xref: /openbmc/linux/arch/sh/kernel/ptrace_32.c (revision aafdac9a)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * SuperH process tracing
4  *
5  * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
6  * Copyright (C) 2002 - 2009  Paul Mundt
7  *
8  * Audit support by Yuichi Nakamura <ynakam@hitachisoft.jp>
9  */
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/sched/task_stack.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/errno.h>
16 #include <linux/ptrace.h>
17 #include <linux/user.h>
18 #include <linux/security.h>
19 #include <linux/signal.h>
20 #include <linux/io.h>
21 #include <linux/audit.h>
22 #include <linux/seccomp.h>
23 #include <linux/elf.h>
24 #include <linux/regset.h>
25 #include <linux/hw_breakpoint.h>
26 #include <linux/uaccess.h>
27 #include <asm/processor.h>
28 #include <asm/mmu_context.h>
29 #include <asm/syscalls.h>
30 #include <asm/fpu.h>
31 
32 #define CREATE_TRACE_POINTS
33 #include <trace/events/syscalls.h>
34 
35 /*
36  * This routine will get a word off of the process kernel stack.
37  */
get_stack_long(struct task_struct * task,int offset)38 static inline int get_stack_long(struct task_struct *task, int offset)
39 {
40 	unsigned char *stack;
41 
42 	stack = (unsigned char *)task_pt_regs(task);
43 	stack += offset;
44 	return (*((int *)stack));
45 }
46 
47 /*
48  * This routine will put a word on the process kernel stack.
49  */
put_stack_long(struct task_struct * task,int offset,unsigned long data)50 static inline int put_stack_long(struct task_struct *task, int offset,
51 				 unsigned long data)
52 {
53 	unsigned char *stack;
54 
55 	stack = (unsigned char *)task_pt_regs(task);
56 	stack += offset;
57 	*(unsigned long *) stack = data;
58 	return 0;
59 }
60 
ptrace_triggered(struct perf_event * bp,struct perf_sample_data * data,struct pt_regs * regs)61 void ptrace_triggered(struct perf_event *bp,
62 		      struct perf_sample_data *data, struct pt_regs *regs)
63 {
64 	struct perf_event_attr attr;
65 
66 	/*
67 	 * Disable the breakpoint request here since ptrace has defined a
68 	 * one-shot behaviour for breakpoint exceptions.
69 	 */
70 	attr = bp->attr;
71 	attr.disabled = true;
72 	modify_user_hw_breakpoint(bp, &attr);
73 }
74 
set_single_step(struct task_struct * tsk,unsigned long addr)75 static int set_single_step(struct task_struct *tsk, unsigned long addr)
76 {
77 	struct thread_struct *thread = &tsk->thread;
78 	struct perf_event *bp;
79 	struct perf_event_attr attr;
80 
81 	bp = thread->ptrace_bps[0];
82 	if (!bp) {
83 		ptrace_breakpoint_init(&attr);
84 
85 		attr.bp_addr = addr;
86 		attr.bp_len = HW_BREAKPOINT_LEN_2;
87 		attr.bp_type = HW_BREAKPOINT_R;
88 
89 		bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
90 						 NULL, tsk);
91 		if (IS_ERR(bp))
92 			return PTR_ERR(bp);
93 
94 		thread->ptrace_bps[0] = bp;
95 	} else {
96 		int err;
97 
98 		attr = bp->attr;
99 		attr.bp_addr = addr;
100 		/* reenable breakpoint */
101 		attr.disabled = false;
102 		err = modify_user_hw_breakpoint(bp, &attr);
103 		if (unlikely(err))
104 			return err;
105 	}
106 
107 	return 0;
108 }
109 
user_enable_single_step(struct task_struct * child)110 void user_enable_single_step(struct task_struct *child)
111 {
112 	unsigned long pc = get_stack_long(child, offsetof(struct pt_regs, pc));
113 
114 	set_tsk_thread_flag(child, TIF_SINGLESTEP);
115 
116 	set_single_step(child, pc);
117 }
118 
user_disable_single_step(struct task_struct * child)119 void user_disable_single_step(struct task_struct *child)
120 {
121 	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
122 }
123 
124 /*
125  * Called by kernel/ptrace.c when detaching..
126  *
127  * Make sure single step bits etc are not set.
