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kprobes-test.c
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1 /*
2  * arch/arm/kernel/kprobes-test.c
3  *
4  * Copyright (C) 2011 Jon Medhurst <[email protected]>.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 /*
12  * This file contains test code for ARM kprobes.
13  *
14  * The top level function run_all_tests() executes tests for all of the
15  * supported instruction sets: ARM, 16-bit Thumb, and 32-bit Thumb. These tests
16  * fall into two categories; run_api_tests() checks basic functionality of the
17  * kprobes API, and run_test_cases() is a comprehensive test for kprobes
18  * instruction decoding and simulation.
19  *
20  * run_test_cases() first checks the kprobes decoding table for self consistency
21  * (using table_test()) then executes a series of test cases for each of the CPU
22  * instruction forms. coverage_start() and coverage_end() are used to verify
23  * that these test cases cover all of the possible combinations of instructions
24  * described by the kprobes decoding tables.
25  *
26  * The individual test cases are in kprobes-test-arm.c and kprobes-test-thumb.c
27  * which use the macros defined in kprobes-test.h. The rest of this
28  * documentation will describe the operation of the framework used by these
29  * test cases.
30  */
31 
32 /*
33  * TESTING METHODOLOGY
34  * -------------------
35  *
36  * The methodology used to test an ARM instruction 'test_insn' is to use
37  * inline assembler like:
38  *
39  * test_before: nop
40  * test_case: test_insn
41  * test_after: nop
42  *
43  * When the test case is run a kprobe is placed of each nop. The
44  * post-handler of the test_before probe is used to modify the saved CPU
45  * register context to that which we require for the test case. The
46  * pre-handler of the of the test_after probe saves a copy of the CPU
47  * register context. In this way we can execute test_insn with a specific
48  * register context and see the results afterwards.
49  *
50  * To actually test the kprobes instruction emulation we perform the above
51  * step a second time but with an additional kprobe on the test_case
52  * instruction itself. If the emulation is accurate then the results seen
53  * by the test_after probe will be identical to the first run which didn't
54  * have a probe on test_case.
55  *
56  * Each test case is run several times with a variety of variations in the
57  * flags value of stored in CPSR, and for Thumb code, different ITState.
58  *
59  * For instructions which can modify PC, a second test_after probe is used
60  * like this:
61  *
62  * test_before: nop
63  * test_case: test_insn
64  * test_after: nop
65  * b test_done
66  * test_after2: nop
67  * test_done:
68  *
69  * The test case is constructed such that test_insn branches to
70  * test_after2, or, if testing a conditional instruction, it may just
71  * continue to test_after. The probes inserted at both locations let us
72  * determine which happened. A similar approach is used for testing
73  * backwards branches...
74  *
75  * b test_before
76  * b test_done @ helps to cope with off by 1 branches
77  * test_after2: nop
78  * b test_done
79  * test_before: nop
80  * test_case: test_insn
81  * test_after: nop
82  * test_done:
83  *
84  * The macros used to generate the assembler instructions describe above
85  * are TEST_INSTRUCTION, TEST_BRANCH_F (branch forwards) and TEST_BRANCH_B
86  * (branch backwards). In these, the local variables numbered 1, 50, 2 and
87  * 99 represent: test_before, test_case, test_after2 and test_done.
88  *
89  * FRAMEWORK
90  * ---------
91  *
92  * Each test case is wrapped between the pair of macros TESTCASE_START and
93  * TESTCASE_END. As well as performing the inline assembler boilerplate,
94  * these call out to the kprobes_test_case_start() and
95  * kprobes_test_case_end() functions which drive the execution of the test
96  * case. The specific arguments to use for each test case are stored as
97  * inline data constructed using the various TEST_ARG_* macros. Putting
98  * this all together, a simple test case may look like:
99  *
100  * TESTCASE_START("Testing mov r0, r7")
101  * TEST_ARG_REG(7, 0x12345678) // Set r7=0x12345678
102  * TEST_ARG_END("")
103  * TEST_INSTRUCTION("mov r0, r7")
104  * TESTCASE_END
105  *
106  * Note, in practice the single convenience macro TEST_R would be used for this
107  * instead.
108  *
109  * The above would expand to assembler looking something like:
110  *
111  * @ TESTCASE_START
112  * bl __kprobes_test_case_start
113  * @ start of inline data...
114  * .ascii "mov r0, r7" @ text title for test case
115  * .byte 0
116  * .align 2
117  *
118  * @ TEST_ARG_REG
119  * .byte ARG_TYPE_REG
120  * .byte 7
121  * .short 0
122  * .word 0x1234567
123  *
124  * @ TEST_ARG_END
125  * .byte ARG_TYPE_END
126  * .byte TEST_ISA @ flags, including ISA being tested
127  * .short 50f-0f @ offset of 'test_before'
128  * .short 2f-0f @ offset of 'test_after2' (if relevent)
129  * .short 99f-0f @ offset of 'test_done'
130  * @ start of test case code...
131  * 0:
132  * .code TEST_ISA @ switch to ISA being tested
133  *
134  * @ TEST_INSTRUCTION
135  * 50: nop @ location for 'test_before' probe
136  * 1: mov r0, r7 @ the test case instruction 'test_insn'
137  * nop @ location for 'test_after' probe
138  *
139  * // TESTCASE_END
140  * 2:
141  * 99: bl __kprobes_test_case_end_##TEST_ISA
142  * .code NONMAL_ISA
143  *
144  * When the above is execute the following happens...
145  *
146  * __kprobes_test_case_start() is an assembler wrapper which sets up space
147  * for a stack buffer and calls the C function kprobes_test_case_start().
148  * This C function will do some initial processing of the inline data and
149  * setup some global state. It then inserts the test_before and test_after
150  * kprobes and returns a value which causes the assembler wrapper to jump
151  * to the start of the test case code, (local label '0').
152  *
153  * When the test case code executes, the test_before probe will be hit and
154  * test_before_post_handler will call setup_test_context(). This fills the
155  * stack buffer and CPU registers with a test pattern and then processes
156  * the test case arguments. In our example there is one TEST_ARG_REG which
157  * indicates that R7 should be loaded with the value 0x12345678.
