xref: /linux/arch/arc/kernel/ptrace.c (revision acbf6de674ef7b1b5870b25e7b3c695bf84273d0)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4  */
5 
6 #include <linux/ptrace.h>
7 #include <linux/sched/task_stack.h>
8 #include <linux/regset.h>
9 #include <linux/unistd.h>
10 #include <linux/elf.h>
11 
12 #define CREATE_TRACE_POINTS
13 #include <trace/events/syscalls.h>
14 
15 struct pt_regs_offset {
16 	const char *name;
17 	int offset;
18 };
19 
20 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
21 #define REG_OFFSET_END {.name = NULL, .offset = 0}
22 
23 #ifdef CONFIG_ISA_ARCOMPACT
24 static const struct pt_regs_offset regoffset_table[] = {
25 	REG_OFFSET_NAME(bta),
26 	REG_OFFSET_NAME(lp_start),
27 	REG_OFFSET_NAME(lp_end),
28 	REG_OFFSET_NAME(lp_count),
29 	REG_OFFSET_NAME(status32),
30 	REG_OFFSET_NAME(ret),
31 	REG_OFFSET_NAME(blink),
32 	REG_OFFSET_NAME(fp),
33 	REG_OFFSET_NAME(r26),
34 	REG_OFFSET_NAME(r12),
35 	REG_OFFSET_NAME(r11),
36 	REG_OFFSET_NAME(r10),
37 	REG_OFFSET_NAME(r9),
38 	REG_OFFSET_NAME(r8),
39 	REG_OFFSET_NAME(r7),
40 	REG_OFFSET_NAME(r6),
41 	REG_OFFSET_NAME(r5),
42 	REG_OFFSET_NAME(r4),
43 	REG_OFFSET_NAME(r3),
44 	REG_OFFSET_NAME(r2),
45 	REG_OFFSET_NAME(r1),
46 	REG_OFFSET_NAME(r0),
47 	REG_OFFSET_NAME(sp),
48 	REG_OFFSET_NAME(orig_r0),
49 	REG_OFFSET_NAME(ecr),
50 	REG_OFFSET_END,
51 };
52 
53 #else
54 
55 static const struct pt_regs_offset regoffset_table[] = {
56 	REG_OFFSET_NAME(orig_r0),
57 	REG_OFFSET_NAME(ecr),
58 	REG_OFFSET_NAME(bta),
59 	REG_OFFSET_NAME(r26),
60 	REG_OFFSET_NAME(fp),
61 	REG_OFFSET_NAME(sp),
62 	REG_OFFSET_NAME(r12),
63 	REG_OFFSET_NAME(r30),
64 #ifdef CONFIG_ARC_HAS_ACCL_REGS
65 	REG_OFFSET_NAME(r58),
66 	REG_OFFSET_NAME(r59),
67 #endif
68 #ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
69 	REG_OFFSET_NAME(DSP_CTRL),
70 #endif
71 	REG_OFFSET_NAME(r0),
72 	REG_OFFSET_NAME(r1),
73 	REG_OFFSET_NAME(r2),
74 	REG_OFFSET_NAME(r3),
75 	REG_OFFSET_NAME(r4),
76 	REG_OFFSET_NAME(r5),
77 	REG_OFFSET_NAME(r6),
78 	REG_OFFSET_NAME(r7),
79 	REG_OFFSET_NAME(r8),
80 	REG_OFFSET_NAME(r9),
81 	REG_OFFSET_NAME(r10),
82 	REG_OFFSET_NAME(r11),
83 	REG_OFFSET_NAME(blink),
84 	REG_OFFSET_NAME(lp_end),
85 	REG_OFFSET_NAME(lp_start),
86 	REG_OFFSET_NAME(lp_count),
87 	REG_OFFSET_NAME(ei),
88 	REG_OFFSET_NAME(ldi),
89 	REG_OFFSET_NAME(jli),
90 	REG_OFFSET_NAME(ret),
91 	REG_OFFSET_NAME(status32),
92 	REG_OFFSET_END,
93 };
94 #endif
95 
96 static struct callee_regs *task_callee_regs(struct task_struct *tsk)
97 {
98 	struct callee_regs *tmp = (struct callee_regs *)tsk->thread.callee_reg;
99 	return tmp;
100 }
101 
102 static int genregs_get(struct task_struct *target,
103 		       const struct user_regset *regset,
104 		       struct membuf to)
105 {
106 	const struct pt_regs *ptregs = task_pt_regs(target);
107 	const struct callee_regs *cregs = task_callee_regs(target);
108 	unsigned int stop_pc_val;
109 
110 	membuf_zero(&to, 4);	// pad
111 	membuf_store(&to, ptregs->bta);
112 	membuf_store(&to, ptregs->lp_start);