128  */
ptrace_disable(struct task_struct * child)129 void ptrace_disable(struct task_struct *child)
130 {
131 	user_disable_single_step(child);
132 }
133 
genregs_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)134 static int genregs_get(struct task_struct *target,
135 		       const struct user_regset *regset,
136 		       struct membuf to)
137 {
138 	const struct pt_regs *regs = task_pt_regs(target);
139 
140 	return membuf_write(&to, regs, sizeof(struct pt_regs));
141 }
142 
genregs_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)143 static int genregs_set(struct task_struct *target,
144 		       const struct user_regset *regset,
145 		       unsigned int pos, unsigned int count,
146 		       const void *kbuf, const void __user *ubuf)
147 {
148 	struct pt_regs *regs = task_pt_regs(target);
149 	int ret;
150 
151 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
152 				 regs->regs,
153 				 0, 16 * sizeof(unsigned long));
154 	if (!ret && count > 0)
155 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
156 					 &regs->pc,
157 					 offsetof(struct pt_regs, pc),
158 					 sizeof(struct pt_regs));
159 	if (!ret)
160 		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
161 					  sizeof(struct pt_regs), -1);
162 
163 	return ret;
164 }
165 
166 #ifdef CONFIG_SH_FPU
fpregs_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)167 static int fpregs_get(struct task_struct *target,
168 	       const struct user_regset *regset,
169 	       struct membuf to)
170 {
171 	int ret;
172 
173 	ret = init_fpu(target);
174 	if (ret)
175 		return ret;
176 
177 	return membuf_write(&to, target->thread.xstate,
178 			    sizeof(struct user_fpu_struct));
179 }
180 
fpregs_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 fpregs_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 	int ret;
187 
188 	ret = init_fpu(target);
189 	if (ret)
190 		return ret;
191 
192 	set_stopped_child_used_math(target);
193 
194 	if ((boot_cpu_data.flags & CPU_HAS_FPU))
195 		return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
196 					  &target->thread.xstate->hardfpu, 0, -1);
197 
198 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
199 				  &target->thread.xstate->softfpu, 0, -1);
200 }
201 
fpregs_active(struct task_struct * target,const struct user_regset * regset)202 static int fpregs_active(struct task_struct *target,
203 			 const struct user_regset *regset)
204 {
205 	return tsk_used_math(target) ? regset->n : 0;
206 }
207 #endif
208 
209 #ifdef CONFIG_SH_DSP
dspregs_get(struct task_struct * target,const struct user_regset * regset,struct membuf to)210 static int dspregs_get(struct task_struct *target,
211 		       const struct user_regset *regset,
212 		       struct membuf to)
213 {
214 	const struct pt_dspregs *regs =
215 		(struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
216 
217 	return membuf_write(&to, regs, sizeof(struct pt_dspregs));
218 }
219 
dspregs_set(struct task_struct * target,const struct user_regset * regset,unsigned int pos,unsigned int count,const void * kbuf,const void __user * ubuf)220 static int dspregs_set(struct task_struct *target,
221 		       const struct user_regset *regset,
222 		       unsigned int pos, unsigned int count,
223 		       const void *kbuf, const void __user *ubuf)
224 {
225 	struct pt_dspregs *regs =
226 		(struct pt_dspregs *)&target->thread.dsp_status.dsp_regs;
227 	int ret;
228 
229 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs,
230 				 0, sizeof(struct pt_dspregs));
231 	if (!ret)
232 		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
233 					  sizeof(struct pt_dspregs), -1);
234 
235 	return ret;
236 }
237 
dspregs_active(struct task_struct * target,const struct user_regset * regset)238 static int dspregs_active(struct task_struct *target,
239 			  const struct user_regset *regset)
240 {
241 	struct pt_regs *regs = task_pt_regs(target);
242 
243 	return regs->sr & SR_DSP ? regset->n : 0;
244 }
245 #endif
246 
247 const struct pt_regs_offset regoffset_table[] = {
248 	REGS_OFFSET_NAME(0),
249 	REGS_OFFSET_NAME(1),
250 	REGS_OFFSET_NAME(2),
251 	REGS_OFFSET_NAME(3),
252 	REGS_OFFSET_NAME(4),
253 	REGS_OFFSET_NAME(5),
254 	REGS_OFFSET_NAME(6),
255 	REGS_OFFSET_NAME(7),
256 	REGS_OFFSET_NAME(8),
257 	REGS_OFFSET_NAME(9),
258 	REGS_OFFSET_NAME(10),
259 	REGS_OFFSET_NAME(11),
260 	REGS_OFFSET_NAME(12),
261 	REGS_OFFSET_NAME(13),
262 	REGS_OFFSET_NAME(14),
263 	REGS_OFFSET_NAME(15),
264 	REG_OFFSET_NAME(pc),
265 	REG_OFFSET_NAME(pr),
266 	REG_OFFSET_NAME(sr),
267 	REG_OFFSET_NAME(gbr),
268 	REG_OFFSET_NAME(mach),
269 	REG_OFFSET_NAME(macl),
270 	REG_OFFSET_NAME(tra),
271 	REG_OFFSET_END,
272 };
273 
274 /*
275  * These are our native regset flavours.
