/arch/sh/kernel/ptrace_32.c

  1/*
  2 * SuperH process tracing
  3 *
  4 * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
  5 * Copyright (C) 2002 - 2009  Paul Mundt
  6 *
  7 * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
  8 *
  9 * This file is subject to the terms and conditions of the GNU General Public
 10 * License.  See the file "COPYING" in the main directory of this archive
 11 * for more details.
 12 */
 13#include <linux/kernel.h>
 14#include <linux/sched.h>
 15#include <linux/mm.h>
 16#include <linux/smp.h>
 17#include <linux/errno.h>
 18#include <linux/ptrace.h>
 19#include <linux/user.h>
 20#include <linux/security.h>
 21#include <linux/signal.h>
 22#include <linux/io.h>
 23#include <linux/audit.h>
 24#include <linux/seccomp.h>
 25#include <linux/tracehook.h>
 26#include <linux/elf.h>
 27#include <linux/regset.h>
 28#include <linux/hw_breakpoint.h>
 29#include <asm/uaccess.h>
 30#include <asm/pgtable.h>
 31#include <asm/processor.h>
 32#include <asm/mmu_context.h>
 33#include <asm/syscalls.h>
 34#include <asm/fpu.h>
 35
 36#define CREATE_TRACE_POINTS
 37#include <trace/events/syscalls.h>
 38
 39/*
 40 * This routine will get a word off of the process kernel stack.
 41 */
 42static inline int get_stack_long(struct task_struct *task, int offset)
 43{
 44	unsigned char *stack;
 45
 46	stack = (unsigned char *)task_pt_regs(task);
 47	stack += offset;
 48	return (*((int *)stack));
 49}
 50
 51/*
 52 * This routine will put a word on the process kernel stack.
 53 */
 54static inline int put_stack_long(struct task_struct *task, int offset,
 55				 unsigned long data)
 56{
 57	unsigned char *stack;
 58
 59	stack = (unsigned char *)task_pt_regs(task);
 60	stack += offset;
 61	*(unsigned long *) stack = data;
 62	return 0;
 63}
 64
 65void ptrace_triggered(struct perf_event *bp,
 66		      struct perf_sample_data *data, struct pt_regs *regs)
 67{
 68	struct perf_event_attr attr;
 69
 70	/*
 71	 * Disable the breakpoint request here since ptrace has defined a
 72	 * one-shot behaviour for breakpoint exceptions.
 73	 */
 74	attr = bp->attr;
 75	attr.disabled = true;
 76	modify_user_hw_breakpoint(bp, &attr);
 77}
 78
 79static int set_single_step(struct task_struct *tsk, unsigned long addr)
 80{
 81	struct thread_struct *thread = &tsk->thread;
 82	struct perf_event *bp;
 83	struct perf_event_attr attr;
 84
 85	bp = thread->ptrace_bps[0];
 86	if (!bp) {
 87		ptrace_breakpoint_init(&attr);
 88
 89		attr.bp_addr = addr;
 90		attr.bp_len = HW_BREAKPOINT_LEN_2;
 91		attr.bp_type = HW_BREAKPOINT_R;
 92
 93		bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
 94						 NULL, tsk);
 95		if (IS_ERR(bp))
 96			return PTR_ERR(bp);
 97
 98		thread->ptrace_bps[0] = bp;
 99	} else {
100		int err;
101
102		attr = bp->attr;
103		attr.bp_addr = addr;
104		/* reenable breakpoint */
105		attr.disabled = false;
106		err = modify_user_hw_breakpoint(bp, &attr);
107		if (unlikely(err))
108			return err;
109	}
110
111	return 0;
112}
113
114void user_enable_single_step(struct task_struct *child)
115{
116	unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));
117
118	set_tsk_thread_flag(child, TIF_SINGLESTEP);
119
120	set_single_step(child, pc);
121}
122
123void user_disable_single_step(struct task_struct *child)
124{
125	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
126}
127
128/*
129 * Called by kernel/ptrace.c when detaching..
130 *
131 * Make sure single step bits etc are not set.
