & 0xf000) != 0xf000) | |
221 | break; | |
222 | ||
223 | aluop1 = ptrace_getrn(child, insn); | |
224 | aluop2 = ptrace_getaluop2(child, insn); | |
225 | ccbit = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0; | |
226 | ||
227 | switch (insn & OP_MASK) { | |
228 | case OP_AND: alt = aluop1 & aluop2; break; | |
229 | case OP_EOR: alt = aluop1 ^ aluop2; break; | |
230 | case OP_SUB: alt = aluop1 - aluop2; break; | |
231 | case OP_RSB: alt = aluop2 - aluop1; break; | |
232 | case OP_ADD: alt = aluop1 + aluop2; break; | |
233 | case OP_ADC: alt = aluop1 + aluop2 + ccbit; break; | |
234 | case OP_SBC: alt = aluop1 - aluop2 + ccbit; break; | |
235 | case OP_RSC: alt = aluop2 - aluop1 + ccbit; break; | |
236 | case OP_ORR: alt = aluop1 | aluop2; break; | |
237 | case OP_MOV: alt = aluop2; break; | |
238 | case OP_BIC: alt = aluop1 & ~aluop2; break; | |
239 | case OP_MVN: alt = ~aluop2; break; | |
240 | } | |
241 | break; | |
242 | } | |
243 | ||
244 | case 0x04000000: | |
245 | case 0x06000000: | |
246 | /* | |
247 | * ldr | |
248 | */ | |
249 | if ((insn & 0x0010f000) == 0x0010f000) { | |
250 | unsigned long base; | |
251 | ||
252 | base = ptrace_getrn(child, insn); | |
253 | if (insn & 1 << 24) { | |
254 | long aluop2; | |
255 | ||
256 | if (insn & 0x02000000) | |
257 | aluop2 = ptrace_getldrop2(child, insn); | |
258 | else | |
259 | aluop2 = insn & 0xfff; | |
260 | ||
261 | if (insn & 1 << 23) | |
262 | base += aluop2; | |
263 | else | |
264 | base -= aluop2; | |
265 | } | |
266 | if (read_u32(child, base, &alt) == 0) | |
267 | alt = pc_pointer(alt); | |
268 | } | |
269 | break; | |
270 | ||
271 | case 0x08000000: | |
272 | /* | |
273 | * ldm | |
274 | */ | |
275 | if ((insn & 0x00108000) == 0x00108000) { | |
276 | unsigned long base; | |
277 | unsigned int nr_regs; | |
278 | ||
279 | if (insn & (1 << 23)) { | |
280 | nr_regs = hweight16(insn & 65535) << 2; | |
281 | ||
282 | if (!(insn & (1 << 24))) | |
283 | nr_regs -= 4; | |
284 | } else { | |
285 | if (insn & (1 << 24)) | |
286 | nr_regs = -4; | |
287 | else | |
288 | nr_regs = 0; | |
289 | } | |
290 | ||
291 | base = ptrace_getrn(child, insn); | |
292 | ||
293 | if (read_u32(child, base + nr_regs, &alt) == 0) | |
294 | alt = pc_pointer(alt); | |
295 | break; | |
296 | } | |
297 | break; | |
298 | ||
299 | case 0x0a000000: { | |
300 | /* | |
301 | * bl or b | |
302 | */ | |
303 | signed long displ; | |
304 | /* It's a branch/branch link: instead of trying to | |
305 | * figure out whether the branch will be taken or not, | |
306 | * we'll put a breakpoint at both locations. This is | |
307 | * simpler, more reliable, and probably not a whole lot | |
308 | * slower than the alternative approach of emulating the | |
309 | * branch. | |
310 | */ | |
311 | displ = (insn & 0x00ffffff) << 8; | |
312 | displ = (displ >> 6) + 8; | |
313 | if (displ != 0 && displ != 4) | |
314 | alt = pc + displ; | |
315 | } | |
316 | break; | |
317 | } | |
318 | ||
319 | return alt; | |
320 | } | |
321 | ||
322 | static int | |
323 | swap_insn(struct task_struct *task, unsigned long addr, | |
324 | void *old_insn, void *new_insn, int size) | |
325 | { | |
326 | int ret; | |
327 | ||
