• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * arch/sh/kernel/ptrace_64.c
3  *
4  * Copyright (C) 2000, 2001  Paolo Alberelli
5  * Copyright (C) 2003 - 2008  Paul Mundt
6  *
7  * Started from SH3/4 version:
8  *   SuperH version:   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
9  *
10  *   Original x86 implementation:
11  *	By Ross Biro 1/23/92
12  *	edited by Linus Torvalds
13  *
14  * This file is subject to the terms and conditions of the GNU General Public
15  * License.  See the file "COPYING" in the main directory of this archive
16  * for more details.
17  */
18 #include <linux/kernel.h>
19 #include <linux/rwsem.h>
20 #include <linux/sched.h>
21 #include <linux/mm.h>
22 #include <linux/smp.h>
23 #include <linux/bitops.h>
24 #include <linux/errno.h>
25 #include <linux/ptrace.h>
26 #include <linux/user.h>
27 #include <linux/signal.h>
28 #include <linux/syscalls.h>
29 #include <linux/audit.h>
30 #include <linux/seccomp.h>
31 #include <linux/tracehook.h>
32 #include <linux/elf.h>
33 #include <linux/regset.h>
34 #include <asm/io.h>
35 #include <asm/uaccess.h>
36 #include <asm/pgtable.h>
37 #include <asm/processor.h>
38 #include <asm/mmu_context.h>
39 #include <asm/syscalls.h>
40 #include <asm/fpu.h>
41 #include <asm/traps.h>
42 
43 #define CREATE_TRACE_POINTS
44 #include <trace/events/syscalls.h>
45 
46 /* This mask defines the bits of the SR which the user is not allowed to
47    change, which are everything except S, Q, M, PR, SZ, FR. */
48 #define SR_MASK      (0xffff8cfd)
49 
50 /*
51  * does not yet catch signals sent when the child dies.
52  * in exit.c or in signal.c.
53  */
54 
55 /*
56  * This routine will get a word from the user area in the process kernel stack.
57  */
get_stack_long(struct task_struct * task,int offset)58 static inline int get_stack_long(struct task_struct *task, int offset)
59 {
60 	unsigned char *stack;
61 
62 	stack = (unsigned char *)(task->thread.uregs);
63 	stack += offset;
64 	return (*((int *)stack));
65 }
66 
67 static inline unsigned long
get_fpu_long(struct task_struct * task,unsigned long addr)68 get_fpu_long(struct task_struct *task, unsigned long addr)
69 {
70 	unsigned long tmp;
71 	struct pt_regs *regs;
72 	regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
73 
74 	if (!tsk_used_math(task)) {
75 		if (addr == offsetof(struct user_fpu_struct, fpscr)) {
76 			tmp = FPSCR_INIT;
77 		} else {
78 			tmp = 0xffffffffUL; /* matches initial value in fpu.c */
79 		}
80 		return tmp;
81 	}
82 
83 	if (last_task_used_math == task) {
84 		enable_fpu();
85 		save_fpu(task);
86 		disable_fpu();
87 		last_task_used_math = 0;
88 		regs->sr |= SR_FD;
89 	}
90 
91 	tmp = ((long *)task->thread.xstate)[addr / sizeof(unsigned long)];
92 	return tmp;
93 }
94 
95 /*
96  * This routine will put a word into the user area in the process kernel stack.