158  *
159  * When the test_before probe ends, the test case continues and executes
160  * the "mov r0, r7" instruction. It then hits the test_after probe and the
161  * pre-handler for this (test_after_pre_handler) will save a copy of the
162  * CPU register context. This should now have R0 holding the same value as
163  * R7.
164  *
165  * Finally we get to the call to __kprobes_test_case_end_{32,16}. This is
166  * an assembler wrapper which switches back to the ISA used by the test
167  * code and calls the C function kprobes_test_case_end().
168  *
169  * For each run through the test case, test_case_run_count is incremented
170  * by one. For even runs, kprobes_test_case_end() saves a copy of the
171  * register and stack buffer contents from the test case just run. It then
172  * inserts a kprobe on the test case instruction 'test_insn' and returns a
173  * value to cause the test case code to be re-run.
174  *
175  * For odd numbered runs, kprobes_test_case_end() compares the register and
176  * stack buffer contents to those that were saved on the previous even
177  * numbered run (the one without the kprobe on test_insn). These should be
178  * the same if the kprobe instruction simulation routine is correct.
179  *
180  * The pair of test case runs is repeated with different combinations of
181  * flag values in CPSR and, for Thumb, different ITState. This is
182  * controlled by test_context_cpsr().
183  *
184  * BUILDING TEST CASES
185  * -------------------
186  *
187  *
188  * As an aid to building test cases, the stack buffer is initialised with
189  * some special values:
190  *
191  * [SP+13*4] Contains SP+120. This can be used to test instructions
192  * which load a value into SP.
193  *
194  * [SP+15*4] When testing branching instructions using TEST_BRANCH_{F,B},
195  * this holds the target address of the branch, 'test_after2'.
196  * This can be used to test instructions which load a PC value
197  * from memory.
198  */
199 
200 #include <linux/kernel.h>
201 #include <linux/module.h>
202 #include <linux/slab.h>
203 #include <linux/kprobes.h>
204 
205 #include <asm/opcodes.h>
206 
207 #include "kprobes.h"
208 #include "kprobes-test.h"
209 
210 
211 #define BENCHMARKING 1
212 
213 
214 /*
215  * Test basic API
216  */
217 
218 static bool test_regs_ok;
219 static int test_func_instance;
220 static int pre_handler_called;
221 static int post_handler_called;
222 static int jprobe_func_called;
223 static int kretprobe_handler_called;
224 
225 #define FUNC_ARG1 0x12345678
226 #define FUNC_ARG2 0xabcdef
227 
228 
229 #ifndef CONFIG_THUMB2_KERNEL
230 
231 long arm_func(long r0, long r1);
232 
233 static void __used __naked __arm_kprobes_test_func(void)
234 {
235  __asm__ __volatile__ (
236  ".arm \n\t"
237  ".type arm_func, %%function \n\t"
238  "arm_func: \n\t"
239  "adds r0, r0, r1 \n\t"
240  "bx lr \n\t"
241  ".code "NORMAL_ISA /* Back to Thumb if necessary */
242  : : : "r0", "r1", "cc"
243  );
244 }
245 
246 #else /* CONFIG_THUMB2_KERNEL */
247 
248 long thumb16_func(long r0, long r1);
249 long thumb32even_func(long r0, long r1);
250 long thumb32odd_func(long r0, long r1);
251 
252 static void __used __naked __thumb_kprobes_test_funcs(void)
253 {
254  __asm__ __volatile__ (
255  ".type thumb16_func, %%function \n\t"
256  "thumb16_func: \n\t"
257  "adds.n r0, r0, r1 \n\t"
258  "bx lr \n\t"
259 
260  ".align \n\t"
261  ".type thumb32even_func, %%function \n\t"
262  "thumb32even_func: \n\t"
263  "adds.w r0, r0, r1 \n\t"
264  "bx lr \n\t"
265 
266  ".align \n\t"
267  "nop.n \n\t"
268  ".type thumb32odd_func, %%function \n\t"
269  "thumb32odd_func: \n\t"
270  "adds.w r0, r0, r1 \n\t"
271  "bx lr \n\t"
272 
273  : : : "r0", "r1", "cc"
274  );
275 }
276 
277 #endif /* CONFIG_THUMB2_KERNEL */
278 
279 
280 static int call_test_func(long (*func)(long, long), bool check_test_regs)
281 {
282  long ret;
283 
284  ++test_func_instance;
285  test_regs_ok = false;
286 
287  ret = (*func)(FUNC_ARG1, FUNC_ARG2);
288  if (ret != FUNC_ARG1 + FUNC_ARG2) {
289  pr_err("FAIL: call_test_func: func returned %lx\n", ret);
290  return false;
291  }
292 
293  if (check_test_regs && !test_regs_ok) {
294  pr_err("FAIL: test regs not OK\n");
295  return false;
296  }
297 
298  return true;
299 }
300 
301 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
302 {
303  pre_handler_called = test_func_instance;
304  if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
305  test_regs_ok = true;
306  return 0;
307 }
308 
309 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
310  unsigned long flags)
311 {
312  post_handler_called = test_func_instance;
313  if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
314  test_regs_ok = false;
315 }
316 
317 static struct kprobe the_kprobe = {
318  .addr = 0,
319  .pre_handler = pre_handler,
320  .post_handler = post_handler
321 };
322 
323 static int test_kprobe(long (*func)(long, long))
324 {
325  int ret;
326 
327  the_kprobe.addr = (kprobe_opcode_t *)func;
328  ret = register_kprobe(&the_kprobe);
329  if (ret < 0) {
330  pr_err("FAIL: register_kprobe failed with %d\n", ret);
331  return ret;
332  }
333 
334  ret = call_test_func(func, true);
335 
336  unregister_kprobe(&the_kprobe);
337  the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
338 
339  if (!ret)
340  return -EINVAL;
341  if (pre_handler_called != test_func_instance) {
342  pr_err("FAIL: kprobe pre_handler not called\n");
343  return -EINVAL;
344  }
345  if (post_handler_called != test_func_instance) {
346  pr_err("FAIL: kprobe post_handler not called\n");
347  return -EINVAL;