113 	membuf_store(&to, ptregs->lp_end);
114 	membuf_store(&to, ptregs->lp_count);
115 	membuf_store(&to, ptregs->status32);
116 	membuf_store(&to, ptregs->ret);
117 	membuf_store(&to, ptregs->blink);
118 	membuf_store(&to, ptregs->fp);
119 	membuf_store(&to, ptregs->r26);	// gp
120 	membuf_store(&to, ptregs->r12);
121 	membuf_store(&to, ptregs->r11);
122 	membuf_store(&to, ptregs->r10);
123 	membuf_store(&to, ptregs->r9);
124 	membuf_store(&to, ptregs->r8);
125 	membuf_store(&to, ptregs->r7);
126 	membuf_store(&to, ptregs->r6);
127 	membuf_store(&to, ptregs->r5);
128 	membuf_store(&to, ptregs->r4);
129 	membuf_store(&to, ptregs->r3);
130 	membuf_store(&to, ptregs->r2);
131 	membuf_store(&to, ptregs->r1);
132 	membuf_store(&to, ptregs->r0);
133 	membuf_store(&to, ptregs->sp);
134 	membuf_zero(&to, 4);	// pad2
135 	membuf_store(&to, cregs->r25);
136 	membuf_store(&to, cregs->r24);
137 	membuf_store(&to, cregs->r23);
138 	membuf_store(&to, cregs->r22);
139 	membuf_store(&to, cregs->r21);
140 	membuf_store(&to, cregs->r20);
141 	membuf_store(&to, cregs->r19);
142 	membuf_store(&to, cregs->r18);
143 	membuf_store(&to, cregs->r17);
144 	membuf_store(&to, cregs->r16);
145 	membuf_store(&to, cregs->r15);
146 	membuf_store(&to, cregs->r14);
147 	membuf_store(&to, cregs->r13);
148 	membuf_store(&to, target->thread.fault_address); // efa
149 
150 	if (in_brkpt_trap(ptregs)) {
151 		stop_pc_val = target->thread.fault_address;
152 		pr_debug("\t\tstop_pc (brk-pt)\n");
153 	} else {
154 		stop_pc_val = ptregs->ret;
155 		pr_debug("\t\tstop_pc (others)\n");
156 	}
157 
158 	return membuf_store(&to, stop_pc_val); // stop_pc
159 }
160 
161 static int genregs_set(struct task_struct *target,
162 		       const struct user_regset *regset,
163 		       unsigned int pos, unsigned int count,
164 		       const void *kbuf, const void __user *ubuf)
165 {
166 	const struct pt_regs *ptregs = task_pt_regs(target);
167 	const struct callee_regs *cregs = task_callee_regs(target);
168 	int ret = 0;
169 
170 #define REG_IN_CHUNK(FIRST, NEXT, PTR)	\
171 	if (!ret)			\
172 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
173 			(void *)(PTR), \
174 			offsetof(struct user_regs_struct, FIRST), \
175 			offsetof(struct user_regs_struct, NEXT));
176 
177 #define REG_IN_ONE(LOC, PTR)		\
178 	if (!ret)			\
179 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
180 			(void *)(PTR), \
181 			offsetof(struct user_regs_struct, LOC), \
182 			offsetof(struct user_regs_struct, LOC) + 4);
183 
184 #define REG_IGNORE_ONE(LOC)		\
185 	if (!ret)			\
186 		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
187 			offsetof(struct user_regs_struct, LOC), \
188 			offsetof(struct user_regs_struct, LOC) + 4);
189 
190 	REG_IGNORE_ONE(pad);
191 
192 	REG_IN_ONE(scratch.bta, &ptregs->bta);
193 	REG_IN_ONE(scratch.lp_start, &ptregs->lp_start);
194 	REG_IN_ONE(scratch.lp_end, &ptregs->lp_end);
195 	REG_IN_ONE(scratch.lp_count, &ptregs->lp_count);
196 
197 	REG_IGNORE_ONE(scratch.status32);
198 
199 	REG_IN_ONE(scratch.ret, &ptregs->ret);
