1 // SPDX-License-Identifier: GPL-2.0-only
2 /* By Ross Biro 1/23/92 */
3 /*
4  * Pentium III FXSR, SSE support
5  *	Gareth Hughes <gareth@valinux.com>, May 2000
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/sched.h>
10 #include <linux/sched/task_stack.h>
11 #include <linux/mm.h>
12 #include <linux/smp.h>
13 #include <linux/errno.h>
14 #include <linux/slab.h>
15 #include <linux/ptrace.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 #include <linux/nospec.h>
28 
29 #include <linux/uaccess.h>
30 #include <asm/processor.h>
31 #include <asm/fpu/signal.h>
32 #include <asm/fpu/regset.h>
33 #include <asm/fpu/xstate.h>
34 #include <asm/debugreg.h>
35 #include <asm/ldt.h>
36 #include <asm/desc.h>
37 #include <asm/prctl.h>
38 #include <asm/proto.h>
39 #include <asm/hw_breakpoint.h>
40 #include <asm/traps.h>
41 #include <asm/syscall.h>
42 #include <asm/fsgsbase.h>
43 #include <asm/io_bitmap.h>
44 
45 #include "tls.h"
46 
47 enum x86_regset_32 {
48 	REGSET32_GENERAL,
49 	REGSET32_FP,
50 	REGSET32_XFP,
51 	REGSET32_XSTATE,
52 	REGSET32_TLS,
53 	REGSET32_IOPERM,
54 };
55 
56 enum x86_regset_64 {
57 	REGSET64_GENERAL,
58 	REGSET64_FP,
59 	REGSET64_IOPERM,
60 	REGSET64_XSTATE,
61 };
62 
63 #define REGSET_GENERAL \
64 ({ \
65 	BUILD_BUG_ON((int)REGSET32_GENERAL != (int)REGSET64_GENERAL); \
66 	REGSET32_GENERAL; \
67 })
68 
69 #define REGSET_FP \
70 ({ \
71 	BUILD_BUG_ON((int)REGSET32_FP != (int)REGSET64_FP); \
72 	REGSET32_FP; \
73 })
74 
75 
76 struct pt_regs_offset {
77 	const char *name;
78 	int offset;
79 };
80 
81 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
82 #define REG_OFFSET_END {.name = NULL, .offset = 0}
83 
84 static const struct pt_regs_offset regoffset_table[] = {
85 #ifdef CONFIG_X86_64
86 	REG_OFFSET_NAME(r15),
87 	REG_OFFSET_NAME(r14),
88 	REG_OFFSET_NAME(r13),
89 	REG_OFFSET_NAME(r12),
90 	REG_OFFSET_NAME(r11),
91 	REG_OFFSET_NAME(r10),
92 	REG_OFFSET_NAME(r9),
93 	REG_OFFSET_NAME(r8),
94 #endif
95 	REG_OFFSET_NAME(bx),
96 	REG_OFFSET_NAME(cx),
97 	REG_OFFSET_NAME(dx),
98 	REG_OFFSET_NAME(si),
99 	REG_OFFSET_NAME(di),
100 	REG_OFFSET_NAME(bp),
101 	REG_OFFSET_NAME(ax),
102 #ifdef CONFIG_X86_32
103 	REG_OFFSET_NAME(ds),
104 	REG_OFFSET_NAME(es),
105 	REG_OFFSET_NAME(fs),
106 	REG_OFFSET_NAME(gs),
107 #endif
108 	REG_OFFSET_NAME(orig_ax),
109 	REG_OFFSET_NAME(ip),
110 	REG_OFFSET_NAME(cs),
111 	REG_OFFSET_NAME(flags),
112 	REG_OFFSET_NAME(sp),
113 	REG_OFFSET_NAME(ss),
114 	REG_OFFSET_END,
115 };
116 
117 /**
118  * regs_query_register_offset() - query register offset from its name
119  * @name:	the name of a register
120  *
121  * regs_query_register_offset() returns the offset of a register in struct
122  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
123  */
regs_query_register_offset(const char * name)124 int regs_query_register_offset(const char *name)
125 {
126 	const struct pt_regs_offset *roff;
127 	for (roff = regoffset_table; roff->name != NULL; roff++)
128 		if (!strcmp(roff->name, name))
129 			return roff->offset;
130 	return -EINVAL;
131 }
132 
133 /**
134  * regs_query_register_name() - query register name from its offset
135  * @offset:	the offset of a register in struct pt_regs.
136  *
137  * regs_query_register_name() returns the name of a register from its
138  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
139  */
regs_query_register_name(unsigned int offset)140 const char *regs_query_register_name(unsigned int offset)
141 {
142 	const struct pt_regs_offset *roff;
143 	for (roff = regoffset_table; roff->name != NULL; roff++)
144 		if (roff->offset == offset)
145 			return roff->name;
146 	return NULL;
147 }
148 
149 /*
150  * does not yet catch signals sent when the child dies.
151  * in exit.c or in signal.c.
152  */
153 
154 /*
155  * Determines which flags the user has access to [1 = access, 0 = no access].
156  */
157 #define FLAG_MASK_32		((unsigned long)			\
158 				 (X86_EFLAGS_CF | X86_EFLAGS_PF |	\
159 				  X86_EFLAGS_AF | X86_EFLAGS_ZF |	\
160 				  X86_EFLAGS_SF | X86_EFLAGS_TF |	\
161 				  X86_EFLAGS_DF | X86_EFLAGS_OF |	\
162 				  X86_EFLAGS_RF | X86_EFLAGS_AC))
163 
164 /*
165  * Determines whether a value may be installed in a segment register.
166  */
invalid_selector(u16 value)167 static inline bool invalid_selector(u16 value)
168 {
169 	return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
170 }
171 
172 #ifdef CONFIG_X86_32
173 
174 #define FLAG_MASK		FLAG_MASK_32
175 
pt_regs_access(struct pt_regs * regs,unsigned long regno)176 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
177 {
178 	BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
179 	return &regs->bx + (regno >> 2);
180 }
181 
get_segment_reg(struct task_struct * task,unsigned long offset)182 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
183 {
184 	/*
185 	 * Returning the value truncates it to 16 bits.