132 */
133void ptrace_disable(struct task_struct *child)
134{
135	user_disable_single_step(child);
136}
137
138static int genregs_get(struct task_struct *target,
139		       const struct user_regset *regset,
140		       unsigned int pos, unsigned int count,
141		       void *kbuf, void __user *ubuf)
142{
143	const struct pt_regs *regs = task_pt_regs(target);
144	int ret;
145
146	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
147				  regs->regs,
148				  0, 16 * sizeof(unsigned long));
149	if (!ret)
150		/* PC, PR, SR, GBR, MACH, MACL, TRA */
151		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
152					  &regs->pc,
153					  offsetof(struct pt_regs, pc),
154					  sizeof(struct pt_regs));
155	if (!ret)
156		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
157					       sizeof(struct pt_regs), -1);
158
159	return ret;
160}
161
162static int genregs_set(struct task_struct *target,
163		       const struct user_regset *regset,
164		       unsigned int pos, unsigned int count,
165		       const void *kbuf, const void __user *ubuf)
166{
167	struct pt_regs *regs = task_pt_regs(target);
168	int ret;
169
170	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
171				 regs->regs,
172				 0, 16 * sizeof(unsigned long));
173	if (!ret && count > 0)
174		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
175					 &regs->pc,
176					 offsetof(struct pt_regs, pc),
177					 sizeof(struct pt_regs));
178	if (!ret)
179		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
180						sizeof(struct pt_regs), -1);
181
182	return ret;
183}
184
185#ifdef CONFIG_SH_FPU
186int fpregs_get(struct task_struct *target,
187	       const struct user_regset *regset,
188	       unsigned int pos, unsigned int count,
189	       void *kbuf, void __user *ubuf)
190{
191	int ret;
192
193	ret = init_fpu(target);
194	if (ret)
195		return ret;
196
197	if ((boot_cpu_data.flags & CPU_HAS_FPU))
198		return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
199					   &target->thread.xstate->hardfpu, 0, -1);
200
201	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
202				   &target->thread.xstate->softfpu, 0, -1);
203}
204
205static int fpregs_set(struct task_struct *target,
206		       const struct user_regset *regset,
207		       unsigned int pos, unsigned int count,
208		       const void *kbuf, const void __user *ubuf)
209{
210	int ret;
211
212	ret = init_fpu(target);
213	if (ret)
214		return ret;
215
216	set_stopped_child_used_math(target);
217
218	if ((boot_cpu_data.flags & CPU_HAS_FPU))
219		return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
220					  &target->thread.xstate->hardfpu, 0, -1);
221
222	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
223				  &target->thread.xstate->softfpu, 0, -1);
224}
225
226static int fpregs_active(struct task_struct *target,
227			 const struct user_regset *regset)
228{
229	return tsk_used_math(target) ? regset->n : 0;
230}
231#endif
232
233#ifdef CONFIG_SH_DSP
234static int dspregs_get(struct task_struct *target,
235		       const struct user_regset *regset,
236		       unsigned int pos, unsigned int count,
237		       void *kbuf, void __user *ubuf)
238{
239	const struct pt_dspregs *regs =
240		(struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
241	int ret;
242
243	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs,
244				  0, sizeof(struct pt_dspregs));
245	if (!ret)
246		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
247					       sizeof(struct pt_dspregs), -1);
248
249	return ret;
250}
251
252static int dspregs_set(struct task_struct *target,
253		       const struct user_regset *regset,
254		       unsigned int pos, unsigned int count,
255		       const void *kbuf, const void __user *ubuf)
256{
257	struct pt_dspregs *regs =
258		(struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
259	int ret;
260
261	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
262				 0, sizeof(struct pt_dspregs));
263	if (!ret)
264		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
265						sizeof(struct pt_dspregs), -1);
266
267	return ret;
268}
269
270static int dspregs_active(struct task_struct *target,
271			  const struct user_regset *regset)
272{
273	struct pt_regs *regs = task_pt_regs(target);
274
275	return regs->sr & SR_DSP ? regset->n : 0;
276}
277#endif
278
279const struct pt_regs_offset regoffset_table[] = {
280	REGS_OFFSET_NAME(0),
281	REGS_OFFSET_NAME(1),
282	REGS_OFFSET_NAME(2),
283	REGS_OFFSET_NAME(3),
284	REGS_OFFSET_NAME(4),
285	REGS_OFFSET_NAME(5),
286	REGS_OFFSET_NAME(6),
287	REGS_OFFSET_NAME(7),
288	REGS_OFFSET_NAME(8),
289	REGS_OFFSET_NAME(9),
290	REGS_OFFSET_NAME(10),
291	REGS_OFFSET_NAME(11),
292	REGS_OFFSET_NAME(12),
293	REGS_OFFSET_NAME(13),
294	REGS_OFFSET_NAME(14),
295	REGS_OFFSET_NAME(15),
296	REG_OFFSET_NAME(pc),
297	REG_OFFSET_NAME(pr),
298	REG_OFFSET_NAME(sr),
299	REG_OFFSET_NAME(gbr),
300	REG_OFFSET_NAME(mach),
301	REG_OFFSET_NAME(macl),
302	REG_OFFSET_NAME(tra),
303	REG_OFFSET_END,
304};
305
306/*
307 * These are our native regset flavours.
