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
231
232
233
234
235bool is_conditional_branch(struct ppc_inst instr)
236{
237 unsigned int opcode = ppc_inst_primary_opcode(instr);
238
239 if (opcode == 16)
240 return true;
241 if (opcode == 19) {
242 switch ((ppc_inst_val(instr) >> 1) & 0x3ff) {
243 case 16:
244 case 528:
245 case 560:
246 return true;
247 }
248 }
249 return false;
250}
251NOKPROBE_SYMBOL(is_conditional_branch);
252
253int create_branch(struct ppc_inst *instr, const u32 *addr,
254 unsigned long target, int flags)
255{
256 long offset;
257
258 *instr = ppc_inst(0);
259 offset = target;
260 if (! (flags & BRANCH_ABSOLUTE))
261 offset = offset - (unsigned long)addr;
262
263
264 if (!is_offset_in_branch_range(offset))
265 return 1;
266
267
268 *instr = ppc_inst(0x48000000 | (flags & 0x3) | (offset & 0x03FFFFFC));
269
270 return 0;
271}
272
273int create_cond_branch(struct ppc_inst *instr, const u32 *addr,
274 unsigned long target, int flags)
275{
276 long offset;
277
278 offset = target;
279 if (! (flags & BRANCH_ABSOLUTE))
280 offset = offset - (unsigned long)addr;
281
282
283 if (offset < -0x8000 || offset > 0x7FFF || offset & 0x3)
284 return 1;
285
286
287 *instr = ppc_inst(0x40000000 | (flags & 0x3FF0003) | (offset & 0xFFFC));
288
289 return 0;
290}
291
292static unsigned int branch_opcode(struct ppc_inst instr)
293{
294 return ppc_inst_primary_opcode(instr) & 0x3F;
295}
296
297static int instr_is_branch_iform(struct ppc_inst instr)
298{
299 return branch_opcode(instr) == 18;
300}
301
302static int instr_is_branch_bform(struct ppc_inst instr)
303{
304 return branch_opcode(instr) == 16;
305}
306
307int instr_is_relative_branch(struct ppc_inst instr)
308{
309 if (ppc_inst_val(instr) & BRANCH_ABSOLUTE)
310 return 0;
311
312 return instr_is_branch_iform(instr) || instr_is_branch_bform(instr);
313}
314
315int instr_is_relative_link_branch(struct ppc_inst instr)
316{
317 return instr_is_relative_branch(instr) && (ppc_inst_val(instr) & BRANCH_SET_LINK);
318}
319
320static unsigned long branch_iform_target(const u32 *instr)
321{
322 signed long imm;
323
324 imm = ppc_inst_val(ppc_inst_read(instr)) & 0x3FFFFFC;
325
326
327 if (imm & 0x2000000)
328 imm -= 0x4000000;
329
330 if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0)
331 imm += (unsigned long)instr;
332
333 return (unsigned long)imm;
334}
335
336static unsigned long branch_bform_target(const u32 *instr)
337{
338 signed long imm;
339
340 imm = ppc_inst_val(ppc_inst_read(instr)) & 0xFFFC;
341
342
343 if (imm & 0x8000)
344 imm -= 0x10000;
345
346 if ((ppc_inst_val(ppc_inst_read(instr)) & BRANCH_ABSOLUTE) == 0)
347 imm += (unsigned long)instr;
348
349 return (unsigned long)imm;
350}
351
352unsigned long branch_target(const u32 *instr)
353{
354 if (instr_is_branch_iform(ppc_inst_read(instr)))
355 return branch_iform_target(instr);
356 else if (instr_is_branch_bform(ppc_inst_read(instr)))
357 return branch_bform_target(instr);
358
359 return 0;
360}
361
362int translate_branch(struct ppc_inst *instr, const u32 *dest, const u32 *src)
363{
364 unsigned long target;
365 target = branch_target(src);
366
367 if (instr_is_branch_iform(ppc_inst_read(src)))
368 return create_branch(instr, dest, target,
369 ppc_inst_val(ppc_inst_read(src)));
370 else if (instr_is_branch_bform(ppc_inst_read(src)))
371 return create_cond_branch(instr, dest, target,