186 	 */
187 	unsigned int retval;
188 	if (offset != offsetof(struct user_regs_struct, gs))
189 		retval = *pt_regs_access(task_pt_regs(task), offset);
190 	else {
191 		if (task == current)
192 			savesegment(gs, retval);
193 		else
194 			retval = task->thread.gs;
195 	}
196 	return retval;
197 }
198 
set_segment_reg(struct task_struct * task,unsigned long offset,u16 value)199 static int set_segment_reg(struct task_struct *task,
200 			   unsigned long offset, u16 value)
201 {
202 	if (WARN_ON_ONCE(task == current))
203 		return -EIO;
204 
205 	/*
206 	 * The value argument was already truncated to 16 bits.
207 	 */
208 	if (invalid_selector(value))
209 		return -EIO;
210 
211 	/*
212 	 * For %cs and %ss we cannot permit a null selector.
213 	 * We can permit a bogus selector as long as it has USER_RPL.
214 	 * Null selectors are fine for other segment registers, but
215 	 * we will never get back to user mode with invalid %cs or %ss
216 	 * and will take the trap in iret instead.  Much code relies
217 	 * on user_mode() to distinguish a user trap frame (which can
218 	 * safely use invalid selectors) from a kernel trap frame.
219 	 */
220 	switch (offset) {
221 	case offsetof(struct user_regs_struct, cs):
222 	case offsetof(struct user_regs_struct, ss):
223 		if (unlikely(value == 0))
224 			return -EIO;
225 		fallthrough;
226 
227 	default:
228 		*pt_regs_access(task_pt_regs(task), offset) = value;
229 		break;
230 
231 	case offsetof(struct user_regs_struct, gs):
232 		task->thread.gs = value;
233 	}
234 
235 	return 0;
236 }
237 
238 #else  /* CONFIG_X86_64 */
239 
240 #define FLAG_MASK		(FLAG_MASK_32 | X86_EFLAGS_NT)
241 
pt_regs_access(struct pt_regs * regs,unsigned long offset)242 static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
243 {
244 	BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
245 	return &regs->r15 + (offset / sizeof(regs->r15));
246 }
247 
get_segment_reg(struct task_struct * task,unsigned long offset)248 static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
249 {
250 	/*
251 	 * Returning the value truncates it to 16 bits.
252 	 */
253 	unsigned int seg;
254 
255 	switch (offset) {
256 	case offsetof(struct user_regs_struct, fs):
257 		if (task == current) {
258 			/* Older gas can't assemble movq %?s,%r?? */
259 			asm("movl %%fs,%0" : "=r" (seg));
260 			return seg;
261 		}
262 		return task->thread.fsindex;
263 	case offsetof(struct user_regs_struct, gs):
264 		if (task == current) {
265 			asm("movl %%gs,%0" : "=r" (seg));
266 			return seg;
267 		}
268 		return task->thread.gsindex;
269 	case offsetof(struct user_regs_struct, ds):
270 		if (task == current) {
271 			asm("movl %%ds,%0" : "=r" (seg));
272 			return seg;
273 		}
274 		return task->thread.ds;
275 	case offsetof(struct user_regs_struct, es):
276 		if (task == current) {
277 			asm("movl %%es,%0" : "=r" (seg));
278 			return seg;
279 		}
280 		return task->thread.es;
281 
282 	case offsetof(struct user_regs_struct, cs):
283 	case offsetof(struct user_regs_struct, ss):
284 		break;
285 	}
286 	return *pt_regs_access(task_pt_regs(task), offset);
287 }
288 
set_segment_reg(struct task_struct * task,unsigned long offset,u16 value)289 static int set_segment_reg(struct task_struct *task,
290 			   unsigned long offset, u16 value)
291 {
292 	if (WARN_ON_ONCE(task == current))
293 		return -EIO;
294 
295 	/*
296 	 * The value argument was already truncated to 16 bits.
297 	 */
298 	if (invalid_selector(value))
299 		return -EIO;
300 
301 	/*
302 	 * Writes to FS and GS will change the stored selector.  Whether
303 	 * this changes the segment base as well depends on whether
304 	 * FSGSBASE is enabled.
305 	 */
306 
307 	switch (offset) {
308 	case offsetof(struct user_regs_struct,fs):
309 		task->thread.fsindex = value;
310 		break;
311 	case offsetof(struct user_regs_struct,gs):
312 		task->thread.gsindex = value;
313 		break;
314 	case offsetof(struct user_regs_struct,ds):
315 		task->thread.ds = value;
316 		break;
317 	case offsetof(struct user_regs_struct,es):
318 		task->thread.es = value;
319 		break;
320 
321 		/*
322 		 * Can't actually change these in 64-bit mode.
323 		 */
324 	case offsetof(struct user_regs_struct,cs):
325 		if (unlikely(value == 0))
326 			return -EIO;
327 		task_pt_regs(task)->cs = value;
328 		break;
329 	case offsetof(struct user_regs_struct,ss):
330 		if (unlikely(value == 0))
331 			return -EIO;
332 		task_pt_regs(task)->ss = value;
333 		break;
334 	}
335 
336 	return 0;
337 }
338 
339 #endif	/* CONFIG_X86_32 */
340 
get_flags(struct task_struct * task)341 static unsigned long get_flags(struct task_struct *task)
342 {
343 	unsigned long retval = task_pt_regs(task)->flags;
344 
345 	/*
346 	 * If the debugger set TF, hide it from the readout.
347 	 */
348 	if (test_tsk_thread_flag(task, TIF_FORCED_TF))
349 		retval &= ~X86_EFLAGS_TF;
350 
351 	return retval;
352 }
353 
set_flags(struct task_struct * task,unsigned long value)354 static int set_flags(struct task_struct *task, unsigned long value)
355 {
356 	struct pt_regs *regs = task_pt_regs(task);
357 
358 	/*
359 	 * If the user value contains TF, mark that
360 	 * it was not "us" (the debugger) that set it.
361 	 * If not, make sure it stays set if we had.
