xref: /openbmc/linux/arch/arc/kernel/ptrace.c (revision 9a29f5fc)
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(event),
50 	REG_OFFSET_NAME(user_r25),
51 	REG_OFFSET_END,
52 };
53 
54 #else
55 
56 static const struct pt_regs_offset regoffset_table[] = {
57 	REG_OFFSET_NAME(orig_r0),
58 	REG_OFFSET_NAME(event),
59 	REG_OFFSET_NAME(bta),
60 	REG_OFFSET_NAME(user_r25),
61 	REG_OFFSET_NAME(r26),
62 	REG_OFFSET_NAME(fp),
63 	REG_OFFSET_NAME(sp),
64 	REG_OFFSET_NAME(r12),
65 	REG_OFFSET_NAME(r30),
66 #ifdef CONFIG_ARC_HAS_ACCL_REGS
67 	REG_OFFSET_NAME(r58),
68 	REG_OFFSET_NAME(r59),
69 #endif
70 #ifdef CONFIG_ARC_DSP_SAVE_RESTORE_REGS
71 	REG_OFFSET_NAME(DSP_CTRL),
72 #endif
73 	REG_OFFSET_NAME(r0),
74 	REG_OFFSET_NAME(r1),
75 	REG_OFFSET_NAME(r2),
76 	REG_OFFSET_NAME(r3),
77 	REG_OFFSET_NAME(r4),
78 	REG_OFFSET_NAME(r5),
79 	REG_OFFSET_NAME(r6),
80 	REG_OFFSET_NAME(r7),
81 	REG_OFFSET_NAME(r8),
82 	REG_OFFSET_NAME(r9),
83 	REG_OFFSET_NAME(r10),
84 	REG_OFFSET_NAME(r11),
85 	REG_OFFSET_NAME(blink),
86 	REG_OFFSET_NAME(lp_end),
87 	REG_OFFSET_NAME(lp_start),
88 	REG_OFFSET_NAME(lp_count),
89 	REG_OFFSET_NAME(ei),
90 	REG_OFFSET_NAME(ldi),
91 	REG_OFFSET_NAME(jli),
92 	REG_OFFSET_NAME(ret),
93 	REG_OFFSET_NAME(status32),
94 	REG_OFFSET_END,
95 };
96 #endif
97 
98 static struct callee_regs *task_callee_regs(struct task_struct *tsk)
99 {
100 	struct callee_regs *tmp = (struct callee_regs *)tsk->thread.callee_reg;
101 	return tmp;
102 }
103 
104 static int genregs_get(struct task_struct *target,
105 		       const struct user_regset *regset,
106 		       struct membuf to)
107 {
108 	const struct pt_regs *ptregs = task_pt_regs(target);
109 	const struct callee_regs *cregs = task_callee_regs(target);
110 	unsigned int stop_pc_val;
111 
112 	membuf_zero(&to, 4);	// pad
113 	membuf_store(&to, ptregs->bta);
114 	membuf_store(&to, ptregs->lp_start);
115 	membuf_store(&to, ptregs->lp_end);
116 	membuf_store(&to, ptregs->lp_count);
117 	membuf_store(&to, ptregs->status32);
118 	membuf_store(&to, ptregs->ret);
119 	membuf_store(&to, ptregs->blink);
120 	membuf_store(&to, ptregs->fp);
121 	membuf_store(&to, ptregs->r26);	// gp
122 	membuf_store(&to, ptregs->r12);
123 	membuf_store(&to, ptregs->r11);
124 	membuf_store(&to, ptregs->r10);
125 	membuf_store(&to, ptregs->r9);
126 	membuf_store(&to, ptregs->r8);
127 	membuf_store(&to, ptregs->r7);
128 	membuf_store(&to, ptregs->r6);
129 	membuf_store(&to, ptregs->r5);
130 	membuf_store(&to, ptregs->r4);
131 	membuf_store(&to, ptregs->r3);
132 	membuf_store(&to, ptregs->r2);
133 	membuf_store(&to, ptregs->r1);
134 	membuf_store(&to, ptregs->r0);
135 	membuf_store(&to, ptregs->sp);
136 	membuf_zero(&to, 4);	// pad2
137 	membuf_store(&to, cregs->r25);
138 	membuf_store(&to, cregs->r24);
139 	membuf_store(&to, cregs->r23);
140 	membuf_store(&to, cregs->r22);
141 	membuf_store(&to, cregs->r21);
142 	membuf_store(&to, cregs->r20);
143 	membuf_store(&to, cregs->r19);
144 	membuf_store(&to, cregs->r18);
145 	membuf_store(&to, cregs->r17);
146 	membuf_store(&to, cregs->r16);
147 	membuf_store(&to, cregs->r15);
148 	membuf_store(&to, cregs->r14);
149 	membuf_store(&to, cregs->r13);
150 	membuf_store(&to, target->thread.fault_address); // efa
151 
152 	if (in_brkpt_trap(ptregs)) {
153 		stop_pc_val = target->thread.fault_address;
154 		pr_debug("\t\tstop_pc (brk-pt)\n");
155 	} else {
156 		stop_pc_val = ptregs->ret;
157 		pr_debug("\t\tstop_pc (others)\n");
158 	}
159 
160 	return membuf_store(&to, stop_pc_val); // stop_pc
161 }
162 
163 static int genregs_set(struct task_struct *target,
164 		       const struct user_regset *regset,
165 		       unsigned int pos, unsigned int count,