328 | ret = access_process_vm(task, addr, old_insn, size, 0); | |
329 | if (ret == size) | |
330 | ret = access_process_vm(task, addr, new_insn, size, 1); | |
331 | return ret; | |
332 | } | |
333 | ||
334 | static void | |
335 | add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr) | |
336 | { | |
337 | int nr = dbg->nsaved; | |
338 | ||
339 | if (nr < 2) { | |
340 | u32 new_insn = BREAKINST_ARM; | |
341 | int res; | |
342 | ||
343 | res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4); | |
344 | ||
345 | if (res == 4) { | |
346 | dbg->bp[nr].address = addr; | |
347 | dbg->nsaved += 1; | |
348 | } | |
349 | } else | |
350 | printk(KERN_ERR "ptrace: too many breakpoints\n"); | |
351 | } | |
352 | ||
353 | /* | |
354 | * Clear one breakpoint in the user program. We copy what the hardware | |
355 | * does and use bit 0 of the address to indicate whether this is a Thumb | |
356 | * breakpoint or an ARM breakpoint. | |
357 | */ | |
358 | static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp) | |
359 | { | |
360 | unsigned long addr = bp->address; | |
361 | u32 old_insn; | |
362 | int ret; | |
363 | ||
364 | ret = swap_insn(task, addr & ~3, &old_insn, | |
365 | &bp->insn, 4); | |
366 | ||
367 | if (ret != 4 || old_insn != BREAKINST_ARM) | |
368 | printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at " | |
369 | "0x%08lx (0x%08x)\n", task->comm, task->pid, | |
370 | addr, old_insn); | |
371 | } | |
372 | ||
373 | void ptrace_set_bpt(struct task_struct *child) | |
374 | { | |
375 | struct pt_regs *regs; | |
376 | unsigned long pc; | |
377 | u32 insn; | |
378 | int res; | |
379 | ||
380 | regs = get_user_regs(child); | |
381 | pc = instruction_pointer(regs); | |
382 | ||
383 | res = read_instr(child, pc, &insn); | |
384 | if (!res) { | |
385 | struct debug_info *dbg = &child->thread.debug; | |
386 | unsigned long alt; | |
387 | ||
388 | dbg->nsaved = 0; | |
389 | ||
390 | alt = get_branch_address(child, pc, insn); | |
391 | if (alt) | |
392 | add_breakpoint(child, dbg, alt); | |
393 | ||
394 | /* | |
395 | * Note that we ignore the result of setting the above | |
396 | * breakpoint since it may fail. When it does, this is | |
397 | * not so much an error, but a forewarning that we may | |
398 | * be receiving a prefetch abort shortly. | |
399 | * | |
400 | * If we don't set this breakpoint here, then we can | |
401 | * lose control of the thread during single stepping. | |
402 | */ | |
403 | if (!alt || predicate(insn) != PREDICATE_ALWAYS) | |
404 | add_breakpoint(child, dbg, pc + 4); | |
405 | } | |
406 | } | |
407 | ||
408 | /* | |
409 | * Ensure no single-step breakpoint is pending. Returns non-zero | |
410 | * value if child was being single-stepped. | |
411 | */ | |
412 | void ptrace_cancel_bpt(struct task_struct *child) | |
413 | { | |
414 | int i, nsaved = child->thread.debug.nsaved; | |
415 | ||
416 | child->thread.debug.nsaved = 0; | |
417 | ||
418 | if (nsaved > 2) { | |
419 | printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved); | |
420 | nsaved = 2; | |
421 | } | |
422 | ||
423 | for (i = 0; i < nsaved; i++) | |
424 | clear_breakpoint(child, &child->thread.debug.bp[i]); | |
425 | } | |
426 | ||
427 | /* | |
