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13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/spinlock.h>
16#include <linux/hardirq.h>
17#include <linux/uaccess.h>
18#include <linux/ftrace.h>
19#include <linux/percpu.h>
20#include <linux/sched.h>
21#include <linux/slab.h>
22#include <linux/init.h>
23#include <linux/list.h>
24#include <linux/module.h>
25#include <linux/memory.h>
26#include <linux/vmalloc.h>
27
28#include <trace/syscall.h>
29
30#include <asm/set_memory.h>
31#include <asm/kprobes.h>
32#include <asm/ftrace.h>
33#include <asm/nops.h>
34#include <asm/text-patching.h>
35
36#ifdef CONFIG_DYNAMIC_FTRACE
37
38static int ftrace_poke_late = 0;
39
40int ftrace_arch_code_modify_prepare(void)
41 __acquires(&text_mutex)
42{
43
44
45
46
47
48 mutex_lock(&text_mutex);
49 ftrace_poke_late = 1;
50 return 0;
51}
52
53int ftrace_arch_code_modify_post_process(void)
54 __releases(&text_mutex)
55{
56
57
58
59
60
61 text_poke_finish();
62 ftrace_poke_late = 0;
63 mutex_unlock(&text_mutex);
64 return 0;
65}
66
67static const char *ftrace_nop_replace(void)
68{
69 return x86_nops[5];
70}
71
72static const char *ftrace_call_replace(unsigned long ip, unsigned long addr)
73{
74 return text_gen_insn(CALL_INSN_OPCODE, (void *)ip, (void *)addr);
75}
76
77static int ftrace_verify_code(unsigned long ip, const char *old_code)
78{
79 char cur_code[MCOUNT_INSN_SIZE];
80
81
82
83
84
85
86
87
88
89 if (copy_from_kernel_nofault(cur_code, (void *)ip, MCOUNT_INSN_SIZE)) {
90 WARN_ON(1);
91 return -EFAULT;
92 }
93
94
95 if (memcmp(cur_code, old_code, MCOUNT_INSN_SIZE) != 0) {
96 WARN_ON(1);
97 return -EINVAL;
98 }
99
100 return 0;
101}
102
103
104
105
106
107
108static int __ref
109ftrace_modify_code_direct(unsigned long ip, const char *old_code,
110 const char *new_code)
111{
112 int ret = ftrace_verify_code(ip, old_code);
113 if (ret)
114 return ret;
115
116
117 if (ftrace_poke_late)
118 text_poke_queue((void *)ip, new_code, MCOUNT_INSN_SIZE, NULL);
119 else
120 text_poke_early((void *)ip, new_code, MCOUNT_INSN_SIZE);
121 return 0;
122}
123
124int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
125{
126 unsigned long ip = rec->ip;
127 const char *new, *old;
128
129 old = ftrace_call_replace(ip, addr);
130 new = ftrace_nop_replace();
131
132
133
134
135
136
137
138
139
140 if (addr == MCOUNT_ADDR)
141 return ftrace_modify_code_direct(ip, old, new);
142
143
144
145
146
147 WARN_ONCE(1, "invalid use of ftrace_make_nop");
148 return -EINVAL;
149}
150
151int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
152{
153 unsigned long ip = rec->ip;
154 const char *new, *old;
155
156 old = ftrace_nop_replace();
157 new = ftrace_call_replace(ip, addr);
158
159
160 return ftrace_modify_code_direct(rec->ip, old, new);
161}
162
163
164
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166
167
168
169
170
171int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
172 unsigned long addr)
173{
174 WARN_ON(1);
175 return -EINVAL;
176}
177
178int ftrace_update_ftrace_func(ftrace_func_t func)
179{
180 unsigned long ip;
181 const char *new;
182
183 ip = (unsigned long)(&ftrace_call);
184 new = ftrace_call_replace(ip, (unsigned long)func);
185 text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
186
187 ip = (unsigned long)(&ftrace_regs_call);
188 new = ftrace_call_replace(ip, (unsigned long)func);
189 text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
190
191 return 0;
192}
193
194void ftrace_replace_code(int enable)
195{
196 struct ftrace_rec_iter *iter;
197 struct dyn_ftrace *rec;
198 const char *new, *old;
199 int ret;
200
201 for_ftrace_rec_iter(iter) {
202 rec = ftrace_rec_iter_record(iter);
203
204 switch (ftrace_test_record(rec, enable)) {
