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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/s390/kernel/ptrace.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/s390/kernel/ptrace.c')
-rw-r--r--arch/s390/kernel/ptrace.c738
1 files changed, 738 insertions, 0 deletions
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
new file mode 100644
index 000000000000..647233c02fc8
--- /dev/null
+++ b/arch/s390/kernel/ptrace.c
@@ -0,0 +1,738 @@
1/*
2 * arch/s390/kernel/ptrace.c
3 *
4 * S390 version
5 * Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6 * Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
7 * Martin Schwidefsky (schwidefsky@de.ibm.com)
8 *
9 * Based on PowerPC version
10 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
11 *
12 * Derived from "arch/m68k/kernel/ptrace.c"
13 * Copyright (C) 1994 by Hamish Macdonald
14 * Taken from linux/kernel/ptrace.c and modified for M680x0.
15 * linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
16 *
17 * Modified by Cort Dougan (cort@cs.nmt.edu)
18 *
19 *
20 * This file is subject to the terms and conditions of the GNU General
21 * Public License. See the file README.legal in the main directory of
22 * this archive for more details.
23 */
24
25#include <linux/kernel.h>
26#include <linux/sched.h>
27#include <linux/mm.h>
28#include <linux/smp.h>
29#include <linux/smp_lock.h>
30#include <linux/errno.h>
31#include <linux/ptrace.h>
32#include <linux/user.h>
33#include <linux/security.h>
34#include <linux/audit.h>
35
36#include <asm/segment.h>
37#include <asm/page.h>
38#include <asm/pgtable.h>
39#include <asm/pgalloc.h>
40#include <asm/system.h>
41#include <asm/uaccess.h>
42
43#ifdef CONFIG_S390_SUPPORT
44#include "compat_ptrace.h"
45#endif
46
47static void
48FixPerRegisters(struct task_struct *task)
49{
50 struct pt_regs *regs;
51 per_struct *per_info;
52
53 regs = __KSTK_PTREGS(task);
54 per_info = (per_struct *) &task->thread.per_info;
55 per_info->control_regs.bits.em_instruction_fetch =
56 per_info->single_step | per_info->instruction_fetch;
57
58 if (per_info->single_step) {
59 per_info->control_regs.bits.starting_addr = 0;
60#ifdef CONFIG_S390_SUPPORT
61 if (test_thread_flag(TIF_31BIT))
62 per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
63 else
64#endif
65 per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
66 } else {
67 per_info->control_regs.bits.starting_addr =
68 per_info->starting_addr;
69 per_info->control_regs.bits.ending_addr =
70 per_info->ending_addr;
71 }
72 /*
73 * if any of the control reg tracing bits are on
74 * we switch on per in the psw
75 */
76 if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
77 regs->psw.mask |= PSW_MASK_PER;
78 else
79 regs->psw.mask &= ~PSW_MASK_PER;
80
81 if (per_info->control_regs.bits.em_storage_alteration)
82 per_info->control_regs.bits.storage_alt_space_ctl = 1;
83 else
84 per_info->control_regs.bits.storage_alt_space_ctl = 0;
85}
86
87void
88set_single_step(struct task_struct *task)
89{
90 task->thread.per_info.single_step = 1;
91 FixPerRegisters(task);
92}
93
94void
95clear_single_step(struct task_struct *task)
96{
97 task->thread.per_info.single_step = 0;
98 FixPerRegisters(task);
99}
100
101/*
102 * Called by kernel/ptrace.c when detaching..
103 *
104 * Make sure single step bits etc are not set.
105 */
106void
107ptrace_disable(struct task_struct *child)
108{
109 /* make sure the single step bit is not set. */
110 clear_single_step(child);
111}
112
113#ifndef CONFIG_ARCH_S390X
114# define __ADDR_MASK 3
115#else
116# define __ADDR_MASK 7
117#endif
118
119/*
120 * Read the word at offset addr from the user area of a process. The
121 * trouble here is that the information is littered over different
122 * locations. The process registers are found on the kernel stack,
123 * the floating point stuff and the trace settings are stored in
124 * the task structure. In addition the different structures in
125 * struct user contain pad bytes that should be read as zeroes.