97  */
put_stack_long(struct task_struct * task,int offset,unsigned long data)98 static inline int put_stack_long(struct task_struct *task, int offset,
99 				 unsigned long data)
100 {
101 	unsigned char *stack;
102 
103 	stack = (unsigned char *)(task->thread.uregs);
104 	stack += offset;
105 	*(unsigned long *) stack = data;
106 	return 0;
107 }
108 
109 static inline int
put_fpu_long(struct task_struct * task,unsigned long addr,unsigned long data)110 put_fpu_long(struct task_struct *task, unsigned long addr, unsigned long data)
111 {
112 	struct pt_regs *regs;
113 
114 	regs = (struct pt_regs*)((unsigned char *)task + THREAD_SIZE) - 1;
115 
116 	if (!tsk_used_math(task)) {
117 		init_fpu(task);
118 	} else if (last_task_used_math == task) {
119 		enable_fpu();
120 		save_fpu(task);
121 		disable_fpu();
122 		last_task_used_math = 0;
123 		regs->sr |= SR_FD;
124 	}
125 
126 	((long *)task->thread.xstate)[addr / sizeof(unsigned long)] = data;
127 	return 0;
128 }
129 
user_enable_single_step(struct task_struct * child)130 void user_enable_single_step(struct task_struct *child)
131 {
132 	struct pt_regs *regs = child->thread.uregs;
133 
134 	regs->sr |= SR_SSTEP;	/* auto-resetting upon exception */
135 
136 	set_tsk_thread_flag(child, TIF_SINGLESTEP);
137 }
138 
user_disable_single_step(struct task_struct * child)139 void user_disable_single_step(struct task_struct *child)
140 {
141 	struct pt_regs *regs = child->thread.uregs;
142 
143 	regs->sr &= ~SR_SSTEP;
144 
145 	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
146 }
147 
genregs_get(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,void * kbuf,void __user * ubuf)148 static int genregs_get(struct task_struct *target,
149 		       const struct user_regset *regset,
150 		       unsigned int pos, unsigned int count,
151 		       void *kbuf, void __user *ubuf)
152 {
153 	const struct pt_regs *regs = task_pt_regs(target);
154 	int ret;
155 
156 	/* PC, SR, SYSCALL */
157 	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
158 				  &regs->pc,
159 				  0, 3 * sizeof(unsigned long long));
160 
161 	/* R1 -> R63 */
162 	if (!ret)
163 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
164 					  regs->regs,
165 					  offsetof(struct pt_regs, regs[0]),
166 					  63 * sizeof(unsigned long long));
167 	/* TR0 -> TR7 */
168 	if (!ret)
169 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
170 					  regs->tregs,
171 					  offsetof(struct pt_regs, tregs[0]),
172 					  8 * sizeof(unsigned long long));
173 
174 	if (!ret)
175 		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
176 					       sizeof(struct pt_regs), -1);
177 
178 	return ret;
179 }
180 
genregs_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)181 static int genregs_set(struct task_struct *target,
182 		       const struct user_regset *regset,
183 		       unsigned int pos, unsigned int count,
184 		       const void *kbuf, const void __user *ubuf)
185 {
186 	struct pt_regs *regs = task_pt_regs(target);
187 	int ret;
188 
189 	/* PC, SR, SYSCALL */
190 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
191 				 &regs->pc,
192 				 0, 3 * sizeof(unsigned long long));
193 
194 	/* R1 -> R63 */
195 	if (!ret && count > 0)
196 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
197 					 regs->regs,
198 					 offsetof(struct pt_regs, regs[0]),
199 					 63 * sizeof(unsigned long long));
200 
201 	/* TR0 -> TR7 */
202 	if (!ret && count > 0)
203 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
204 					 regs->tregs,
205 					 offsetof(struct pt_regs, tregs[0]),
206 					 8 * sizeof(unsigned long long));