348  }
349  if (!call_test_func(func, false))
350  return -EINVAL;
351  if (pre_handler_called == test_func_instance ||
352  post_handler_called == test_func_instance) {
353  pr_err("FAIL: probe called after unregistering\n");
354  return -EINVAL;
355  }
356 
357  return 0;
358 }
359 
360 static void __kprobes jprobe_func(long r0, long r1)
361 {
362  jprobe_func_called = test_func_instance;
363  if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
364  test_regs_ok = true;
365  jprobe_return();
366 }
367 
368 static struct jprobe the_jprobe = {
369  .entry = jprobe_func,
370 };
371 
372 static int test_jprobe(long (*func)(long, long))
373 {
374  int ret;
375 
376  the_jprobe.kp.addr = (kprobe_opcode_t *)func;
377  ret = register_jprobe(&the_jprobe);
378  if (ret < 0) {
379  pr_err("FAIL: register_jprobe failed with %d\n", ret);
380  return ret;
381  }
382 
383  ret = call_test_func(func, true);
384 
385  unregister_jprobe(&the_jprobe);
386  the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
387 
388  if (!ret)
389  return -EINVAL;
390  if (jprobe_func_called != test_func_instance) {
391  pr_err("FAIL: jprobe handler function not called\n");
392  return -EINVAL;
393  }
394  if (!call_test_func(func, false))
395  return -EINVAL;
396  if (jprobe_func_called == test_func_instance) {
397  pr_err("FAIL: probe called after unregistering\n");
398  return -EINVAL;
399  }
400 
401  return 0;
402 }
403 
404 static int __kprobes
405 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
406 {
407  kretprobe_handler_called = test_func_instance;
408  if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
409  test_regs_ok = true;
410  return 0;
411 }
412 
413 static struct kretprobe the_kretprobe = {
414  .handler = kretprobe_handler,
415 };
416 
417 static int test_kretprobe(long (*func)(long, long))
418 {
419  int ret;
420 
421  the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
422  ret = register_kretprobe(&the_kretprobe);
423  if (ret < 0) {
424  pr_err("FAIL: register_kretprobe failed with %d\n", ret);
425  return ret;
426  }
427 
428  ret = call_test_func(func, true);
429 
430  unregister_kretprobe(&the_kretprobe);
431  the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
432 
433  if (!ret)
434  return -EINVAL;
435  if (kretprobe_handler_called != test_func_instance) {
436  pr_err("FAIL: kretprobe handler not called\n");
437  return -EINVAL;
438  }
439  if (!call_test_func(func, false))
440  return -EINVAL;
441  if (jprobe_func_called == test_func_instance) {
442  pr_err("FAIL: kretprobe called after unregistering\n");
443  return -EINVAL;
444  }
445 
446  return 0;
447 }
448 
449 static int run_api_tests(long (*func)(long, long))
450 {
451  int ret;
452 
453  pr_info(" kprobe\n");
454  ret = test_kprobe(func);
455  if (ret < 0)
456  return ret;
457 
458  pr_info(" jprobe\n");
459  ret = test_jprobe(func);
460  if (ret < 0)
461  return ret;
462 
463  pr_info(" kretprobe\n");
464  ret = test_kretprobe(func);
465  if (ret < 0)
466  return ret;
467 
468  return 0;
469 }
470 
471 
472 /*
473  * Benchmarking
474  */
475 
476 #if BENCHMARKING
477 
478 static void __naked benchmark_nop(void)
479 {
480  __asm__ __volatile__ (
481  "nop \n\t"
482  "bx lr"
483  );
484 }
485 
486 #ifdef CONFIG_THUMB2_KERNEL
487 #define wide ".w"
488 #else
489 #define wide
490 #endif
491 
492 static void __naked benchmark_pushpop1(void)
493 {
494  __asm__ __volatile__ (
495  "stmdb"wide" sp!, {r3-r11,lr} \n\t"
496  "ldmia"wide" sp!, {r3-r11,pc}"
497  );
498 }
499 
500 static void __naked benchmark_pushpop2(void)
501 {
502  __asm__ __volatile__ (
503  "stmdb"wide" sp!, {r0-r8,lr} \n\t"
504  "ldmia"wide" sp!, {r0-r8,pc}"
505  );
506 }
507 
508 static void __naked benchmark_pushpop3(void)
509 {
510  __asm__ __volatile__ (
511  "stmdb"wide" sp!, {r4,lr} \n\t"
512  "ldmia"wide" sp!, {r4,pc}"
513  );
514 }
515 
516 static void __naked benchmark_pushpop4(void)
517 {
518  __asm__ __volatile__ (
519  "stmdb"wide" sp!, {r0,lr} \n\t"
520  "ldmia"wide" sp!, {r0,pc}"
521  );
522 }
523 
524 
525 #ifdef CONFIG_THUMB2_KERNEL
526 
527 static void __naked benchmark_pushpop_thumb(void)
528 {
529  __asm__ __volatile__ (
530  "push.n {r0-r7,lr} \n\t"
531  "pop.n {r0-r7,pc}"
532  );
533 }
534 
535 #endif
536 
537 static int __kprobes
538 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
539 {
540  return 0;
541 }
542 
543 static int benchmark(void(*fn)(void))
544 {
545  unsigned n, i, t, t0;
546 
547  for (n = 1000; ; n *= 2) {
548  t0 = sched_clock();
549  for (i = n; i > 0; --i)
550  fn();
551  t = sched_clock() - t0;
552  if (t >= 250000000)
553  break; /* Stop once we took more than 0.25 seconds */
554  }
555  return t / n; /* Time for one iteration in nanoseconds */
556 };
557 
558 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
559 {
560  struct kprobe k = {
561  .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset),
562  .pre_handler = benchmark_pre_handler,
563  };
564 
565  int ret = register_kprobe(&k);
566  if (ret < 0) {
567  pr_err("FAIL: register_kprobe failed with %d\n", ret);
568  return ret;
569  }
570 
571  ret = benchmark(fn);
572 
573  unregister_kprobe(&k);
574  return ret;
575 };
576 
577 struct benchmarks {
578  void (*fn)(void);
579  unsigned offset;
580  const char *title;
581 };
582 
583 static int run_benchmarks(void)
584 {
585  int ret;
586  struct benchmarks list[] = {
587  {&benchmark_nop, 0, "nop"},
588  /*
589  * benchmark_pushpop{1,3} will have the optimised
590  * instruction emulation, whilst benchmark_pushpop{2,4} will
591  * be the equivalent unoptimised instructions.