362 	 */
363 	if (value & X86_EFLAGS_TF)
364 		clear_tsk_thread_flag(task, TIF_FORCED_TF);
365 	else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
366 		value |= X86_EFLAGS_TF;
367 
368 	regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
369 
370 	return 0;
371 }
372 
putreg(struct task_struct * child,unsigned long offset,unsigned long value)373 static int putreg(struct task_struct *child,
374 		  unsigned long offset, unsigned long value)
375 {
376 	switch (offset) {
377 	case offsetof(struct user_regs_struct, cs):
378 	case offsetof(struct user_regs_struct, ds):
379 	case offsetof(struct user_regs_struct, es):
380 	case offsetof(struct user_regs_struct, fs):
381 	case offsetof(struct user_regs_struct, gs):
382 	case offsetof(struct user_regs_struct, ss):
383 		return set_segment_reg(child, offset, value);
384 
385 	case offsetof(struct user_regs_struct, flags):
386 		return set_flags(child, value);
387 
388 #ifdef CONFIG_X86_64
389 	case offsetof(struct user_regs_struct,fs_base):
390 		if (value >= TASK_SIZE_MAX)
391 			return -EIO;
392 		x86_fsbase_write_task(child, value);
393 		return 0;
394 	case offsetof(struct user_regs_struct,gs_base):
395 		if (value >= TASK_SIZE_MAX)
396 			return -EIO;
397 		x86_gsbase_write_task(child, value);
398 		return 0;
399 #endif
400 	}
401 
402 	*pt_regs_access(task_pt_regs(child), offset) = value;
403 	return 0;
404 }
405 
getreg(struct task_struct * task,unsigned long offset)406 static unsigned long getreg(struct task_struct *task, unsigned long offset)
407 {
408 	switch (offset) {
409 	case offsetof(struct user_regs_struct, cs):
410 	case offsetof(struct user_regs_struct, ds):
411 	case offsetof(struct user_regs_struct, es):
412 	case offsetof(struct user_regs_struct, fs):
413 	case offsetof(struct user_regs_struct, gs):
414 	case offsetof(struct user_regs_struct, ss):
415 		return get_segment_reg(task, offset);
416 
417 	case offsetof(struct user_regs_struct, flags):
418 		return get_flags(task);
419 
420 #ifdef CONFIG_X86_64
421 	case offsetof(struct user_regs_struct, fs_base):
422 		return x86_fsbase_read_task(task);
423 	case offsetof(struct user_regs_struct, gs_base):
424 		return x86_gsbase_read_task(task);
425 #endif
426 	}
427 
428 	return *pt_regs_access(task_pt_regs(task), offset);
429 }
430 
genregs_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)431 static int genregs_get(struct task_struct *target,
432 		       const struct user_regset *regset,
433 		       struct membuf to)
434 {
435 	int reg;
436 
437 	for (reg = 0; to.left; reg++)
438 		membuf_store(&to, getreg(target, reg * sizeof(unsigned long)));
439 	return 0;
440 }
441 
genregs_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)442 static int genregs_set(struct task_struct *target,
443 		       const struct user_regset *regset,
444 		       unsigned int pos, unsigned int count,
445 		       const void *kbuf, const void __user *ubuf)
446 {
447 	int ret = 0;
448 	if (kbuf) {
449 		const unsigned long *k = kbuf;
450 		while (count >= sizeof(*k) && !ret) {
451 			ret = putreg(target, pos, *k++);
452 			count -= sizeof(*k);
453 			pos += sizeof(*k);
454 		}
455 	} else {
456 		const unsigned long  __user *u = ubuf;
457 		while (count >= sizeof(*u) && !ret) {
458 			unsigned long word;
459 			ret = __get_user(word, u++);
460 			if (ret)
461 				break;
462 			ret = putreg(target, pos, word);
463 			count -= sizeof(*u);
464 			pos += sizeof(*u);
465 		}
466 	}
467 	return ret;
468 }
469 
ptrace_triggered(struct perf_event * bp,struct perf_sample_data * data,struct pt_regs * regs)470 static void ptrace_triggered(struct perf_event *bp,
471 			     struct perf_sample_data *data,
472 			     struct pt_regs *regs)
473 {
474 	int i;
475 	struct thread_struct *thread = &(current->thread);
476 
477 	/*
478 	 * Store in the virtual DR6 register the fact that the breakpoint
479 	 * was hit so the thread's debugger will see it.
480 	 */
481 	for (i = 0; i < HBP_NUM; i++) {
482 		if (thread->ptrace_bps[i] == bp)
483 			break;
484 	}
485 
486 	thread->virtual_dr6 |= (DR_TRAP0 << i);
487 }
488 
489 /*
490  * Walk through every ptrace breakpoints for this thread and
491  * build the dr7 value on top of their attributes.
492  *
493  */
ptrace_get_dr7(struct perf_event * bp[])494 static unsigned long ptrace_get_dr7(struct perf_event *bp[])
495 {
496 	int i;
497 	int dr7 = 0;
498 	struct arch_hw_breakpoint *info;
499 
500 	for (i = 0; i < HBP_NUM; i++) {
501 		if (bp[i] && !bp[i]->attr.disabled) {
502 			info = counter_arch_bp(bp[i]);
503 			dr7 |= encode_dr7(i, info->len, info->type);
504 		}
505 	}
506 
507 	return dr7;
508 }
509 
ptrace_fill_bp_fields(struct perf_event_attr * attr,int len,int type,bool disabled)510 static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
511 					int len, int type, bool disabled)
512 {
513 	int err, bp_len, bp_type;
514 
515 	err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);
516 	if (!err) {
517 		attr->bp_len = bp_len;
518 		attr->bp_type = bp_type;
519 		attr->disabled = disabled;
520 	}
521 
522 	return err;
523 }
524 
525 static struct perf_event *
ptrace_register_breakpoint(struct task_struct * tsk,int len,int type,unsigned long addr,bool disabled)526 ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,
527 				unsigned long addr, bool disabled)
528 {
529 	struct perf_event_attr attr;
530 	int err;
531 
532 	ptrace_breakpoint_init(&attr);
533 	attr.bp_addr = addr;
534 
535 	err = ptrace_fill_bp_fields(&attr, len, type, disabled);
536 	if (err)
537 		return ERR_PTR(err);
538 
539 	return register_user_hw_breakpoint(&attr, ptrace_triggered,
540 						 NULL, tsk);
541 }
542 
ptrace_modify_breakpoint(struct perf_event * bp,int len,int type,int disabled)543 static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
544 					int disabled)
545 {
546 	struct perf_event_attr attr = bp->attr;
547 	int err;
548 
549 	err = ptrace_fill_bp_fields(&attr, len, type, disabled);
550 	if (err)
551 		return err;
552 
553 	return modify_user_hw_breakpoint(bp, &attr);
554 }
555 
556 /*
557  * Handle ptrace writes to debug register 7.