428 | * Called by kernel/ptrace.c when detaching.. | |
429 | * | |
430 | * Make sure the single step bit is not set. | |
431 | */ | |
432 | void ptrace_disable(struct task_struct *child) | |
433 | { | |
434 | child->ptrace &= ~PT_SINGLESTEP; | |
435 | ptrace_cancel_bpt(child); | |
436 | } | |
437 | ||
438 | /* | |
439 | * Handle hitting a breakpoint. | |
440 | */ | |
441 | void ptrace_break(struct task_struct *tsk, struct pt_regs *regs) | |
442 | { | |
443 | siginfo_t info; | |
444 | ||
445 | /* | |
446 | * The PC is always left pointing at the next instruction. Fix this. | |
447 | */ | |
448 | regs->ARM_pc -= 4; | |
449 | ||
450 | if (tsk->thread.debug.nsaved == 0) | |
451 | printk(KERN_ERR "ptrace: bogus breakpoint trap\n"); | |
452 | ||
453 | ptrace_cancel_bpt(tsk); | |
454 | ||
455 | info.si_signo = SIGTRAP; | |
456 | info.si_errno = 0; | |
457 | info.si_code = TRAP_BRKPT; | |
458 | info.si_addr = (void *)instruction_pointer(regs) - 4; | |
459 | ||
460 | force_sig_info(SIGTRAP, &info, tsk); | |
461 | } | |
462 | ||
463 | /* | |
464 | * Read the word at offset "off" into the "struct user". We | |
465 | * actually access the pt_regs stored on the kernel stack. | |
466 | */ | |
467 | static int ptrace_read_user(struct task_struct *tsk, unsigned long off, | |
468 | unsigned long *ret) | |
469 | { | |
470 | unsigned long tmp; | |
471 | ||
472 | if (off & 3 || off >= sizeof(struct user)) | |
473 | return -EIO; | |
474 | ||
475 | tmp = 0; | |
476 | if (off < sizeof(struct pt_regs)) | |
477 | tmp = get_user_reg(tsk, off >> 2); | |
478 | ||
479 | return put_user(tmp, ret); | |
480 | } | |
481 | ||
482 | /* | |
483 | * Write the word at offset "off" into "struct user". We | |
484 | * actually access the pt_regs stored on the kernel stack. | |
485 | */ | |
486 | static int ptrace_write_user(struct task_struct *tsk, unsigned long off, | |
487 | unsigned long val) | |
488 | { | |
489 | if (off & 3 || off >= sizeof(struct user)) | |
490 | return -EIO; | |
491 | ||
492 | if (off >= sizeof(struct pt_regs)) | |
493 | return 0; | |
494 | ||
495 | return put_user_reg(tsk, off >> 2, val); | |
496 | } | |
497 | ||
498 | /* | |
499 | * Get all user integer registers. | |
500 | */ | |
501 | static int ptrace_getregs(struct task_struct *tsk, void *uregs) | |
502 | { | |
503 | struct pt_regs *regs = get_user_regs(tsk); | |
504 | ||
505 | return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0; | |
506 | } | |
507 | ||
508 | /* | |
509 | * Set all user integer registers. | |
510 | */ | |
511 | static int ptrace_setregs(struct task_struct *tsk, void *uregs) | |
512 | { | |
513 | struct pt_regs newregs; | |
514 | int ret; | |
515 | ||
516 | ret = -EFAULT; | |
517 | if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) { | |
518 | struct pt_regs *regs = get_user_regs(tsk); | |
519 | ||
520 | ret = -EINVAL; | |
521 | if (valid_user_regs(&newregs)) { | |
522 | *regs = newregs; | |
523 | ret = 0; | |
524 | } | |
525 | } | |
526 | ||
527 | return ret; | |
528 | } | |
529 | ||
530 | /* | |
531 | * Get the child FPU state. | |
532 | */ | |
533 | static int ptrace_getfpregs(struct task_struct *tsk, void *ufp) | |
534 | { | |
535 | return copy_to_user(ufp, &tsk->thread_info->fpstate, | |
