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-rw-r--r--arch/arm/kernel/ptrace.c861
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diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
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1/*
2 * linux/arch/arm/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>
21#include <linux/init.h>
22
23#include <asm/uaccess.h>
24#include <asm/pgtable.h>
25#include <asm/system.h>
26#include <asm/traps.h>
27
28#include "ptrace.h"
29
30#define REG_PC 15
31#define REG_PSR 16
32/*
33 * does not yet catch signals sent when the child dies.
34 * in exit.c or in signal.c.
35 */
36
37#if 0
38/*
39 * Breakpoint SWI instruction: SWI &9F0001
40 */
41#define BREAKINST_ARM 0xef9f0001
42#define BREAKINST_THUMB 0xdf00 /* fill this in later */
43#else
44/*
45 * New breakpoints - use an undefined instruction. The ARM architecture
46 * reference manual guarantees that the following instruction space
47 * will produce an undefined instruction exception on all CPUs:
48 *
49 * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
50 * Thumb: 1101 1110 xxxx xxxx
51 */
52#define BREAKINST_ARM 0xe7f001f0
53#define BREAKINST_THUMB 0xde01
54#endif
55
56/*
57 * Get the address of the live pt_regs for the specified task.
58 * These are saved onto the top kernel stack when the process
59 * is not running.
60 *
61 * Note: if a user thread is execve'd from kernel space, the
62 * kernel stack will not be empty on entry to the kernel, so
63 * ptracing these tasks will fail.
64 */
65static inline struct pt_regs *
66get_user_regs(struct task_struct *task)
67{
68 return (struct pt_regs *)
69 ((unsigned long)task->thread_info + THREAD_SIZE -
70 8 - sizeof(struct pt_regs));
71}
72
73/*
74 * this routine will get a word off of the processes privileged stack.
75 * the offset is how far from the base addr as stored in the THREAD.
76 * this routine assumes that all the privileged stacks are in our
77 * data space.
78 */
79static inline long get_user_reg(struct task_struct *task, int offset)
80{
81 return get_user_regs(task)->uregs[offset];
82}
83
84/*
85 * this routine will put a word on the processes privileged stack.
86 * the offset is how far from the base addr as stored in the THREAD.
87 * this routine assumes that all the privileged stacks are in our
88 * data space.
89 */
90static inline int
91put_user_reg(struct task_struct *task, int offset, long data)
92{
93 struct pt_regs newregs, *regs = get_user_regs(task);
94 int ret = -EINVAL;
95
96 newregs = *regs;
97 newregs.uregs[offset] = data;
98
99 if (valid_user_regs(&newregs)) {
100 regs->uregs[offset] = data;
101 ret = 0;
102 }
103
104 return ret;
105}
106
107static inline int
108read_u32(struct task_struct *task, unsigned long addr, u32 *res)
109{
110 int ret;
111
112 ret = access_process_vm(task, addr, res, sizeof(*res), 0);
113
114 return ret == sizeof(*res) ? 0 : -EIO;
115}
116
117static inline int
118read_instr(struct task_struct *task, unsigned long addr, u32 *res)
119{
120 int ret;
121
122 if (addr & 1) {
123 u16 val;
124 ret = access_process_vm(task, addr & ~1, &val, sizeof(val), 0);
125 ret = ret == sizeof(val) ? 0 : -EIO;
126 *res = val;
127 } else {
128 u32 val;
129 ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0);
130 ret = ret == sizeof(val) ? 0 : -EIO;
131 *res = val;
132 }
133 return ret;
134}
135
136/*
137 * Get value of register `rn' (in the instruction)
138 */
139static unsigned long
140ptrace_getrn(struct task_struct *child, unsigned long insn)
141{
142 unsigned int reg = (insn >> 16) & 15;
143 unsigned long val;
144
145 val = get_user_reg(child, reg);
146 if (reg == 15)
147 val = pc_pointer(val + 8);
148
149 return val;
150}
151
152/*
153 * Get value of operand 2 (in an ALU instruction)
154 */
155static unsigned long
156ptrace_getaluop2(struct task_struct *child, unsigned long insn)
157{
158 unsigned long val;
159 int shift;
160 int type;
161
162 if (insn & 1 << 25) {
163 val = insn & 255;