558  */
ptrace_write_dr7(struct task_struct * tsk,unsigned long data)559 static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
560 {
561 	struct thread_struct *thread = &tsk->thread;
562 	unsigned long old_dr7;
563 	bool second_pass = false;
564 	int i, rc, ret = 0;
565 
566 	data &= ~DR_CONTROL_RESERVED;
567 	old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
568 
569 restore:
570 	rc = 0;
571 	for (i = 0; i < HBP_NUM; i++) {
572 		unsigned len, type;
573 		bool disabled = !decode_dr7(data, i, &len, &type);
574 		struct perf_event *bp = thread->ptrace_bps[i];
575 
576 		if (!bp) {
577 			if (disabled)
578 				continue;
579 
580 			bp = ptrace_register_breakpoint(tsk,
581 					len, type, 0, disabled);
582 			if (IS_ERR(bp)) {
583 				rc = PTR_ERR(bp);
584 				break;
585 			}
586 
587 			thread->ptrace_bps[i] = bp;
588 			continue;
589 		}
590 
591 		rc = ptrace_modify_breakpoint(bp, len, type, disabled);
592 		if (rc)
593 			break;
594 	}
595 
596 	/* Restore if the first pass failed, second_pass shouldn't fail. */
597 	if (rc && !WARN_ON(second_pass)) {
598 		ret = rc;
599 		data = old_dr7;
600 		second_pass = true;
601 		goto restore;
602 	}
603 
604 	return ret;
605 }
606 
607 /*
608  * Handle PTRACE_PEEKUSR calls for the debug register area.
609  */
ptrace_get_debugreg(struct task_struct * tsk,int n)610 static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
611 {
612 	struct thread_struct *thread = &tsk->thread;
613 	unsigned long val = 0;
614 
615 	if (n < HBP_NUM) {
616 		int index = array_index_nospec(n, HBP_NUM);
617 		struct perf_event *bp = thread->ptrace_bps[index];
618 
619 		if (bp)
620 			val = bp->hw.info.address;
621 	} else if (n == 6) {
622 		val = thread->virtual_dr6 ^ DR6_RESERVED; /* Flip back to arch polarity */
623 	} else if (n == 7) {
624 		val = thread->ptrace_dr7;
625 	}
626 	return val;
627 }
628 
ptrace_set_breakpoint_addr(struct task_struct * tsk,int nr,unsigned long addr)629 static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
630 				      unsigned long addr)
631 {
632 	struct thread_struct *t = &tsk->thread;
633 	struct perf_event *bp = t->ptrace_bps[nr];
634 	int err = 0;
635 
636 	if (!bp) {
637 		/*
638 		 * Put stub len and type to create an inactive but correct bp.
639 		 *
640 		 * CHECKME: the previous code returned -EIO if the addr wasn't
641 		 * a valid task virtual addr. The new one will return -EINVAL in
642 		 *  this case.
643 		 * -EINVAL may be what we want for in-kernel breakpoints users,
644 		 * but -EIO looks better for ptrace, since we refuse a register
645 		 * writing for the user. And anyway this is the previous
646 		 * behaviour.
647 		 */
648 		bp = ptrace_register_breakpoint(tsk,
649 				X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
650 				addr, true);
651 		if (IS_ERR(bp))
652 			err = PTR_ERR(bp);
653 		else
654 			t->ptrace_bps[nr] = bp;
655 	} else {
656 		struct perf_event_attr attr = bp->attr;
657 
658 		attr.bp_addr = addr;
659 		err = modify_user_hw_breakpoint(bp, &attr);
660 	}
661 
662 	return err;
663 }
664 
665 /*
666  * Handle PTRACE_POKEUSR calls for the debug register area.
667  */
ptrace_set_debugreg(struct task_struct * tsk,int n,unsigned long val)668 static int ptrace_set_debugreg(struct task_struct *tsk, int n,
669 			       unsigned long val)
670 {
671 	struct thread_struct *thread = &tsk->thread;
672 	/* There are no DR4 or DR5 registers */
673 	int rc = -EIO;
674 
675 	if (n < HBP_NUM) {
676 		rc = ptrace_set_breakpoint_addr(tsk, n, val);
677 	} else if (n == 6) {
678 		thread->virtual_dr6 = val ^ DR6_RESERVED; /* Flip to positive polarity */
679 		rc = 0;
680 	} else if (n == 7) {
681 		rc = ptrace_write_dr7(tsk, val);
682 		if (!rc)
683 			thread->ptrace_dr7 = val;
684 	}
685 	return rc;
686 }
687 
688 /*
689  * These access the current or another (stopped) task's io permission
690  * bitmap for debugging or core dump.
691  */
ioperm_active(struct task_struct * target,const struct user_regset * regset)692 static int ioperm_active(struct task_struct *target,
693 			 const struct user_regset *regset)
694 {
695 	struct io_bitmap *iobm = target->thread.io_bitmap;
696 
697 	return iobm ? DIV_ROUND_UP(iobm->max, regset->size) : 0;
698 }
699 
ioperm_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)700 static int ioperm_get(struct task_struct *target,
701 		      const struct user_regset *regset,
702 		      struct membuf to)
703 {
704 	struct io_bitmap *iobm = target->thread.io_bitmap;
705 
706 	if (!iobm)
707 		return -ENXIO;
708 
709 	return membuf_write(&to, iobm->bitmap, IO_BITMAP_BYTES);
710 }
711 
712 /*
713  * Called by kernel/ptrace.c when detaching..
714  *
715  * Make sure the single step bit is not set.
