1
2
3
4
5
6#include <linux/kernel.h>
7#include <linux/kprobes.h>
8#include <linux/vmalloc.h>
9#include <linux/init.h>
10#include <linux/mm.h>
11#include <linux/cpuhotplug.h>
12#include <linux/slab.h>
13#include <linux/uaccess.h>
14
15#include <asm/tlbflush.h>
16#include <asm/page.h>
17#include <asm/code-patching.h>
18#include <asm/setup.h>
19#include <asm/inst.h>
20
21static int __patch_instruction(u32 *exec_addr, struct ppc_inst instr, u32 *patch_addr)
22{
23 if (!ppc_inst_prefixed(instr)) {
24 u32 val = ppc_inst_val(instr);
25
26 __put_kernel_nofault(patch_addr, &val, u32, failed);
27 } else {
28 u64 val = ppc_inst_as_ulong(instr);
29
30 __put_kernel_nofault(patch_addr, &val, u64, failed);
31 }
32
33 asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr),
34 "r" (exec_addr));
35
36 return 0;
37
38failed:
39 return -EFAULT;
40}
41
42int raw_patch_instruction(u32 *addr, struct ppc_inst instr)
43{
44 return __patch_instruction(addr, instr, addr);
45}
46
47#ifdef CONFIG_STRICT_KERNEL_RWX
48static DEFINE_PER_CPU(struct vm_struct *, text_poke_area);
49
50static int text_area_cpu_up(unsigned int cpu)
51{
52 struct vm_struct *area;
53
54 area = get_vm_area(PAGE_SIZE, VM_ALLOC);
55 if (!area) {
56 WARN_ONCE(1, "Failed to create text area for cpu %d\n",
57 cpu);
58 return -1;
59 }
60 this_cpu_write(text_poke_area, area);
61
62 return 0;
63}
64
65static int text_area_cpu_down(unsigned int cpu)
66{
67 free_vm_area(this_cpu_read(text_poke_area));
68 return 0;
69}
70
71
72
73
74
75
76void __init poking_init(void)
77{
78 BUG_ON(!cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
79 "powerpc/text_poke:online", text_area_cpu_up,
80 text_area_cpu_down));
81}
82
83
84
85
86static int map_patch_area(void *addr, unsigned long text_poke_addr)
87{
88 unsigned long pfn;
89 int err;
90
91 if (is_vmalloc_or_module_addr(addr))
92 pfn = vmalloc_to_pfn(addr);
93 else
94 pfn = __pa_symbol(addr) >> PAGE_SHIFT;
95
96 err = map_kernel_page(text_poke_addr, (pfn << PAGE_SHIFT), PAGE_KERNEL);
97
98 pr_devel("Mapped addr %lx with pfn %lx:%d\n", text_poke_addr, pfn, err);
99 if (err)
100 return -1;
101
102 return 0;
103}
104
105static inline int unmap_patch_area(unsigned long addr)
106{
107 pte_t *ptep;
108 pmd_t *pmdp;
109 pud_t *pudp;
110 p4d_t *p4dp;
111 pgd_t *pgdp;
112
113 pgdp = pgd_offset_k(addr);
114 if (unlikely(!pgdp))
115 return -EINVAL;
116
117 p4dp = p4d_offset(pgdp, addr);
118 if (unlikely(!p4dp))
119 return -EINVAL;
120
121 pudp = pud_offset(p4dp, addr);
122 if (unlikely(!pudp))
123 return -EINVAL;
124
125 pmdp = pmd_offset(pudp, addr);
126 if (unlikely(!pmdp))
127 return -EINVAL;
128
129 ptep = pte_offset_kernel(pmdp, addr);
130 if (unlikely(!ptep))
131 return -EINVAL;
132
133 pr_devel("clearing mm %p, pte %p, addr %lx\n", &init_mm, ptep, addr);
134
135
136
137
138 pte_clear(&init_mm, addr, ptep);
139 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
140
141 return 0;
142}
143
144static int do_patch_instruction(u32 *addr, struct ppc_inst instr)
145{
146 int err;
147 u32 *patch_addr = NULL;
148 unsigned long flags;
149 unsigned long text_poke_addr;
150 unsigned long kaddr = (unsigned long)addr;
151
152
153
154
155
156
157 if (!this_cpu_read(text_poke_area))
158 return raw_patch_instruction(addr, instr);
159
160 local_irq_save(flags);
161
162 text_poke_addr = (unsigned long)__this_cpu_read(text_poke_area)->addr;
163 if (map_patch_area(addr, text_poke_addr)) {
164 err = -1;
165 goto out;
166 }
167
168 patch_addr = (u32 *)(text_poke_addr + (kaddr & ~PAGE_MASK));
169
170 __patch_instruction(addr, instr, patch_addr);
171
172 err = unmap_patch_area(text_poke_addr);
173 if (err)