164 shift = (insn >> 8) & 15;
165 type = 3;
166 } else {
167 val = get_user_reg (child, insn & 15);
168
169 if (insn & (1 << 4))
170 shift = (int)get_user_reg (child, (insn >> 8) & 15);
171 else
172 shift = (insn >> 7) & 31;
173
174 type = (insn >> 5) & 3;
175 }
176
177 switch (type) {
178 case 0: val <<= shift; break;
179 case 1: val >>= shift; break;
180 case 2:
181 val = (((signed long)val) >> shift);
182 break;
183 case 3:
184 val = (val >> shift) | (val << (32 - shift));
185 break;
186 }
187 return val;
188}
189
190/*
191 * Get value of operand 2 (in a LDR instruction)
192 */
193static unsigned long
194ptrace_getldrop2(struct task_struct *child, unsigned long insn)
195{
196 unsigned long val;
197 int shift;
198 int type;
199
200 val = get_user_reg(child, insn & 15);
201 shift = (insn >> 7) & 31;
202 type = (insn >> 5) & 3;
203
204 switch (type) {
205 case 0: val <<= shift; break;
206 case 1: val >>= shift; break;
207 case 2:
208 val = (((signed long)val) >> shift);
209 break;
210 case 3:
211 val = (val >> shift) | (val << (32 - shift));
212 break;
213 }
214 return val;
215}
216
217#define OP_MASK 0x01e00000
218#define OP_AND 0x00000000
219#define OP_EOR 0x00200000
220#define OP_SUB 0x00400000
221#define OP_RSB 0x00600000
222#define OP_ADD 0x00800000
223#define OP_ADC 0x00a00000
224#define OP_SBC 0x00c00000
225#define OP_RSC 0x00e00000
226#define OP_ORR 0x01800000
227#define OP_MOV 0x01a00000
228#define OP_BIC 0x01c00000
229#define OP_MVN 0x01e00000
230
231static unsigned long
232get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn)
233{
234 u32 alt = 0;
235
236 switch (insn & 0x0e000000) {
237 case 0x00000000:
238 case 0x02000000: {
239 /*
240 * data processing
241 */
242 long aluop1, aluop2, ccbit;
243
244 if ((insn & 0xf000) != 0xf000)
245 break;
246
247 aluop1 = ptrace_getrn(child, insn);
248 aluop2 = ptrace_getaluop2(child, insn);
249 ccbit = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;
250
251 switch (insn & OP_MASK) {
252 case OP_AND: alt = aluop1 & aluop2; break;
253 case OP_EOR: alt = aluop1 ^ aluop2; break;
254 case OP_SUB: alt = aluop1 - aluop2; break;
255 case OP_RSB: alt = aluop2 - aluop1; break;
256 case OP_ADD: alt = aluop1 + aluop2; break;
257 case OP_ADC: alt = aluop1 + aluop2 + ccbit; break;
258 case OP_SBC: alt = aluop1 - aluop2 + ccbit; break;
259 case OP_RSC: alt = aluop2 - aluop1 + ccbit; break;
260 case OP_ORR: alt = aluop1 | aluop2; break;
261 case OP_MOV: alt = aluop2; break;
262 case OP_BIC: alt = aluop1 & ~aluop2; break;
263 case OP_MVN: alt = ~aluop2; break;
264 }
265 break;
266 }
267
268 case 0x04000000:
269 case 0x06000000:
270 /*
271 * ldr
272 */
273 if ((insn & 0x0010f000) == 0x0010f000) {
274 unsigned long base;
275
276 base = ptrace_getrn(child, insn);
277 if (insn & 1 << 24) {
278 long aluop2;
279
280 if (insn & 0x02000000)
281 aluop2 = ptrace_getldrop2(child, insn);
282 else
283 aluop2 = insn & 0xfff;
284
285 if (insn & 1 << 23)
286 base += aluop2;
287 else
288 base -= aluop2;
289 }
290 if (read_u32(child, base, &alt) == 0)
291 alt = pc_pointer(alt);
292 }
293 break;
294
295 case 0x08000000:
296 /*
297 * ldm
298 */
299 if ((insn & 0x00108000) == 0x00108000) {
300 unsigned long base;
301 unsigned int nr_regs;
302
303 if (insn & (1 << 23)) {
304 nr_regs = hweight16(insn & 65535) << 2;
305
306 if (!(insn & (1 << 24)))
307 nr_regs -= 4;
308 } else {
309 if (insn & (1 << 24))
310 nr_regs = -4;
311 else
312 nr_regs = 0;
313 }
314
315 base = ptrace_getrn(child, insn);
316
317 if (read_u32(child, base + nr_regs, &alt) == 0)
318 alt = pc_pointer(alt);
319 break;
320 }
321 break;
322
323 case 0x0a000000: {
324 /*
325 * bl or b
326 */
327 signed long displ;
328 /* It's a branch/branch link: instead of trying to
329 * figure out whether the branch will be taken or not,
330 * we'll put a breakpoint at both locations. This is
331 * simpler, more reliable, and probably not a whole lot
332 * slower than the alternative approach of emulating the
333 * branch.