716  */
ptrace_disable(struct task_struct * child)717 void ptrace_disable(struct task_struct *child)
718 {
719 	user_disable_single_step(child);
720 }
721 
722 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
723 static const struct user_regset_view user_x86_32_view; /* Initialized below. */
724 #endif
725 #ifdef CONFIG_X86_64
726 static const struct user_regset_view user_x86_64_view; /* Initialized below. */
727 #endif
728 
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)729 long arch_ptrace(struct task_struct *child, long request,
730 		 unsigned long addr, unsigned long data)
731 {
732 	int ret;
733 	unsigned long __user *datap = (unsigned long __user *)data;
734 
735 #ifdef CONFIG_X86_64
736 	/* This is native 64-bit ptrace() */
737 	const struct user_regset_view *regset_view = &user_x86_64_view;
738 #else
739 	/* This is native 32-bit ptrace() */
740 	const struct user_regset_view *regset_view = &user_x86_32_view;
741 #endif
742 
743 	switch (request) {
744 	/* read the word at location addr in the USER area. */
745 	case PTRACE_PEEKUSR: {
746 		unsigned long tmp;
747 
748 		ret = -EIO;
749 		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
750 			break;
751 
752 		tmp = 0;  /* Default return condition */
753 		if (addr < sizeof(struct user_regs_struct))
754 			tmp = getreg(child, addr);
755 		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
756 			 addr <= offsetof(struct user, u_debugreg[7])) {
757 			addr -= offsetof(struct user, u_debugreg[0]);
758 			tmp = ptrace_get_debugreg(child, addr / sizeof(data));
759 		}
760 		ret = put_user(tmp, datap);
761 		break;
762 	}
763 
764 	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
765 		ret = -EIO;
766 		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
767 			break;
768 
769 		if (addr < sizeof(struct user_regs_struct))
770 			ret = putreg(child, addr, data);
771 		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
772 			 addr <= offsetof(struct user, u_debugreg[7])) {
773 			addr -= offsetof(struct user, u_debugreg[0]);
774 			ret = ptrace_set_debugreg(child,
775 						  addr / sizeof(data), data);
776 		}
777 		break;
778 
779 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
780 		return copy_regset_to_user(child,
781 					   regset_view,
782 					   REGSET_GENERAL,
783 					   0, sizeof(struct user_regs_struct),
784 					   datap);
785 
786 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
787 		return copy_regset_from_user(child,
788 					     regset_view,
789 					     REGSET_GENERAL,
790 					     0, sizeof(struct user_regs_struct),
791 					     datap);
792 
793 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
794 		return copy_regset_to_user(child,
795 					   regset_view,
796 					   REGSET_FP,
797 					   0, sizeof(struct user_i387_struct),
798 					   datap);
799 
800 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
801 		return copy_regset_from_user(child,
802 					     regset_view,
803 					     REGSET_FP,
804 					     0, sizeof(struct user_i387_struct),
805 					     datap);
806 
807 #ifdef CONFIG_X86_32
808 	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
809 		return copy_regset_to_user(child, &user_x86_32_view,
810 					   REGSET32_XFP,
811 					   0, sizeof(struct user_fxsr_struct),
812 					   datap) ? -EIO : 0;
813 
814 	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
815 		return copy_regset_from_user(child, &user_x86_32_view,
816 					     REGSET32_XFP,
817 					     0, sizeof(struct user_fxsr_struct),
818 					     datap) ? -EIO : 0;
819 #endif
820 
821 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
822 	case PTRACE_GET_THREAD_AREA:
823 		if ((int) addr < 0)
824 			return -EIO;
825 		ret = do_get_thread_area(child, addr,
826 					(struct user_desc __user *)data);
827 		break;
828 
829 	case PTRACE_SET_THREAD_AREA:
830 		if ((int) addr < 0)
831 			return -EIO;
832 		ret = do_set_thread_area(child, addr,
833 					(struct user_desc __user *)data, 0);
834 		break;
835 #endif
836 
837 #ifdef CONFIG_X86_64
838 		/* normal 64bit interface to access TLS data.
839 		   Works just like arch_prctl, except that the arguments
840 		   are reversed. */
841 	case PTRACE_ARCH_PRCTL:
842 		ret = do_arch_prctl_64(child, data, addr);
843 		break;
844 #endif
845 
846 	default:
847 		ret = ptrace_request(child, request, addr, data);
848 		break;
849 	}
850 
851 	return ret;
852 }
853 
854 #ifdef CONFIG_IA32_EMULATION
855 
856 #include <linux/compat.h>
857 #include <linux/syscalls.h>
858 #include <asm/ia32.h>
859 #include <asm/user32.h>
860 
861 #define R32(l,q)							\
862 	case offsetof(struct user32, regs.l):				\
863 		regs->q = value; break
864 
865 #define SEG32(rs)							\
866 	case offsetof(struct user32, regs.rs):				\
867 		return set_segment_reg(child,				\
868 				       offsetof(struct user_regs_struct, rs), \
869 				       value);				\
870 		break
871 
putreg32(struct task_struct * child,unsigned regno,u32 value)872 static int putreg32(struct task_struct *child, unsigned regno, u32 value)
873 {
874 	struct pt_regs *regs = task_pt_regs(child);
875 	int ret;
876 
877 	switch (regno) {
878 
879 	SEG32(cs);
880 	SEG32(ds);
881 	SEG32(es);
882 
883 	/*
884 	 * A 32-bit ptracer on a 64-bit kernel expects that writing
885 	 * FS or GS will also update the base.  This is needed for
886 	 * operations like PTRACE_SETREGS to fully restore a saved
887 	 * CPU state.
888 	 */
889 
890 	case offsetof(struct user32, regs.fs):
891 		ret = set_segment_reg(child,
892 				      offsetof(struct user_regs_struct, fs),
893 				      value);
894 		if (ret == 0)
895 			child->thread.fsbase =
896 				x86_fsgsbase_read_task(child, value);
897 		return ret;
898 
899 	case offsetof(struct user32, regs.gs):
900 		ret = set_segment_reg(child,
901 				      offsetof(struct user_regs_struct, gs),
902 				      value);
903 		if (ret == 0)
904 			child->thread.gsbase =
905 				x86_fsgsbase_read_task(child, value);
906 		return ret;
907 
908 	SEG32(ss);
909 
910 	R32(ebx, bx);
911 	R32(ecx, cx);
912 	R32(edx, dx);
913 	R32(edi, di);
914 	R32(esi, si);
915 	R32(ebp, bp);
916 	R32(eax, ax);
917 	R32(eip, ip);
918 	R32(esp, sp);
919 
920 	case offsetof(struct user32, regs.orig_eax):
921 		/*
922 		 * Warning: bizarre corner case fixup here.  A 32-bit
923 		 * debugger setting orig_eax to -1 wants to disable
924 		 * syscall restart.  Make sure that the syscall
925 		 * restart code sign-extends orig_ax.  Also make sure
926 		 * we interpret the -ERESTART* codes correctly if
927 		 * loaded into regs->ax in case the task is not
928 		 * actually still sitting at the exit from a 32-bit
929 		 * syscall with TS_COMPAT still set.