205 case FTRACE_UPDATE_IGNORE:
206 default:
207 continue;
208
209 case FTRACE_UPDATE_MAKE_CALL:
210 old = ftrace_nop_replace();
211 break;
212
213 case FTRACE_UPDATE_MODIFY_CALL:
214 case FTRACE_UPDATE_MAKE_NOP:
215 old = ftrace_call_replace(rec->ip, ftrace_get_addr_curr(rec));
216 break;
217 }
218
219 ret = ftrace_verify_code(rec->ip, old);
220 if (ret) {
221 ftrace_bug(ret, rec);
222 return;
223 }
224 }
225
226 for_ftrace_rec_iter(iter) {
227 rec = ftrace_rec_iter_record(iter);
228
229 switch (ftrace_test_record(rec, enable)) {
230 case FTRACE_UPDATE_IGNORE:
231 default:
232 continue;
233
234 case FTRACE_UPDATE_MAKE_CALL:
235 case FTRACE_UPDATE_MODIFY_CALL:
236 new = ftrace_call_replace(rec->ip, ftrace_get_addr_new(rec));
237 break;
238
239 case FTRACE_UPDATE_MAKE_NOP:
240 new = ftrace_nop_replace();
241 break;
242 }
243
244 text_poke_queue((void *)rec->ip, new, MCOUNT_INSN_SIZE, NULL);
245 ftrace_update_record(rec, enable);
246 }
247 text_poke_finish();
248}
249
250void arch_ftrace_update_code(int command)
251{
252 ftrace_modify_all_code(command);
253}
254
255int __init ftrace_dyn_arch_init(void)
256{
257 return 0;
258}
259
260
261#ifdef CONFIG_X86_64
262
263#ifdef CONFIG_MODULES
264#include <linux/moduleloader.h>
265
266static inline void *alloc_tramp(unsigned long size)
267{
268 return module_alloc(size);
269}
270static inline void tramp_free(void *tramp)
271{
272 module_memfree(tramp);
273}
274#else
275
276static inline void *alloc_tramp(unsigned long size)
277{
278 return NULL;
279}
280static inline void tramp_free(void *tramp) { }
281#endif
282
283
284extern void ftrace_regs_caller_end(void);
285extern void ftrace_regs_caller_ret(void);
286extern void ftrace_caller_end(void);
287extern void ftrace_caller_op_ptr(void);
288extern void ftrace_regs_caller_op_ptr(void);
289extern void ftrace_regs_caller_jmp(void);
290
291
292
293#define OP_REF_SIZE 7
294
295
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297
298
299
300
301
302
303union ftrace_op_code_union {
304 char code[OP_REF_SIZE];
305 struct {
306 char op[3];
307 int offset;
308 } __attribute__((packed));
309};
310
311#define RET_SIZE 1
312
313static unsigned long
314create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
315{
316 unsigned long start_offset;
317 unsigned long end_offset;
318 unsigned long op_offset;
319 unsigned long call_offset;
320 unsigned long jmp_offset;
321 unsigned long offset;
322 unsigned long npages;
323 unsigned long size;
324 unsigned long retq;
325 unsigned long *ptr;
326 void *trampoline;
327 void *ip;
328
329 unsigned const char op_ref[] = { 0x48, 0x8b, 0x15 };
330 union ftrace_op_code_union op_ptr;
331 int ret;
332
333 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
334 start_offset = (unsigned long)ftrace_regs_caller;
335 end_offset = (unsigned long)ftrace_regs_caller_end;
336 op_offset = (unsigned long)ftrace_regs_caller_op_ptr;
337 call_offset = (unsigned long)ftrace_regs_call;
338 jmp_offset = (unsigned long)ftrace_regs_caller_jmp;
339 } else {
340 start_offset = (unsigned long)ftrace_caller;
341 end_offset = (unsigned long)ftrace_caller_end;
342 op_offset = (unsigned long)ftrace_caller_op_ptr;
343 call_offset = (unsigned long)ftrace_call;
344 jmp_offset = 0;
345 }
346
347 size = end_offset - start_offset;
348
349
350
351
352
353
354 trampoline = alloc_tramp(size + RET_SIZE + sizeof(void *));
355 if (!trampoline)
356 return 0;
357
358 *tramp_size = size + RET_SIZE + sizeof(void *);
359 npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE);
360
361
362 ret = copy_from_kernel_nofault(trampoline, (void *)start_offset, size);
363 if (WARN_ON(ret < 0))
364 goto fail;
365
366 ip = trampoline + size;
