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[deliverable/linux.git] / arch / x86 / kernel / ptrace.c
1 /* By Ross Biro 1/23/92 */
2 /*
3 * Pentium III FXSR, SSE support
4 * Gareth Hughes <gareth@valinux.com>, May 2000
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/sched.h>
9 #include <linux/mm.h>
10 #include <linux/smp.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/ptrace.h>
14 #include <linux/regset.h>
15 #include <linux/tracehook.h>
16 #include <linux/user.h>
17 #include <linux/elf.h>
18 #include <linux/security.h>
19 #include <linux/audit.h>
20 #include <linux/seccomp.h>
21 #include <linux/signal.h>
22 #include <linux/perf_event.h>
23 #include <linux/hw_breakpoint.h>
24 #include <linux/rcupdate.h>
25 #include <linux/export.h>
26 #include <linux/context_tracking.h>
27
28 #include <asm/uaccess.h>
29 #include <asm/pgtable.h>
30 #include <asm/processor.h>
31 #include <asm/fpu/internal.h>
32 #include <asm/debugreg.h>
33 #include <asm/ldt.h>
34 #include <asm/desc.h>
35 #include <asm/prctl.h>
36 #include <asm/proto.h>
37 #include <asm/hw_breakpoint.h>
38 #include <asm/traps.h>
39
40 #include "tls.h"
41
42 #define CREATE_TRACE_POINTS
43 #include <trace/events/syscalls.h>
44
45 enum x86_regset {
46 REGSET_GENERAL,
47 REGSET_FP,
48 REGSET_XFP,
49 REGSET_IOPERM64 = REGSET_XFP,
50 REGSET_XSTATE,
51 REGSET_TLS,
52 REGSET_IOPERM32,
53 };
54
55 struct pt_regs_offset {
56 const char *name;
57 int offset;
58 };
59
60 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
61 #define REG_OFFSET_END {.name = NULL, .offset = 0}
62
63 static const struct pt_regs_offset regoffset_table[] = {
64 #ifdef CONFIG_X86_64
65 REG_OFFSET_NAME(r15),
66 REG_OFFSET_NAME(r14),
67 REG_OFFSET_NAME(r13),
68 REG_OFFSET_NAME(r12),
69 REG_OFFSET_NAME(r11),
70 REG_OFFSET_NAME(r10),
71 REG_OFFSET_NAME(r9),
72 REG_OFFSET_NAME(r8),
73 #endif
74 REG_OFFSET_NAME(bx),
75 REG_OFFSET_NAME(cx),
76 REG_OFFSET_NAME(dx),
77 REG_OFFSET_NAME(si),
78 REG_OFFSET_NAME(di),
79 REG_OFFSET_NAME(bp),
80 REG_OFFSET_NAME(ax),
81 #ifdef CONFIG_X86_32
82 REG_OFFSET_NAME(ds),
83 REG_OFFSET_NAME(es),
84 REG_OFFSET_NAME(fs),
85 REG_OFFSET_NAME(gs),
86 #endif
87 REG_OFFSET_NAME(orig_ax),
88 REG_OFFSET_NAME(ip),
89 REG_OFFSET_NAME(cs),
90 REG_OFFSET_NAME(flags),
91 REG_OFFSET_NAME(sp),
92 REG_OFFSET_NAME(ss),
93 REG_OFFSET_END,
94 };
95
96 /**
97 * regs_query_register_offset() - query register offset from its name
98 * @name: the name of a register
99 *
100 * regs_query_register_offset() returns the offset of a register in struct
101 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
102 */
103 int regs_query_register_offset(const char *name)
104 {
105 const struct pt_regs_offset *roff;
106 for (roff = regoffset_table; roff->name != NULL; roff++)
107 if (!strcmp(roff->name, name))
108 return roff->offset;
109 return -EINVAL;
110 }
111
112 /**
113 * regs_query_register_name() - query register name from its offset
114 * @offset: the offset of a register in struct pt_regs.
115 *
116 * regs_query_register_name() returns the name of a register from its
117 * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
118 */
119 const char *regs_query_register_name(unsigned int offset)
120 {
121 const struct pt_regs_offset *roff;
122 for (roff = regoffset_table; roff->name != NULL; roff++)
123 if (roff->offset == offset)
124 return roff->name;
125 return NULL;
126 }
127
128 static const int arg_offs_table[] = {
129 #ifdef CONFIG_X86_32
130 [0] = offsetof(struct pt_regs, ax),
131 [1] = offsetof(struct pt_regs, dx),
132 [2] = offsetof(struct pt_regs, cx)
133 #else /* CONFIG_X86_64 */
134 [0] = offsetof(struct pt_regs, di),
135 [1] = offsetof(struct pt_regs, si),
136 [2] = offsetof(struct pt_regs, dx),
137 [3] = offsetof(struct pt_regs, cx),
138 [4] = offsetof(struct pt_regs, r8),
139 [5] = offsetof(struct pt_regs, r9)
140 #endif
141 };
142
143 /*
144 * does not yet catch signals sent when the child dies.
145 * in exit.c or in signal.c.
146 */
147
148 /*
149 * Determines which flags the user has access to [1 = access, 0 = no access].
150 */
151 #define FLAG_MASK_32 ((unsigned long) \
152 (X86_EFLAGS_CF | X86_EFLAGS_PF | \
153 X86_EFLAGS_AF | X86_EFLAGS_ZF | \
154 X86_EFLAGS_SF | X86_EFLAGS_TF | \
155 X86_EFLAGS_DF | X86_EFLAGS_OF | \
156 X86_EFLAGS_RF | X86_EFLAGS_AC))
157
158 /*
159 * Determines whether a value may be installed in a segment register.
160 */
161 static inline bool invalid_selector(u16 value)
162 {
163 return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
164 }
165
166 #ifdef CONFIG_X86_32
167
168 #define FLAG_MASK FLAG_MASK_32
169
170 /*
171 * X86_32 CPUs don't save ss and esp if the CPU is already in kernel mode
172 * when it traps. The previous stack will be directly underneath the saved
173 * registers, and 'sp/ss' won't even have been saved. Thus the '&regs->sp'.
174 *
175 * Now, if the stack is empty, '&regs->sp' is out of range. In this
176 * case we try to take the previous stack. To always return a non-null
177 * stack pointer we fall back to regs as stack if no previous stack
178 * exists.
179 *
180 * This is valid only for kernel mode traps.