166 		       const void *kbuf, const void __user *ubuf)
167 {
168 	const struct pt_regs *ptregs = task_pt_regs(target);
169 	const struct callee_regs *cregs = task_callee_regs(target);
170 	int ret = 0;
171 
172 #define REG_IN_CHUNK(FIRST, NEXT, PTR)	\
173 	if (!ret)			\
174 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
175 			(void *)(PTR), \
176 			offsetof(struct user_regs_struct, FIRST), \
177 			offsetof(struct user_regs_struct, NEXT));
178 
179 #define REG_IN_ONE(LOC, PTR)		\
180 	if (!ret)			\
181 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, \
182 			(void *)(PTR), \
183 			offsetof(struct user_regs_struct, LOC), \
184 			offsetof(struct user_regs_struct, LOC) + 4);
185 
186 #define REG_IGNORE_ONE(LOC)		\
187 	if (!ret)			\
188 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, \
189 			offsetof(struct user_regs_struct, LOC), \
190 			offsetof(struct user_regs_struct, LOC) + 4);
191 
192 	REG_IGNORE_ONE(pad);
193 
194 	REG_IN_ONE(scratch.bta, &ptregs->bta);
195 	REG_IN_ONE(scratch.lp_start, &ptregs->lp_start);
196 	REG_IN_ONE(scratch.lp_end, &ptregs->lp_end);
197 	REG_IN_ONE(scratch.lp_count, &ptregs->lp_count);
198 
199 	REG_IGNORE_ONE(scratch.status32);
200 
201 	REG_IN_ONE(scratch.ret, &ptregs->ret);
202 	REG_IN_ONE(scratch.blink, &ptregs->blink);
203 	REG_IN_ONE(scratch.fp, &ptregs->fp);
204 	REG_IN_ONE(scratch.gp, &ptregs->r26);
205 	REG_IN_ONE(scratch.r12, &ptregs->r12);
206 	REG_IN_ONE(scratch.r11, &ptregs->r11);
207 	REG_IN_ONE(scratch.r10, &ptregs->r10);
208 	REG_IN_ONE(scratch.r9, &ptregs->r9);
209 	REG_IN_ONE(scratch.r8, &ptregs->r8);
210 	REG_IN_ONE(scratch.r7, &ptregs->r7);
211 	REG_IN_ONE(scratch.r6, &ptregs->r6);
212 	REG_IN_ONE(scratch.r5, &ptregs->r5);
213 	REG_IN_ONE(scratch.r4, &ptregs->r4);
214 	REG_IN_ONE(scratch.r3, &ptregs->r3);
215 	REG_IN_ONE(scratch.r2, &ptregs->r2);
216 	REG_IN_ONE(scratch.r1, &ptregs->r1);
217 	REG_IN_ONE(scratch.r0, &ptregs->r0);
218 	REG_IN_ONE(scratch.sp, &ptregs->sp);
219 
220 	REG_IGNORE_ONE(pad2);
221 
222 	REG_IN_ONE(callee.r25, &cregs->r25);
223 	REG_IN_ONE(callee.r24, &cregs->r24);
224 	REG_IN_ONE(callee.r23, &cregs->r23);
225 	REG_IN_ONE(callee.r22, &cregs->r22);
226 	REG_IN_ONE(callee.r21, &cregs->r21);
227 	REG_IN_ONE(callee.r20, &cregs->r20);
228 	REG_IN_ONE(callee.r19, &cregs->r19);
229 	REG_IN_ONE(callee.r18, &cregs->r18);
230 	REG_IN_ONE(callee.r17, &cregs->r17);
231 	REG_IN_ONE(callee.r16, &cregs->r16);
232 	REG_IN_ONE(callee.r15, &cregs->r15);
233 	REG_IN_ONE(callee.r14, &cregs->r14);
234 	REG_IN_ONE(callee.r13, &cregs->r13);
235 
236 	REG_IGNORE_ONE(efa);			/* efa update invalid */
237 	REG_IGNORE_ONE(stop_pc);		/* PC updated via @ret */
238 
239 	return ret;
240 }
241 
242 #ifdef CONFIG_ISA_ARCV2
243 static int arcv2regs_get(struct task_struct *target,
244 		       const struct user_regset *regset,
245 		       struct membuf to)
246 {
247 	const struct pt_regs *regs = task_pt_regs(target);
248 
249 	if (IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS))
250 		/*
251 		 * itemized copy not needed like above as layout of regs (r30,r58,r59)
252 		 * is exactly same in kernel (pt_regs) and userspace (user_regs_arcv2)
253 		 */
254 		return membuf_write(&to, &regs->r30, sizeof(struct user_regs_arcv2));
255 
256 
257 	membuf_write(&to, &regs->r30, 4); /* r30 only */
258 	return membuf_zero(&to, sizeof(struct user_regs_arcv2) - 4);
259 }
260 
261 static int arcv2regs_set(struct task_struct *target,
262 		       const struct user_regset *regset,
263 		       unsigned int pos, unsigned int count,
264 		       const void *kbuf, const void __user *ubuf)
265 {
266 	const struct pt_regs *regs = task_pt_regs(target);