126 * Lovely...
127 */
128static int
129peek_user(struct task_struct *child, addr_t addr, addr_t data)
130{
131 struct user *dummy = NULL;
132 addr_t offset, tmp;
133
134 /*
135 * Stupid gdb peeks/pokes the access registers in 64 bit with
136 * an alignment of 4. Programmers from hell...
137 */
138 if ((addr & 3) || addr > sizeof(struct user) - __ADDR_MASK)
139 return -EIO;
140
141 if (addr < (addr_t) &dummy->regs.acrs) {
142 /*
143 * psw and gprs are stored on the stack
144 */
145 tmp = *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr);
146 if (addr == (addr_t) &dummy->regs.psw.mask)
147 /* Remove per bit from user psw. */
148 tmp &= ~PSW_MASK_PER;
149
150 } else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
151 /*
152 * access registers are stored in the thread structure
153 */
154 offset = addr - (addr_t) &dummy->regs.acrs;
155 tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
156
157 } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
158 /*
159 * orig_gpr2 is stored on the kernel stack
160 */
161 tmp = (addr_t) __KSTK_PTREGS(child)->orig_gpr2;
162
163 } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
164 /*
165 * floating point regs. are stored in the thread structure
166 */
167 offset = addr - (addr_t) &dummy->regs.fp_regs;
168 tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
169
170 } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
171 /*
172 * per_info is found in the thread structure
173 */
174 offset = addr - (addr_t) &dummy->regs.per_info;
175 tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
176
177 } else
178 tmp = 0;
179
180 return put_user(tmp, (addr_t __user *) data);
181}
182
183/*
184 * Write a word to the user area of a process at location addr. This
185 * operation does have an additional problem compared to peek_user.
186 * Stores to the program status word and on the floating point
187 * control register needs to get checked for validity.
188 */
189static int
190poke_user(struct task_struct *child, addr_t addr, addr_t data)
191{
192 struct user *dummy = NULL;
193 addr_t offset;
194
195 /*
196 * Stupid gdb peeks/pokes the access registers in 64 bit with
197 * an alignment of 4. Programmers from hell indeed...
198 */
199 if ((addr & 3) || addr > sizeof(struct user) - __ADDR_MASK)
200 return -EIO;
201
202 if (addr < (addr_t) &dummy->regs.acrs) {
203 /*
204 * psw and gprs are stored on the stack
205 */
206 if (addr == (addr_t) &dummy->regs.psw.mask &&
207#ifdef CONFIG_S390_SUPPORT
208 data != PSW_MASK_MERGE(PSW_USER32_BITS, data) &&
209#endif
210 data != PSW_MASK_MERGE(PSW_USER_BITS, data))
211 /* Invalid psw mask. */
212 return -EINVAL;
213#ifndef CONFIG_ARCH_S390X
214 if (addr == (addr_t) &dummy->regs.psw.addr)
215 /* I'd like to reject addresses without the
216 high order bit but older gdb's rely on it */
217 data |= PSW_ADDR_AMODE;
218#endif
219 *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr) = data;
220
221 } else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
222 /*
223 * access registers are stored in the thread structure
224 */
225 offset = addr - (addr_t) &dummy->regs.acrs;
226 *(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
227
228 } else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
229 /*
230 * orig_gpr2 is stored on the kernel stack
231 */