592  */
593  {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
594  {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
595  {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
596  {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
597  {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
598  {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
599  {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
600  {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
601 #ifdef CONFIG_THUMB2_KERNEL
602  {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"},
603  {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"},
604 #endif
605  {0}
606  };
607 
608  struct benchmarks *b;
609  for (b = list; b->fn; ++b) {
610  ret = kprobe_benchmark(b->fn, b->offset);
611  if (ret < 0)
612  return ret;
613  pr_info(" %dns for kprobe %s\n", ret, b->title);
614  }
615 
616  pr_info("\n");
617  return 0;
618 }
619 
620 #endif /* BENCHMARKING */
621 
622 
623 /*
624  * Decoding table self-consistency tests
625  */
626 
627 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
628  [DECODE_TYPE_TABLE] = sizeof(struct decode_table),
629  [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
630  [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
631  [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
632  [DECODE_TYPE_OR] = sizeof(struct decode_or),
633  [DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
634 };
635 
636 static int table_iter(const union decode_item *table,
637  int (*fn)(const struct decode_header *, void *),
638  void *args)
639 {
640  const struct decode_header *h = (struct decode_header *)table;
641  int result;
642 
643  for (;;) {
645 
646  if (type == DECODE_TYPE_END)
647  return 0;
648 
649  result = fn(h, args);
650  if (result)
651  return result;
652 
653  h = (struct decode_header *)
654  ((uintptr_t)h + decode_struct_sizes[type]);
655 
656  }
657 }
658 
659 static int table_test_fail(const struct decode_header *h, const char* message)
660 {
661 
662  pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
663  message, h->mask.bits, h->value.bits);
664  return -EINVAL;
665 }
666 
668  const union decode_item *root_table;
671 };
672 
673 static int table_test_fn(const struct decode_header *h, void *args)
674 {
675  struct table_test_args *a = (struct table_test_args *)args;
676  enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
677 
678  if (h->value.bits & ~h->mask.bits)
679  return table_test_fail(h, "Match value has bits not in mask");
680 
681  if ((h->mask.bits & a->parent_mask) != a->parent_mask)
682  return table_test_fail(h, "Mask has bits not in parent mask");
683 
684  if ((h->value.bits ^ a->parent_value) & a->parent_mask)
685  return table_test_fail(h, "Value is inconsistent with parent");
686 
687  if (type == DECODE_TYPE_TABLE) {
688  struct decode_table *d = (struct decode_table *)h;
689  struct table_test_args args2 = *a;
690  args2.parent_mask = h->mask.bits;
691  args2.parent_value = h->value.bits;
692  return table_iter(d->table.table, table_test_fn, &args2);
693  }
694 
695  return 0;
696 }
697 
698 static int table_test(const union decode_item *table)
699 {
700  struct table_test_args args = {
701  .root_table = table,
702  .parent_mask = 0,
703  .parent_value = 0
704  };
705  return table_iter(args.root_table, table_test_fn, &args);
706 }
707 
708 
709 /*
710  * Decoding table test coverage analysis
711  *
712  * coverage_start() builds a coverage_table which contains a list of
713  * coverage_entry's to match each entry in the specified kprobes instruction
714  * decoding table.
715  *
716  * When test cases are run, coverage_add() is called to process each case.
717  * This looks up the corresponding entry in the coverage_table and sets it as
718  * being matched, as well as clearing the regs flag appropriate for the test.
719  *
720  * After all test cases have been run, coverage_end() is called to check that
721  * all entries in coverage_table have been matched and that all regs flags are
722  * cleared. I.e. that all possible combinations of instructions described by
723  * the kprobes decoding tables have had a test case executed for them.
724  */
725 
727 
728 #define MAX_COVERAGE_ENTRIES 256
729 
731  const struct decode_header *header;
732  unsigned regs;
733  unsigned nesting;
734  char matched;
735 };
736 
739  unsigned num_entries;
740  unsigned nesting;
741 };
742 
744 
745 #define COVERAGE_ANY_REG (1<<0)
746 #define COVERAGE_SP (1<<1)
747 #define COVERAGE_PC (1<<2)
748 #define COVERAGE_PCWB (1<<3)
749 
750 static const char coverage_register_lookup[16] = {
761 };
762 
763 unsigned coverage_start_registers(const struct decode_header *h)
764 {
765  unsigned regs = 0;
766  int i;
767  for (i = 0; i < 20; i += 4) {
768  int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
769  regs |= coverage_register_lookup[r] << i;
770  }
771  return regs;
772 }
773 
774 static int coverage_start_fn(const struct decode_header *h, void *args)
775 {
776  struct coverage_table *coverage = (struct coverage_table *)args;
777  enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
778  struct coverage_entry *entry = coverage->base + coverage->num_entries;
779 
780  if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
781  pr_err("FAIL: Out of space for test coverage data");
782  return -ENOMEM;
783  }
784 
785  ++coverage->num_entries;
786 
787  entry->header = h;
788  entry->regs = coverage_start_registers(h);
789  entry->nesting = coverage->nesting;
790  entry->matched = false;
791 
792  if (type == DECODE_TYPE_TABLE) {
793  struct decode_table *d = (struct decode_table *)h;
794  int ret;
795  ++coverage->nesting;
796  ret = table_iter(d->table.table, coverage_start_fn, coverage);
797  --coverage->nesting;