308 */
309enum sh_regset {
310	REGSET_GENERAL,
311#ifdef CONFIG_SH_FPU
312	REGSET_FPU,
313#endif
314#ifdef CONFIG_SH_DSP
315	REGSET_DSP,
316#endif
317};
318
319static const struct user_regset sh_regsets[] = {
320	/*
321	 * Format is:
322	 *	R0 --> R15
323	 *	PC, PR, SR, GBR, MACH, MACL, TRA
324	 */
325	[REGSET_GENERAL] = {
326		.core_note_type	= NT_PRSTATUS,
327		.n		= ELF_NGREG,
328		.size		= sizeof(long),
329		.align		= sizeof(long),
330		.get		= genregs_get,
331		.set		= genregs_set,
332	},
333
334#ifdef CONFIG_SH_FPU
335	[REGSET_FPU] = {
336		.core_note_type	= NT_PRFPREG,
337		.n		= sizeof(struct user_fpu_struct) / sizeof(long),
338		.size		= sizeof(long),
339		.align		= sizeof(long),
340		.get		= fpregs_get,
341		.set		= fpregs_set,
342		.active		= fpregs_active,
343	},
344#endif
345
346#ifdef CONFIG_SH_DSP
347	[REGSET_DSP] = {
348		.n		= sizeof(struct pt_dspregs) / sizeof(long),
349		.size		= sizeof(long),
350		.align		= sizeof(long),
351		.get		= dspregs_get,
352		.set		= dspregs_set,
353		.active		= dspregs_active,
354	},
355#endif
356};
357
358static const struct user_regset_view user_sh_native_view = {
359	.name		= "sh",
360	.e_machine	= EM_SH,
361	.regsets	= sh_regsets,
362	.n		= ARRAY_SIZE(sh_regsets),
363};
364
365const struct user_regset_view *task_user_regset_view(struct task_struct *task)
366{
367	return &user_sh_native_view;
368}
369
370long arch_ptrace(struct task_struct *child, long request,
371		 unsigned long addr, unsigned long data)
372{
373	unsigned long __user *datap = (unsigned long __user *)data;
374	int ret;
375
376	switch (request) {
377	/* read the word at location addr in the USER area. */
378	case PTRACE_PEEKUSR: {
379		unsigned long tmp;
380
381		ret = -EIO;
382		if ((addr & 3) || addr < 0 ||
383		    addr > sizeof(struct user) - 3)
384			break;
385
386		if (addr < sizeof(struct pt_regs))
387			tmp = get_stack_long(child, addr);
388		else if (addr >= offsetof(struct user, fpu) &&
389			 addr < offsetof(struct user, u_fpvalid)) {
390			if (!tsk_used_math(child)) {
391				if (addr == offsetof(struct user, fpu.fpscr))
392					tmp = FPSCR_INIT;
393				else
394					tmp = 0;
395			} else {
396				unsigned long index;
397				ret = init_fpu(child);
398				if (ret)
399					break;
400				index = addr - offsetof(struct user, fpu);
401				tmp = ((unsigned long *)child->thread.xstate)
402					[index >> 2];
403			}
404		} else if (addr == offsetof(struct user, u_fpvalid))
405			tmp = !!tsk_used_math(child);
406		else if (addr == PT_TEXT_ADDR)
407			tmp = child->mm->start_code;
408		else if (addr == PT_DATA_ADDR)
409			tmp = child->mm->start_data;
410		else if (addr == PT_TEXT_END_ADDR)
411			tmp = child->mm->end_code;
412		else if (addr == PT_TEXT_LEN)
413			tmp = child->mm->end_code - child->mm->start_code;
414		else
415			tmp = 0;
416		ret = put_user(tmp, datap);
417		break;
418	}
419
420	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
421		ret = -EIO;
422		if ((addr & 3) || addr < 0 ||
423		    addr > sizeof(struct user) - 3)
424			break;
425
426		if (addr < sizeof(struct pt_regs))