232 __KSTK_PTREGS(child)->orig_gpr2 = data;
233
234 } else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
235 /*
236 * floating point regs. are stored in the thread structure
237 */
238 if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
239 (data & ~FPC_VALID_MASK) != 0)
240 return -EINVAL;
241 offset = addr - (addr_t) &dummy->regs.fp_regs;
242 *(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
243
244 } else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
245 /*
246 * per_info is found in the thread structure
247 */
248 offset = addr - (addr_t) &dummy->regs.per_info;
249 *(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
250
251 }
252
253 FixPerRegisters(child);
254 return 0;
255}
256
257static int
258do_ptrace_normal(struct task_struct *child, long request, long addr, long data)
259{
260 unsigned long tmp;
261 ptrace_area parea;
262 int copied, ret;
263
264 switch (request) {
265 case PTRACE_PEEKTEXT:
266 case PTRACE_PEEKDATA:
267 /* Remove high order bit from address (only for 31 bit). */
268 addr &= PSW_ADDR_INSN;
269 /* read word at location addr. */
270 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
271 if (copied != sizeof(tmp))
272 return -EIO;
273 return put_user(tmp, (unsigned long __user *) data);
274
275 case PTRACE_PEEKUSR:
276 /* read the word at location addr in the USER area. */
277 return peek_user(child, addr, data);
278
279 case PTRACE_POKETEXT:
280 case PTRACE_POKEDATA:
281 /* Remove high order bit from address (only for 31 bit). */
282 addr &= PSW_ADDR_INSN;
283 /* write the word at location addr. */
284 copied = access_process_vm(child, addr, &data, sizeof(data),1);
285 if (copied != sizeof(data))
286 return -EIO;
287 return 0;
288
289 case PTRACE_POKEUSR:
290 /* write the word at location addr in the USER area */
291 return poke_user(child, addr, data);
292
293 case PTRACE_PEEKUSR_AREA:
294 case PTRACE_POKEUSR_AREA:
295 if (copy_from_user(&parea, (void __user *) addr,
296 sizeof(parea)))
297 return -EFAULT;
298 addr = parea.kernel_addr;
299 data = parea.process_addr;
300 copied = 0;
301 while (copied < parea.len) {
302 if (request == PTRACE_PEEKUSR_AREA)
303 ret = peek_user(child, addr, data);
304 else {
305 addr_t tmp;
306 if (get_user (tmp, (addr_t __user *) data))
307 return -EFAULT;
308 ret = poke_user(child, addr, tmp);
309 }
310 if (ret)
311 return ret;
312 addr += sizeof(unsigned long);
313 data += sizeof(unsigned long);
314 copied += sizeof(unsigned long);
315 }
316 return 0;
317 }
318 return ptrace_request(child, request, addr, data);
319}
320
321#ifdef CONFIG_S390_SUPPORT
322/*
323 * Now the fun part starts... a 31 bit program running in the
324 * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
325 * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
326 * to handle, the difference to the 64 bit versions of the requests
327 * is that the access is done in multiples of 4 byte instead of
328 * 8 bytes (sizeof(unsigned long) on 31/64 bit).
329 * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
330 * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
331 * is a 31 bit program too, the content of struct user can be
332 * emulated. A 31 bit program peeking into the struct user of
333 * a 64 bit program is a no-no.
334 */
335
336/*
337 * Same as peek_user but for a 31 bit program.