334 */
335 displ = (insn & 0x00ffffff) << 8;
336 displ = (displ >> 6) + 8;
337 if (displ != 0 && displ != 4)
338 alt = pc + displ;
339 }
340 break;
341 }
342
343 return alt;
344}
345
346static int
347swap_insn(struct task_struct *task, unsigned long addr,
348 void *old_insn, void *new_insn, int size)
349{
350 int ret;
351
352 ret = access_process_vm(task, addr, old_insn, size, 0);
353 if (ret == size)
354 ret = access_process_vm(task, addr, new_insn, size, 1);
355 return ret;
356}
357
358static void
359add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr)
360{
361 int nr = dbg->nsaved;
362
363 if (nr < 2) {
364 u32 new_insn = BREAKINST_ARM;
365 int res;
366
367 res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4);
368
369 if (res == 4) {
370 dbg->bp[nr].address = addr;
371 dbg->nsaved += 1;
372 }
373 } else
374 printk(KERN_ERR "ptrace: too many breakpoints\n");
375}
376
377/*
378 * Clear one breakpoint in the user program. We copy what the hardware
379 * does and use bit 0 of the address to indicate whether this is a Thumb
380 * breakpoint or an ARM breakpoint.
381 */
382static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp)
383{
384 unsigned long addr = bp->address;
385 union debug_insn old_insn;
386 int ret;
387
388 if (addr & 1) {
389 ret = swap_insn(task, addr & ~1, &old_insn.thumb,
390 &bp->insn.thumb, 2);
391
392 if (ret != 2 || old_insn.thumb != BREAKINST_THUMB)
393 printk(KERN_ERR "%s:%d: corrupted Thumb breakpoint at "
394 "0x%08lx (0x%04x)\n", task->comm, task->pid,
395 addr, old_insn.thumb);
396 } else {
397 ret = swap_insn(task, addr & ~3, &old_insn.arm,
398 &bp->insn.arm, 4);
399
400 if (ret != 4 || old_insn.arm != BREAKINST_ARM)
401 printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at "
402 "0x%08lx (0x%08x)\n", task->comm, task->pid,
403 addr, old_insn.arm);
404 }
405}
406
407void ptrace_set_bpt(struct task_struct *child)
408{
409 struct pt_regs *regs;
410 unsigned long pc;
411 u32 insn;
412 int res;
413
414 regs = get_user_regs(child);
415 pc = instruction_pointer(regs);
416
417 if (thumb_mode(regs)) {
418 printk(KERN_WARNING "ptrace: can't handle thumb mode\n");
419 return;
420 }
421
422 res = read_instr(child, pc, &insn);
423 if (!res) {
424 struct debug_info *dbg = &child->thread.debug;
425 unsigned long alt;
426
427 dbg->nsaved = 0;
428
429 alt = get_branch_address(child, pc, insn);
430 if (alt)
431 add_breakpoint(child, dbg, alt);
432
433 /*
434 * Note that we ignore the result of setting the above
435 * breakpoint since it may fail. When it does, this is
436 * not so much an error, but a forewarning that we may
437 * be receiving a prefetch abort shortly.