536 | sizeof(struct user_fp)) ? -EFAULT : 0; | |
537 | } | |
538 | ||
539 | /* | |
540 | * Set the child FPU state. | |
541 | */ | |
542 | static int ptrace_setfpregs(struct task_struct *tsk, void *ufp) | |
543 | { | |
544 | set_stopped_child_used_math(tsk); | |
545 | return copy_from_user(&tsk->thread_info->fpstate, ufp, | |
546 | sizeof(struct user_fp)) ? -EFAULT : 0; | |
547 | } | |
548 | ||
549 | static int do_ptrace(int request, struct task_struct *child, long addr, long data) | |
550 | { | |
551 | unsigned long tmp; | |
552 | int ret; | |
553 | ||
554 | switch (request) { | |
555 | /* | |
556 | * read word at location "addr" in the child process. | |
557 | */ | |
558 | case PTRACE_PEEKTEXT: | |
559 | case PTRACE_PEEKDATA: | |
560 | ret = access_process_vm(child, addr, &tmp, | |
561 | sizeof(unsigned long), 0); | |
562 | if (ret == sizeof(unsigned long)) | |
563 | ret = put_user(tmp, (unsigned long *) data); | |
564 | else | |
565 | ret = -EIO; | |
566 | break; | |
567 | ||
568 | case PTRACE_PEEKUSR: | |
569 | ret = ptrace_read_user(child, addr, (unsigned long *)data); | |
570 | break; | |
571 | ||
572 | /* | |
573 | * write the word at location addr. | |
574 | */ | |
575 | case PTRACE_POKETEXT: | |
576 | case PTRACE_POKEDATA: | |
577 | ret = access_process_vm(child, addr, &data, | |
578 | sizeof(unsigned long), 1); | |
579 | if (ret == sizeof(unsigned long)) | |
580 | ret = 0; | |
581 | else | |
582 | ret = -EIO; | |
583 | break; | |
584 | ||
585 | case PTRACE_POKEUSR: | |
586 | ret = ptrace_write_user(child, addr, data); | |
587 | break; | |
588 | ||
589 | /* | |
590 | * continue/restart and stop at next (return from) syscall | |
591 | */ | |
592 | case PTRACE_SYSCALL: | |
593 | case PTRACE_CONT: | |
594 | ret = -EIO; | |
7ed20e1a | 595 | if (!valid_signal(data)) |
1da177e4 LT |
596 | break; |
597 | if (request == PTRACE_SYSCALL) | |
598 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
599 | else | |
600 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
601 | child->exit_code = data; | |
602 | /* make sure single-step breakpoint is gone. */ | |
603 | child->ptrace &= ~PT_SINGLESTEP; | |
604 | ptrace_cancel_bpt(child); | |
605 | wake_up_process(child); | |
606 | ret = 0; | |
607 | break; | |
608 | ||
609 | /* | |
610 | * make the child exit. Best I can do is send it a sigkill. | |
611 | * perhaps it should be put in the status that it wants to | |
612 | * exit. | |
613 | */ | |
614 | case PTRACE_KILL: | |
615 | /* make sure single-step breakpoint is gone. */ | |
616 | child->ptrace &= ~PT_SINGLESTEP; | |
617 | ptrace_cancel_bpt(child); | |
618 | if (child->exit_state != EXIT_ZOMBIE) { | |
619 | child->exit_code = SIGKILL; | |
620 | wake_up_process(child); | |
621 | } | |
622 | ret = 0; | |
623 | break; | |
624 | ||
625 | /* | |
626 | * execute single instruction. | |
627 | */ | |
628 | case PTRACE_SINGLESTEP: | |
629 | ret = -EIO; | |
7ed20e1a | 630 | if (!valid_signal(data)) |
1da177e4 LT |
631 | break; |
632 | child->ptrace |= PT_SINGLESTEP; | |
633 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
634 | child->exit_code = data; | |
635 | /* give it a chance to run. */ | |
636 | wake_up_process(child); | |