207 
208 	if (!ret)
209 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
210 						sizeof(struct pt_regs), -1);
211 
212 	return ret;
213 }
214 
215 #ifdef CONFIG_SH_FPU
fpregs_get(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,void * kbuf,void __user * ubuf)216 int fpregs_get(struct task_struct *target,
217 	       const struct user_regset *regset,
218 	       unsigned int pos, unsigned int count,
219 	       void *kbuf, void __user *ubuf)
220 {
221 	int ret;
222 
223 	ret = init_fpu(target);
224 	if (ret)
225 		return ret;
226 
227 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
228 				   &target->thread.xstate->hardfpu, 0, -1);
229 }
230 
fpregs_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)231 static int fpregs_set(struct task_struct *target,
232 		       const struct user_regset *regset,
233 		       unsigned int pos, unsigned int count,
234 		       const void *kbuf, const void __user *ubuf)
235 {
236 	int ret;
237 
238 	ret = init_fpu(target);
239 	if (ret)
240 		return ret;
241 
242 	set_stopped_child_used_math(target);
243 
244 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
245 				  &target->thread.xstate->hardfpu, 0, -1);
246 }
247 
fpregs_active(struct task_struct * target,const struct user_regset * regset)248 static int fpregs_active(struct task_struct *target,
249 			 const struct user_regset *regset)
250 {
251 	return tsk_used_math(target) ? regset->n : 0;
252 }
253 #endif
254 
255 const struct pt_regs_offset regoffset_table[] = {
256 	REG_OFFSET_NAME(pc),
257 	REG_OFFSET_NAME(sr),
258 	REG_OFFSET_NAME(syscall_nr),
259 	REGS_OFFSET_NAME(0),
260 	REGS_OFFSET_NAME(1),
261 	REGS_OFFSET_NAME(2),
262 	REGS_OFFSET_NAME(3),
263 	REGS_OFFSET_NAME(4),
264 	REGS_OFFSET_NAME(5),
265 	REGS_OFFSET_NAME(6),
266 	REGS_OFFSET_NAME(7),
267 	REGS_OFFSET_NAME(8),
268 	REGS_OFFSET_NAME(9),
269 	REGS_OFFSET_NAME(10),
270 	REGS_OFFSET_NAME(11),
271 	REGS_OFFSET_NAME(12),
272 	REGS_OFFSET_NAME(13),
273 	REGS_OFFSET_NAME(14),
274 	REGS_OFFSET_NAME(15),
275 	REGS_OFFSET_NAME(16),
276 	REGS_OFFSET_NAME(17),
277 	REGS_OFFSET_NAME(18),
278 	REGS_OFFSET_NAME(19),
279 	REGS_OFFSET_NAME(20),
280 	REGS_OFFSET_NAME(21),
281 	REGS_OFFSET_NAME(22),
282 	REGS_OFFSET_NAME(23),
283 	REGS_OFFSET_NAME(24),
284 	REGS_OFFSET_NAME(25),
285 	REGS_OFFSET_NAME(26),
286 	REGS_OFFSET_NAME(27),
287 	REGS_OFFSET_NAME(28),
288 	REGS_OFFSET_NAME(29),
289 	REGS_OFFSET_NAME(30),
290 	REGS_OFFSET_NAME(31),
291 	REGS_OFFSET_NAME(32),
292 	REGS_OFFSET_NAME(33),
293 	REGS_OFFSET_NAME(34),
294 	REGS_OFFSET_NAME(35),
295 	REGS_OFFSET_NAME(36),
296 	REGS_OFFSET_NAME(37),
297 	REGS_OFFSET_NAME(38),
298 	REGS_OFFSET_NAME(39),
299 	REGS_OFFSET_NAME(40),
300 	REGS_OFFSET_NAME(41),
301 	REGS_OFFSET_NAME(42),
302 	REGS_OFFSET_NAME(43),
303 	REGS_OFFSET_NAME(44),
304 	REGS_OFFSET_NAME(45),
305 	REGS_OFFSET_NAME(46),
306 	REGS_OFFSET_NAME(47),
307 	REGS_OFFSET_NAME(48),
308 	REGS_OFFSET_NAME(49),
309 	REGS_OFFSET_NAME(50),
310 	REGS_OFFSET_NAME(51),
311 	REGS_OFFSET_NAME(52),
312 	REGS_OFFSET_NAME(53),
313 	REGS_OFFSET_NAME(54),
314 	REGS_OFFSET_NAME(55),
315 	REGS_OFFSET_NAME(56),
316 	REGS_OFFSET_NAME(57),
317 	REGS_OFFSET_NAME(58),
318 	REGS_OFFSET_NAME(59),
319 	REGS_OFFSET_NAME(60),
320 	REGS_OFFSET_NAME(61),
321 	REGS_OFFSET_NAME(62),
322 	REGS_OFFSET_NAME(63),
323 	TREGS_OFFSET_NAME(0),
324 	TREGS_OFFSET_NAME(1),
325 	TREGS_OFFSET_NAME(2),
326 	TREGS_OFFSET_NAME(3),
327 	TREGS_OFFSET_NAME(4),
328 	TREGS_OFFSET_NAME(5),
329 	TREGS_OFFSET_NAME(6),
330 	TREGS_OFFSET_NAME(7),
331 	REG_OFFSET_END,
332 };
333 
334 /*
335  * These are our native regset flavours.