181 */
182 unsigned long kernel_stack_pointer(struct pt_regs *regs)
183 {
184 unsigned long context = (unsigned long)regs & ~(THREAD_SIZE - 1);
185 unsigned long sp = (unsigned long)&regs->sp;
186 u32 *prev_esp;
187
188 if (context == (sp & ~(THREAD_SIZE - 1)))
189 return sp;
190
191 prev_esp = (u32 *)(context);
192 if (prev_esp)
193 return (unsigned long)prev_esp;
194
195 return (unsigned long)regs;
196 }
197 EXPORT_SYMBOL_GPL(kernel_stack_pointer);
198
199 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
200 {
201 BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
202 return &regs->bx + (regno >> 2);
203 }
204
205 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
206 {
207 /*
208 * Returning the value truncates it to 16 bits.
209 */
210 unsigned int retval;
211 if (offset != offsetof(struct user_regs_struct, gs))
212 retval = *pt_regs_access(task_pt_regs(task), offset);
213 else {
214 if (task == current)
215 retval = get_user_gs(task_pt_regs(task));
216 else
217 retval = task_user_gs(task);
218 }
219 return retval;
220 }
221
222 static int set_segment_reg(struct task_struct *task,
223 unsigned long offset, u16 value)
224 {
225 /*
226 * The value argument was already truncated to 16 bits.
227 */
228 if (invalid_selector(value))
229 return -EIO;
230
231 /*
232 * For %cs and %ss we cannot permit a null selector.
233 * We can permit a bogus selector as long as it has USER_RPL.
234 * Null selectors are fine for other segment registers, but
235 * we will never get back to user mode with invalid %cs or %ss
236 * and will take the trap in iret instead. Much code relies
237 * on user_mode() to distinguish a user trap frame (which can
238 * safely use invalid selectors) from a kernel trap frame.
239 */
240 switch (offset) {
241 case offsetof(struct user_regs_struct, cs):
242 case offsetof(struct user_regs_struct, ss):
243 if (unlikely(value == 0))
244 return -EIO;
245
246 default:
247 *pt_regs_access(task_pt_regs(task), offset) = value;
248 break;
249
250 case offsetof(struct user_regs_struct, gs):
251 if (task == current)
252 set_user_gs(task_pt_regs(task), value);
253 else
254 task_user_gs(task) = value;
255 }
256
257 return 0;
258 }
259
260 #else /* CONFIG_X86_64 */
261
262 #define FLAG_MASK (FLAG_MASK_32 | X86_EFLAGS_NT)
263
264 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
265 {
266 BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
267 return &regs->r15 + (offset / sizeof(regs->r15));
268 }
269
270 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
271 {
272 /*
273 * Returning the value truncates it to 16 bits.
274 */
275 unsigned int seg;
276
277 switch (offset) {
278 case offsetof(struct user_regs_struct, fs):
279 if (task == current) {
280 /* Older gas can't assemble movq %?s,%r?? */
281 asm("movl %%fs,%0" : "=r" (seg));
282 return seg;
283 }
284 return task->thread.fsindex;
285 case offsetof(struct user_regs_struct, gs):
286 if (task == current) {
287 asm("movl %%gs,%0" : "=r" (seg));
288 return seg;
289 }
290 return task->thread.gsindex;
291 case offsetof(struct user_regs_struct, ds):
292 if (task == current) {
293 asm("movl %%ds,%0" : "=r" (seg));
294 return seg;
295 }
296 return task->thread.ds;
297 case offsetof(struct user_regs_struct, es):
298 if (task == current) {
299 asm("movl %%es,%0" : "=r" (seg));
300 return seg;
301 }
302 return task->thread.es;
303
304 case offsetof(struct user_regs_struct, cs):
305 case offsetof(struct user_regs_struct, ss):
306 break;
307 }
308 return *pt_regs_access(task_pt_regs(task), offset);
309 }
310
311 static int set_segment_reg(struct task_struct *task,
312 unsigned long offset, u16 value)
313 {
314 /*
315 * The value argument was already truncated to 16 bits.
316 */
317 if (invalid_selector(value))
318 return -EIO;
319
320 switch (offset) {
321 case offsetof(struct user_regs_struct,fs):
322 /*
323 * If this is setting fs as for normal 64-bit use but
324 * setting fs_base has implicitly changed it, leave it.
325 */
326 if ((value == FS_TLS_SEL && task->thread.fsindex == 0 &&
327 task->thread.fs != 0) ||
328 (value == 0 && task->thread.fsindex == FS_TLS_SEL &&
329 task->thread.fs == 0))
330 break;
331 task->thread.fsindex = value;
332 if (task == current)
333 loadsegment(fs, task->thread.fsindex);
334 break;
335 case offsetof(struct user_regs_struct,gs):
336 /*
337 * If this is setting gs as for normal 64-bit use but
338 * setting gs_base has implicitly changed it, leave it.
339 */
340 if ((value == GS_TLS_SEL && task->thread.gsindex == 0 &&
341 task->thread.gs != 0) ||
342 (value == 0 && task->thread.gsindex == GS_TLS_SEL &&
343 task->thread.gs == 0))
344 break;
345 task->thread.gsindex = value;
346 if (task == current)
347 load_gs_index(task->thread.gsindex);
348 break;
349 case offsetof(struct user_regs_struct,ds):
350 task->thread.ds = value;
351 if (task == current)
352 loadsegment(ds, task->thread.ds);
353 break;
354 case offsetof(struct user_regs_struct,es):
355 task->thread.es = value;
356 if (task == current)
357 loadsegment(es, task->thread.es);
358 break;
359
360 /*
361 * Can't actually change these in 64-bit mode.
362 */
363 case offsetof(struct user_regs_struct,cs):
364 if (unlikely(value == 0))
365 return -EIO;
366 task_pt_regs(task)->cs = value;
367 break;
368 case offsetof(struct user_regs_struct,ss):
369 if (unlikely(value == 0))
370 return -EIO;
371 task_pt_regs(task)->ss = value;
372 break;
373 }
374
375 return 0;
376 }
377
378 #endif /* CONFIG_X86_32 */
379
380 static unsigned long get_flags(struct task_struct *task)
381 {
382 unsigned long retval = task_pt_regs(task)->flags;
383
384 /*
385 * If the debugger set TF, hide it from the readout.
386 */
387 if (test_tsk_thread_flag(task, TIF_FORCED_TF))
388 retval &= ~X86_EFLAGS_TF;
389
390 return retval;
391 }
392
393 static int set_flags(struct task_struct *task, unsigned long value)
394 {
395 struct pt_regs *regs = task_pt_regs(task);
396
397 /*
398 * If the user value contains TF, mark that
399 * it was not "us" (the debugger) that set it.
400 * If not, make sure it stays set if we had.