798  return ret;
799  }
800 
801  return 0;
802 }
803 
804 static int coverage_start(const union decode_item *table)
805 {
806  coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
807  sizeof(struct coverage_entry), GFP_KERNEL);
808  coverage.num_entries = 0;
809  coverage.nesting = 0;
810  return table_iter(table, coverage_start_fn, &coverage);
811 }
812 
813 static void
814 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
815 {
816  int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
817  int i;
818  for (i = 0; i < 20; i += 4) {
819  enum decode_reg_type reg_type = (regs >> i) & 0xf;
820  int reg = (insn >> i) & 0xf;
821  int flag;
822 
823  if (!reg_type)
824  continue;
825 
826  if (reg == 13)
827  flag = COVERAGE_SP;
828  else if (reg == 15)
829  flag = COVERAGE_PC;
830  else
831  flag = COVERAGE_ANY_REG;
832  entry->regs &= ~(flag << i);
833 
834  switch (reg_type) {
835 
836  case REG_TYPE_NONE:
837  case REG_TYPE_ANY:
838  case REG_TYPE_SAMEAS16:
839  break;
840 
841  case REG_TYPE_SP:
842  if (reg != 13)
843  return;
844  break;
845 
846  case REG_TYPE_PC:
847  if (reg != 15)
848  return;
849  break;
850 
851  case REG_TYPE_NOSP:
852  if (reg == 13)
853  return;
854  break;
855 
856  case REG_TYPE_NOSPPC:
857  case REG_TYPE_NOSPPCX:
858  if (reg == 13 || reg == 15)
859  return;
860  break;
861 
862  case REG_TYPE_NOPCWB:
863  if (!is_writeback(insn))
864  break;
865  if (reg == 15) {
866  entry->regs &= ~(COVERAGE_PCWB << i);
867  return;
868  }
869  break;
870 
871  case REG_TYPE_NOPC:
872  case REG_TYPE_NOPCX:
873  if (reg == 15)
874  return;
875  break;
876  }
877 
878  }
879 }
880 
881 static void coverage_add(kprobe_opcode_t insn)
882 {
883  struct coverage_entry *entry = coverage.base;
884  struct coverage_entry *end = coverage.base + coverage.num_entries;
885  bool matched = false;
886  unsigned nesting = 0;
887 
888  for (; entry < end; ++entry) {
889  const struct decode_header *h = entry->header;
890  enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
891 
892  if (entry->nesting > nesting)
893  continue; /* Skip sub-table we didn't match */
894 
895  if (entry->nesting < nesting)
896  break; /* End of sub-table we were scanning */
897 
898  if (!matched) {
899  if ((insn & h->mask.bits) != h->value.bits)
900  continue;
901  entry->matched = true;
902  }
903 
904  switch (type) {
905 
906  case DECODE_TYPE_TABLE:
907  ++nesting;
908  break;
909 
910  case DECODE_TYPE_CUSTOM:
912  case DECODE_TYPE_EMULATE:
913  coverage_add_registers(entry, insn);
914  return;
915 
916  case DECODE_TYPE_OR:
917  matched = true;
918  break;
919 
920  case DECODE_TYPE_REJECT:
921  default:
922  return;
923  }
924 
925  }
926 }
927 
928 static void coverage_end(void)
929 {
930  struct coverage_entry *entry = coverage.base;
931  struct coverage_entry *end = coverage.base + coverage.num_entries;
932 
933  for (; entry < end; ++entry) {
934  u32 mask = entry->header->mask.bits;
935  u32 value = entry->header->value.bits;
936 
937  if (entry->regs) {
938  pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
939  mask, value, entry->regs);
940  coverage_fail = true;
941  }
942  if (!entry->matched) {
943  pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
944  mask, value);
945  coverage_fail = true;
946  }
947  }
948 
949  kfree(coverage.base);
950 }
951 
952 
953 /*
954  * Framework for instruction set test cases
955  */
956 
958 {
959  __asm__ __volatile__ (
960  "stmdb sp!, {r4-r11} \n\t"
961  "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
962  "bic r0, lr, #1 @ r0 = inline title string \n\t"
963  "mov r1, sp \n\t"
964  "bl kprobes_test_case_start \n\t"
965  "bx r0 \n\t"
966  );
967 }
968 
969 #ifndef CONFIG_THUMB2_KERNEL
970 
972 {
973  __asm__ __volatile__ (
974  "mov r4, lr \n\t"
975  "bl kprobes_test_case_end \n\t"
976  "cmp r0, #0 \n\t"
977  "movne pc, r0 \n\t"
978  "mov r0, r4 \n\t"
979  "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
980  "ldmia sp!, {r4-r11} \n\t"
981  "mov pc, r0 \n\t"
982  );
983 }
984 
985 #else /* CONFIG_THUMB2_KERNEL */
986 
987 void __naked __kprobes_test_case_end_16(void)
988 {
989  __asm__ __volatile__ (
990  "mov r4, lr \n\t"
991  "bl kprobes_test_case_end \n\t"
992  "cmp r0, #0 \n\t"
993  "bxne r0 \n\t"
994  "mov r0, r4 \n\t"
995  "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
996  "ldmia sp!, {r4-r11} \n\t"
997  "bx r0 \n\t"
998  );
999 }
1000 
1002 {
1003  __asm__ __volatile__ (
1004  ".arm \n\t"
1005  "orr lr, lr, #1 @ will return to Thumb code \n\t"
1006  "ldr pc, 1f \n\t"
1007  "1: \n\t"
1008  ".word __kprobes_test_case_end_16 \n\t"
1009  );
1010 }
1011 
1012 #endif
1013 
1014 
1017 
1018 static int test_try_count;
1019 static int test_pass_count;
1020 static int test_fail_count;
1021 
1022 static struct pt_regs initial_regs;
1023 static struct pt_regs expected_regs;
1024 static struct pt_regs result_regs;
1025 
1026 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1027 
1028 static const char *current_title;
1029 static struct test_arg *current_args;
1030 static u32 *current_stack;
1031 static uintptr_t current_branch_target;
1032 
1033 static uintptr_t current_code_start;
1034 static kprobe_opcode_t current_instruction;
1035 
1036 
1037 #define TEST_CASE_PASSED -1
1038 #define TEST_CASE_FAILED -2
1039 
1040 static int test_case_run_count;
1041 static bool test_case_is_thumb;
1042 static int test_instance;
1043 
1044 /*
1045  * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
1046  * can change randomly as the kernel doesn't take care to preserve or initialise
1047  * this across context switches. Also, with Security Extentions, the flag may
1048  * not be under control of the kernel; for this reason we ignore the state of
1049  * the FIQ disable flag CPSR.F as well.