336  */
337 enum sh_regset {
338 	REGSET_GENERAL,
339 #ifdef CONFIG_SH_FPU
340 	REGSET_FPU,
341 #endif
342 };
343 
344 static const struct user_regset sh_regsets[] = {
345 	/*
346 	 * Format is:
347 	 *	PC, SR, SYSCALL,
348 	 *	R1 --> R63,
349 	 *	TR0 --> TR7,
350 	 */
351 	[REGSET_GENERAL] = {
352 		.core_note_type	= NT_PRSTATUS,
353 		.n		= ELF_NGREG,
354 		.size		= sizeof(long long),
355 		.align		= sizeof(long long),
356 		.get		= genregs_get,
357 		.set		= genregs_set,
358 	},
359 
360 #ifdef CONFIG_SH_FPU
361 	[REGSET_FPU] = {
362 		.core_note_type	= NT_PRFPREG,
363 		.n		= sizeof(struct user_fpu_struct) /
364 				  sizeof(long long),
365 		.size		= sizeof(long long),
366 		.align		= sizeof(long long),
367 		.get		= fpregs_get,
368 		.set		= fpregs_set,
369 		.active		= fpregs_active,
370 	},
371 #endif
372 };
373 
374 static const struct user_regset_view user_sh64_native_view = {
375 	.name		= "sh64",
376 	.e_machine	= EM_SH,
377 	.regsets	= sh_regsets,
378 	.n		= ARRAY_SIZE(sh_regsets),
379 };
380 
task_user_regset_view(struct task_struct * task)381 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
382 {
383 	return &user_sh64_native_view;
384 }
385 
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)386 long arch_ptrace(struct task_struct *child, long request,
387 		 unsigned long addr, unsigned long data)
388 {
389 	int ret;
390 	unsigned long __user *datap = (unsigned long __user *) data;
391 
392 	switch (request) {
393 	/* read the word at location addr in the USER area. */
394 	case PTRACE_PEEKUSR: {
395 		unsigned long tmp;
396 
397 		ret = -EIO;
398 		if ((addr & 3) || addr < 0)
399 			break;
400 
401 		if (addr < sizeof(struct pt_regs))
402 			tmp = get_stack_long(child, addr);
403 		else if ((addr >= offsetof(struct user, fpu)) &&
404 			 (addr <  offsetof(struct user, u_fpvalid))) {
405 			unsigned long index;
406 			ret = init_fpu(child);
407 			if (ret)
408 				break;
409 			index = addr - offsetof(struct user, fpu);
410 			tmp = get_fpu_long(child, index);
411 		} else if (addr == offsetof(struct user, u_fpvalid)) {
412 			tmp = !!tsk_used_math(child);
413 		} else {
414 			break;
415 		}
416 		ret = put_user(tmp, datap);
417 		break;
418 	}
419 
420 	case PTRACE_POKEUSR:
421                 /* write the word at location addr in the USER area. We must
422                    disallow any changes to certain SR bits or u_fpvalid, since
423                    this could crash the kernel or result in a security
424                    loophole. */
425 		ret = -EIO;
426 		if ((addr & 3) || addr < 0)
427 			break;
428 
429 		if (addr < sizeof(struct pt_regs)) {
430 			/* Ignore change of top 32 bits of SR */
431 			if (addr == offsetof (struct pt_regs, sr)+4)
432 			{
433 				ret = 0;
434 				break;
435 			}
436 			/* If lower 32 bits of SR, ignore non-user bits */
437 			if (addr == offsetof (struct pt_regs, sr))
438 			{
439 				long cursr = get_stack_long(child, addr);
440 				data &= ~(SR_MASK);
441 				data |= (cursr & SR_MASK);
442 			}
443 			ret = put_stack_long(child, addr, data);
444 		}
445 		else if ((addr >= offsetof(struct user, fpu)) &&
446 			 (addr <  offsetof(struct user, u_fpvalid))) {
447 			unsigned long index;
448 			ret = init_fpu(child);
449 			if (ret)
450 				break;
451 			index = addr - offsetof(struct user, fpu);
452 			ret = put_fpu_long(child, index, data);
453 		}
454 		break;
455 
456 	case PTRACE_GETREGS:
457 		return copy_regset_to_user(child, &user_sh64_native_view,
458 					   REGSET_GENERAL,
459 					   0, sizeof(struct pt_regs),
460 					   datap);
461 	case PTRACE_SETREGS:
462 		return copy_regset_from_user(child, &user_sh64_native_view,
463 					     REGSET_GENERAL,
464 					     0, sizeof(struct pt_regs),
465 					     datap);
466 #ifdef CONFIG_SH_FPU
467 	case PTRACE_GETFPREGS:
468 		return copy_regset_to_user(child, &user_sh64_native_view,
469 					   REGSET_FPU,
470 					   0, sizeof(struct user_fpu_struct),
471 					   datap);
472 	case PTRACE_SETFPREGS:
473 		return copy_regset_from_user(child, &user_sh64_native_view,
474 					     REGSET_FPU,
475 					     0, sizeof(struct user_fpu_struct),
476 					     datap);
477 #endif
478 	default:
479 		ret = ptrace_request(child, request, addr, data);
480 		break;
481 	}
482 
483 	return ret;
484 }
485 
sh64_ptrace(long request,long pid,unsigned long addr,unsigned long data)486 asmlinkage int sh64_ptrace(long request, long pid,
487 			   unsigned long addr, unsigned long data)
488 {
489 #define WPC_DBRMODE 0x0d104008
490 	static unsigned long first_call;
491 
492 	if (!test_and_set_bit(0, &first_call)) {
493 		/* Set WPC.DBRMODE to 0.  This makes all debug events get
494 		 * delivered through RESVEC, i.e. into the handlers in entry.S.
