xref: /openbmc/linux/arch/csky/kernel/ptrace.c (revision f97769fd)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
3 
4 #include <linux/audit.h>
5 #include <linux/elf.h>
6 #include <linux/errno.h>
7 #include <linux/kernel.h>
8 #include <linux/mm.h>
9 #include <linux/ptrace.h>
10 #include <linux/regset.h>
11 #include <linux/sched.h>
12 #include <linux/sched/task_stack.h>
13 #include <linux/signal.h>
14 #include <linux/smp.h>
15 #include <linux/tracehook.h>
16 #include <linux/uaccess.h>
17 #include <linux/user.h>
18 
19 #include <asm/thread_info.h>
20 #include <asm/page.h>
21 #include <asm/processor.h>
22 #include <asm/asm-offsets.h>
23 
24 #include <abi/regdef.h>
25 
26 #define CREATE_TRACE_POINTS
27 #include <trace/events/syscalls.h>
28 
29 /* sets the trace bits. */
30 #define TRACE_MODE_SI      (1 << 14)
31 #define TRACE_MODE_RUN     0
32 #define TRACE_MODE_MASK    ~(0x3 << 14)
33 
34 /*
35  * Make sure the single step bit is not set.
36  */
37 static void singlestep_disable(struct task_struct *tsk)
38 {
39 	struct pt_regs *regs;
40 
41 	regs = task_pt_regs(tsk);
42 	regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_RUN;
43 
44 	/* Enable irq */
45 	regs->sr |= BIT(6);
46 }
47 
48 static void singlestep_enable(struct task_struct *tsk)
49 {
50 	struct pt_regs *regs;
51 
52 	regs = task_pt_regs(tsk);
53 	regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_SI;
54 
55 	/* Disable irq */
56 	regs->sr &= ~BIT(6);
57 }
58 
59 /*
60  * Make sure the single step bit is set.
61  */
62 void user_enable_single_step(struct task_struct *child)
63 {
64 	singlestep_enable(child);
65 }
66 
67 void user_disable_single_step(struct task_struct *child)
68 {
69 	singlestep_disable(child);
70 }
71 
72 enum csky_regset {
73 	REGSET_GPR,
74 	REGSET_FPR,
75 };
76 
77 static int gpr_get(struct task_struct *target,
78 		   const struct user_regset *regset,
79 		   struct membuf to)
80 {
81 	struct pt_regs *regs = task_pt_regs(target);
82 
83 	/* Abiv1 regs->tls is fake and we need sync here. */
84 	regs->tls = task_thread_info(target)->tp_value;
85 
86 	return membuf_write(&to, regs, sizeof(regs));
87 }
88 
89 static int gpr_set(struct task_struct *target,
90 		    const struct user_regset *regset,
91 		    unsigned int pos, unsigned int count,
92 		    const void *kbuf, const void __user *ubuf)
93 {
94 	int ret;
95 	struct pt_regs regs;
96 
97 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &regs, 0, -1);
98 	if (ret)
99 		return ret;
100 
101 	regs.sr = task_pt_regs(target)->sr;
102 #ifdef CONFIG_CPU_HAS_HILO
103 	regs.dcsr = task_pt_regs(target)->dcsr;
104 #endif
105 	task_thread_info(target)->tp_value = regs.tls;
106 
107 	*task_pt_regs(target) = regs;
108 
109 	return 0;
110 }
111 
112 static int fpr_get(struct task_struct *target,
113 		   const struct user_regset *regset,
114 		   struct membuf to)
115 {
116 	struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;
117 
118 #if defined(CONFIG_CPU_HAS_FPUV2) && !defined(CONFIG_CPU_HAS_VDSP)
119 	int i;
120 	struct user_fp tmp = *regs;
121 
122 	for (i = 0; i < 16; i++) {
123 		tmp.vr[i*4] = regs->vr[i*2];
124 		tmp.vr[i*4 + 1] = regs->vr[i*2 + 1];
125 	}
126 
127 	for (i = 0; i < 32; i++)
128 		tmp.vr[64 + i] = regs->vr[32 + i];
129 
130 	return membuf_write(&to, &tmp, sizeof(tmp));
131 #else
132 	return membuf_write(&to, regs, sizeof(*regs));
133 #endif
134 }
135 
136 static int fpr_set(struct task_struct *target,
137 		   const struct user_regset *regset,
138 		   unsigned int pos, unsigned int count,
139 		   const void *kbuf, const void __user *ubuf)
140 {
141 	int ret;
142 	struct user_fp *regs = (struct user_fp *)&target->thread.user_fp;
143 
144 #if defined(CONFIG_CPU_HAS_FPUV2) && !defined(CONFIG_CPU_HAS_VDSP)
145 	int i;
146 	struct user_fp tmp;
147 
148 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tmp, 0, -1);
149 
150 	*regs = tmp;
151 
152 	for (i = 0; i < 16; i++) {