367
368
369 retq = (unsigned long)ftrace_stub;
370 ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE);
371 if (WARN_ON(ret < 0))
372 goto fail;
373
374
375 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
376
377 ip = trampoline + (jmp_offset - start_offset);
378 if (WARN_ON(*(char *)ip != 0x75))
379 goto fail;
380 ret = copy_from_kernel_nofault(ip, x86_nops[2], 2);
381 if (ret < 0)
382 goto fail;
383 }
384
385
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387
388
389
390
391
392
393 ptr = (unsigned long *)(trampoline + size + RET_SIZE);
394 *ptr = (unsigned long)ops;
395
396 op_offset -= start_offset;
397 memcpy(&op_ptr, trampoline + op_offset, OP_REF_SIZE);
398
399
400 if (WARN_ON(memcmp(op_ptr.op, op_ref, 3) != 0))
401 goto fail;
402
403
404 offset = (unsigned long)ptr;
405 offset -= (unsigned long)trampoline + op_offset + OP_REF_SIZE;
406
407 op_ptr.offset = offset;
408
409
410 memcpy(trampoline + op_offset, &op_ptr, OP_REF_SIZE);
411
412
413 mutex_lock(&text_mutex);
414 call_offset -= start_offset;
415 memcpy(trampoline + call_offset,
416 text_gen_insn(CALL_INSN_OPCODE,
417 trampoline + call_offset,
418 ftrace_ops_get_func(ops)), CALL_INSN_SIZE);
419 mutex_unlock(&text_mutex);
420
421
422 ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
423
424 set_vm_flush_reset_perms(trampoline);
425
426 if (likely(system_state != SYSTEM_BOOTING))
427 set_memory_ro((unsigned long)trampoline, npages);
428 set_memory_x((unsigned long)trampoline, npages);
429 return (unsigned long)trampoline;
430fail:
431 tramp_free(trampoline);
432 return 0;
433}
434
435void set_ftrace_ops_ro(void)
436{
437 struct ftrace_ops *ops;
438 unsigned long start_offset;
439 unsigned long end_offset;
440 unsigned long npages;
441 unsigned long size;
442
443 do_for_each_ftrace_op(ops, ftrace_ops_list) {
444 if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
445 continue;
446
447 if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
448 start_offset = (unsigned long)ftrace_regs_caller;
449 end_offset = (unsigned long)ftrace_regs_caller_end;
450 } else {
451 start_offset = (unsigned long)ftrace_caller;
452 end_offset = (unsigned long)ftrace_caller_end;
453 }
454 size = end_offset - start_offset;
455 size = size + RET_SIZE + sizeof(void *);
456 npages = DIV_ROUND_UP(size, PAGE_SIZE);
457 set_memory_ro((unsigned long)ops->trampoline, npages);
458 } while_for_each_ftrace_op(ops);
459}
460
461static unsigned long calc_trampoline_call_offset(bool save_regs)
462{
463 unsigned long start_offset;
464 unsigned long call_offset;
465
466 if (save_regs) {
467 start_offset = (unsigned long)ftrace_regs_caller;
468 call_offset = (unsigned long)ftrace_regs_call;
469 } else {
470 start_offset = (unsigned long)ftrace_caller;
471 call_offset = (unsigned long)ftrace_call;
472 }
473
474 return call_offset - start_offset;
475}
476
477void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
478{
479 ftrace_func_t func;
480 unsigned long offset;
481 unsigned long ip;
482 unsigned int size;
483 const char *new;
484
485 if (!ops->trampoline) {
486 ops->trampoline = create_trampoline(ops, &size);
487 if (!ops->trampoline)
488 return;
489 ops->trampoline_size = size;
490 return;
491 }
492
493
494
495
496
497 if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
498 return;
499
500 offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS);
501 ip = ops->trampoline + offset;
502 func = ftrace_ops_get_func(ops);
503
504 mutex_lock(&text_mutex);
505
506 new = ftrace_call_replace(ip, (unsigned long)func);
507 text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
508 mutex_unlock(&text_mutex);
509}
510
511
512static void *addr_from_call(void *ptr)
513{