1050  */
1051 #define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
1052 
1053 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1054 {
1055  int ret = arm_check_condition(cc << 28, cpsr);
1056 
1057  return (ret != ARM_OPCODE_CONDTEST_FAIL);
1058 }
1059 
1060 static int is_last_scenario;
1061 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1062 static int memory_needs_checking;
1063 
1064 static unsigned long test_context_cpsr(int scenario)
1065 {
1066  unsigned long cpsr;
1067 
1068  probe_should_run = 1;
1069 
1070  /* Default case is that we cycle through 16 combinations of flags */
1071  cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1072  cpsr |= (scenario & 0xf) << 16; /* GE flags */
1073  cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1074 
1075  if (!test_case_is_thumb) {
1076  /* Testing ARM code */
1077  int cc = current_instruction >> 28;
1078 
1079  probe_should_run = test_check_cc(cc, cpsr) != 0;
1080  if (scenario == 15)
1081  is_last_scenario = true;
1082 
1083  } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1084  /* Testing Thumb code without setting ITSTATE */
1085  if (kprobe_test_cc_position) {
1086  int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1087  probe_should_run = test_check_cc(cc, cpsr) != 0;
1088  }
1089 
1090  if (scenario == 15)
1091  is_last_scenario = true;
1092 
1093  } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1094  /* Testing Thumb code with all combinations of ITSTATE */
1095  unsigned x = (scenario >> 4);
1096  unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1097  unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
1098 
1099  if (mask > 0x1f) {
1100  /* Finish by testing state from instruction 'itt al' */
1101  cond_base = 7;
1102  mask = 0x4;
1103  if ((scenario & 0xf) == 0xf)
1104  is_last_scenario = true;
1105  }
1106 
1107  cpsr |= cond_base << 13; /* ITSTATE<7:5> */
1108  cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
1109  cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
1110  cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
1111  cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
1112  cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
1113 
1114  probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1115 
1116  } else {
1117  /* Testing Thumb code with several combinations of ITSTATE */
1118  switch (scenario) {
1119  case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1120  cpsr = 0x00000800;
1121  probe_should_run = 0;
1122  break;
1123  case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1124  cpsr = 0xf0007800;
1125  probe_should_run = 0;
1126  break;
1127  case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1128  cpsr = 0x00009800;
1129  break;
1130  case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1131  cpsr = 0xf0002800;
1132  is_last_scenario = true;
1133  break;
1134  }
1135  }
1136 
1137  return cpsr;
1138 }
1139 
1140 static void setup_test_context(struct pt_regs *regs)
1141 {
1142  int scenario = test_case_run_count>>1;
1143  unsigned long val;
1144  struct test_arg *args;
1145  int i;
1146 
1147  is_last_scenario = false;
1148  memory_needs_checking = false;
1149 
1150  /* Initialise test memory on stack */
1151  val = (scenario & 1) ? VALM : ~VALM;
1152  for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1153  current_stack[i] = val + (i << 8);
1154  /* Put target of branch on stack for tests which load PC from memory */
1155  if (current_branch_target)
1156  current_stack[15] = current_branch_target;
1157  /* Put a value for SP on stack for tests which load SP from memory */
1158  current_stack[13] = (u32)current_stack + 120;
1159 
1160  /* Initialise register values to their default state */
1161  val = (scenario & 2) ? VALR : ~VALR;
1162  for (i = 0; i < 13; ++i)
1163  regs->uregs[i] = val ^ (i << 8);
1164  regs->ARM_lr = val ^ (14 << 8);
1165  regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1166  regs->ARM_cpsr |= test_context_cpsr(scenario);
1167 
1168  /* Perform testcase specific register setup */
1169  args = current_args;
1170  for (; args[0].type != ARG_TYPE_END; ++args)
1171  switch (args[0].type) {
1172  case ARG_TYPE_REG: {
1173  struct test_arg_regptr *arg =
1174  (struct test_arg_regptr *)args;
1175  regs->uregs[arg->reg] = arg->val;
1176  break;
1177  }
1178  case ARG_TYPE_PTR: {
1179  struct test_arg_regptr *arg =
1180  (struct test_arg_regptr *)args;
1181  regs->uregs[arg->reg] =
1182  (unsigned long)current_stack + arg->val;
1183  memory_needs_checking = true;
1184  break;
1185  }
1186  case ARG_TYPE_MEM: {
1187  struct test_arg_mem *arg = (struct test_arg_mem *)args;
1188  current_stack[arg->index] = arg->val;
1189  break;
1190  }
1191  default:
1192  break;
1193  }
1194 }
1195 
1196 struct test_probe {
1197  struct kprobe kprobe;
1199  int hit;
1200 };
1201 
1202 static void unregister_test_probe(struct test_probe *probe)
1203 {
1204  if (probe->registered) {
1205  unregister_kprobe(&probe->kprobe);
1206  probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1207  }
1208  probe->registered = false;
1209 }
1210 
1211 static int register_test_probe(struct test_probe *probe)
1212 {
1213  int ret;
1214 
1215  if (probe->registered)
1216  BUG();
1217 
1218  ret = register_kprobe(&probe->kprobe);
1219  if (ret >= 0) {
1220  probe->registered = true;
1221  probe->hit = -1;
1222  }
1223  return ret;
1224 }
1225 
1226 static int __kprobes
1227 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1228 {
1229  container_of(p, struct test_probe, kprobe)->hit = test_instance;
1230  return 0;
1231 }
1232 
1233 static void __kprobes
1234 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1235  unsigned long flags)
1236 {
1237  setup_test_context(regs);
1238  initial_regs = *regs;
1239  initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1240 }
1241 
1242 static int __kprobes
1243 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1244 {
1245  container_of(p, struct test_probe, kprobe)->hit = test_instance;
1246  return 0;
1247 }
1248 
1249 static int __kprobes
1250 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1251 {
1252  if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1253  return 0; /* Already run for this test instance */
1254 
1255  result_regs = *regs;
1256  result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1257 
1258  /* Undo any changes done to SP by the test case */
1259  regs->ARM_sp = (unsigned long)current_stack;
1260 
1261  container_of(p, struct test_probe, kprobe)->hit = test_instance;
1262  return 0;
1263 }
1264 
1265 static struct test_probe test_before_probe = {
1266  .kprobe.pre_handler = test_before_pre_handler,
1267  .kprobe.post_handler = test_before_post_handler,
1268 };
1269 
1270 static struct test_probe test_case_probe = {
1271  .kprobe.pre_handler = test_case_pre_handler,
1272 };
1273 
1274 static struct test_probe test_after_probe = {
1275  .kprobe.pre_handler = test_after_pre_handler,
1276 };
1277 
1278 static struct test_probe test_after2_probe = {
1279  .kprobe.pre_handler = test_after_pre_handler,
1280 };
1281 
1282 static void test_case_cleanup(void)
1283 {
1284  unregister_test_probe(&test_before_probe);