276  */
277 enum sh_regset {
278 	REGSET_GENERAL,
279 #ifdef CONFIG_SH_FPU
280 	REGSET_FPU,
281 #endif
282 #ifdef CONFIG_SH_DSP
283 	REGSET_DSP,
284 #endif
285 };
286 
287 static const struct user_regset sh_regsets[] = {
288 	/*
289 	 * Format is:
290 	 *	R0 --> R15
291 	 *	PC, PR, SR, GBR, MACH, MACL, TRA
292 	 */
293 	[REGSET_GENERAL] = {
294 		.core_note_type	= NT_PRSTATUS,
295 		.n		= ELF_NGREG,
296 		.size		= sizeof(long),
297 		.align		= sizeof(long),
298 		.regset_get		= genregs_get,
299 		.set		= genregs_set,
300 	},
301 
302 #ifdef CONFIG_SH_FPU
303 	[REGSET_FPU] = {
304 		.core_note_type	= NT_PRFPREG,
305 		.n		= sizeof(struct user_fpu_struct) / sizeof(long),
306 		.size		= sizeof(long),
307 		.align		= sizeof(long),
308 		.regset_get		= fpregs_get,
309 		.set		= fpregs_set,
310 		.active		= fpregs_active,
311 	},
312 #endif
313 
314 #ifdef CONFIG_SH_DSP
315 	[REGSET_DSP] = {
316 		.n		= sizeof(struct pt_dspregs) / sizeof(long),
317 		.size		= sizeof(long),
318 		.align		= sizeof(long),
319 		.regset_get		= dspregs_get,
320 		.set		= dspregs_set,
321 		.active		= dspregs_active,
322 	},
323 #endif
324 };
325 
326 static const struct user_regset_view user_sh_native_view = {
327 	.name		= "sh",
328 	.e_machine	= EM_SH,
329 	.regsets	= sh_regsets,
330 	.n		= ARRAY_SIZE(sh_regsets),
331 };
332 
task_user_regset_view(struct task_struct * task)333 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
334 {
335 	return &user_sh_native_view;
336 }
337 
arch_ptrace(struct task_struct * child,long request,unsigned long addr,unsigned long data)338 long arch_ptrace(struct task_struct *child, long request,
339 		 unsigned long addr, unsigned long data)
340 {
341 	unsigned long __user *datap = (unsigned long __user *)data;
342 	int ret;
343 
344 	switch (request) {
345 	/* read the word at location addr in the USER area. */
346 	case PTRACE_PEEKUSR: {
347 		unsigned long tmp;
348 
349 		ret = -EIO;
350 		if ((addr & 3) || addr < 0 ||
351 		    addr > sizeof(struct user) - 3)
352 			break;
353 
354 		if (addr < sizeof(struct pt_regs))
355 			tmp = get_stack_long(child, addr);
356 		else if (addr >= offsetof(struct user, fpu) &&
357 			 addr < offsetof(struct user, u_fpvalid)) {
358 			if (!tsk_used_math(child)) {
359 				if (addr == offsetof(struct user, fpu.fpscr))
360 					tmp = FPSCR_INIT;
361 				else
362 					tmp = 0;
363 			} else {
364 				unsigned long index;
365 				ret = init_fpu(child);
366 				if (ret)
367 					break;
368 				index = addr - offsetof(struct user, fpu);
369 				tmp = ((unsigned long *)child->thread.xstate)
370 					[index >> 2];
371 			}
372 		} else if (addr == offsetof(struct user, u_fpvalid))
373 			tmp = !!tsk_used_math(child);
374 		else if (addr == PT_TEXT_ADDR)
375 			tmp = child->mm->start_code;
376 		else if (addr == PT_DATA_ADDR)
377 			tmp = child->mm->start_data;
378 		else if (addr == PT_TEXT_END_ADDR)
379 			tmp = child->mm->end_code;
380 		else if (addr == PT_TEXT_LEN)
381 			tmp = child->mm->end_code - child->mm->start_code;
382 		else
383 			tmp = 0;
384 		ret = put_user(tmp, datap);
385 		break;
386 	}
387 