930 		 */
931 		regs->orig_ax = value;
932 		if (syscall_get_nr(child, regs) != -1)
933 			child->thread_info.status |= TS_I386_REGS_POKED;
934 		break;
935 
936 	case offsetof(struct user32, regs.eflags):
937 		return set_flags(child, value);
938 
939 	case offsetof(struct user32, u_debugreg[0]) ...
940 		offsetof(struct user32, u_debugreg[7]):
941 		regno -= offsetof(struct user32, u_debugreg[0]);
942 		return ptrace_set_debugreg(child, regno / 4, value);
943 
944 	default:
945 		if (regno > sizeof(struct user32) || (regno & 3))
946 			return -EIO;
947 
948 		/*
949 		 * Other dummy fields in the virtual user structure
950 		 * are ignored
951 		 */
952 		break;
953 	}
954 	return 0;
955 }
956 
957 #undef R32
958 #undef SEG32
959 
960 #define R32(l,q)							\
961 	case offsetof(struct user32, regs.l):				\
962 		*val = regs->q; break
963 
964 #define SEG32(rs)							\
965 	case offsetof(struct user32, regs.rs):				\
966 		*val = get_segment_reg(child,				\
967 				       offsetof(struct user_regs_struct, rs)); \
968 		break
969 
getreg32(struct task_struct * child,unsigned regno,u32 * val)970 static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
971 {
972 	struct pt_regs *regs = task_pt_regs(child);
973 
974 	switch (regno) {
975 
976 	SEG32(ds);
977 	SEG32(es);
978 	SEG32(fs);
979 	SEG32(gs);
980 
981 	R32(cs, cs);
982 	R32(ss, ss);
983 	R32(ebx, bx);
984 	R32(ecx, cx);
985 	R32(edx, dx);
986 	R32(edi, di);
987 	R32(esi, si);
988 	R32(ebp, bp);
989 	R32(eax, ax);
990 	R32(orig_eax, orig_ax);
991 	R32(eip, ip);
992 	R32(esp, sp);
993 
994 	case offsetof(struct user32, regs.eflags):
995 		*val = get_flags(child);
996 		break;
997 
998 	case offsetof(struct user32, u_debugreg[0]) ...
999 		offsetof(struct user32, u_debugreg[7]):
1000 		regno -= offsetof(struct user32, u_debugreg[0]);
1001 		*val = ptrace_get_debugreg(child, regno / 4);
1002 		break;
1003 
1004 	default:
1005 		if (regno > sizeof(struct user32) || (regno & 3))
1006 			return -EIO;
1007 
1008 		/*
1009 		 * Other dummy fields in the virtual user structure
1010 		 * are ignored
1011 		 */
1012 		*val = 0;
1013 		break;
1014 	}
1015 	return 0;
1016 }
1017 
1018 #undef R32
1019 #undef SEG32
1020 
genregs32_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)1021 static int genregs32_get(struct task_struct *target,
1022 			 const struct user_regset *regset,
1023 			 struct membuf to)
1024 {
1025 	int reg;
1026 
1027 	for (reg = 0; to.left; reg++) {
1028 		u32 val;
1029 		getreg32(target, reg * 4, &val);
1030 		membuf_store(&to, val);
1031 	}
1032 	return 0;
1033 }
1034 
genregs32_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)1035 static int genregs32_set(struct task_struct *target,
1036 			 const struct user_regset *regset,
1037 			 unsigned int pos, unsigned int count,
1038 			 const void *kbuf, const void __user *ubuf)
1039 {
1040 	int ret = 0;
1041 	if (kbuf) {
1042 		const compat_ulong_t *k = kbuf;
1043 		while (count >= sizeof(*k) && !ret) {
1044 			ret = putreg32(target, pos, *k++);
1045 			count -= sizeof(*k);
1046 			pos += sizeof(*k);
1047 		}
1048 	} else {
1049 		const compat_ulong_t __user *u = ubuf;
1050 		while (count >= sizeof(*u) && !ret) {
1051 			compat_ulong_t word;
1052 			ret = __get_user(word, u++);
1053 			if (ret)
1054 				break;
1055 			ret = putreg32(target, pos, word);
1056 			count -= sizeof(*u);
1057 			pos += sizeof(*u);
1058 		}
1059 	}
1060 	return ret;
1061 }
1062 
ia32_arch_ptrace(struct task_struct * child,compat_long_t request,compat_ulong_t caddr,compat_ulong_t cdata)1063 static long ia32_arch_ptrace(struct task_struct *child, compat_long_t request,
1064 			     compat_ulong_t caddr, compat_ulong_t cdata)
1065 {
1066 	unsigned long addr = caddr;
1067 	unsigned long data = cdata;
1068 	void __user *datap = compat_ptr(data);
1069 	int ret;
1070 	__u32 val;
1071 
1072 	switch (request) {
1073 	case PTRACE_PEEKUSR:
1074 		ret = getreg32(child, addr, &val);
1075 		if (ret == 0)
1076 			ret = put_user(val, (__u32 __user *)datap);
1077 		break;
1078 
1079 	case PTRACE_POKEUSR:
1080 		ret = putreg32(child, addr, data);
1081 		break;
1082 
1083 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
1084 		return copy_regset_to_user(child, &user_x86_32_view,
1085 					   REGSET_GENERAL,
1086 					   0, sizeof(struct user_regs_struct32),
1087 					   datap);
1088 
1089 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
1090 		return copy_regset_from_user(child, &user_x86_32_view,
1091 					     REGSET_GENERAL, 0,
1092 					     sizeof(struct user_regs_struct32),
1093 					     datap);
1094 
1095 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
1096 		return copy_regset_to_user(child, &user_x86_32_view,
1097 					   REGSET_FP, 0,
1098 					   sizeof(struct user_i387_ia32_struct),
1099 					   datap);
1100 
1101 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
1102 		return copy_regset_from_user(
1103 			child, &user_x86_32_view, REGSET_FP,
1104 			0, sizeof(struct user_i387_ia32_struct), datap);
1105 
1106 	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
1107 		return copy_regset_to_user(child, &user_x86_32_view,
1108 					   REGSET32_XFP, 0,
1109 					   sizeof(struct user32_fxsr_struct),
1110 					   datap);
1111 