174 pr_warn("failed to unmap %lx\n", text_poke_addr);
175
176out:
177 local_irq_restore(flags);
178
179 return err;
180}
181#else
182
183static int do_patch_instruction(u32 *addr, struct ppc_inst instr)
184{
185 return raw_patch_instruction(addr, instr);
186}
187
188#endif
189
190int patch_instruction(u32 *addr, struct ppc_inst instr)
191{
192
193 if (init_mem_is_free && init_section_contains(addr, 4)) {
194 pr_debug("Skipping init section patching addr: 0x%px\n", addr);
195 return 0;
196 }
197 return do_patch_instruction(addr, instr);
198}
199NOKPROBE_SYMBOL(patch_instruction);
200
201int patch_branch(u32 *addr, unsigned long target, int flags)
202{
203 struct ppc_inst instr;
204
205 create_branch(&instr, addr, target, flags);
206 return patch_instruction(addr, instr);
207}
208
209bool is_offset_in_branch_range(long offset)
210{
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228 return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));
229}
230
231bool is_offset_in_cond_branch_range(long offset)
232{
233 return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);
234}
235
236
237
238
239
240bool is_conditional_branch(struct ppc_inst instr)
241{
242 unsigned int opcode = ppc_inst_primary_opcode(instr);
243
244 if (opcode == 16)
245 return true;
246 if (opcode == 19) {
247 switch ((ppc_inst_val(instr) >> 1) & 0x3ff) {
248 case 16:
249 case 528:
250 case 560:
251 return true;
252 }
253 }
254 return false;
255}
256NOKPROBE_SYMBOL(is_conditional_branch);
257
258int create_branch(struct ppc_inst *instr, const u32 *addr,
259 unsigned long target, int flags)
260{
261 long offset;
262
263 *instr = ppc_inst(0);
264 offset = target;
265 if (! (flags & BRANCH_ABSOLUTE))
266 offset = offset - (unsigned long)addr;
267
268
269 if (!is_offset_in_branch_range(offset))
270 return 1;
271
272
273 *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC));
274
275 return 0;
276}
277
278int create_cond_branch(struct ppc_inst *instr, const u32 *addr,
279 unsigned long target, int flags)
280{
281 long offset;
282
283 offset = target;
284 if (! (flags & BRANCH_ABSOLUTE))
285 offset = offset - (unsigned long)addr;
286
287
288 if (!is_offset_in_cond_branch_range(offset))
289 return 1;
290
291
292 *instr = ppc_inst(0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC));
293
294 return 0;
295}
296
297static unsigned int branch_opcode(struct ppc_inst instr)
298{
299 return ppc_inst_primary_opcode(instr) & 0x3F;
300}
301
302static int instr_is_branch_iform(struct ppc_inst instr)
303{
304 return branch_opcode(instr) == 18;
305}
306
307static int instr_is_branch_bform(struct ppc_inst instr)
308{
309 return branch_opcode(instr) == 16;
310}
311
312int instr_is_relative_branch(struct ppc_inst instr)
313{
314 if (ppc_inst_val(instr) & BRANCH_ABSOLUTE)
315 return 0;
316
317 return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
318}
319
320int instr_is_relative_link_branch(struct ppc_inst instr)
321{
322 return instr_is_relative_branch(instr) && (ppc_inst_val(instr) & BRANCH_SET_LINK);
323}
324
325static unsigned long branch_iform_target(const u32 *instr)
326{
327 signed long imm;
328
329 imm = ppc_inst_val(ppc_inst_read(instr)) & 0x3FFFFFC;
330
331
332 if (imm & 0x2000000)
333 imm -= 0x4000000;
334
335 if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0)
336 imm += (unsigned long)instr;
337
338 return (unsigned long)imm;
339}
340
341static unsigned long branch_bform_target(const u32 *instr)
342{
343 signed long imm;
344
345 imm = ppc_inst_val(ppc_inst_read(instr)) & 0xFFFC;
346
347
348 if (imm & 0x8000)
349 imm -= 0x10000;
350
351 if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0)