438 *
439 * If we don't set this breakpoint here, then we can
440 * lose control of the thread during single stepping.
441 */
442 if (!alt || predicate(insn) != PREDICATE_ALWAYS)
443 add_breakpoint(child, dbg, pc + 4);
444 }
445}
446
447/*
448 * Ensure no single-step breakpoint is pending. Returns non-zero
449 * value if child was being single-stepped.
450 */
451void ptrace_cancel_bpt(struct task_struct *child)
452{
453 int i, nsaved = child->thread.debug.nsaved;
454
455 child->thread.debug.nsaved = 0;
456
457 if (nsaved > 2) {
458 printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
459 nsaved = 2;
460 }
461
462 for (i = 0; i < nsaved; i++)
463 clear_breakpoint(child, &child->thread.debug.bp[i]);
464}
465
466/*
467 * Called by kernel/ptrace.c when detaching..
468 *
469 * Make sure the single step bit is not set.
470 */
471void ptrace_disable(struct task_struct *child)
472{
473 child->ptrace &= ~PT_SINGLESTEP;
474 ptrace_cancel_bpt(child);
475}
476
477/*
478 * Handle hitting a breakpoint.
479 */
480void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
481{
482 siginfo_t info;
483
484 ptrace_cancel_bpt(tsk);
485
486 info.si_signo = SIGTRAP;
487 info.si_errno = 0;
488 info.si_code = TRAP_BRKPT;
489 info.si_addr = (void __user *)instruction_pointer(regs);
490
491 force_sig_info(SIGTRAP, &info, tsk);
492}
493
494static int break_trap(struct pt_regs *regs, unsigned int instr)
495{
496 ptrace_break(current, regs);
497 return 0;
498}
499
500static struct undef_hook arm_break_hook = {
501 .instr_mask = 0x0fffffff,
502 .instr_val = 0x07f001f0,
503 .cpsr_mask = PSR_T_BIT,
504 .cpsr_val = 0,
505 .fn = break_trap,
506};
507
508static struct undef_hook thumb_break_hook = {
509 .instr_mask = 0xffff,
510 .instr_val = 0xde01,
511 .cpsr_mask = PSR_T_BIT,
512 .cpsr_val = PSR_T_BIT,
513 .fn = break_trap,
514};
515
516static int __init ptrace_break_init(void)
517{
518 register_undef_hook(&arm_break_hook);
519 register_undef_hook(&thumb_break_hook);
520 return 0;
521}
522
523core_initcall(ptrace_break_init);
524
525/*
526 * Read the word at offset "off" into the "struct user". We
527 * actually access the pt_regs stored on the kernel stack.
528 */
529static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
530 unsigned long __user *ret)
531{
532 unsigned long tmp;
533
534 if (off & 3 || off >= sizeof(struct user))
535 return -EIO;
536
537 tmp = 0;
538 if (off < sizeof(struct pt_regs))
539 tmp = get_user_reg(tsk, off >> 2);
540
541 return put_user(tmp, ret);
542}
543
544/*
545 * Write the word at offset "off" into "struct user". We
546 * actually access the pt_regs stored on the kernel stack.
547 */
548static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
549 unsigned long val)
550{
551 if (off & 3 || off >= sizeof(struct user))
552 return -EIO;
553
554 if (off >= sizeof(struct pt_regs))
555 return 0;
556
557 return put_user_reg(tsk, off >> 2, val);
558}
559
560/*
561 * Get all user integer registers.
562 */
563static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
564{
565 struct pt_regs *regs = get_user_regs(tsk);
566
567 return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
568}
569
570/*
571 * Set all user integer registers.
572 */
573static int ptrace_setregs(struct task_struct *tsk, void __user *uregs)
574{
575 struct pt_regs newregs;
576 int ret;
577
578 ret = -EFAULT;
579 if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
580 struct pt_regs *regs = get_user_regs(tsk);
581
582 ret = -EINVAL;
583 if (valid_user_regs(&newregs)) {
584 *regs = newregs;
585 ret = 0;
586 }
587 }
588
589 return ret;
590}
591
592/*
593 * Get the child FPU state.