1112 	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
1113 		return copy_regset_from_user(child, &user_x86_32_view,
1114 					     REGSET32_XFP, 0,
1115 					     sizeof(struct user32_fxsr_struct),
1116 					     datap);
1117 
1118 	case PTRACE_GET_THREAD_AREA:
1119 	case PTRACE_SET_THREAD_AREA:
1120 		return arch_ptrace(child, request, addr, data);
1121 
1122 	default:
1123 		return compat_ptrace_request(child, request, addr, data);
1124 	}
1125 
1126 	return ret;
1127 }
1128 #endif /* CONFIG_IA32_EMULATION */
1129 
1130 #ifdef CONFIG_X86_X32_ABI
x32_arch_ptrace(struct task_struct * child,compat_long_t request,compat_ulong_t caddr,compat_ulong_t cdata)1131 static long x32_arch_ptrace(struct task_struct *child,
1132 			    compat_long_t request, compat_ulong_t caddr,
1133 			    compat_ulong_t cdata)
1134 {
1135 	unsigned long addr = caddr;
1136 	unsigned long data = cdata;
1137 	void __user *datap = compat_ptr(data);
1138 	int ret;
1139 
1140 	switch (request) {
1141 	/* Read 32bits at location addr in the USER area.  Only allow
1142 	   to return the lower 32bits of segment and debug registers.  */
1143 	case PTRACE_PEEKUSR: {
1144 		u32 tmp;
1145 
1146 		ret = -EIO;
1147 		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1148 		    addr < offsetof(struct user_regs_struct, cs))
1149 			break;
1150 
1151 		tmp = 0;  /* Default return condition */
1152 		if (addr < sizeof(struct user_regs_struct))
1153 			tmp = getreg(child, addr);
1154 		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1155 			 addr <= offsetof(struct user, u_debugreg[7])) {
1156 			addr -= offsetof(struct user, u_debugreg[0]);
1157 			tmp = ptrace_get_debugreg(child, addr / sizeof(data));
1158 		}
1159 		ret = put_user(tmp, (__u32 __user *)datap);
1160 		break;
1161 	}
1162 
1163 	/* Write the word at location addr in the USER area.  Only allow
1164 	   to update segment and debug registers with the upper 32bits
1165 	   zero-extended. */
1166 	case PTRACE_POKEUSR:
1167 		ret = -EIO;
1168 		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
1169 		    addr < offsetof(struct user_regs_struct, cs))
1170 			break;
1171 
1172 		if (addr < sizeof(struct user_regs_struct))
1173 			ret = putreg(child, addr, data);
1174 		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
1175 			 addr <= offsetof(struct user, u_debugreg[7])) {
1176 			addr -= offsetof(struct user, u_debugreg[0]);
1177 			ret = ptrace_set_debugreg(child,
1178 						  addr / sizeof(data), data);
1179 		}
1180 		break;
1181 
1182 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
1183 		return copy_regset_to_user(child,
1184 					   &user_x86_64_view,
1185 					   REGSET_GENERAL,
1186 					   0, sizeof(struct user_regs_struct),
1187 					   datap);
1188 
1189 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
1190 		return copy_regset_from_user(child,
1191 					     &user_x86_64_view,
1192 					     REGSET_GENERAL,
1193 					     0, sizeof(struct user_regs_struct),
1194 					     datap);
1195 
1196 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
1197 		return copy_regset_to_user(child,
1198 					   &user_x86_64_view,
1199 					   REGSET_FP,
1200 					   0, sizeof(struct user_i387_struct),
1201 					   datap);
1202 
1203 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
1204 		return copy_regset_from_user(child,
1205 					     &user_x86_64_view,
1206 					     REGSET_FP,
1207 					     0, sizeof(struct user_i387_struct),
1208 					     datap);
1209 
1210 	default:
1211 		return compat_ptrace_request(child, request, addr, data);
1212 	}
1213 
1214 	return ret;
1215 }
1216 #endif
1217 
1218 #ifdef CONFIG_COMPAT
compat_arch_ptrace(struct task_struct * child,compat_long_t request,compat_ulong_t caddr,compat_ulong_t cdata)1219 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
1220 			compat_ulong_t caddr, compat_ulong_t cdata)
1221 {
1222 #ifdef CONFIG_X86_X32_ABI
1223 	if (!in_ia32_syscall())
1224 		return x32_arch_ptrace(child, request, caddr, cdata);
1225 #endif
1226 #ifdef CONFIG_IA32_EMULATION
1227 	return ia32_arch_ptrace(child, request, caddr, cdata);
1228 #else
1229 	return 0;
1230 #endif
1231 }
1232 #endif	/* CONFIG_COMPAT */
1233 
1234 #ifdef CONFIG_X86_64
1235 
1236 static struct user_regset x86_64_regsets[] __ro_after_init = {
1237 	[REGSET64_GENERAL] = {
1238 		.core_note_type	= NT_PRSTATUS,
1239 		.n		= sizeof(struct user_regs_struct) / sizeof(long),
1240 		.size		= sizeof(long),
1241 		.align		= sizeof(long),
1242 		.regset_get	= genregs_get,
1243 		.set		= genregs_set
1244 	},
1245 	[REGSET64_FP] = {
1246 		.core_note_type	= NT_PRFPREG,
1247 		.n		= sizeof(struct fxregs_state) / sizeof(long),
1248 		.size		= sizeof(long),
1249 		.align		= sizeof(long),
1250 		.active		= regset_xregset_fpregs_active,
1251 		.regset_get	= xfpregs_get,
1252 		.set		= xfpregs_set
1253 	},
1254 	[REGSET64_XSTATE] = {
1255 		.core_note_type	= NT_X86_XSTATE,
1256 		.size		= sizeof(u64),
1257 		.align		= sizeof(u64),
1258 		.active		= xstateregs_active,
1259 		.regset_get	= xstateregs_get,
1260 		.set		= xstateregs_set
1261 	},
1262 	[REGSET64_IOPERM] = {
1263 		.core_note_type	= NT_386_IOPERM,
1264 		.n		= IO_BITMAP_LONGS,
1265 		.size		= sizeof(long),
1266 		.align		= sizeof(long),
1267 		.active		= ioperm_active,
1268 		.regset_get	= ioperm_get