401 */
402 if (value & X86_EFLAGS_TF)
403 clear_tsk_thread_flag(task, TIF_FORCED_TF);
404 else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
405 value |= X86_EFLAGS_TF;
406
407 regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
408
409 return 0;
410 }
411
412 static int putreg(struct task_struct *child,
413 unsigned long offset, unsigned long value)
414 {
415 switch (offset) {
416 case offsetof(struct user_regs_struct, cs):
417 case offsetof(struct user_regs_struct, ds):
418 case offsetof(struct user_regs_struct, es):
419 case offsetof(struct user_regs_struct, fs):
420 case offsetof(struct user_regs_struct, gs):
421 case offsetof(struct user_regs_struct, ss):
422 return set_segment_reg(child, offset, value);
423
424 case offsetof(struct user_regs_struct, flags):
425 return set_flags(child, value);
426
427 #ifdef CONFIG_X86_64
428 case offsetof(struct user_regs_struct,fs_base):
429 if (value >= TASK_SIZE_OF(child))
430 return -EIO;
431 /*
432 * When changing the segment base, use do_arch_prctl
433 * to set either thread.fs or thread.fsindex and the
434 * corresponding GDT slot.
435 */
436 if (child->thread.fs != value)
437 return do_arch_prctl(child, ARCH_SET_FS, value);
438 return 0;
439 case offsetof(struct user_regs_struct,gs_base):
440 /*
441 * Exactly the same here as the %fs handling above.
442 */
443 if (value >= TASK_SIZE_OF(child))
444 return -EIO;
445 if (child->thread.gs != value)
446 return do_arch_prctl(child, ARCH_SET_GS, value);
447 return 0;
448 #endif
449 }
450
451 *pt_regs_access(task_pt_regs(child), offset) = value;
452 return 0;
453 }
454
455 static unsigned long getreg(struct task_struct *task, unsigned long offset)
456 {
457 switch (offset) {
458 case offsetof(struct user_regs_struct, cs):
459 case offsetof(struct user_regs_struct, ds):
460 case offsetof(struct user_regs_struct, es):
461 case offsetof(struct user_regs_struct, fs):
462 case offsetof(struct user_regs_struct, gs):
463 case offsetof(struct user_regs_struct, ss):
464 return get_segment_reg(task, offset);
465
466 case offsetof(struct user_regs_struct, flags):
467 return get_flags(task);
468
469 #ifdef CONFIG_X86_64
470 case offsetof(struct user_regs_struct, fs_base): {
471 /*
472 * do_arch_prctl may have used a GDT slot instead of
473 * the MSR. To userland, it appears the same either
474 * way, except the %fs segment selector might not be 0.
475 */
476 unsigned int seg = task->thread.fsindex;
477 if (task->thread.fs != 0)
478 return task->thread.fs;
479 if (task == current)
480 asm("movl %%fs,%0" : "=r" (seg));
481 if (seg != FS_TLS_SEL)
482 return 0;
483 return get_desc_base(&task->thread.tls_array[FS_TLS]);
484 }
485 case offsetof(struct user_regs_struct, gs_base): {
486 /*
487 * Exactly the same here as the %fs handling above.
488 */
489 unsigned int seg = task->thread.gsindex;
490 if (task->thread.gs != 0)
491 return task->thread.gs;
492 if (task == current)
493 asm("movl %%gs,%0" : "=r" (seg));
494 if (seg != GS_TLS_SEL)
495 return 0;
496 return get_desc_base(&task->thread.tls_array[GS_TLS]);
497 }
498 #endif
499 }
500
501 return *pt_regs_access(task_pt_regs(task), offset);
502 }
503
504 static int genregs_get(struct task_struct *target,
505 const struct user_regset *regset,
506 unsigned int pos, unsigned int count,
507 void *kbuf, void __user *ubuf)
508 {
509 if (kbuf) {
510 unsigned long *k = kbuf;
511 while (count >= sizeof(*k)) {
512 *k++ = getreg(target, pos);
513 count -= sizeof(*k);
514 pos += sizeof(*k);
515 }
516 } else {
517 unsigned long __user *u = ubuf;
518 while (count >= sizeof(*u)) {
519 if (__put_user(getreg(target, pos), u++))
520 return -EFAULT;
521 count -= sizeof(*u);
522 pos += sizeof(*u);
523 }
524 }
525
526 return 0;
527 }
528
529 static int genregs_set(struct task_struct *target,
530 const struct user_regset *regset,
531 unsigned int pos, unsigned int count,
532 const void *kbuf, const void __user *ubuf)
533 {
534 int ret = 0;
535 if (kbuf) {
536 const unsigned long *k = kbuf;
537 while (count >= sizeof(*k) && !ret) {
538 ret = putreg(target, pos, *k++);
539 count -= sizeof(*k);
540 pos += sizeof(*k);
541 }
542 } else {
543 const unsigned long __user *u = ubuf;
544 while (count >= sizeof(*u) && !ret) {
545 unsigned long word;
546 ret = __get_user(word, u++);
547 if (ret)
548 break;
549 ret = putreg(target, pos, word);
550 count -= sizeof(*u);
551 pos += sizeof(*u);
552 }
553 }
554 return ret;
555 }
556
557 static void ptrace_triggered(struct perf_event *bp,
558 struct perf_sample_data *data,
559 struct pt_regs *regs)
560 {
561 int i;
562 struct thread_struct *thread = &(current->thread);
563
564 /*
565 * Store in the virtual DR6 register the fact that the breakpoint
566 * was hit so the thread's debugger will see it.
567 */
568 for (i = 0; i < HBP_NUM; i++) {
569 if (thread->ptrace_bps[i] == bp)
570 break;
571 }
572
573 thread->debugreg6 |= (DR_TRAP0 << i);
574 }
575
576 /*
577 * Walk through every ptrace breakpoints for this thread and
578 * build the dr7 value on top of their attributes.
579 *
580 */
581 static unsigned long ptrace_get_dr7(struct perf_event *bp[])
582 {
583 int i;
584 int dr7 = 0;
585 struct arch_hw_breakpoint *info;
586
587 for (i = 0; i < HBP_NUM; i++) {
588 if (bp[i] && !bp[i]->attr.disabled) {
589 info = counter_arch_bp(bp[i]);
590 dr7 |= encode_dr7(i, info->len, info->type);
591 }
592 }
593
594 return dr7;
595 }
596
597 static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
598 int len, int type, bool disabled)
599 {
600 int err, bp_len, bp_type;
601
602 err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);
603 if (!err) {
604 attr->bp_len = bp_len;
605 attr->bp_type = bp_type;
606 attr->disabled = disabled;
607 }
608
609 return err;
610 }
611
612 static struct perf_event *
613 ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,
614 unsigned long addr, bool disabled)
615 {
616 struct perf_event_attr attr;
617 int err;
618
619 ptrace_breakpoint_init(&attr);
620 attr.bp_addr = addr;
621
622 err = ptrace_fill_bp_fields(&attr, len, type, disabled);
623 if (err)
624 return ERR_PTR(err);
625
626 return register_user_hw_breakpoint(&attr, ptrace_triggered,
627 NULL, tsk);
628 }
629
630 static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
631 int disabled)
632 {
633 struct perf_event_attr attr = bp->attr;
634 int err;
635
636 err = ptrace_fill_bp_fields(&attr, len, type, disabled);
637 if (err)
638 return err;
639
640 return modify_user_hw_breakpoint(bp, &attr);
641 }
642
643 /*
644 * Handle ptrace writes to debug register 7.