153 		regs->vr[i*2] = tmp.vr[i*4];
154 		regs->vr[i*2 + 1] = tmp.vr[i*4 + 1];
155 	}
156 
157 	for (i = 0; i < 32; i++)
158 		regs->vr[32 + i] = tmp.vr[64 + i];
159 #else
160 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
161 #endif
162 
163 	return ret;
164 }
165 
166 static const struct user_regset csky_regsets[] = {
167 	[REGSET_GPR] = {
168 		.core_note_type = NT_PRSTATUS,
169 		.n = sizeof(struct pt_regs) / sizeof(u32),
170 		.size = sizeof(u32),
171 		.align = sizeof(u32),
172 		.regset_get = gpr_get,
173 		.set = gpr_set,
174 	},
175 	[REGSET_FPR] = {
176 		.core_note_type = NT_PRFPREG,
177 		.n = sizeof(struct user_fp) / sizeof(u32),
178 		.size = sizeof(u32),
179 		.align = sizeof(u32),
180 		.regset_get = fpr_get,
181 		.set = fpr_set,
182 	},
183 };
184 
185 static const struct user_regset_view user_csky_view = {
186 	.name = "csky",
187 	.e_machine = ELF_ARCH,
188 	.regsets = csky_regsets,
189 	.n = ARRAY_SIZE(csky_regsets),
190 };
191 
192 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
193 {
194 	return &user_csky_view;
195 }
196 
197 struct pt_regs_offset {
198 	const char *name;
199 	int offset;
200 };
201 
202 #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
203 #define REG_OFFSET_END {.name = NULL, .offset = 0}
204 
205 static const struct pt_regs_offset regoffset_table[] = {
206 	REG_OFFSET_NAME(tls),
207 	REG_OFFSET_NAME(lr),
208 	REG_OFFSET_NAME(pc),
209 	REG_OFFSET_NAME(sr),
210 	REG_OFFSET_NAME(usp),
211 	REG_OFFSET_NAME(orig_a0),
212 	REG_OFFSET_NAME(a0),
213 	REG_OFFSET_NAME(a1),
214 	REG_OFFSET_NAME(a2),
215 	REG_OFFSET_NAME(a3),
216 	REG_OFFSET_NAME(regs[0]),
217 	REG_OFFSET_NAME(regs[1]),
218 	REG_OFFSET_NAME(regs[2]),
219 	REG_OFFSET_NAME(regs[3]),
220 	REG_OFFSET_NAME(regs[4]),
221 	REG_OFFSET_NAME(regs[5]),
222 	REG_OFFSET_NAME(regs[6]),
223 	REG_OFFSET_NAME(regs[7]),
224 	REG_OFFSET_NAME(regs[8]),
225 	REG_OFFSET_NAME(regs[9]),
226 #if defined(__CSKYABIV2__)
227 	REG_OFFSET_NAME(exregs[0]),
228 	REG_OFFSET_NAME(exregs[1]),
229 	REG_OFFSET_NAME(exregs[2]),
230 	REG_OFFSET_NAME(exregs[3]),
231 	REG_OFFSET_NAME(exregs[4]),
232 	REG_OFFSET_NAME(exregs[5]),
233 	REG_OFFSET_NAME(exregs[6]),
234 	REG_OFFSET_NAME(exregs[7]),
235 	REG_OFFSET_NAME(exregs[8]),
236 	REG_OFFSET_NAME(exregs[9]),
237 	REG_OFFSET_NAME(exregs[10]),
238 	REG_OFFSET_NAME(exregs[11]),
239 	REG_OFFSET_NAME(exregs[12]),
240 	REG_OFFSET_NAME(exregs[13]),
241 	REG_OFFSET_NAME(exregs[14]),
242 	REG_OFFSET_NAME(rhi),
243 	REG_OFFSET_NAME(rlo),
244 	REG_OFFSET_NAME(dcsr),
245 #endif
246 	REG_OFFSET_END,
247 };
248 
249 /**
250  * regs_query_register_offset() - query register offset from its name
251  * @name:	the name of a register
252  *
253  * regs_query_register_offset() returns the offset of a register in struct
254  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
255  */
256 int regs_query_register_offset(const char *name)
257 {
258 	const struct pt_regs_offset *roff;
259 
260 	for (roff = regoffset_table; roff->name != NULL; roff++)
261 		if (!strcmp(roff->name, name))
262 			return roff->offset;
263 	return -EINVAL;
264 }
265 
266 /**
267  * regs_within_kernel_stack() - check the address in the stack
268  * @regs:      pt_regs which contains kernel stack pointer.
269  * @addr:      address which is checked.
270  *
271  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
272  * If @addr is within the kernel stack, it returns true. If not, returns false.
273  */
274 static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
275 {
276 	return (addr & ~(THREAD_SIZE - 1))  ==
277 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1));
278 }
279 
280 /**
281  * regs_get_kernel_stack_nth() - get Nth entry of the stack
282  * @regs:	pt_regs which contains kernel stack pointer.
283  * @n:		stack entry number.
284  *
285  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
286  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
287  * this returns 0.