1269 	},
1270 };
1271 
1272 static const struct user_regset_view user_x86_64_view = {
1273 	.name = "x86_64", .e_machine = EM_X86_64,
1274 	.regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
1275 };
1276 
1277 #else  /* CONFIG_X86_32 */
1278 
1279 #define user_regs_struct32	user_regs_struct
1280 #define genregs32_get		genregs_get
1281 #define genregs32_set		genregs_set
1282 
1283 #endif	/* CONFIG_X86_64 */
1284 
1285 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1286 static struct user_regset x86_32_regsets[] __ro_after_init = {
1287 	[REGSET32_GENERAL] = {
1288 		.core_note_type	= NT_PRSTATUS,
1289 		.n		= sizeof(struct user_regs_struct32) / sizeof(u32),
1290 		.size		= sizeof(u32),
1291 		.align		= sizeof(u32),
1292 		.regset_get	= genregs32_get,
1293 		.set		= genregs32_set
1294 	},
1295 	[REGSET32_FP] = {
1296 		.core_note_type	= NT_PRFPREG,
1297 		.n		= sizeof(struct user_i387_ia32_struct) / sizeof(u32),
1298 		.size		= sizeof(u32),
1299 		.align		= sizeof(u32),
1300 		.active		= regset_fpregs_active,
1301 		.regset_get	= fpregs_get,
1302 		.set		= fpregs_set
1303 	},
1304 	[REGSET32_XFP] = {
1305 		.core_note_type	= NT_PRXFPREG,
1306 		.n		= sizeof(struct fxregs_state) / sizeof(u32),
1307 		.size		= sizeof(u32),
1308 		.align		= sizeof(u32),
1309 		.active		= regset_xregset_fpregs_active,
1310 		.regset_get	= xfpregs_get,
1311 		.set		= xfpregs_set
1312 	},
1313 	[REGSET32_XSTATE] = {
1314 		.core_note_type	= NT_X86_XSTATE,
1315 		.size		= sizeof(u64),
1316 		.align		= sizeof(u64),
1317 		.active		= xstateregs_active,
1318 		.regset_get	= xstateregs_get,
1319 		.set		= xstateregs_set
1320 	},
1321 	[REGSET32_TLS] = {
1322 		.core_note_type	= NT_386_TLS,
1323 		.n		= GDT_ENTRY_TLS_ENTRIES,
1324 		.bias		= GDT_ENTRY_TLS_MIN,
1325 		.size		= sizeof(struct user_desc),
1326 		.align		= sizeof(struct user_desc),
1327 		.active		= regset_tls_active,
1328 		.regset_get	= regset_tls_get,
1329 		.set		= regset_tls_set
1330 	},
1331 	[REGSET32_IOPERM] = {
1332 		.core_note_type	= NT_386_IOPERM,
1333 		.n		= IO_BITMAP_BYTES / sizeof(u32),
1334 		.size		= sizeof(u32),
1335 		.align		= sizeof(u32),
1336 		.active		= ioperm_active,
1337 		.regset_get	= ioperm_get
1338 	},
1339 };
1340 
1341 static const struct user_regset_view user_x86_32_view = {
1342 	.name = "i386", .e_machine = EM_386,
1343 	.regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
1344 };
1345 #endif
1346 
1347 /*
1348  * This represents bytes 464..511 in the memory layout exported through
1349  * the REGSET_XSTATE interface.
1350  */
1351 u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
1352 
update_regset_xstate_info(unsigned int size,u64 xstate_mask)1353 void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask)
1354 {
1355 #ifdef CONFIG_X86_64
1356 	x86_64_regsets[REGSET64_XSTATE].n = size / sizeof(u64);
1357 #endif
1358 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1359 	x86_32_regsets[REGSET32_XSTATE].n = size / sizeof(u64);
1360 #endif
1361 	xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
1362 }
1363 
1364 /*
1365  * This is used by the core dump code to decide which regset to dump.  The
1366  * core dump code writes out the resulting .e_machine and the corresponding
1367  * regsets.  This is suboptimal if the task is messing around with its CS.L
1368  * field, but at worst the core dump will end up missing some information.
1369  *
1370  * Unfortunately, it is also used by the broken PTRACE_GETREGSET and
1371  * PTRACE_SETREGSET APIs.  These APIs look at the .regsets field but have
1372  * no way to make sure that the e_machine they use matches the caller's
1373  * expectations.  The result is that the data format returned by
1374  * PTRACE_GETREGSET depends on the returned CS field (and even the offset
1375  * of the returned CS field depends on its value!) and the data format
1376  * accepted by PTRACE_SETREGSET is determined by the old CS value.  The
1377  * upshot is that it is basically impossible to use these APIs correctly.
1378  *
1379  * The best way to fix it in the long run would probably be to add new
1380  * improved ptrace() APIs to read and write registers reliably, possibly by
1381  * allowing userspace to select the ELF e_machine variant that they expect.
1382  */
task_user_regset_view(struct task_struct * task)1383 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1384 {
1385 #ifdef CONFIG_IA32_EMULATION
1386 	if (!user_64bit_mode(task_pt_regs(task)))
1387 #endif
1388 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
1389 		return &user_x86_32_view;
1390 #endif
1391 #ifdef CONFIG_X86_64
1392 	return &user_x86_64_view;
1393 #endif
1394 }
1395 
send_sigtrap(struct pt_regs * regs,int error_code,int si_code)1396 void send_sigtrap(struct pt_regs *regs, int error_code, int si_code)
1397 {
1398 	struct task_struct *tsk = current;
1399 
1400 	tsk->thread.trap_nr = X86_TRAP_DB;
1401 	tsk->thread.error_code = error_code;
1402 
1403 	/* Send us the fake SIGTRAP */
1404 	force_sig_fault(SIGTRAP, si_code,
1405 			user_mode(regs) ? (void __user *)regs->ip : NULL);
1406 }
1407 
user_single_step_report(struct pt_regs * regs)1408 void user_single_step_report(struct pt_regs *regs)
1409 {
1410 	send_sigtrap(regs, 0, TRAP_BRKPT);
1411 }
1412