645 */
646 static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
647 {
648 struct thread_struct *thread = &tsk->thread;
649 unsigned long old_dr7;
650 bool second_pass = false;
651 int i, rc, ret = 0;
652
653 data &= ~DR_CONTROL_RESERVED;
654 old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
655
656 restore:
657 rc = 0;
658 for (i = 0; i < HBP_NUM; i++) {
659 unsigned len, type;
660 bool disabled = !decode_dr7(data, i, &len, &type);
661 struct perf_event *bp = thread->ptrace_bps[i];
662
663 if (!bp) {
664 if (disabled)
665 continue;
666
667 bp = ptrace_register_breakpoint(tsk,
668 len, type, 0, disabled);
669 if (IS_ERR(bp)) {
670 rc = PTR_ERR(bp);
671 break;
672 }
673
674 thread->ptrace_bps[i] = bp;
675 continue;
676 }
677
678 rc = ptrace_modify_breakpoint(bp, len, type, disabled);
679 if (rc)
680 break;
681 }
682
683 /* Restore if the first pass failed, second_pass shouldn't fail. */
684 if (rc && !WARN_ON(second_pass)) {
685 ret = rc;
686 data = old_dr7;
687 second_pass = true;
688 goto restore;
689 }
690
691 return ret;
692 }
693
694 /*
695 * Handle PTRACE_PEEKUSR calls for the debug register area.
696 */
697 static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
698 {
699 struct thread_struct *thread = &tsk->thread;
700 unsigned long val = 0;
701
702 if (n < HBP_NUM) {
703 struct perf_event *bp = thread->ptrace_bps[n];
704
705 if (bp)
706 val = bp->hw.info.address;
707 } else if (n == 6) {
708 val = thread->debugreg6;
709 } else if (n == 7) {
710 val = thread->ptrace_dr7;
711 }
712 return val;
713 }
714
715 static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
716 unsigned long addr)
717 {
718 struct thread_struct *t = &tsk->thread;
719 struct perf_event *bp = t->ptrace_bps[nr];
720 int err = 0;
721
722 if (!bp) {
723 /*
724 * Put stub len and type to create an inactive but correct bp.
725 *
726 * CHECKME: the previous code returned -EIO if the addr wasn't
727 * a valid task virtual addr. The new one will return -EINVAL in
728 * this case.
729 * -EINVAL may be what we want for in-kernel breakpoints users,
730 * but -EIO looks better for ptrace, since we refuse a register
731 * writing for the user. And anyway this is the previous
732 * behaviour.
733 */
734 bp = ptrace_register_breakpoint(tsk,
735 X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
736 addr, true);
737 if (IS_ERR(bp))
738 err = PTR_ERR(bp);
739 else
740 t->ptrace_bps[nr] = bp;
741 } else {
742 struct perf_event_attr attr = bp->attr;
743
744 attr.bp_addr = addr;
745 err = modify_user_hw_breakpoint(bp, &attr);
746 }
747
748 return err;
749 }
750
751 /*
752 * Handle PTRACE_POKEUSR calls for the debug register area.
753 */
754 static int ptrace_set_debugreg(struct task_struct *tsk, int n,
755 unsigned long val)
756 {
757 struct thread_struct *thread = &tsk->thread;
758 /* There are no DR4 or DR5 registers */
759 int rc = -EIO;
760
761 if (n < HBP_NUM) {
762 rc = ptrace_set_breakpoint_addr(tsk, n, val);
763 } else if (n == 6) {
764 thread->debugreg6 = val;
765 rc = 0;
766 } else if (n == 7) {
767 rc = ptrace_write_dr7(tsk, val);
768 if (!rc)
769 thread->ptrace_dr7 = val;
770 }
771 return rc;
772 }
773
774 /*
775 * These access the current or another (stopped) task's io permission
776 * bitmap for debugging or core dump.
777 */
778 static int ioperm_active(struct task_struct *target,
779 const struct user_regset *regset)
780 {
781 return target->thread.io_bitmap_max / regset->size;
782 }
783
784 static int ioperm_get(struct task_struct *target,
785 const struct user_regset *regset,
786 unsigned int pos, unsigned int count,
787 void *kbuf, void __user *ubuf)
788 {
789 if (!target->thread.io_bitmap_ptr)
790 return -ENXIO;
791
792 return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
793 target->thread.io_bitmap_ptr,
794 0, IO_BITMAP_BYTES);
795 }
796
797 /*
798 * Called by kernel/ptrace.c when detaching..
799 *
800 * Make sure the single step bit is not set.
801 */
802 void ptrace_disable(struct task_struct *child)
803 {
804 user_disable_single_step(child);
805 #ifdef TIF_SYSCALL_EMU
806 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
807 #endif
808 }
809
810 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
811 static const struct user_regset_view user_x86_32_view; /* Initialized below. */
812 #endif
813
814 long arch_ptrace(struct task_struct *child, long request,
815 unsigned long addr, unsigned long data)
816 {
817 int ret;
818 unsigned long __user *datap = (unsigned long __user *)data;
819
820 switch (request) {
821 /* read the word at location addr in the USER area. */
822 case PTRACE_PEEKUSR: {
823 unsigned long tmp;
824
825 ret = -EIO;
826 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
827 break;
828
829 tmp = 0; /* Default return condition */
830 if (addr < sizeof(struct user_regs_struct))
831 tmp = getreg(child, addr);
832 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
833 addr <= offsetof(struct user, u_debugreg[7])) {
834 addr -= offsetof(struct user, u_debugreg[0]);
835 tmp = ptrace_get_debugreg(child, addr / sizeof(data));
836 }
837 ret = put_user(tmp, datap);
838 break;
839 }
840
841 case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
842 ret = -EIO;
843 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
844 break;
845
846 if (addr < sizeof(struct user_regs_struct))
847 ret = putreg(child, addr, data);
848 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
849 addr <= offsetof(struct user, u_debugreg[7])) {
850 addr -= offsetof(struct user, u_debugreg[0]);
851 ret = ptrace_set_debugreg(child,
852 addr / sizeof(data), data);
853 }
854 break;
855
856 case PTRACE_GETREGS: /* Get all gp regs from the child. */
857 return copy_regset_to_user(child,
858 task_user_regset_view(current),
859 REGSET_GENERAL,
860 0, sizeof(struct user_regs_struct),
861 datap);
862
863 case PTRACE_SETREGS: /* Set all gp regs in the child. */
864 return copy_regset_from_user(child,
865 task_user_regset_view(current),
866 REGSET_GENERAL,
867 0, sizeof(struct user_regs_struct),
868 datap);
869
870 case PTRACE_GETFPREGS: /* Get the child FPU state. */
871 return copy_regset_to_user(child,
872 task_user_regset_view(current),
873 REGSET_FP,
874 0, sizeof(struct user_i387_struct),
875 datap);
876
877 case PTRACE_SETFPREGS: /* Set the child FPU state. */
878 return copy_regset_from_user(child,
879 task_user_regset_view(current),
880 REGSET_FP,
881 0, sizeof(struct user_i387_struct),
882 datap);
883
884 #ifdef CONFIG_X86_32
885 case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
886 return copy_regset_to_user(child, &user_x86_32_view,
887 REGSET_XFP,
888 0, sizeof(struct user_fxsr_struct),
889 datap) ? -EIO : 0;
890
891 case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
892 return copy_regset_from_user(child, &user_x86_32_view,
893 REGSET_XFP,
894 0, sizeof(struct user_fxsr_struct),
895 datap) ? -EIO : 0;
896 #endif
897
898 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
899 case PTRACE_GET_THREAD_AREA:
900 if ((int) addr < 0)
901 return -EIO;
902 ret = do_get_thread_area(child, addr,
903 (struct user_desc __user *)data);
904 break;
905
906 case PTRACE_SET_THREAD_AREA:
907 if ((int) addr < 0)
908 return -EIO;
909 ret = do_set_thread_area(child, addr,
910 (struct user_desc __user *)data, 0);
911 break;
912 #endif
913
914 #ifdef CONFIG_X86_64
915 /* normal 64bit interface to access TLS data.