288  */
289 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
290 {
291 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
292 
293 	addr += n;
294 	if (regs_within_kernel_stack(regs, (unsigned long)addr))
295 		return *addr;
296 	else
297 		return 0;
298 }
299 
300 void ptrace_disable(struct task_struct *child)
301 {
302 	singlestep_disable(child);
303 }
304 
305 long arch_ptrace(struct task_struct *child, long request,
306 		 unsigned long addr, unsigned long data)
307 {
308 	long ret = -EIO;
309 
310 	switch (request) {
311 	default:
312 		ret = ptrace_request(child, request, addr, data);
313 		break;
314 	}
315 
316 	return ret;
317 }
318 
319 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
320 {
321 	if (test_thread_flag(TIF_SYSCALL_TRACE))
322 		if (tracehook_report_syscall_entry(regs))
323 			return -1;
324 
325 	if (secure_computing() == -1)
326 		return -1;
327 
328 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
329 		trace_sys_enter(regs, syscall_get_nr(current, regs));
330 
331 	audit_syscall_entry(regs_syscallid(regs), regs->a0, regs->a1, regs->a2, regs->a3);
332 	return 0;
333 }
334 
335 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
336 {
337 	audit_syscall_exit(regs);
338 
339 	if (test_thread_flag(TIF_SYSCALL_TRACE))
340 		tracehook_report_syscall_exit(regs, 0);
341 
342 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
343 		trace_sys_exit(regs, syscall_get_return_value(current, regs));
344 }
345 
346 void show_regs(struct pt_regs *fp)
347 {
348 	pr_info("\nCURRENT PROCESS:\n\n");
349 	pr_info("COMM=%s PID=%d\n", current->comm, current->pid);
350 
351 	if (current->mm) {
352 		pr_info("TEXT=%08x-%08x DATA=%08x-%08x BSS=%08x-%08x\n",
353 		       (int) current->mm->start_code,
354 		       (int) current->mm->end_code,
355 		       (int) current->mm->start_data,
356 		       (int) current->mm->end_data,
357 		       (int) current->mm->end_data,
358 		       (int) current->mm->brk);
359 		pr_info("USER-STACK=%08x  KERNEL-STACK=%08x\n\n",
360 		       (int) current->mm->start_stack,
361 		       (int) (((unsigned long) current) + 2 * PAGE_SIZE));
362 	}
363 
364 	pr_info("PC: 0x%08lx (%pS)\n", (long)fp->pc, (void *)fp->pc);
365 	pr_info("LR: 0x%08lx (%pS)\n", (long)fp->lr, (void *)fp->lr);
366 	pr_info("SP: 0x%08lx\n", (long)fp);
367 	pr_info("orig_a0: 0x%08lx\n", fp->orig_a0);
368 	pr_info("PSR: 0x%08lx\n", (long)fp->sr);
369 
370 	pr_info(" a0: 0x%08lx   a1: 0x%08lx   a2: 0x%08lx   a3: 0x%08lx\n",
371 		fp->a0, fp->a1, fp->a2, fp->a3);
372 #if defined(__CSKYABIV2__)
373 	pr_info(" r4: 0x%08lx   r5: 0x%08lx   r6: 0x%08lx   r7: 0x%08lx\n",
374 		fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
375 	pr_info(" r8: 0x%08lx   r9: 0x%08lx  r10: 0x%08lx  r11: 0x%08lx\n",
376 		fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
377 	pr_info("r12: 0x%08lx  r13: 0x%08lx  r15: 0x%08lx\n",
378 		fp->regs[8], fp->regs[9], fp->lr);
379 	pr_info("r16: 0x%08lx  r17: 0x%08lx  r18: 0x%08lx  r19: 0x%08lx\n",
380 		fp->exregs[0], fp->exregs[1], fp->exregs[2], fp->exregs[3]);
381 	pr_info("r20: 0x%08lx  r21: 0x%08lx  r22: 0x%08lx  r23: 0x%08lx\n",
382 		fp->exregs[4], fp->exregs[5], fp->exregs[6], fp->exregs[7]);
383 	pr_info("r24: 0x%08lx  r25: 0x%08lx  r26: 0x%08lx  r27: 0x%08lx\n",
384 		fp->exregs[8], fp->exregs[9], fp->exregs[10], fp->exregs[11]);
385 	pr_info("r28: 0x%08lx  r29: 0x%08lx  r30: 0x%08lx  tls: 0x%08lx\n",
386 		fp->exregs[12], fp->exregs[13], fp->exregs[14], fp->tls);
387 	pr_info(" hi: 0x%08lx   lo: 0x%08lx\n",
388 		fp->rhi, fp->rlo);
389 #else
390 	pr_info(" r6: 0x%08lx   r7: 0x%08lx   r8: 0x%08lx   r9: 0x%08lx\n",
391 		fp->regs[0], fp->regs[1], fp->regs[2], fp->regs[3]);
392 	pr_info("r10: 0x%08lx  r11: 0x%08lx  r12: 0x%08lx  r13: 0x%08lx\n",
393 		fp->regs[4], fp->regs[5], fp->regs[6], fp->regs[7]);
394 	pr_info("r14: 0x%08lx   r1: 0x%08lx\n",
395 		fp->regs[8], fp->regs[9]);
396 #endif
397 
398 	return;
399 }
400