388 	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
389 		ret = -EIO;
390 		if ((addr & 3) || addr < 0 ||
391 		    addr > sizeof(struct user) - 3)
392 			break;
393 
394 		if (addr < sizeof(struct pt_regs))
395 			ret = put_stack_long(child, addr, data);
396 		else if (addr >= offsetof(struct user, fpu) &&
397 			 addr < offsetof(struct user, u_fpvalid)) {
398 			unsigned long index;
399 			ret = init_fpu(child);
400 			if (ret)
401 				break;
402 			index = addr - offsetof(struct user, fpu);
403 			set_stopped_child_used_math(child);
404 			((unsigned long *)child->thread.xstate)
405 				[index >> 2] = data;
406 			ret = 0;
407 		} else if (addr == offsetof(struct user, u_fpvalid)) {
408 			conditional_stopped_child_used_math(data, child);
409 			ret = 0;
410 		}
411 		break;
412 
413 	case PTRACE_GETREGS:
414 		return copy_regset_to_user(child, &user_sh_native_view,
415 					   REGSET_GENERAL,
416 					   0, sizeof(struct pt_regs),
417 					   datap);
418 	case PTRACE_SETREGS:
419 		return copy_regset_from_user(child, &user_sh_native_view,
420 					     REGSET_GENERAL,
421 					     0, sizeof(struct pt_regs),
422 					     datap);
423 #ifdef CONFIG_SH_FPU
424 	case PTRACE_GETFPREGS:
425 		return copy_regset_to_user(child, &user_sh_native_view,
426 					   REGSET_FPU,
427 					   0, sizeof(struct user_fpu_struct),
428 					   datap);
429 	case PTRACE_SETFPREGS:
430 		return copy_regset_from_user(child, &user_sh_native_view,
431 					     REGSET_FPU,
432 					     0, sizeof(struct user_fpu_struct),
433 					     datap);
434 #endif
435 #ifdef CONFIG_SH_DSP
436 	case PTRACE_GETDSPREGS:
437 		return copy_regset_to_user(child, &user_sh_native_view,
438 					   REGSET_DSP,
439 					   0, sizeof(struct pt_dspregs),
440 					   datap);
441 	case PTRACE_SETDSPREGS:
442 		return copy_regset_from_user(child, &user_sh_native_view,
443 					     REGSET_DSP,
444 					     0, sizeof(struct pt_dspregs),
445 					     datap);
446 #endif
447 	default:
448 		ret = ptrace_request(child, request, addr, data);
449 		break;
450 	}
451 
452 	return ret;
453 }
454 
do_syscall_trace_enter(struct pt_regs * regs)455 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
456 {
457 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
458 	    ptrace_report_syscall_entry(regs)) {
459 		regs->regs[0] = -ENOSYS;
460 		return -1;
461 	}
462 
463 	if (secure_computing() == -1)
464 		return -1;
465 
466 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
467 		trace_sys_enter(regs, regs->regs[0]);
468 
469 	audit_syscall_entry(regs->regs[3], regs->regs[4], regs->regs[5],
470 			    regs->regs[6], regs->regs[7]);
471 
472 	return 0;
473 }
474 
do_syscall_trace_leave(struct pt_regs * regs)475 asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
476 {
477 	int step;
478 
479 	audit_syscall_exit(regs);
480 
481 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
482 		trace_sys_exit(regs, regs->regs[0]);
483 
484 	step = test_thread_flag(TIF_SINGLESTEP);
485 	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
486 		ptrace_report_syscall_exit(regs, step);
487 }
488