427			ret = put_stack_long(child, addr, data);
428		else if (addr >= offsetof(struct user, fpu) &&
429			 addr < offsetof(struct user, u_fpvalid)) {
430			unsigned long index;
431			ret = init_fpu(child);
432			if (ret)
433				break;
434			index = addr - offsetof(struct user, fpu);
435			set_stopped_child_used_math(child);
436			((unsigned long *)child->thread.xstate)
437				[index >> 2] = data;
438			ret = 0;
439		} else if (addr == offsetof(struct user, u_fpvalid)) {
440			conditional_stopped_child_used_math(data, child);
441			ret = 0;
442		}
443		break;
444
445	case PTRACE_GETREGS:
446		return copy_regset_to_user(child, &user_sh_native_view,
447					   REGSET_GENERAL,
448					   0, sizeof(struct pt_regs),
449					   datap);
450	case PTRACE_SETREGS:
451		return copy_regset_from_user(child, &user_sh_native_view,
452					     REGSET_GENERAL,
453					     0, sizeof(struct pt_regs),
454					     datap);
455#ifdef CONFIG_SH_FPU
456	case PTRACE_GETFPREGS:
457		return copy_regset_to_user(child, &user_sh_native_view,
458					   REGSET_FPU,
459					   0, sizeof(struct user_fpu_struct),
460					   datap);
461	case PTRACE_SETFPREGS:
462		return copy_regset_from_user(child, &user_sh_native_view,
463					     REGSET_FPU,
464					     0, sizeof(struct user_fpu_struct),
465					     datap);
466#endif
467#ifdef CONFIG_SH_DSP
468	case PTRACE_GETDSPREGS:
469		return copy_regset_to_user(child, &user_sh_native_view,
470					   REGSET_DSP,
471					   0, sizeof(struct pt_dspregs),
472					   datap);
473	case PTRACE_SETDSPREGS:
474		return copy_regset_from_user(child, &user_sh_native_view,
475					     REGSET_DSP,
476					     0, sizeof(struct pt_dspregs),
477					     datap);
478#endif
479	default:
480		ret = ptrace_request(child, request, addr, data);
481		break;
482	}
483
484	return ret;
485}
486
487static inline int audit_arch(void)
488{
489	int arch = EM_SH;
490
491#ifdef CONFIG_CPU_LITTLE_ENDIAN
492	arch |= __AUDIT_ARCH_LE;
493#endif
494
495	return arch;
496}
497
498asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
499{
500	long ret = 0;
501
502	secure_computing_strict(regs->regs[0]);
503
504	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
505	    tracehook_report_syscall_entry(regs))
506		/*
507		 * Tracing decided this syscall should not happen.
508		 * We'll return a bogus call number to get an ENOSYS
509		 * error, but leave the original number in regs->regs[0].
510		 */
511		ret = -1L;
512
513	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
514		trace_sys_enter(regs, regs->regs[0]);
515
516	audit_syscall_entry(audit_arch(), regs->regs[3],
517			    regs->regs[4], regs->regs[5],
518			    regs->regs[6], regs->regs[7]);
519
520	return ret ?: regs->regs[0];
521}
522
523asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
524{
525	int step;
526
527	audit_syscall_exit(regs);
528
529	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
530		trace_sys_exit(regs, regs->regs[0]);
531
532	step = test_thread_flag(TIF_SINGLESTEP);
533	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
534		tracehook_report_syscall_exit(regs, step);
535}