338 */
339static int
340peek_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
341{
342 struct user32 *dummy32 = NULL;
343 per_struct32 *dummy_per32 = NULL;
344 addr_t offset;
345 __u32 tmp;
346
347 if (!test_thread_flag(TIF_31BIT) ||
348 (addr & 3) || addr > sizeof(struct user) - 3)
349 return -EIO;
350
351 if (addr < (addr_t) &dummy32->regs.acrs) {
352 /*
353 * psw and gprs are stored on the stack
354 */
355 if (addr == (addr_t) &dummy32->regs.psw.mask) {
356 /* Fake a 31 bit psw mask. */
357 tmp = (__u32)(__KSTK_PTREGS(child)->psw.mask >> 32);
358 tmp = PSW32_MASK_MERGE(PSW32_USER_BITS, tmp);
359 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
360 /* Fake a 31 bit psw address. */
361 tmp = (__u32) __KSTK_PTREGS(child)->psw.addr |
362 PSW32_ADDR_AMODE31;
363 } else {
364 /* gpr 0-15 */
365 tmp = *(__u32 *)((addr_t) &__KSTK_PTREGS(child)->psw +
366 addr*2 + 4);
367 }
368 } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
369 /*
370 * access registers are stored in the thread structure
371 */
372 offset = addr - (addr_t) &dummy32->regs.acrs;
373 tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
374
375 } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
376 /*
377 * orig_gpr2 is stored on the kernel stack
378 */
379 tmp = *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4);
380
381 } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
382 /*
383 * floating point regs. are stored in the thread structure
384 */
385 offset = addr - (addr_t) &dummy32->regs.fp_regs;
386 tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
387
388 } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
389 /*
390 * per_info is found in the thread structure
391 */
392 offset = addr - (addr_t) &dummy32->regs.per_info;
393 /* This is magic. See per_struct and per_struct32. */
394 if ((offset >= (addr_t) &dummy_per32->control_regs &&
395 offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
396 (offset >= (addr_t) &dummy_per32->starting_addr &&
397 offset <= (addr_t) &dummy_per32->ending_addr) ||
398 offset == (addr_t) &dummy_per32->lowcore.words.address)
399 offset = offset*2 + 4;
400 else
401 offset = offset*2;
402 tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
403
404 } else
405 tmp = 0;
406
407 return put_user(tmp, (__u32 __user *) data);
408}
409
410/*
411 * Same as poke_user but for a 31 bit program.
412 */
413static int
414poke_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
415{
416 struct user32 *dummy32 = NULL;
417 per_struct32 *dummy_per32 = NULL;
418 addr_t offset;
419 __u32 tmp;
420
421 if (!test_thread_flag(TIF_31BIT) ||
422 (addr & 3) || addr > sizeof(struct user32) - 3)
423 return -EIO;
424
425 tmp = (__u32) data;
426
427 if (addr < (addr_t) &dummy32->regs.acrs) {
428 /*
429 * psw, gprs, acrs and orig_gpr2 are stored on the stack
430 */
431 if (addr == (addr_t) &dummy32->regs.psw.mask) {
432 /* Build a 64 bit psw mask from 31 bit mask. */
433 if (tmp != PSW32_MASK_MERGE(PSW32_USER_BITS, tmp))
434 /* Invalid psw mask. */
435 return -EINVAL;
436 __KSTK_PTREGS(child)->psw.mask =
437 PSW_MASK_MERGE(PSW_USER32_BITS, (__u64) tmp << 32);
438 } else if (addr == (addr_t) &dummy32->regs.psw.addr) {
439 /* Build a 64 bit psw address from 31 bit address. */
440 __KSTK_PTREGS(child)->psw.addr =
441 (__u64) tmp & PSW32_ADDR_INSN;
442 } else {
443 /* gpr 0-15 */
444 *(__u32*)((addr_t) &__KSTK_PTREGS(child)->psw
445 + addr*2 + 4) = tmp;
446 }
447 } else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
448 /*
449 * access registers are stored in the thread structure
450 */
451 offset = addr - (addr_t) &dummy32->regs.acrs;
452 *(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
453
454 } else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
455 /*
456 * orig_gpr2 is stored on the kernel stack
457 */
458 *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4) = tmp;
459
460 } else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
461 /*
462 * floating point regs. are stored in the thread structure
463 */
464 if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
465 (tmp & ~FPC_VALID_MASK) != 0)
466 /* Invalid floating point control. */
467 return -EINVAL;
468 offset = addr - (addr_t) &dummy32->regs.fp_regs;
469 *(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
470
471 } else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
472 /*
473 * per_info is found in the thread structure.
474 */
475 offset = addr - (addr_t) &dummy32->regs.per_info;
476 /*
477 * This is magic. See per_struct and per_struct32.
478 * By incident the offsets in per_struct are exactly
479 * twice the offsets in per_struct32 for all fields.
480 * The 8 byte fields need special handling though,
481 * because the second half (bytes 4-7) is needed and
482 * not the first half.