352 imm += (unsigned long)instr;
353
354 return (unsigned long)imm;
355}
356
357unsigned long branch_target(const u32 *instr)
358{
359 if (instr_is_branch_iform(ppc_inst_read(instr)))
360 return branch_iform_target(instr);
361 else if (instr_is_branch_bform(ppc_inst_read(instr)))
362 return branch_bform_target(instr);
363
364 return 0;
365}
366
367int translate_branch(struct ppc_inst *instr, const u32 *dest, const u32 *src)
368{
369 unsigned long target;
370 target = branch_target(src);
371
372 if (instr_is_branch_iform(ppc_inst_read(src)))
373 return create_branch(instr, dest, target,
374 ppc_inst_val(ppc_inst_read(src)));
375 else if (instr_is_branch_bform(ppc_inst_read(src)))
376 return create_cond_branch(instr, dest, target,
377 ppc_inst_val(ppc_inst_read(src)));
378
379 return 1;
380}
381
382#ifdef CONFIG_PPC_BOOK3E_64
383void __patch_exception(int exc, unsigned long addr)
384{
385 extern unsigned int interrupt_base_book3e;
386 unsigned int *ibase = &interrupt_base_book3e;
387
388
389
390
391
392
393
394 patch_branch(ibase + (exc / 4) + 1, addr, 0);
395}
396#endif
397
398#ifdef CONFIG_CODE_PATCHING_SELFTEST
399
400static int instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
401{
402 if (instr_is_branch_iform(ppc_inst_read(instr)) ||
403 instr_is_branch_bform(ppc_inst_read(instr)))
404 return branch_target(instr) == addr;
405
406 return 0;
407}
408
409static void __init test_trampoline(void)
410{
411 asm ("nop;\n");
412}
413
414#define check(x) \
415 if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__);
416
417static void __init test_branch_iform(void)
418{
419 int err;
420 struct ppc_inst instr;
421 u32 tmp[2];
422 u32 *iptr = tmp;
423 unsigned long addr = (unsigned long)tmp;
424
425
426 check(instr_is_branch_iform(ppc_inst(0x48000000)));
427
428 check(instr_is_branch_iform(ppc_inst(0x4bffffff)));
429
430 check(!instr_is_branch_iform(ppc_inst(0xcbffffff)));
431
432 check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
433
434
435 check(instr_is_branch_iform(ppc_inst(0x48000001)));
436
437 check(instr_is_branch_iform(ppc_inst(0x4bfffffd)));
438
439 check(instr_is_branch_iform(ppc_inst(0x4bff00fd)));
440
441 check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
442
443
444 patch_instruction(iptr, ppc_inst(0x48000103));
445 check(instr_is_branch_to_addr(iptr, 0x100));
446
447 patch_instruction(iptr, ppc_inst(0x480420ff));
448 check(instr_is_branch_to_addr(iptr, 0x420fc));
449
450 patch_instruction(iptr, ppc_inst(0x49fffffc));
451 check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
452
453 patch_instruction(iptr, ppc_inst(0x4bfffffc));
454 check(instr_is_branch_to_addr(iptr, addr - 4));
455
456 patch_instruction(iptr, ppc_inst(0x4a000000));
457 check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
458
459
460 err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
461 patch_instruction(iptr, instr);
462 check(instr_is_branch_to_addr(iptr, addr));
463
464
465 err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
466 patch_instruction(iptr, instr);
467 check(instr_is_branch_to_addr(iptr, addr - 0x100));
468
469
470 err = create_branch(&instr, iptr, addr + 0x100, 0);
471 patch_instruction(iptr, instr);
472 check(instr_is_branch_to_addr(iptr, addr + 0x100));
473
474
475 err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
476 patch_instruction(iptr, instr);
477 check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
478
479
480 err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
481 check(err);
482
483
484 err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
485 check(err);
486
487
488 err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