200 	REG_IN_ONE(scratch.blink, &ptregs->blink);
201 	REG_IN_ONE(scratch.fp, &ptregs->fp);
202 	REG_IN_ONE(scratch.gp, &ptregs->r26);
203 	REG_IN_ONE(scratch.r12, &ptregs->r12);
204 	REG_IN_ONE(scratch.r11, &ptregs->r11);
205 	REG_IN_ONE(scratch.r10, &ptregs->r10);
206 	REG_IN_ONE(scratch.r9, &ptregs->r9);
207 	REG_IN_ONE(scratch.r8, &ptregs->r8);
208 	REG_IN_ONE(scratch.r7, &ptregs->r7);
209 	REG_IN_ONE(scratch.r6, &ptregs->r6);
210 	REG_IN_ONE(scratch.r5, &ptregs->r5);
211 	REG_IN_ONE(scratch.r4, &ptregs->r4);
212 	REG_IN_ONE(scratch.r3, &ptregs->r3);
213 	REG_IN_ONE(scratch.r2, &ptregs->r2);
214 	REG_IN_ONE(scratch.r1, &ptregs->r1);
215 	REG_IN_ONE(scratch.r0, &ptregs->r0);
216 	REG_IN_ONE(scratch.sp, &ptregs->sp);
217 
218 	REG_IGNORE_ONE(pad2);
219 
220 	REG_IN_ONE(callee.r25, &cregs->r25);
221 	REG_IN_ONE(callee.r24, &cregs->r24);
222 	REG_IN_ONE(callee.r23, &cregs->r23);
223 	REG_IN_ONE(callee.r22, &cregs->r22);
224 	REG_IN_ONE(callee.r21, &cregs->r21);
225 	REG_IN_ONE(callee.r20, &cregs->r20);
226 	REG_IN_ONE(callee.r19, &cregs->r19);
227 	REG_IN_ONE(callee.r18, &cregs->r18);
228 	REG_IN_ONE(callee.r17, &cregs->r17);
229 	REG_IN_ONE(callee.r16, &cregs->r16);
230 	REG_IN_ONE(callee.r15, &cregs->r15);
231 	REG_IN_ONE(callee.r14, &cregs->r14);
232 	REG_IN_ONE(callee.r13, &cregs->r13);
233 
234 	REG_IGNORE_ONE(efa);			/* efa update invalid */
235 	REG_IGNORE_ONE(stop_pc);		/* PC updated via @ret */
236 
237 	return ret;
238 }
239 
240 #ifdef CONFIG_ISA_ARCV2
241 static int arcv2regs_get(struct task_struct *target,
242 		       const struct user_regset *regset,
243 		       struct membuf to)
244 {
245 	const struct pt_regs *regs = task_pt_regs(target);
246 
247 	if (IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS))
248 		/*
249 		 * itemized copy not needed like above as layout of regs (r30,r58,r59)
250 		 * is exactly same in kernel (pt_regs) and userspace (user_regs_arcv2)
251 		 */
252 		return membuf_write(&to, &regs->r30, sizeof(struct user_regs_arcv2));
253 
254 
255 	membuf_write(&to, &regs->r30, 4); /* r30 only */
256 	return membuf_zero(&to, sizeof(struct user_regs_arcv2) - 4);
257 }
258 
259 static int arcv2regs_set(struct task_struct *target,
260 		       const struct user_regset *regset,
261 		       unsigned int pos, unsigned int count,
262 		       const void *kbuf, const void __user *ubuf)
263 {
264 	const struct pt_regs *regs = task_pt_regs(target);
265 	int ret, copy_sz;
266 
267 	if (IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS))
268 		copy_sz = sizeof(struct user_regs_arcv2);
269 	else
270 		copy_sz = 4;	/* r30 only */
271 
272 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, (void *)&regs->r30,
273 				  0, copy_sz);
274 
275 	return ret;
276 }
277 
278 #endif
279 
280 enum arc_getset {
281 	REGSET_CMN,
282 	REGSET_ARCV2,
283 };
284 
285 static const struct user_regset arc_regsets[] = {
286 	[REGSET_CMN] = {
287 	       .core_note_type = NT_PRSTATUS,
288 	       .n = ELF_NGREG,
289 	       .size = sizeof(unsigned long),