594 */
595static int ptrace_getfpregs(struct task_struct *tsk, void __user *ufp)
596{
597 return copy_to_user(ufp, &tsk->thread_info->fpstate,
598 sizeof(struct user_fp)) ? -EFAULT : 0;
599}
600
601/*
602 * Set the child FPU state.
603 */
604static int ptrace_setfpregs(struct task_struct *tsk, void __user *ufp)
605{
606 struct thread_info *thread = tsk->thread_info;
607 thread->used_cp[1] = thread->used_cp[2] = 1;
608 return copy_from_user(&thread->fpstate, ufp,
609 sizeof(struct user_fp)) ? -EFAULT : 0;
610}
611
612#ifdef CONFIG_IWMMXT
613
614/*
615 * Get the child iWMMXt state.
616 */
617static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
618{
619 struct thread_info *thread = tsk->thread_info;
620 void *ptr = &thread->fpstate;
621
622 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
623 return -ENODATA;
624 iwmmxt_task_disable(thread); /* force it to ram */
625 /* The iWMMXt state is stored doubleword-aligned. */
626 if (((long) ptr) & 4)
627 ptr += 4;
628 return copy_to_user(ufp, ptr, 0x98) ? -EFAULT : 0;
629}
630
631/*
632 * Set the child iWMMXt state.
633 */
634static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
635{
636 struct thread_info *thread = tsk->thread_info;
637 void *ptr = &thread->fpstate;
638
639 if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
640 return -EACCES;
641 iwmmxt_task_release(thread); /* force a reload */
642 /* The iWMMXt state is stored doubleword-aligned. */
643 if (((long) ptr) & 4)
644 ptr += 4;
645 return copy_from_user(ptr, ufp, 0x98) ? -EFAULT : 0;
646}
647
648#endif
649
650static int do_ptrace(int request, struct task_struct *child, long addr, long data)
651{
652 unsigned long tmp;
653 int ret;
654
655 switch (request) {
656 /*
657 * read word at location "addr" in the child process.
658 */
659 case PTRACE_PEEKTEXT:
660 case PTRACE_PEEKDATA:
661 ret = access_process_vm(child, addr, &tmp,
662 sizeof(unsigned long), 0);
663 if (ret == sizeof(unsigned long))
664 ret = put_user(tmp, (unsigned long __user *) data);
665 else
666 ret = -EIO;
667 break;
668
669 case PTRACE_PEEKUSR:
670 ret = ptrace_read_user(child, addr, (unsigned long __user *)data);
671 break;
672
673 /*
674 * write the word at location addr.
675 */
676 case PTRACE_POKETEXT:
677 case PTRACE_POKEDATA:
678 ret = access_process_vm(child, addr, &data,
679 sizeof(unsigned long), 1);
680 if (ret == sizeof(unsigned long))
681 ret = 0;
682 else
683 ret = -EIO;
684 break;
685
686 case PTRACE_POKEUSR:
687 ret = ptrace_write_user(child, addr, data);
688 break;
689
690 /*
691 * continue/restart and stop at next (return from) syscall
692 */
693 case PTRACE_SYSCALL:
694 case PTRACE_CONT:
695 ret = -EIO;
696 if ((unsigned long) data > _NSIG)
697 break;
698 if (request == PTRACE_SYSCALL)
699 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
700 else
701 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
702 child->exit_code = data;
703 /* make sure single-step breakpoint is gone. */
704 child->ptrace &= ~PT_SINGLESTEP;
705 ptrace_cancel_bpt(child);
706 wake_up_process(child);
707 ret = 0;
708 break;
709
710 /*
711 * make the child exit. Best I can do is send it a sigkill.
712 * perhaps it should be put in the status that it wants to
713 * exit.
714 */
715 case PTRACE_KILL:
716 /* make sure single-step breakpoint is gone. */
717 child->ptrace &= ~PT_SINGLESTEP;
718 ptrace_cancel_bpt(child);
719 if (child->exit_state != EXIT_ZOMBIE) {
720 child->exit_code = SIGKILL;
721 wake_up_process(child);
722 }
723 ret = 0;
724 break;
725
726 /*
727 * execute single instruction.