489 check(err);
490
491
492 err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
493 patch_instruction(iptr, instr);
494 check(instr_is_branch_to_addr(iptr, addr));
495 check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
496}
497
498static void __init test_create_function_call(void)
499{
500 u32 *iptr;
501 unsigned long dest;
502 struct ppc_inst instr;
503
504
505 iptr = (u32 *)ppc_function_entry(test_trampoline);
506 dest = ppc_function_entry(test_create_function_call);
507 create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
508 patch_instruction(iptr, instr);
509 check(instr_is_branch_to_addr(iptr, dest));
510}
511
512static void __init test_branch_bform(void)
513{
514 int err;
515 unsigned long addr;
516 struct ppc_inst instr;
517 u32 tmp[2];
518 u32 *iptr = tmp;
519 unsigned int flags;
520
521 addr = (unsigned long)iptr;
522
523
524 check(instr_is_branch_bform(ppc_inst(0x40000000)));
525
526 check(instr_is_branch_bform(ppc_inst(0x43ffffff)));
527
528 check(!instr_is_branch_bform(ppc_inst(0xc3ffffff)));
529
530 check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
531
532
533 patch_instruction(iptr, ppc_inst(0x43ff0103));
534 check(instr_is_branch_to_addr(iptr, 0x100));
535
536 patch_instruction(iptr, ppc_inst(0x43ff20ff));
537 check(instr_is_branch_to_addr(iptr, 0x20fc));
538
539 patch_instruction(iptr, ppc_inst(0x43ff7ffc));
540 check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
541
542 patch_instruction(iptr, ppc_inst(0x43fffffc));
543 check(instr_is_branch_to_addr(iptr, addr - 4));
544
545 patch_instruction(iptr, ppc_inst(0x43ff8000));
546 check(instr_is_branch_to_addr(iptr, addr - 0x8000));
547
548
549 flags = 0x3ff000 | BRANCH_SET_LINK;
550
551
552 err = create_cond_branch(&instr, iptr, addr, flags);
553 patch_instruction(iptr, instr);
554 check(instr_is_branch_to_addr(iptr, addr));
555
556
557 err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
558 patch_instruction(iptr, instr);
559 check(instr_is_branch_to_addr(iptr, addr - 0x100));
560
561
562 err = create_cond_branch(&instr, iptr, addr + 0x100, flags);
563 patch_instruction(iptr, instr);
564 check(instr_is_branch_to_addr(iptr, addr + 0x100));
565
566
567 err = create_cond_branch(&instr, iptr, addr - 0x8000, flags);
568 patch_instruction(iptr, instr);
569 check(instr_is_branch_to_addr(iptr, addr - 0x8000));
570
571
572 err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);
573 check(err);
574
575
576 err = create_cond_branch(&instr, iptr, addr + 0x8000, flags);
577 check(err);
578
579
580 err = create_cond_branch(&instr, iptr, addr + 3, flags);
581 check(err);
582
583
584 err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
585 patch_instruction(iptr, instr);
586 check(instr_is_branch_to_addr(iptr, addr));
587 check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
588}
589
590static void __init test_translate_branch(void)
591{
592 unsigned long addr;
593 void *p, *q;
594 struct ppc_inst instr;
595 void *buf;
596
597 buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
598 check(buf);
599 if (!buf)
600 return;
601
602
603 p = buf;
604 addr = (unsigned long)p;
605 patch_branch(p, addr, 0);
606 check(instr_is_branch_to_addr(p, addr));
607 q = p + 4;
608 translate_branch(&instr, q, p);
609 patch_instruction(q, instr);
610 check(instr_is_branch_to_addr(q, addr));
611
612
613 p = buf;
614 addr = (unsigned long)p;
615 patch_branch(p, addr, 0);
616 q = buf + 0x2000000;
617 translate_branch(&instr, q, p);
618 patch_instruction(q, instr);
619 check(instr_is_branch_to_addr(p, addr));
620 check(instr_is_branch_to_addr(q, addr));
621 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