637 | ret = 0; | |
638 | break; | |
639 | ||
640 | case PTRACE_DETACH: | |
641 | ret = ptrace_detach(child, data); | |
642 | break; | |
643 | ||
644 | case PTRACE_GETREGS: | |
645 | ret = ptrace_getregs(child, (void *)data); | |
646 | break; | |
647 | ||
648 | case PTRACE_SETREGS: | |
649 | ret = ptrace_setregs(child, (void *)data); | |
650 | break; | |
651 | ||
652 | case PTRACE_GETFPREGS: | |
653 | ret = ptrace_getfpregs(child, (void *)data); | |
654 | break; | |
655 | ||
656 | case PTRACE_SETFPREGS: | |
657 | ret = ptrace_setfpregs(child, (void *)data); | |
658 | break; | |
659 | ||
660 | default: | |
661 | ret = ptrace_request(child, request, addr, data); | |
662 | break; | |
663 | } | |
664 | ||
665 | return ret; | |
666 | } | |
667 | ||
668 | asmlinkage int sys_ptrace(long request, long pid, long addr, long data) | |
669 | { | |
670 | struct task_struct *child; | |
671 | int ret; | |
672 | ||
673 | lock_kernel(); | |
674 | ret = -EPERM; | |
675 | if (request == PTRACE_TRACEME) { | |
676 | /* are we already being traced? */ | |
677 | if (current->ptrace & PT_PTRACED) | |
678 | goto out; | |
679 | ret = security_ptrace(current->parent, current); | |
680 | if (ret) | |
681 | goto out; | |
682 | /* set the ptrace bit in the process flags. */ | |
683 | current->ptrace |= PT_PTRACED; | |
684 | ret = 0; | |
685 | goto out; | |
686 | } | |
687 | ret = -ESRCH; | |
688 | read_lock(&tasklist_lock); | |
689 | child = find_task_by_pid(pid); | |
690 | if (child) | |
691 | get_task_struct(child); | |
692 | read_unlock(&tasklist_lock); | |
693 | if (!child) | |
694 | goto out; | |
695 | ||
696 | ret = -EPERM; | |
697 | if (pid == 1) /* you may not mess with init */ | |
698 | goto out_tsk; | |
699 | ||
700 | if (request == PTRACE_ATTACH) { | |
701 | ret = ptrace_attach(child); | |
702 | goto out_tsk; | |
703 | } | |
704 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
705 | if (ret == 0) | |
706 | ret = do_ptrace(request, child, addr, data); | |
707 | ||
708 | out_tsk: | |
709 | put_task_struct(child); | |
710 | out: | |
711 | unlock_kernel(); | |
712 | return ret; | |
713 | } | |
714 | ||
715 | asmlinkage void syscall_trace(int why, struct pt_regs *regs) | |
716 | { | |
717 | unsigned long ip; | |
718 | ||
719 | if (!test_thread_flag(TIF_SYSCALL_TRACE)) | |
720 | return; | |
721 | if (!(current->ptrace & PT_PTRACED)) | |
722 | return; | |
723 | ||
724 | /* | |
725 | * Save IP. IP is used to denote syscall entry/exit: | |
726 | * IP = 0 -> entry, = 1 -> exit | |
727 | */ | |
728 | ip = regs->ARM_ip; | |
729 | regs->ARM_ip = why; | |
730 | ||
731 | /* the 0x80 provides a way for the tracing parent to distinguish | |
732 | between a syscall stop and SIGTRAP delivery */ | |
733 | ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) | |
734 | ? 0x80 : 0)); | |
735 | /* | |
736 | * this isn't the same as continuing with a signal, but it will do | |
737 | * for normal use. strace only continues with a signal if the | |
738 | * stopping signal is not SIGTRAP. -brl | |
739 | */ | |
740 | if (current->exit_code) { | |
741 | send_sig(current->exit_code, current, 1); | |
742 | current->exit_code = 0; | |
743 | } | |
744 | regs->ARM_ip = ip; | |
745 | } |