1285  unregister_test_probe(&test_case_probe);
1286  unregister_test_probe(&test_after_probe);
1287  unregister_test_probe(&test_after2_probe);
1288 }
1289 
1290 static void print_registers(struct pt_regs *regs)
1291 {
1292  pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1293  regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1294  pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1295  regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1296  pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1297  regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1298  pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1299  regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1300  pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1301 }
1302 
1303 static void print_memory(u32 *mem, size_t size)
1304 {
1305  int i;
1306  for (i = 0; i < size / sizeof(u32); i += 4)
1307  pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1308  mem[i+2], mem[i+3]);
1309 }
1310 
1311 static size_t expected_memory_size(u32 *sp)
1312 {
1313  size_t size = sizeof(expected_memory);
1314  int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1315  if (offset > 0)
1316  size -= offset;
1317  return size;
1318 }
1319 
1320 static void test_case_failed(const char *message)
1321 {
1322  test_case_cleanup();
1323 
1324  pr_err("FAIL: %s\n", message);
1325  pr_err("FAIL: Test %s\n", current_title);
1326  pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1327 }
1328 
1329 static unsigned long next_instruction(unsigned long pc)
1330 {
1331 #ifdef CONFIG_THUMB2_KERNEL
1332  if ((pc & 1) && !is_wide_instruction(*(u16 *)(pc - 1)))
1333  return pc + 2;
1334  else
1335 #endif
1336  return pc + 4;
1337 }
1338 
1339 static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
1340 {
1341  struct test_arg *args;
1342  struct test_arg_end *end_arg;
1343  unsigned long test_code;
1344 
1345  args = (struct test_arg *)PTR_ALIGN(title + strlen(title) + 1, 4);
1346 
1347  current_title = title;
1348  current_args = args;
1349  current_stack = stack;
1350 
1351  ++test_try_count;
1352 
1353  while (args->type != ARG_TYPE_END)
1354  ++args;
1355  end_arg = (struct test_arg_end *)args;
1356 
1357  test_code = (unsigned long)(args + 1); /* Code starts after args */
1358 
1359  test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1360  if (test_case_is_thumb)
1361  test_code |= 1;
1362 
1363  current_code_start = test_code;
1364 
1365  current_branch_target = 0;
1366  if (end_arg->branch_offset != end_arg->end_offset)
1367  current_branch_target = test_code + end_arg->branch_offset;
1368 
1369  test_code += end_arg->code_offset;
1370  test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1371 
1372  test_code = next_instruction(test_code);
1373  test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1374 
1375  if (test_case_is_thumb) {
1376  u16 *p = (u16 *)(test_code & ~1);
1377  current_instruction = p[0];
1378  if (is_wide_instruction(current_instruction)) {
1379  current_instruction <<= 16;
1380  current_instruction |= p[1];
1381  }
1382  } else {
1383  current_instruction = *(u32 *)test_code;
1384  }
1385 
1386  if (current_title[0] == '.')
1387  verbose("%s\n", current_title);
1388  else
1389  verbose("%s\t@ %0*x\n", current_title,
1390  test_case_is_thumb ? 4 : 8,
1391  current_instruction);
1392 
1393  test_code = next_instruction(test_code);
1394  test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1395 
1396  if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1397  if (!test_case_is_thumb ||
1398  is_wide_instruction(current_instruction)) {
1399  test_case_failed("expected 16-bit instruction");
1400  goto fail;
1401  }
1402  } else {
1403  if (test_case_is_thumb &&
1404  !is_wide_instruction(current_instruction)) {
1405  test_case_failed("expected 32-bit instruction");
1406  goto fail;
1407  }
1408  }
1409 
1410  coverage_add(current_instruction);
1411 
1412  if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1413  if (register_test_probe(&test_case_probe) < 0)
1414  goto pass;
1415  test_case_failed("registered probe for unsupported instruction");
1416  goto fail;
1417  }
1418 
1419  if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1420  if (register_test_probe(&test_case_probe) >= 0)
1421  goto pass;
1422  test_case_failed("couldn't register probe for supported instruction");
1423  goto fail;
1424  }
1425 
1426  if (register_test_probe(&test_before_probe) < 0) {
1427  test_case_failed("register test_before_probe failed");
1428  goto fail;
1429  }
1430  if (register_test_probe(&test_after_probe) < 0) {
1431  test_case_failed("register test_after_probe failed");
1432  goto fail;
1433  }
1434  if (current_branch_target) {
1435  test_after2_probe.kprobe.addr =
1436  (kprobe_opcode_t *)current_branch_target;
1437  if (register_test_probe(&test_after2_probe) < 0) {
1438  test_case_failed("register test_after2_probe failed");
1439  goto fail;
1440  }
1441  }
1442 
1443  /* Start first run of test case */
1444  test_case_run_count = 0;
1445  ++test_instance;
1446  return current_code_start;
1447 pass:
1448  test_case_run_count = TEST_CASE_PASSED;
1449  return (uintptr_t)test_after_probe.kprobe.addr;
1450 fail:
1451  test_case_run_count = TEST_CASE_FAILED;
1452  return (uintptr_t)test_after_probe.kprobe.addr;
1453 }
1454 
1455 static bool check_test_results(void)
1456 {
1457  size_t mem_size = 0;
1458  u32 *mem = 0;
1459 
1460  if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1461  test_case_failed("registers differ");
1462  goto fail;
1463  }
1464 
1465  if (memory_needs_checking) {
1466  mem = (u32 *)result_regs.ARM_sp;
1467  mem_size = expected_memory_size(mem);
1468  if (memcmp(expected_memory, mem, mem_size)) {
1469  test_case_failed("test memory differs");
1470  goto fail;
1471  }
1472  }
1473 
1474  return true;
1475 
1476 fail:
1477  pr_err("initial_regs:\n");
1478  print_registers(&initial_regs);
1479  pr_err("expected_regs:\n");
1480  print_registers(&expected_regs);
1481  pr_err("result_regs:\n");
1482  print_registers(&result_regs);
1483 
1484  if (mem) {
1485  pr_err("current_stack=%p\n", current_stack);
1486  pr_err("expected_memory:\n");
1487  print_memory(expected_memory, mem_size);
1488  pr_err("result_memory:\n");
1489  print_memory(mem, mem_size);
1490  }
1491 
1492  return false;
1493 }
1494 
1495 static uintptr_t __used kprobes_test_case_end(void)
1496 {
1497  if (test_case_run_count < 0) {
1498  if (test_case_run_count == TEST_CASE_PASSED)
1499  /* kprobes_test_case_start did all the needed testing */
1500  goto pass;
1501  else
1502  /* kprobes_test_case_start failed */
1503  goto fail;
1504  }
1505 
1506  if (test_before_probe.hit != test_instance) {
1507  test_case_failed("test_before_handler not run");
1508  goto fail;
1509  }
1510 
1511  if (test_after_probe.hit != test_instance &&
1512  test_after2_probe.hit != test_instance) {
1513  test_case_failed("test_after_handler not run");
1514  goto fail;
1515  }
1516 
1517  /*
1518  * Even numbered test runs ran without a probe on the test case so
1519  * we can gather reference results. The subsequent odd numbered run
1520  * will have the probe inserted.