372 ppc_inst_val(ppc_inst_read(src)));
373
374 return 1;
375}
376
377#ifdef CONFIG_PPC_BOOK3E_64
378void __patch_exception(int exc, unsigned long addr)
379{
380 extern unsigned int interrupt_base_book3e;
381 unsigned int *ibase = &interrupt_base_book3e;
382
383
384
385
386
387
388
389 patch_branch(ibase + (exc / 4) + 1, addr, 0);
390}
391#endif
392
393#ifdef CONFIG_CODE_PATCHING_SELFTEST
394
395static int instr_is_branch_to_addr(const u32 *instr, unsigned long addr)
396{
397 if (instr_is_branch_iform(ppc_inst_read(instr)) ||
398 instr_is_branch_bform(ppc_inst_read(instr)))
399 return branch_target(instr) == addr;
400
401 return 0;
402}
403
404static void __init test_trampoline(void)
405{
406 asm ("nop;\n");
407}
408
409#define check(x) \
410 if (!(x)) printk("code-patching: test failed at line %d\n", __LINE__);
411
412static void __init test_branch_iform(void)
413{
414 int err;
415 struct ppc_inst instr;
416 u32 tmp[2];
417 u32 *iptr = tmp;
418 unsigned long addr = (unsigned long)tmp;
419
420
421 check(instr_is_branch_iform(ppc_inst(0x48000000)));
422
423 check(instr_is_branch_iform(ppc_inst(0x4bffffff)));
424
425 check(!instr_is_branch_iform(ppc_inst(0xcbffffff)));
426
427 check(!instr_is_branch_iform(ppc_inst(0x7bffffff)));
428
429
430 check(instr_is_branch_iform(ppc_inst(0x48000001)));
431
432 check(instr_is_branch_iform(ppc_inst(0x4bfffffd)));
433
434 check(instr_is_branch_iform(ppc_inst(0x4bff00fd)));
435
436 check(!instr_is_branch_iform(ppc_inst(0x7bfffffd)));
437
438
439 patch_instruction(iptr, ppc_inst(0x48000103));
440 check(instr_is_branch_to_addr(iptr, 0x100));
441
442 patch_instruction(iptr, ppc_inst(0x480420ff));
443 check(instr_is_branch_to_addr(iptr, 0x420fc));
444
445 patch_instruction(iptr, ppc_inst(0x49fffffc));
446 check(instr_is_branch_to_addr(iptr, addr + 0x1FFFFFC));
447
448 patch_instruction(iptr, ppc_inst(0x4bfffffc));
449 check(instr_is_branch_to_addr(iptr, addr - 4));
450
451 patch_instruction(iptr, ppc_inst(0x4a000000));
452 check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
453
454
455 err = create_branch(&instr, iptr, addr, BRANCH_SET_LINK);
456 patch_instruction(iptr, instr);
457 check(instr_is_branch_to_addr(iptr, addr));
458
459
460 err = create_branch(&instr, iptr, addr - 0x100, BRANCH_SET_LINK);
461 patch_instruction(iptr, instr);
462 check(instr_is_branch_to_addr(iptr, addr - 0x100));
463
464
465 err = create_branch(&instr, iptr, addr + 0x100, 0);
466 patch_instruction(iptr, instr);
467 check(instr_is_branch_to_addr(iptr, addr + 0x100));
468
469
470 err = create_branch(&instr, iptr, addr - 0x2000000, BRANCH_SET_LINK);
471 patch_instruction(iptr, instr);
472 check(instr_is_branch_to_addr(iptr, addr - 0x2000000));
473
474
475 err = create_branch(&instr, iptr, addr - 0x2000004, BRANCH_SET_LINK);
476 check(err);
477
478
479 err = create_branch(&instr, iptr, addr + 0x2000000, BRANCH_SET_LINK);
480 check(err);
481
482
483 err = create_branch(&instr, iptr, addr + 3, BRANCH_SET_LINK);
484 check(err);
485
486
487 err = create_branch(&instr, iptr, addr, 0xFFFFFFFC);
488 patch_instruction(iptr, instr);
489 check(instr_is_branch_to_addr(iptr, addr));
490 check(ppc_inst_equal(instr, ppc_inst(0x48000000)));
491}
492
493static void __init test_create_function_call(void)
494{
495 u32 *iptr;
496 unsigned long dest;
497 struct ppc_inst instr;
498
499