483 */
484 if ((offset >= (addr_t) &dummy_per32->control_regs &&
485 offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
486 (offset >= (addr_t) &dummy_per32->starting_addr &&
487 offset <= (addr_t) &dummy_per32->ending_addr) ||
488 offset == (addr_t) &dummy_per32->lowcore.words.address)
489 offset = offset*2 + 4;
490 else
491 offset = offset*2;
492 *(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
493
494 }
495
496 FixPerRegisters(child);
497 return 0;
498}
499
500static int
501do_ptrace_emu31(struct task_struct *child, long request, long addr, long data)
502{
503 unsigned int tmp; /* 4 bytes !! */
504 ptrace_area_emu31 parea;
505 int copied, ret;
506
507 switch (request) {
508 case PTRACE_PEEKTEXT:
509 case PTRACE_PEEKDATA:
510 /* read word at location addr. */
511 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
512 if (copied != sizeof(tmp))
513 return -EIO;
514 return put_user(tmp, (unsigned int __user *) data);
515
516 case PTRACE_PEEKUSR:
517 /* read the word at location addr in the USER area. */
518 return peek_user_emu31(child, addr, data);
519
520 case PTRACE_POKETEXT:
521 case PTRACE_POKEDATA:
522 /* write the word at location addr. */
523 tmp = data;
524 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
525 if (copied != sizeof(tmp))
526 return -EIO;
527 return 0;
528
529 case PTRACE_POKEUSR:
530 /* write the word at location addr in the USER area */
531 return poke_user_emu31(child, addr, data);
532
533 case PTRACE_PEEKUSR_AREA:
534 case PTRACE_POKEUSR_AREA:
535 if (copy_from_user(&parea, (void __user *) addr,
536 sizeof(parea)))
537 return -EFAULT;
538 addr = parea.kernel_addr;
539 data = parea.process_addr;
540 copied = 0;
541 while (copied < parea.len) {
542 if (request == PTRACE_PEEKUSR_AREA)
543 ret = peek_user_emu31(child, addr, data);
544 else {
545 __u32 tmp;
546 if (get_user (tmp, (__u32 __user *) data))
547 return -EFAULT;
548 ret = poke_user_emu31(child, addr, tmp);
549 }
550 if (ret)
551 return ret;
552 addr += sizeof(unsigned int);
553 data += sizeof(unsigned int);
554 copied += sizeof(unsigned int);
555 }
556 return 0;
557 case PTRACE_GETEVENTMSG:
558 return put_user((__u32) child->ptrace_message,
559 (unsigned int __user *) data);
560 case PTRACE_GETSIGINFO:
561 if (child->last_siginfo == NULL)
562 return -EINVAL;
563 return copy_siginfo_to_user32((compat_siginfo_t __user *) data,
564 child->last_siginfo);
565 case PTRACE_SETSIGINFO:
566 if (child->last_siginfo == NULL)
567 return -EINVAL;
568 return copy_siginfo_from_user32(child->last_siginfo,
569 (compat_siginfo_t __user *) data);
570 }
571 return ptrace_request(child, request, addr, data);
572}
573#endif
574
575#define PT32_IEEE_IP 0x13c
576
577static int
578do_ptrace(struct task_struct *child, long request, long addr, long data)
579{
580 int ret;
581
582 if (request == PTRACE_ATTACH)
583 return ptrace_attach(child);
584
585 /*
586 * Special cases to get/store the ieee instructions pointer.
587 */
588 if (child == current) {
589 if (request == PTRACE_PEEKUSR && addr == PT_IEEE_IP)
590 return peek_user(child, addr, data);
591 if (request == PTRACE_POKEUSR && addr == PT_IEEE_IP)
592 return poke_user(child, addr, data);
593#ifdef CONFIG_S390_SUPPORT
594 if (request == PTRACE_PEEKUSR &&
595 addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
596 return peek_user_emu31(child, addr, data);
597 if (request == PTRACE_POKEUSR &&
598 addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
599 return poke_user_emu31(child, addr, data);
600#endif
601 }
602
603 ret = ptrace_check_attach(child, request == PTRACE_KILL);
604 if (ret < 0)
605 return ret;
606
607 switch (request) {
608 case PTRACE_SYSCALL:
609 /* continue and stop at next (return from) syscall */
610 case PTRACE_CONT:
611 /* restart after signal. */
612 if ((unsigned long) data >= _NSIG)
613 return -EIO;
614 if (request == PTRACE_SYSCALL)
615 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
616 else
617 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
618 child->exit_code = data;
619 /* make sure the single step bit is not set. */
620 clear_single_step(child);
621 wake_up_process(child);
622 return 0;
623
624 case PTRACE_KILL:
625 /*
626 * make the child exit. Best I can do is send it a sigkill.