728 */
729 case PTRACE_SINGLESTEP:
730 ret = -EIO;
731 if ((unsigned long) data > _NSIG)
732 break;
733 child->ptrace |= PT_SINGLESTEP;
734 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
735 child->exit_code = data;
736 /* give it a chance to run. */
737 wake_up_process(child);
738 ret = 0;
739 break;
740
741 case PTRACE_DETACH:
742 ret = ptrace_detach(child, data);
743 break;
744
745 case PTRACE_GETREGS:
746 ret = ptrace_getregs(child, (void __user *)data);
747 break;
748
749 case PTRACE_SETREGS:
750 ret = ptrace_setregs(child, (void __user *)data);
751 break;
752
753 case PTRACE_GETFPREGS:
754 ret = ptrace_getfpregs(child, (void __user *)data);
755 break;
756
757 case PTRACE_SETFPREGS:
758 ret = ptrace_setfpregs(child, (void __user *)data);
759 break;
760
761#ifdef CONFIG_IWMMXT
762 case PTRACE_GETWMMXREGS:
763 ret = ptrace_getwmmxregs(child, (void __user *)data);
764 break;
765
766 case PTRACE_SETWMMXREGS:
767 ret = ptrace_setwmmxregs(child, (void __user *)data);
768 break;
769#endif
770
771 case PTRACE_GET_THREAD_AREA:
772 ret = put_user(child->thread_info->tp_value,
773 (unsigned long __user *) data);
774 break;
775
776 default:
777 ret = ptrace_request(child, request, addr, data);
778 break;
779 }
780
781 return ret;
782}
783
784asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
785{
786 struct task_struct *child;
787 int ret;
788
789 lock_kernel();
790 ret = -EPERM;
791 if (request == PTRACE_TRACEME) {
792 /* are we already being traced? */
793 if (current->ptrace & PT_PTRACED)
794 goto out;
795 ret = security_ptrace(current->parent, current);
796 if (ret)
797 goto out;
798 /* set the ptrace bit in the process flags. */
799 current->ptrace |= PT_PTRACED;
800 ret = 0;
801 goto out;
802 }
803 ret = -ESRCH;
804 read_lock(&tasklist_lock);
805 child = find_task_by_pid(pid);
806 if (child)
807 get_task_struct(child);
808 read_unlock(&tasklist_lock);
809 if (!child)
810 goto out;
811
812 ret = -EPERM;
813 if (pid == 1) /* you may not mess with init */
814 goto out_tsk;
815
816 if (request == PTRACE_ATTACH) {
817 ret = ptrace_attach(child);
818 goto out_tsk;
819 }
820 ret = ptrace_check_attach(child, request == PTRACE_KILL);
821 if (ret == 0)
822 ret = do_ptrace(request, child, addr, data);
823
824out_tsk:
825 put_task_struct(child);
826out:
827 unlock_kernel();
828 return ret;
829}
830
831asmlinkage void syscall_trace(int why, struct pt_regs *regs)
832{
833 unsigned long ip;
834
835 if (!test_thread_flag(TIF_SYSCALL_TRACE))
836 return;
837 if (!(current->ptrace & PT_PTRACED))
838 return;
839
840 /*
841 * Save IP. IP is used to denote syscall entry/exit:
842 * IP = 0 -> entry, = 1 -> exit
843 */
844 ip = regs->ARM_ip;
845 regs->ARM_ip = why;
846
847 /* the 0x80 provides a way for the tracing parent to distinguish
848 between a syscall stop and SIGTRAP delivery */
849 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
850 ? 0x80 : 0));
851 /*
852 * this isn't the same as continuing with a signal, but it will do
853 * for normal use. strace only continues with a signal if the
854 * stopping signal is not SIGTRAP. -brl
855 */
856 if (current->exit_code) {
857 send_sig(current->exit_code, current, 1);
858 current->exit_code = 0;
859 }
860 regs->ARM_ip = ip;
861}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-27 01:02:19 -0500