500 iptr = (u32 *)ppc_function_entry(test_trampoline);
501 dest = ppc_function_entry(test_create_function_call);
502 create_branch(&instr, iptr, dest, BRANCH_SET_LINK);
503 patch_instruction(iptr, instr);
504 check(instr_is_branch_to_addr(iptr, dest));
505}
506
507static void __init test_branch_bform(void)
508{
509 int err;
510 unsigned long addr;
511 struct ppc_inst instr;
512 u32 tmp[2];
513 u32 *iptr = tmp;
514 unsigned int flags;
515
516 addr = (unsigned long)iptr;
517
518
519 check(instr_is_branch_bform(ppc_inst(0x40000000)));
520
521 check(instr_is_branch_bform(ppc_inst(0x43ffffff)));
522
523 check(!instr_is_branch_bform(ppc_inst(0xc3ffffff)));
524
525 check(!instr_is_branch_bform(ppc_inst(0x7bffffff)));
526
527
528 patch_instruction(iptr, ppc_inst(0x43ff0103));
529 check(instr_is_branch_to_addr(iptr, 0x100));
530
531 patch_instruction(iptr, ppc_inst(0x43ff20ff));
532 check(instr_is_branch_to_addr(iptr, 0x20fc));
533
534 patch_instruction(iptr, ppc_inst(0x43ff7ffc));
535 check(instr_is_branch_to_addr(iptr, addr + 0x7FFC));
536
537 patch_instruction(iptr, ppc_inst(0x43fffffc));
538 check(instr_is_branch_to_addr(iptr, addr - 4));
539
540 patch_instruction(iptr, ppc_inst(0x43ff8000));
541 check(instr_is_branch_to_addr(iptr, addr - 0x8000));
542
543
544 flags = 0x3ff000 | BRANCH_SET_LINK;
545
546
547 err = create_cond_branch(&instr, iptr, addr, flags);
548 patch_instruction(iptr, instr);
549 check(instr_is_branch_to_addr(iptr, addr));
550
551
552 err = create_cond_branch(&instr, iptr, addr - 0x100, flags);
553 patch_instruction(iptr, instr);
554 check(instr_is_branch_to_addr(iptr, addr - 0x100));
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 - 0x8000, flags);
563 patch_instruction(iptr, instr);
564 check(instr_is_branch_to_addr(iptr, addr - 0x8000));
565
566
567 err = create_cond_branch(&instr, iptr, addr - 0x8004, flags);
568 check(err);
569
570
571 err = create_cond_branch(&instr, iptr, addr + 0x8000, flags);
572 check(err);
573
574
575 err = create_cond_branch(&instr, iptr, addr + 3, flags);
576 check(err);
577
578
579 err = create_cond_branch(&instr, iptr, addr, 0xFFFFFFFC);
580 patch_instruction(iptr, instr);
581 check(instr_is_branch_to_addr(iptr, addr));
582 check(ppc_inst_equal(instr, ppc_inst(0x43FF0000)));
583}
584
585static void __init test_translate_branch(void)
586{
587 unsigned long addr;
588 void *p, *q;
589 struct ppc_inst instr;
590 void *buf;
591
592 buf = vmalloc(PAGE_ALIGN(0x2000000 + 1));
593 check(buf);
594 if (!buf)
595 return;
596
597
598 p = buf;
599 addr = (unsigned long)p;
600 patch_branch(p, addr, 0);
601 check(instr_is_branch_to_addr(p, addr));
602 q = p + 4;
603 translate_branch(&instr, q, p);
604 patch_instruction(q, instr);
605 check(instr_is_branch_to_addr(q, addr));
606
607
608 p = buf;
609 addr = (unsigned long)p;
610 patch_branch(p, addr, 0);
611 q = buf + 0x2000000;
612 translate_branch(&instr, q, p);
613 patch_instruction(q, instr);
614 check(instr_is_branch_to_addr(p, addr));
615 check(instr_is_branch_to_addr(q, addr));
616 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000)));
617
618
619 p = buf + 0x2000000;
620 addr = (unsigned long)p;
621 patch_branch(p, addr, 0);
622 q = buf + 4;
623 translate_branch(&instr, q, p);
624 patch_instruction(q, instr);
625 check(instr_is_branch_to_addr(p, addr));
626 check(instr_is_branch_to_addr(q, addr));