916 Works just like arch_prctl, except that the arguments
917 are reversed. */
918 case PTRACE_ARCH_PRCTL:
919 ret = do_arch_prctl(child, data, addr);
920 break;
921 #endif
922
923 default:
924 ret = ptrace_request(child, request, addr, data);
925 break;
926 }
927
928 return ret;
929 }
930
931 #ifdef CONFIG_IA32_EMULATION
932
933 #include <linux/compat.h>
934 #include <linux/syscalls.h>
935 #include <asm/ia32.h>
936 #include <asm/user32.h>
937
938 #define R32(l,q) \
939 case offsetof(struct user32, regs.l): \
940 regs->q = value; break
941
942 #define SEG32(rs) \
943 case offsetof(struct user32, regs.rs): \
944 return set_segment_reg(child, \
945 offsetof(struct user_regs_struct, rs), \
946 value); \
947 break
948
949 static int putreg32(struct task_struct *child, unsigned regno, u32 value)
950 {
951 struct pt_regs *regs = task_pt_regs(child);
952
953 switch (regno) {
954
955 SEG32(cs);
956 SEG32(ds);
957 SEG32(es);
958 SEG32(fs);
959 SEG32(gs);
960 SEG32(ss);
961
962 R32(ebx, bx);
963 R32(ecx, cx);
964 R32(edx, dx);
965 R32(edi, di);
966 R32(esi, si);
967 R32(ebp, bp);
968 R32(eax, ax);
969 R32(eip, ip);
970 R32(esp, sp);
971
972 case offsetof(struct user32, regs.orig_eax):
973 /*
974 * A 32-bit debugger setting orig_eax means to restore
975 * the state of the task restarting a 32-bit syscall.
976 * Make sure we interpret the -ERESTART* codes correctly
977 * in case the task is not actually still sitting at the
978 * exit from a 32-bit syscall with TS_COMPAT still set.
979 */
980 regs->orig_ax = value;
981 if (syscall_get_nr(child, regs) >= 0)
982 task_thread_info(child)->status |= TS_COMPAT;
983 break;
984
985 case offsetof(struct user32, regs.eflags):
986 return set_flags(child, value);
987
988 case offsetof(struct user32, u_debugreg[0]) ...
989 offsetof(struct user32, u_debugreg[7]):
990 regno -= offsetof(struct user32, u_debugreg[0]);
991 return ptrace_set_debugreg(child, regno / 4, value);
992
993 default:
994 if (regno > sizeof(struct user32) || (regno & 3))
995 return -EIO;
996
997 /*
998 * Other dummy fields in the virtual user structure
999 * are ignored
1000 */
1001 break;
1002 }
1003 return 0;
1004 }
1005
1006 #undef R32
1007 #undef SEG32
1008
1009 #define R32(l,q) \
1010 case offsetof(struct user32, regs.l): \
1011 *val = regs->q; break
1012
1013 #define SEG32(rs) \
1014 case offsetof(struct user32, regs.rs): \
1015 *val = get_segment_reg(child, \
1016 offsetof(struct user_regs_struct, rs)); \
1017 break
1018
1019 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
1020 {
1021 struct pt_regs *regs = task_pt_regs(child);
1022
1023 switch (regno) {
1024
1025 SEG32(ds);
1026 SEG32(es);
1027 SEG32(fs);
1028 SEG32(gs);
1029
1030 R32(cs, cs);
1031 R32(ss, ss);
1032 R32(ebx, bx);
1033 R32(ecx, cx);
1034 R32(edx, dx);
1035 R32(edi, di);
1036 R32(esi, si);
1037 R32(ebp, bp);
1038 R32(eax, ax);
1039 R32(orig_eax, orig_ax);
1040 R32(eip, ip);
1041 R32(esp, sp);
1042
1043 case offsetof(struct user32, regs.eflags):
1044 *val = get_flags(child);
1045 break;
1046
1047 case offsetof(struct user32, u_debugreg[0]) ...