514 union text_poke_insn call;
515 int ret;
516
517 ret = copy_from_kernel_nofault(&call, ptr, CALL_INSN_SIZE);
518 if (WARN_ON_ONCE(ret < 0))
519 return NULL;
520
521
522 if (WARN_ON_ONCE(call.opcode != CALL_INSN_OPCODE)) {
523 pr_warn("Expected E8, got %x\n", call.opcode);
524 return NULL;
525 }
526
527 return ptr + CALL_INSN_SIZE + call.disp;
528}
529
530void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
531 unsigned long frame_pointer);
532
533
534
535
536
537static void *static_tramp_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
538{
539 unsigned long offset;
540 bool save_regs = rec->flags & FTRACE_FL_REGS_EN;
541 void *ptr;
542
543 if (ops && ops->trampoline) {
544#ifdef CONFIG_FUNCTION_GRAPH_TRACER
545
546
547
548
549 if (ops->trampoline == FTRACE_GRAPH_ADDR)
550 return (void *)prepare_ftrace_return;
551#endif
552 return NULL;
553 }
554
555 offset = calc_trampoline_call_offset(save_regs);
556
557 if (save_regs)
558 ptr = (void *)FTRACE_REGS_ADDR + offset;
559 else
560 ptr = (void *)FTRACE_ADDR + offset;
561
562 return addr_from_call(ptr);
563}
564
565void *arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
566{
567 unsigned long offset;
568
569
570 if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
571 return static_tramp_func(ops, rec);
572
573 offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS);
574 return addr_from_call((void *)ops->trampoline + offset);
575}
576
577void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
578{
579 if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
580 return;
581
582 tramp_free((void *)ops->trampoline);
583 ops->trampoline = 0;
584}
585
586#endif
587#endif
588
589#ifdef CONFIG_FUNCTION_GRAPH_TRACER
590
591#ifdef CONFIG_DYNAMIC_FTRACE
592extern void ftrace_graph_call(void);
593
594static const char *ftrace_jmp_replace(unsigned long ip, unsigned long addr)
595{
596 return text_gen_insn(JMP32_INSN_OPCODE, (void *)ip, (void *)addr);
597}
598
599static int ftrace_mod_jmp(unsigned long ip, void *func)
600{
601 const char *new;
602
603 new = ftrace_jmp_replace(ip, (unsigned long)func);
604 text_poke_bp((void *)ip, new, MCOUNT_INSN_SIZE, NULL);
605 return 0;
606}
607
608int ftrace_enable_ftrace_graph_caller(void)
609{
610 unsigned long ip = (unsigned long)(&ftrace_graph_call);
611
612 return ftrace_mod_jmp(ip, &ftrace_graph_caller);
613}
614
615int ftrace_disable_ftrace_graph_caller(void)
616{
617 unsigned long ip = (unsigned long)(&ftrace_graph_call);
618
619 return ftrace_mod_jmp(ip, &ftrace_stub);
620}
621
622#endif
623
624
625
626
627
628void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
629 unsigned long frame_pointer)
630{
631 unsigned long return_hooker = (unsigned long)&return_to_handler;
632 unsigned long old;
633 int faulted;
634
635
636
637
638
639
640
641
642
643
644 if (unlikely((long)__builtin_frame_address(0) >= 0))
645 return;
646
647 if (unlikely(ftrace_graph_is_dead()))
648 return;
649
650 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
651 return;
652
653
654
655
656
657
658 asm volatile(
659 "1: " _ASM_MOV " (%[parent]), %[old]\n"
660 "2: " _ASM_MOV " %[return_hooker], (%[parent])\n"
661 " movl $0, %[faulted]\n"
662 "3:\n"
663
664 ".section .fixup, \"ax\"\n"
665 "4: movl $1, %[faulted]\n"
666 " jmp 3b\n"
667 ".previous\n"
668
669 _ASM_EXTABLE(1b, 4b)
670 _ASM_EXTABLE(2b, 4b)
671
672 : [old] "=&r" (old), [faulted] "=r" (faulted)
673 : [parent] "r" (parent), [return_hooker] "r" (return_hooker)
674 : "memory"
675 );
676
677 if (unlikely(faulted)) {
678 ftrace_graph_stop();
679 WARN_ON(1);
680 return;
681 }
682
683 if (function_graph_enter(old, self_addr, frame_pointer, parent))
684 *parent = old;
685}
686#endif
687