495 		 * (If the kernel was downloaded using a remote gdb, WPC.DBRMODE
496 		 * would normally be left set to 1, which makes debug events get
497 		 * delivered through DBRVEC, i.e. into the remote gdb's
498 		 * handlers.  This prevents ptrace getting them, and confuses
499 		 * the remote gdb.) */
500 		printk("DBRMODE set to 0 to permit native debugging\n");
501 		poke_real_address_q(WPC_DBRMODE, 0);
502 	}
503 
504 	return sys_ptrace(request, pid, addr, data);
505 }
506 
audit_arch(void)507 static inline int audit_arch(void)
508 {
509 	int arch = EM_SH;
510 
511 #ifdef CONFIG_64BIT
512 	arch |= __AUDIT_ARCH_64BIT;
513 #endif
514 #ifdef CONFIG_CPU_LITTLE_ENDIAN
515 	arch |= __AUDIT_ARCH_LE;
516 #endif
517 
518 	return arch;
519 }
520 
do_syscall_trace_enter(struct pt_regs * regs)521 asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
522 {
523 	long long ret = 0;
524 
525 	secure_computing_strict(regs->regs[9]);
526 
527 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
528 	    tracehook_report_syscall_entry(regs))
529 		/*
530 		 * Tracing decided this syscall should not happen.
531 		 * We'll return a bogus call number to get an ENOSYS
532 		 * error, but leave the original number in regs->regs[0].
533 		 */
534 		ret = -1LL;
535 
536 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
537 		trace_sys_enter(regs, regs->regs[9]);
538 
539 	audit_syscall_entry(audit_arch(), regs->regs[1],
540 			    regs->regs[2], regs->regs[3],
541 			    regs->regs[4], regs->regs[5]);
542 
543 	return ret ?: regs->regs[9];
544 }
545 
do_syscall_trace_leave(struct pt_regs * regs)546 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
547 {
548 	int step;
549 
550 	audit_syscall_exit(regs);
551 
552 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
553 		trace_sys_exit(regs, regs->regs[9]);
554 
555 	step = test_thread_flag(TIF_SINGLESTEP);
556 	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
557 		tracehook_report_syscall_exit(regs, step);
558 }
559 
560 /* Called with interrupts disabled */
do_single_step(unsigned long long vec,struct pt_regs * regs)561 asmlinkage void do_single_step(unsigned long long vec, struct pt_regs *regs)
562 {
563 	/* This is called after a single step exception (DEBUGSS).
564 	   There is no need to change the PC, as it is a post-execution
565 	   exception, as entry.S does not do anything to the PC for DEBUGSS.
566 	   We need to clear the Single Step setting in SR to avoid
567 	   continually stepping. */
568 	local_irq_enable();
569 	regs->sr &= ~SR_SSTEP;
570 	force_sig(SIGTRAP, current);
571 }
572 
573 /* Called with interrupts disabled */
BUILD_TRAP_HANDLER(breakpoint)574 BUILD_TRAP_HANDLER(breakpoint)
575 {
576 	TRAP_HANDLER_DECL;
577 
578 	/* We need to forward step the PC, to counteract the backstep done
579 	   in signal.c. */
580 	local_irq_enable();
581 	force_sig(SIGTRAP, current);
582 	regs->pc += 4;
583 }
584 
585 /*
586  * Called by kernel/ptrace.c when detaching..
587  *
588  * Make sure single step bits etc are not set.
589  */
ptrace_disable(struct task_struct * child)590 void ptrace_disable(struct task_struct *child)
591 {
592 	user_disable_single_step(child);
593 }
594