1048 offsetof(struct user32, u_debugreg[7]):
1049 regno -= offsetof(struct user32, u_debugreg[0]);
1050 *val = ptrace_get_debugreg(child, regno / 4);
1051 break;
1052
1053 default:
1054 if (regno > sizeof(struct user32) || (regno & 3))
1055 return -EIO;
1056
1057 /*
1058 * Other dummy fields in the virtual user structure
1059 * are ignored
1060 */
1061 *val = 0;
1062 break;
1063 }
1064 return 0;
1065 }
1066
1067 #undef R32
1068 #undef SEG32
1069
1070 static int genregs32_get(struct task_struct *target,
1071 const struct user_regset *regset,
1072 unsigned int pos, unsigned int count,
1073 void *kbuf, void __user *ubuf)
1074 {
1075 if (kbuf) {
1076 compat_ulong_t *k = kbuf;
1077 while (count >= sizeof(*k)) {
1078 getreg32(target, pos, k++);
1079 count -= sizeof(*k);
1080 pos += sizeof(*k);
1081 }
1082 } else {
1083 compat_ulong_t __user *u = ubuf;
1084 while (count >= sizeof(*u)) {
1085 compat_ulong_t word;
1086 getreg32(target, pos, &word);
1087 if (__put_user(word, u++))
1088 return -EFAULT;
1089 count -= sizeof(*u);
1090 pos += sizeof(*u);
1091 }
1092 }
1093
1094 return 0;
1095 }
1096
1097 static int genregs32_set(struct task_struct *target,
1098 const struct user_regset *regset,
1099 unsigned int pos, unsigned int count,
1100 const void *kbuf, const void __user *ubuf)
1101 {
1102 int ret = 0;
1103 if (kbuf) {
1104 const compat_ulong_t *k = kbuf;
1105 while (count >= sizeof(*k) && !ret) {
1106 ret = putreg32(target, pos, *k++);
1107 count -= sizeof(*k);
1108 pos += sizeof(*k);
1109 }
1110 } else {
1111 const compat_ulong_t __user *u = ubuf;
1112 while (count >= sizeof(*u) && !ret) {
1113 compat_ulong_t word;
1114 ret = __get_user(word, u++);
1115 if (ret)
1116 break;
1117 ret = putreg32(target, pos, word);
1118 count -= sizeof(*u);
1119 pos += sizeof(*u);
1120 }
1121 }
1122 return ret;
1123 }
1124
1125 #ifdef CONFIG_X86_X32_ABI
1126 static long x32_arch_ptrace(struct task_struct *child,
1127 compat_long_t request, compat_ulong_t caddr,
1128 compat_ulong_t cdata)
1129 {
1130 unsigned long addr = caddr;
1131 unsigned long data = cdata;
1132 void __user *datap = compat_ptr(data);
1133 int ret;
1134
1135 switch (request) {
1136 /* Read 32bits at location addr in the USER area. Only allow
1137 to return the lower 32bits of segment and debug registers. */
1138 case PTRACE_PEEKUSR: {
1139 u32 tmp;
1140
1141 ret = -EIO;
1142 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1143 addr < offsetof(struct user_regs_struct, cs))
1144 break;
1145
1146 tmp = 0; /* Default return condition */
1147 if (addr < sizeof(struct user_regs_struct))
1148 tmp = getreg(child, addr);
1149 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1150 addr <= offsetof(struct user, u_debugreg[7])) {
1151 addr -= offsetof(struct user, u_debugreg[0]);
1152 tmp = ptrace_get_debugreg(child, addr / sizeof(data));
1153 }
1154 ret = put_user(tmp, (__u32 __user *)datap);
1155 break;
1156 }
1157
1158 /* Write the word at location addr in the USER area. Only allow
1159 to update segment and debug registers with the upper 32bits
1160 zero-extended. */
1161 case PTRACE_POKEUSR:
1162 ret = -EIO;
1163 if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1164 addr < offsetof(struct user_regs_struct, cs))
1165 break;
1166
1167 if (addr < sizeof(struct user_regs_struct))
1168 ret = putreg(child, addr, data);
1169 else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1170 addr <= offsetof(struct user, u_debugreg[7])) {
1171 addr -= offsetof(struct user, u_debugreg[0]);
1172 ret = ptrace_set_debugreg(child,
1173 addr / sizeof(data), data);
1174 }
1175 break;
1176
1177 case PTRACE_GETREGS: /* Get all gp regs from the child. */
1178 return copy_regset_to_user(child,
1179 task_user_regset_view(current),
1180 REGSET_GENERAL,
1181 0, sizeof(struct user_regs_struct),
1182 datap);
1183
1184 case PTRACE_SETREGS: /* Set all gp regs in the child. */
1185 return copy_regset_from_user(child,
1186 task_user_regset_view(current),
1187 REGSET_GENERAL,
1188 0, sizeof(struct user_regs_struct),
1189 datap);
1190
1191 case PTRACE_GETFPREGS: /* Get the child FPU state. */
1192 return copy_regset_to_user(child,
1193 task_user_regset_view(current),
1194 REGSET_FP,
1195 0, sizeof(struct user_i387_struct),
1196 datap);
1197
1198 case PTRACE_SETFPREGS: /* Set the child FPU state. */
1199 return copy_regset_from_user(child,
1200 task_user_regset_view(current),
1201 REGSET_FP,
1202 0, sizeof(struct user_i387_struct),
1203 datap);
1204
1205 default:
1206 return compat_ptrace_request(child, request, addr, data);
1207 }
1208
1209 return ret;
1210 }
1211 #endif
1212
1213 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1214 compat_ulong_t caddr, compat_ulong_t cdata)
1215 {
1216 unsigned long addr = caddr;
1217 unsigned long data = cdata;
1218 void __user *datap = compat_ptr(data);
1219 int ret;
1220 __u32 val;
1221
1222 #ifdef CONFIG_X86_X32_ABI
1223 if (!is_ia32_task())
1224 return x32_arch_ptrace(child, request, caddr, cdata);
1225 #endif
1226
1227 switch (request) {
1228 case PTRACE_PEEKUSR:
1229 ret = getreg32(child, addr, &val);
1230 if (ret == 0)
1231 ret = put_user(val, (__u32 __user *)datap);
1232 break;
1233
1234 case PTRACE_POKEUSR:
1235 ret = putreg32(child, addr, data);
1236 break;
1237
1238 case PTRACE_GETREGS: /* Get all gp regs from the child. */
1239 return copy_regset_to_user(child, &user_x86_32_view,
1240 REGSET_GENERAL,
1241 0, sizeof(struct user_regs_struct32),
1242 datap);
1243
1244 case PTRACE_SETREGS: /* Set all gp regs in the child. */
1245 return copy_regset_from_user(child, &user_x86_32_view,
1246 REGSET_GENERAL, 0,
1247 sizeof(struct user_regs_struct32),
1248 datap);
1249
1250 case PTRACE_GETFPREGS: /* Get the child FPU state. */
1251 return copy_regset_to_user(child, &user_x86_32_view,
1252 REGSET_FP, 0,
1253 sizeof(struct user_i387_ia32_struct),
1254 datap);
1255
1256 case PTRACE_SETFPREGS: /* Set the child FPU state. */
1257 return copy_regset_from_user(
1258 child, &user_x86_32_view, REGSET_FP,
1259 0, sizeof(struct user_i387_ia32_struct), datap);
1260
1261 case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