622
623
624 p = buf + 0x2000000;
625 addr = (unsigned long)p;
626 patch_branch(p, addr, 0);
627 q = buf + 4;
628 translate_branch(&instr, q, p);
629 patch_instruction(q, instr);
630 check(instr_is_branch_to_addr(p, addr));
631 check(instr_is_branch_to_addr(q, addr));
632 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
633
634
635 p = buf;
636 addr = 0x1000000 + (unsigned long)buf;
637 patch_branch(p, addr, BRANCH_SET_LINK);
638 q = buf + 0x1400000;
639 translate_branch(&instr, q, p);
640 patch_instruction(q, instr);
641 check(instr_is_branch_to_addr(p, addr));
642 check(instr_is_branch_to_addr(q, addr));
643
644
645 p = buf + 0x1000000;
646 addr = 0x2000000 + (unsigned long)buf;
647 patch_branch(p, addr, 0);
648 q = buf + 4;
649 translate_branch(&instr, q, p);
650 patch_instruction(q, instr);
651 check(instr_is_branch_to_addr(p, addr));
652 check(instr_is_branch_to_addr(q, addr));
653
654
655
656
657
658 p = buf;
659 addr = (unsigned long)p;
660 create_cond_branch(&instr, p, addr, 0);
661 patch_instruction(p, instr);
662 check(instr_is_branch_to_addr(p, addr));
663 q = buf + 4;
664 translate_branch(&instr, q, p);
665 patch_instruction(q, instr);
666 check(instr_is_branch_to_addr(q, addr));
667
668
669 p = buf;
670 addr = (unsigned long)p;
671 create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
672 patch_instruction(p, instr);
673 q = buf + 0x8000;
674 translate_branch(&instr, q, p);
675 patch_instruction(q, instr);
676 check(instr_is_branch_to_addr(p, addr));
677 check(instr_is_branch_to_addr(q, addr));
678 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
679
680
681 p = buf + 0x8000;
682 addr = (unsigned long)p;
683 create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
684 patch_instruction(p, instr);
685 q = buf + 4;
686 translate_branch(&instr, q, p);
687 patch_instruction(q, instr);
688 check(instr_is_branch_to_addr(p, addr));
689 check(instr_is_branch_to_addr(q, addr));
690 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
691
692
693 p = buf;
694 addr = 0x3000 + (unsigned long)buf;
695 create_cond_branch(&instr, p, addr, BRANCH_SET_LINK);
696 patch_instruction(p, instr);
697 q = buf + 0x5000;
698 translate_branch(&instr, q, p);
699 patch_instruction(q, instr);
700 check(instr_is_branch_to_addr(p, addr));
701 check(instr_is_branch_to_addr(q, addr));
702
703
704 p = buf + 0x2000;
705 addr = 0x4000 + (unsigned long)buf;
706 create_cond_branch(&instr, p, addr, 0);
707 patch_instruction(p, instr);
708 q = buf + 4;
709 translate_branch(&instr, q, p);
710 patch_instruction(q, instr);
711 check(instr_is_branch_to_addr(p, addr));
712 check(instr_is_branch_to_addr(q, addr));
713
714
715 vfree(buf);
716}
717
718#ifdef CONFIG_PPC64
719static void __init test_prefixed_patching(void)
720{
721 extern unsigned int code_patching_test1[];
722 extern unsigned int code_patching_test1_expected[];
723 extern unsigned int end_code_patching_test1[];
724
725 __patch_instruction(code_patching_test1,
726 ppc_inst_prefix(OP_PREFIX << 26, 0x00000000),
727 code_patching_test1);
728
729 check(!memcmp(code_patching_test1,
730 code_patching_test1_expected,
731 sizeof(unsigned int) *
732 (end_code_patching_test1 - code_patching_test1)));
733}
734#else
735static inline void test_prefixed_patching(void) {}
736#endif
737
738static int __init test_code_patching(void)
739{
740 printk(KERN_DEBUG "Running code patching self-tests ...\n");
741
742 test_branch_iform();
743 test_branch_bform();
744 test_create_function_call();
745 test_translate_branch();
746 test_prefixed_patching();
747
748 return 0;
749}
750late_initcall(test_code_patching);
751
752#endif
753