290 	       .align = sizeof(unsigned long),
291 	       .regset_get = genregs_get,
292 	       .set = genregs_set,
293 	},
294 #ifdef CONFIG_ISA_ARCV2
295 	[REGSET_ARCV2] = {
296 	       .core_note_type = NT_ARC_V2,
297 	       .n = ELF_ARCV2REG,
298 	       .size = sizeof(unsigned long),
299 	       .align = sizeof(unsigned long),
300 	       .regset_get = arcv2regs_get,
301 	       .set = arcv2regs_set,
302 	},
303 #endif
304 };
305 
306 static const struct user_regset_view user_arc_view = {
307 	.name		= "arc",
308 	.e_machine	= EM_ARC_INUSE,
309 	.regsets	= arc_regsets,
310 	.n		= ARRAY_SIZE(arc_regsets)
311 };
312 
313 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
314 {
315 	return &user_arc_view;
316 }
317 
318 void ptrace_disable(struct task_struct *child)
319 {
320 }
321 
322 long arch_ptrace(struct task_struct *child, long request,
323 		 unsigned long addr, unsigned long data)
324 {
325 	int ret = -EIO;
326 
327 	pr_debug("REQ=%ld: ADDR =0x%lx, DATA=0x%lx)\n", request, addr, data);
328 
329 	switch (request) {
330 	case PTRACE_GET_THREAD_AREA:
331 		ret = put_user(task_thread_info(child)->thr_ptr,
332 			       (unsigned long __user *)data);
333 		break;
334 	default:
335 		ret = ptrace_request(child, request, addr, data);
336 		break;
337 	}
338 
339 	return ret;
340 }
341 
342 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
343 {
344 	if (test_thread_flag(TIF_SYSCALL_TRACE))
345 		if (ptrace_report_syscall_entry(regs))
346 			return ULONG_MAX;
347 
348 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
349 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
350 		trace_sys_enter(regs, syscall_get_nr(current, regs));
351 #endif
352 
353 	return regs->r8;
354 }
355 
356 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
357 {
358 	if (test_thread_flag(TIF_SYSCALL_TRACE))
359 		ptrace_report_syscall_exit(regs, 0);
360 
361 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
362 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
363 		trace_sys_exit(regs, regs_return_value(regs));
364 #endif
365 }
366 
367 int regs_query_register_offset(const char *name)
368 {
369 	const struct pt_regs_offset *roff;
370 
371 	for (roff = regoffset_table; roff->name != NULL; roff++)
372 		if (!strcmp(roff->name, name))
373 			return roff->offset;
374 	return -EINVAL;
375 }
376 
377 const char *regs_query_register_name(unsigned int offset)
378 {
379 	const struct pt_regs_offset *roff;
380 	for (roff = regoffset_table; roff->name != NULL; roff++)
381 		if (roff->offset == offset)
382 			return roff->name;
383 	return NULL;
384 }
385 
386 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
387 {
388 	return (addr & ~(THREAD_SIZE - 1))  ==
389 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
390 }
391 
392 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
393 {
394 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
395 
396 	addr += n;
397 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
398 		return *addr;
399 	else
400 		return 0;
401 }
402