1262 return copy_regset_to_user(child, &user_x86_32_view,
1263 REGSET_XFP, 0,
1264 sizeof(struct user32_fxsr_struct),
1265 datap);
1266
1267 case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
1268 return copy_regset_from_user(child, &user_x86_32_view,
1269 REGSET_XFP, 0,
1270 sizeof(struct user32_fxsr_struct),
1271 datap);
1272
1273 case PTRACE_GET_THREAD_AREA:
1274 case PTRACE_SET_THREAD_AREA:
1275 return arch_ptrace(child, request, addr, data);
1276
1277 default:
1278 return compat_ptrace_request(child, request, addr, data);
1279 }
1280
1281 return ret;
1282 }
1283
1284 #endif /* CONFIG_IA32_EMULATION */
1285
1286 #ifdef CONFIG_X86_64
1287
1288 static struct user_regset x86_64_regsets[] __read_mostly = {
1289 [REGSET_GENERAL] = {
1290 .core_note_type = NT_PRSTATUS,
1291 .n = sizeof(struct user_regs_struct) / sizeof(long),
1292 .size = sizeof(long), .align = sizeof(long),
1293 .get = genregs_get, .set = genregs_set
1294 },
1295 [REGSET_FP] = {
1296 .core_note_type = NT_PRFPREG,
1297 .n = sizeof(struct user_i387_struct) / sizeof(long),
1298 .size = sizeof(long), .align = sizeof(long),
1299 .active = regset_xregset_fpregs_active, .get = xfpregs_get, .set = xfpregs_set
1300 },
1301 [REGSET_XSTATE] = {
1302 .core_note_type = NT_X86_XSTATE,
1303 .size = sizeof(u64), .align = sizeof(u64),
1304 .active = xstateregs_active, .get = xstateregs_get,
1305 .set = xstateregs_set
1306 },
1307 [REGSET_IOPERM64] = {
1308 .core_note_type = NT_386_IOPERM,
1309 .n = IO_BITMAP_LONGS,
1310 .size = sizeof(long), .align = sizeof(long),
1311 .active = ioperm_active, .get = ioperm_get
1312 },
1313 };
1314
1315 static const struct user_regset_view user_x86_64_view = {
1316 .name = "x86_64", .e_machine = EM_X86_64,
1317 .regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
1318 };
1319
1320 #else /* CONFIG_X86_32 */
1321
1322 #define user_regs_struct32 user_regs_struct
1323 #define genregs32_get genregs_get
1324 #define genregs32_set genregs_set
1325
1326 #endif /* CONFIG_X86_64 */
1327
1328 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1329 static struct user_regset x86_32_regsets[] __read_mostly = {
1330 [REGSET_GENERAL] = {
1331 .core_note_type = NT_PRSTATUS,
1332 .n = sizeof(struct user_regs_struct32) / sizeof(u32),
1333 .size = sizeof(u32), .align = sizeof(u32),
1334 .get = genregs32_get, .set = genregs32_set
1335 },
1336 [REGSET_FP] = {
1337 .core_note_type = NT_PRFPREG,
1338 .n = sizeof(struct user_i387_ia32_struct) / sizeof(u32),
1339 .size = sizeof(u32), .align = sizeof(u32),
1340 .active = regset_fpregs_active, .get = fpregs_get, .set = fpregs_set
1341 },
1342 [REGSET_XFP] = {
1343 .core_note_type = NT_PRXFPREG,
1344 .n = sizeof(struct user32_fxsr_struct) / sizeof(u32),
1345 .size = sizeof(u32), .align = sizeof(u32),
1346 .active = regset_xregset_fpregs_active, .get = xfpregs_get, .set = xfpregs_set
1347 },
1348 [REGSET_XSTATE] = {
1349 .core_note_type = NT_X86_XSTATE,
1350 .size = sizeof(u64), .align = sizeof(u64),
1351 .active = xstateregs_active, .get = xstateregs_get,
1352 .set = xstateregs_set
1353 },
1354 [REGSET_TLS] = {
1355 .core_note_type = NT_386_TLS,
1356 .n = GDT_ENTRY_TLS_ENTRIES, .bias = GDT_ENTRY_TLS_MIN,
1357 .size = sizeof(struct user_desc),
1358 .align = sizeof(struct user_desc),
1359 .active = regset_tls_active,
1360 .get = regset_tls_get, .set = regset_tls_set
1361 },
1362 [REGSET_IOPERM32] = {
1363 .core_note_type = NT_386_IOPERM,
1364 .n = IO_BITMAP_BYTES / sizeof(u32),
1365 .size = sizeof(u32), .align = sizeof(u32),
1366 .active = ioperm_active, .get = ioperm_get
1367 },
1368 };
1369
1370 static const struct user_regset_view user_x86_32_view = {
1371 .name = "i386", .e_machine = EM_386,
1372 .regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
1373 };
1374 #endif
1375
1376 /*
1377 * This represents bytes 464..511 in the memory layout exported through
1378 * the REGSET_XSTATE interface.
1379 */
1380 u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
1381
1382 void update_regset_xstate_info(unsigned int size, u64 xstate_mask)
1383 {
1384 #ifdef CONFIG_X86_64
1385 x86_64_regsets[REGSET_XSTATE].n = size / sizeof(u64);
1386 #endif
1387 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1388 x86_32_regsets[REGSET_XSTATE].n = size / sizeof(u64);
1389 #endif
1390 xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
1391 }
1392
1393 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1394 {
1395 #ifdef CONFIG_IA32_EMULATION
1396 if (test_tsk_thread_flag(task, TIF_IA32))
1397 #endif
1398 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1399 return &user_x86_32_view;
1400 #endif
1401 #ifdef CONFIG_X86_64
1402 return &user_x86_64_view;
1403 #endif
1404 }
1405
1406 static void fill_sigtrap_info(struct task_struct *tsk,
1407 struct pt_regs *regs,
1408 int error_code, int si_code,
1409 struct siginfo *info)
1410 {
1411 tsk->thread.trap_nr = X86_TRAP_DB;
1412 tsk->thread.error_code = error_code;
1413
1414 memset(info, 0, sizeof(*info));
1415 info->si_signo = SIGTRAP;
1416 info->si_code = si_code;
1417 info->si_addr = user_mode(regs) ? (void __user *)regs->ip : NULL;
1418 }
1419
1420 void user_single_step_siginfo(struct task_struct *tsk,
1421 struct pt_regs *regs,
1422 struct siginfo *info)
1423 {
1424 fill_sigtrap_info(tsk, regs, 0, TRAP_BRKPT, info);
1425 }
1426
1427 void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
1428 int error_code, int si_code)
1429 {
1430 struct siginfo info;
1431
1432 fill_sigtrap_info(tsk, regs, error_code, si_code, &info);
1433 /* Send us the fake SIGTRAP */
1434 force_sig_info(SIGTRAP, &info, tsk);
1435 }
1436
1437 static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
1438 {
1439 #ifdef CONFIG_X86_64
1440 if (arch == AUDIT_ARCH_X86_64) {
1441 audit_syscall_entry(regs->orig_ax, regs->di,
1442 regs->si, regs->dx, regs->r10);
1443 } else
1444 #endif
1445 {
1446 audit_syscall_entry(regs->orig_ax, regs->bx,
1447 regs->cx, regs->dx, regs->si);
1448 }
1449 }
1450
1451 /*
1452 * We can return 0 to resume the syscall or anything else to go to phase
1453 * 2. If we resume the syscall, we need to put something appropriate in
1454 * regs->orig_ax.