267 	int ret, copy_sz;
268 
269 	if (IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS))
270 		copy_sz = sizeof(struct user_regs_arcv2);
271 	else
272 		copy_sz = 4;	/* r30 only */
273 
274 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, (void *)&regs->r30,
275 				  0, copy_sz);
276 
277 	return ret;
278 }
279 
280 #endif
281 
282 enum arc_getset {
283 	REGSET_CMN,
284 	REGSET_ARCV2,
285 };
286 
287 static const struct user_regset arc_regsets[] = {
288 	[REGSET_CMN] = {
289 	       .core_note_type = NT_PRSTATUS,
290 	       .n = ELF_NGREG,
291 	       .size = sizeof(unsigned long),
292 	       .align = sizeof(unsigned long),
293 	       .regset_get = genregs_get,
294 	       .set = genregs_set,
295 	},
296 #ifdef CONFIG_ISA_ARCV2
297 	[REGSET_ARCV2] = {
298 	       .core_note_type = NT_ARC_V2,
299 	       .n = ELF_ARCV2REG,
300 	       .size = sizeof(unsigned long),
301 	       .align = sizeof(unsigned long),
302 	       .regset_get = arcv2regs_get,
303 	       .set = arcv2regs_set,
304 	},
305 #endif
306 };
307 
308 static const struct user_regset_view user_arc_view = {
309 	.name		= "arc",
310 	.e_machine	= EM_ARC_INUSE,
311 	.regsets	= arc_regsets,
312 	.n		= ARRAY_SIZE(arc_regsets)
313 };
314 
315 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
316 {
317 	return &user_arc_view;
318 }
319 
320 void ptrace_disable(struct task_struct *child)
321 {
322 }
323 
324 long arch_ptrace(struct task_struct *child, long request,
325 		 unsigned long addr, unsigned long data)
326 {
327 	int ret = -EIO;
328 
329 	pr_debug("REQ=%ld: ADDR =0x%lx, DATA=0x%lx)\n", request, addr, data);
330 
331 	switch (request) {
332 	case PTRACE_GET_THREAD_AREA:
333 		ret = put_user(task_thread_info(child)->thr_ptr,
334 			       (unsigned long __user *)data);
335 		break;
336 	default:
337 		ret = ptrace_request(child, request, addr, data);
338 		break;
339 	}
340 
341 	return ret;
342 }
343 
344 asmlinkage int syscall_trace_entry(struct pt_regs *regs)
345 {
346 	if (test_thread_flag(TIF_SYSCALL_TRACE))
347 		if (ptrace_report_syscall_entry(regs))
348 			return ULONG_MAX;
349 
350 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
351 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
352 		trace_sys_enter(regs, syscall_get_nr(current, regs));
353 #endif
354 
355 	return regs->r8;
356 }
357 
358 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
359 {
360 	if (test_thread_flag(TIF_SYSCALL_TRACE))
361 		ptrace_report_syscall_exit(regs, 0);
362 
363 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
364 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
365 		trace_sys_exit(regs, regs_return_value(regs));
366 #endif
367 }
368 
369 int regs_query_register_offset(const char *name)
370 {
371 	const struct pt_regs_offset *roff;
372 
373 	for (roff = regoffset_table; roff->name != NULL; roff++)
374 		if (!strcmp(roff->name, name))
375 			return roff->offset;
376 	return -EINVAL;
377 }
378 
379 const char *regs_query_register_name(unsigned int offset)
380 {
381 	const struct pt_regs_offset *roff;
382 	for (roff = regoffset_table; roff->name != NULL; roff++)
383 		if (roff->offset == offset)
384 			return roff->name;
385 	return NULL;
386 }
387 
388 bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
389 {
390 	return (addr & ~(THREAD_SIZE - 1))  ==
391 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
392 }
393 
394 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
395 {
396 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
397 
398 	addr += n;
399 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
400 		return *addr;
401 	else
402 		return 0;
403 }
404