627 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc)));
628
629
630 p = buf;
631 addr = 0x1000000 + (unsigned long)buf;
632 patch_branch(p, addr, BRANCH_SET_LINK);
633 q = buf + 0x1400000;
634 translate_branch(&instr, q, p);
635 patch_instruction(q, instr);
636 check(instr_is_branch_to_addr(p, addr));
637 check(instr_is_branch_to_addr(q, addr));
638
639
640 p = buf + 0x1000000;
641 addr = 0x2000000 + (unsigned long)buf;
642 patch_branch(p, addr, 0);
643 q = buf + 4;
644 translate_branch(&instr, q, p);
645 patch_instruction(q, instr);
646 check(instr_is_branch_to_addr(p, addr));
647 check(instr_is_branch_to_addr(q, addr));
648
649
650
651
652
653 p = buf;
654 addr = (unsigned long)p;
655 create_cond_branch(&instr, p, addr, 0);
656 patch_instruction(p, instr);
657 check(instr_is_branch_to_addr(p, addr));
658 q = buf + 4;
659 translate_branch(&instr, q, p);
660 patch_instruction(q, instr);
661 check(instr_is_branch_to_addr(q, addr));
662
663
664 p = buf;
665 addr = (unsigned long)p;
666 create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
667 patch_instruction(p, instr);
668 q = buf + 0x8000;
669 translate_branch(&instr, q, p);
670 patch_instruction(q, instr);
671 check(instr_is_branch_to_addr(p, addr));
672 check(instr_is_branch_to_addr(q, addr));
673 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000)));
674
675
676 p = buf + 0x8000;
677 addr = (unsigned long)p;
678 create_cond_branch(&instr, p, addr, 0xFFFFFFFC);
679 patch_instruction(p, instr);
680 q = buf + 4;
681 translate_branch(&instr, q, p);
682 patch_instruction(q, instr);
683 check(instr_is_branch_to_addr(p, addr));
684 check(instr_is_branch_to_addr(q, addr));
685 check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc)));
686
687
688 p = buf;
689 addr = 0x3000 + (unsigned long)buf;
690 create_cond_branch(&instr, p, addr, BRANCH_SET_LINK);
691 patch_instruction(p, instr);
692 q = buf + 0x5000;
693 translate_branch(&instr, q, p);
694 patch_instruction(q, instr);
695 check(instr_is_branch_to_addr(p, addr));
696 check(instr_is_branch_to_addr(q, addr));
697
698
699 p = buf + 0x2000;
700 addr = 0x4000 + (unsigned long)buf;
701 create_cond_branch(&instr, p, addr, 0);
702 patch_instruction(p, instr);
703 q = buf + 4;
704 translate_branch(&instr, q, p);
705 patch_instruction(q, instr);
706 check(instr_is_branch_to_addr(p, addr));
707 check(instr_is_branch_to_addr(q, addr));
708
709
710 vfree(buf);
711}
712
713#ifdef CONFIG_PPC64
714static void __init test_prefixed_patching(void)
715{
716 extern unsigned int code_patching_test1[];
717 extern unsigned int code_patching_test1_expected[];
718 extern unsigned int end_code_patching_test1[];
719
720 __patch_instruction(code_patching_test1,
721 ppc_inst_prefix(OP_PREFIX << 26, 0x00000000),
722 code_patching_test1);
723
724 check(!memcmp(code_patching_test1,
725 code_patching_test1_expected,
726 sizeof(unsigned int) *
727 (end_code_patching_test1 - code_patching_test1)));
728}
729#else
730static inline void test_prefixed_patching(void) {}
731#endif
732
733static int __init test_code_patching(void)
734{
735 printk(KERN_DEBUG "Running code patching self-tests ...\n");
736
737 test_branch_iform();
738 test_branch_bform();
739 test_create_function_call();
740 test_translate_branch();
741 test_prefixed_patching();
742
743 return 0;
744}
745late_initcall(test_code_patching);
746
747#endif
748