1521  */
1522  if ((test_case_run_count & 1) == 0) {
1523  /* Save results from run without probe */
1524  u32 *mem = (u32 *)result_regs.ARM_sp;
1525  expected_regs = result_regs;
1526  memcpy(expected_memory, mem, expected_memory_size(mem));
1527 
1528  /* Insert probe onto test case instruction */
1529  if (register_test_probe(&test_case_probe) < 0) {
1530  test_case_failed("register test_case_probe failed");
1531  goto fail;
1532  }
1533  } else {
1534  /* Check probe ran as expected */
1535  if (probe_should_run == 1) {
1536  if (test_case_probe.hit != test_instance) {
1537  test_case_failed("test_case_handler not run");
1538  goto fail;
1539  }
1540  } else if (probe_should_run == 0) {
1541  if (test_case_probe.hit == test_instance) {
1542  test_case_failed("test_case_handler ran");
1543  goto fail;
1544  }
1545  }
1546 
1547  /* Remove probe for any subsequent reference run */
1548  unregister_test_probe(&test_case_probe);
1549 
1550  if (!check_test_results())
1551  goto fail;
1552 
1553  if (is_last_scenario)
1554  goto pass;
1555  }
1556 
1557  /* Do next test run */
1558  ++test_case_run_count;
1559  ++test_instance;
1560  return current_code_start;
1561 fail:
1562  ++test_fail_count;
1563  goto end;
1564 pass:
1565  ++test_pass_count;
1566 end:
1567  test_case_cleanup();
1568  return 0;
1569 }
1570 
1571 
1572 /*
1573  * Top level test functions
1574  */
1575 
1576 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1577 {
1578  int ret;
1579 
1580  pr_info(" Check decoding tables\n");
1581  ret = table_test(table);
1582  if (ret)
1583  return ret;
1584 
1585  pr_info(" Run test cases\n");
1586  ret = coverage_start(table);
1587  if (ret)
1588  return ret;
1589 
1590  tests();
1591 
1592  coverage_end();
1593  return 0;
1594 }
1595 
1596 
1597 static int __init run_all_tests(void)
1598 {
1599  int ret = 0;
1600 
1601  pr_info("Begining kprobe tests...\n");
1602 
1603 #ifndef CONFIG_THUMB2_KERNEL
1604 
1605  pr_info("Probe ARM code\n");
1606  ret = run_api_tests(arm_func);
1607  if (ret)
1608  goto out;
1609 
1610  pr_info("ARM instruction simulation\n");
1611  ret = run_test_cases(kprobe_arm_test_cases, kprobe_decode_arm_table);
1612  if (ret)
1613  goto out;
1614 
1615 #else /* CONFIG_THUMB2_KERNEL */
1616 
1617  pr_info("Probe 16-bit Thumb code\n");
1618  ret = run_api_tests(thumb16_func);
1619  if (ret)
1620  goto out;
1621 
1622  pr_info("Probe 32-bit Thumb code, even halfword\n");
1623  ret = run_api_tests(thumb32even_func);
1624  if (ret)
1625  goto out;
1626 
1627  pr_info("Probe 32-bit Thumb code, odd halfword\n");
1628  ret = run_api_tests(thumb32odd_func);
1629  if (ret)
1630  goto out;
1631 
1632  pr_info("16-bit Thumb instruction simulation\n");
1633  ret = run_test_cases(kprobe_thumb16_test_cases,
1635  if (ret)
1636  goto out;
1637 
1638  pr_info("32-bit Thumb instruction simulation\n");
1639  ret = run_test_cases(kprobe_thumb32_test_cases,
1641  if (ret)
1642  goto out;
1643 #endif
1644 
1645  pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1646  test_try_count, test_pass_count, test_fail_count);
1647  if (test_fail_count) {
1648  ret = -EINVAL;
1649  goto out;
1650  }
1651 
1652 #if BENCHMARKING
1653  pr_info("Benchmarks\n");
1654  ret = run_benchmarks();
1655  if (ret)
1656  goto out;
1657 #endif
1658 
1659 #if __LINUX_ARM_ARCH__ >= 7
1660  /* We are able to run all test cases so coverage should be complete */
1661  if (coverage_fail) {
1662  pr_err("FAIL: Test coverage checks failed\n");
1663  ret = -EINVAL;
1664  goto out;
1665  }
1666 #endif
1667 
1668 out:
1669  if (ret == 0)
1670  pr_info("Finished kprobe tests OK\n");
1671  else
1672  pr_err("kprobe tests failed\n");
1673 
1674  return ret;
1675 }
1676 
1677 
1678 /*
1679  * Module setup
1680  */
1681 
1682 #ifdef MODULE
1683 
1684 static void __exit kprobe_test_exit(void)
1685 {
1686 }
1687 
1688 module_init(run_all_tests)
1689 module_exit(kprobe_test_exit)
1690 MODULE_LICENSE("GPL");
1691 
1692 #else /* !MODULE */
1693 
1694 late_initcall(run_all_tests);
1695 
1696 #endif