1455 *
1456 * NB: We don't have full pt_regs here, but regs->orig_ax and regs->ax
1457 * are fully functional.
1458 *
1459 * For phase 2's benefit, our return value is:
1460 * 0: resume the syscall
1461 * 1: go to phase 2; no seccomp phase 2 needed
1462 * anything else: go to phase 2; pass return value to seccomp
1463 */
1464 unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
1465 {
1466 unsigned long ret = 0;
1467 u32 work;
1468
1469 BUG_ON(regs != task_pt_regs(current));
1470
1471 work = ACCESS_ONCE(current_thread_info()->flags) &
1472 _TIF_WORK_SYSCALL_ENTRY;
1473
1474 /*
1475 * If TIF_NOHZ is set, we are required to call user_exit() before
1476 * doing anything that could touch RCU.
1477 */
1478 if (work & _TIF_NOHZ) {
1479 user_exit();
1480 work &= ~_TIF_NOHZ;
1481 }
1482
1483 #ifdef CONFIG_SECCOMP
1484 /*
1485 * Do seccomp first -- it should minimize exposure of other
1486 * code, and keeping seccomp fast is probably more valuable
1487 * than the rest of this.
1488 */
1489 if (work & _TIF_SECCOMP) {
1490 struct seccomp_data sd;
1491
1492 sd.arch = arch;
1493 sd.nr = regs->orig_ax;
1494 sd.instruction_pointer = regs->ip;
1495 #ifdef CONFIG_X86_64
1496 if (arch == AUDIT_ARCH_X86_64) {
1497 sd.args[0] = regs->di;
1498 sd.args[1] = regs->si;
1499 sd.args[2] = regs->dx;
1500 sd.args[3] = regs->r10;
1501 sd.args[4] = regs->r8;
1502 sd.args[5] = regs->r9;
1503 } else
1504 #endif
1505 {
1506 sd.args[0] = regs->bx;
1507 sd.args[1] = regs->cx;
1508 sd.args[2] = regs->dx;
1509 sd.args[3] = regs->si;
1510 sd.args[4] = regs->di;
1511 sd.args[5] = regs->bp;
1512 }
1513
1514 BUILD_BUG_ON(SECCOMP_PHASE1_OK != 0);
1515 BUILD_BUG_ON(SECCOMP_PHASE1_SKIP != 1);
1516
1517 ret = seccomp_phase1(&sd);
1518 if (ret == SECCOMP_PHASE1_SKIP) {
1519 regs->orig_ax = -1;
1520 ret = 0;
1521 } else if (ret != SECCOMP_PHASE1_OK) {
1522 return ret; /* Go directly to phase 2 */
1523 }
1524
1525 work &= ~_TIF_SECCOMP;
1526 }
1527 #endif
1528
1529 /* Do our best to finish without phase 2. */
1530 if (work == 0)
1531 return ret; /* seccomp and/or nohz only (ret == 0 here) */
1532
1533 #ifdef CONFIG_AUDITSYSCALL
1534 if (work == _TIF_SYSCALL_AUDIT) {
1535 /*
1536 * If there is no more work to be done except auditing,
1537 * then audit in phase 1. Phase 2 always audits, so, if
1538 * we audit here, then we can't go on to phase 2.
1539 */
1540 do_audit_syscall_entry(regs, arch);
1541 return 0;
1542 }
1543 #endif
1544
1545 return 1; /* Something is enabled that we can't handle in phase 1 */
1546 }
1547
1548 /* Returns the syscall nr to run (which should match regs->orig_ax). */
1549 long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
1550 unsigned long phase1_result)
1551 {
1552 long ret = 0;
1553 u32 work = ACCESS_ONCE(current_thread_info()->flags) &
1554 _TIF_WORK_SYSCALL_ENTRY;
1555
1556 BUG_ON(regs != task_pt_regs(current));
1557
1558 /*
1559 * If we stepped into a sysenter/syscall insn, it trapped in
1560 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
1561 * If user-mode had set TF itself, then it's still clear from
1562 * do_debug() and we need to set it again to restore the user
1563 * state. If we entered on the slow path, TF was already set.
1564 */
1565 if (work & _TIF_SINGLESTEP)
1566 regs->flags |= X86_EFLAGS_TF;
1567
1568 #ifdef CONFIG_SECCOMP
1569 /*
1570 * Call seccomp_phase2 before running the other hooks so that
1571 * they can see any changes made by a seccomp tracer.
1572 */
1573 if (phase1_result > 1 && seccomp_phase2(phase1_result)) {
1574 /* seccomp failures shouldn't expose any additional code. */
1575 return -1;
1576 }
1577 #endif
1578
1579 if (unlikely(work & _TIF_SYSCALL_EMU))
1580 ret = -1L;
1581
1582 if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
1583 tracehook_report_syscall_entry(regs))
1584 ret = -1L;
1585
1586 if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
1587 trace_sys_enter(regs, regs->orig_ax);
1588
1589 do_audit_syscall_entry(regs, arch);
1590
1591 return ret ?: regs->orig_ax;
1592 }
1593
1594 long syscall_trace_enter(struct pt_regs *regs)
1595 {
1596 u32 arch = is_ia32_task() ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
1597 unsigned long phase1_result = syscall_trace_enter_phase1(regs, arch);
1598
1599 if (phase1_result == 0)
1600 return regs->orig_ax;
1601 else
1602 return syscall_trace_enter_phase2(regs, arch, phase1_result);
1603 }
1604
1605 void syscall_trace_leave(struct pt_regs *regs)
1606 {
1607 bool step;
1608
1609 /*
1610 * We may come here right after calling schedule_user()
1611 * or do_notify_resume(), in which case we can be in RCU
1612 * user mode.
1613 */
1614 user_exit();
1615
1616 audit_syscall_exit(regs);
1617
1618 if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
1619 trace_sys_exit(regs, regs->ax);
1620
1621 /*
1622 * If TIF_SYSCALL_EMU is set, we only get here because of
1623 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
1624 * We already reported this syscall instruction in
1625 * syscall_trace_enter().
1626 */
1627 step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
1628 !test_thread_flag(TIF_SYSCALL_EMU);
1629 if (step || test_thread_flag(TIF_SYSCALL_TRACE))
1630 tracehook_report_syscall_exit(regs, step);
1631
1632 user_enter();
1633 }
Linux kernel - Deliverables
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