627 * perhaps it should be put in the status that it wants to
628 * exit.
629 */
630 if (child->exit_state == EXIT_ZOMBIE) /* already dead */
631 return 0;
632 child->exit_code = SIGKILL;
633 /* make sure the single step bit is not set. */
634 clear_single_step(child);
635 wake_up_process(child);
636 return 0;
637
638 case PTRACE_SINGLESTEP:
639 /* set the trap flag. */
640 if ((unsigned long) data >= _NSIG)
641 return -EIO;
642 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
643 child->exit_code = data;
644 if (data)
645 set_tsk_thread_flag(child, TIF_SINGLE_STEP);
646 else
647 set_single_step(child);
648 /* give it a chance to run. */
649 wake_up_process(child);
650 return 0;
651
652 case PTRACE_DETACH:
653 /* detach a process that was attached. */
654 return ptrace_detach(child, data);
655
656
657 /* Do requests that differ for 31/64 bit */
658 default:
659#ifdef CONFIG_S390_SUPPORT
660 if (test_thread_flag(TIF_31BIT))
661 return do_ptrace_emu31(child, request, addr, data);
662#endif
663 return do_ptrace_normal(child, request, addr, data);
664 }
665 /* Not reached. */
666 return -EIO;
667}
668
669asmlinkage long
670sys_ptrace(long request, long pid, long addr, long data)
671{
672 struct task_struct *child;
673 int ret;
674
675 lock_kernel();
676
677 if (request == PTRACE_TRACEME) {
678 /* are we already being traced? */
679 ret = -EPERM;
680 if (current->ptrace & PT_PTRACED)
681 goto out;
682 ret = security_ptrace(current->parent, current);
683 if (ret)
684 goto out;
685 /* set the ptrace bit in the process flags. */
686 current->ptrace |= PT_PTRACED;
687 goto out;
688 }
689
690 ret = -EPERM;
691 if (pid == 1) /* you may not mess with init */
692 goto out;
693
694 ret = -ESRCH;
695 read_lock(&tasklist_lock);
696 child = find_task_by_pid(pid);
697 if (child)
698 get_task_struct(child);
699 read_unlock(&tasklist_lock);
700 if (!child)
701 goto out;
702
703 ret = do_ptrace(child, request, addr, data);
704
705 put_task_struct(child);
706out:
707 unlock_kernel();
708 return ret;
709}
710
711asmlinkage void
712syscall_trace(struct pt_regs *regs, int entryexit)
713{
714 if (unlikely(current->audit_context)) {
715 if (!entryexit)
716 audit_syscall_entry(current, regs->gprs[2],
717 regs->orig_gpr2, regs->gprs[3],
718 regs->gprs[4], regs->gprs[5]);
719 else
720 audit_syscall_exit(current, regs->gprs[2]);
721 }
722 if (!test_thread_flag(TIF_SYSCALL_TRACE))
723 return;
724 if (!(current->ptrace & PT_PTRACED))
725 return;
726 ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
727 ? 0x80 : 0));
728
729 /*
730 * this isn't the same as continuing with a signal, but it will do
731 * for normal use. strace only continues with a signal if the
732 * stopping signal is not SIGTRAP. -brl
733 */
734 if (current->exit_code) {
735 send_sig(current->exit_code, current, 1);
736 current->exit_code = 0;
737 }
738}