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1/*
2 * arch/arm/kernel/kprobes-test.c
3 *
4 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
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
218static bool test_regs_ok;
219static int test_func_instance;
220static int pre_handler_called;
221static int post_handler_called;
222static int jprobe_func_called;
223static int kretprobe_handler_called;
224
225#define FUNC_ARG1 0x12345678
226#define FUNC_ARG2 0xabcdef
227
228
229#ifndef CONFIG_THUMB2_KERNEL
230
231long arm_func(long r0, long r1);
232
233static 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
248long thumb16_func(long r0, long r1);
249long thumb32even_func(long r0, long r1);
250long thumb32odd_func(long r0, long r1);
251
252static 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
280static 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
301static 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
309static 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
317static struct kprobe the_kprobe = {
318 .addr = 0,
319 .pre_handler = pre_handler,
320 .post_handler = post_handler
321};
322
323static 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
360static 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
368static struct jprobe the_jprobe = {
369 .entry = jprobe_func,
370};
371
372static 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
404static int __kprobes
405kretprobe_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
413static struct kretprobe the_kretprobe = {
414 .handler = kretprobe_handler,
415};
416
417static 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
449static 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
478static 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
492static 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
500static 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
508static 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
516static 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
527static 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
537static int __kprobes
538benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
539{
540 return 0;
541}
542
543static 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
558static 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
577struct benchmarks {
578 void (*fn)(void);
579 unsigned offset;
580 const char *title;
581};
582
583static 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
627static 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
636static 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 (;;) {
644 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
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
659static 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
667struct table_test_args {
668 const union decode_item *root_table;
669 u32 parent_mask;
670 u32 parent_value;
671};
672
673static 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
698static 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
726bool coverage_fail;
727
728#define MAX_COVERAGE_ENTRIES 256
729
730struct coverage_entry {
731 const struct decode_header *header;
732 unsigned regs;
733 unsigned nesting;
734 char matched;
735};
736
737struct coverage_table {
738 struct coverage_entry *base;
739 unsigned num_entries;
740 unsigned nesting;
741};
742
743struct coverage_table coverage;
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
750static const char coverage_register_lookup[16] = {
751 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
752 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG,
753 [REG_TYPE_SP] = COVERAGE_SP,
754 [REG_TYPE_PC] = COVERAGE_PC,
755 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP,
756 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
757 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC,
758 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
759 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG,
760 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP,
761};
762
763unsigned 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
774static 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
804static 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
813static void
814coverage_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
881static 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:
911 case DECODE_TYPE_SIMULATE:
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
928static 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
957void __naked __kprobes_test_case_start(void)
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
971void __naked __kprobes_test_case_end_32(void)
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
987void __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
1001void __naked __kprobes_test_case_end_32(void)
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
1015int kprobe_test_flags;
1016int kprobe_test_cc_position;
1017
1018static int test_try_count;
1019static int test_pass_count;
1020static int test_fail_count;
1021
1022static struct pt_regs initial_regs;
1023static struct pt_regs expected_regs;
1024static struct pt_regs result_regs;
1025
1026static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1027
1028static const char *current_title;
1029static struct test_arg *current_args;
1030static u32 *current_stack;
1031static uintptr_t current_branch_target;
1032
1033static uintptr_t current_code_start;
1034static kprobe_opcode_t current_instruction;
1035
1036
1037#define TEST_CASE_PASSED -1
1038#define TEST_CASE_FAILED -2
1039
1040static int test_case_run_count;
1041static bool test_case_is_thumb;
1042static 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
1053static 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
1060static int is_last_scenario;
1061static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1062static int memory_needs_checking;
1063
1064static 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
1140static 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
1196struct test_probe {
1197 struct kprobe kprobe;
1198 bool registered;
1199 int hit;
1200};
1201
1202static 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
1211static 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
1226static int __kprobes
1227test_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
1233static void __kprobes
1234test_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
1242static int __kprobes
1243test_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
1249static int __kprobes
1250test_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
1265static struct test_probe test_before_probe = {
1266 .kprobe.pre_handler = test_before_pre_handler,
1267 .kprobe.post_handler = test_before_post_handler,
1268};
1269
1270static struct test_probe test_case_probe = {
1271 .kprobe.pre_handler = test_case_pre_handler,
1272};
1273
1274static struct test_probe test_after_probe = {
1275 .kprobe.pre_handler = test_after_pre_handler,
1276};
1277
1278static struct test_probe test_after2_probe = {
1279 .kprobe.pre_handler = test_after_pre_handler,
1280};
1281
1282static 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
1290static 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
1303static 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
1311static 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
1320static 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
1329static 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
1339static 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;
1447pass:
1448 test_case_run_count = TEST_CASE_PASSED;
1449 return (uintptr_t)test_after_probe.kprobe.addr;
1450fail:
1451 test_case_run_count = TEST_CASE_FAILED;
1452 return (uintptr_t)test_after_probe.kprobe.addr;
1453}
1454
1455static 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
1476fail:
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
1495static 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;
1561fail:
1562 ++test_fail_count;
1563 goto end;
1564pass:
1565 ++test_pass_count;
1566end:
1567 test_case_cleanup();
1568 return 0;
1569}
1570
1571
1572/*
1573 * Top level test functions
1574 */
1575
1576static 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
1597static 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,
1634 kprobe_decode_thumb16_table);
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,
1640 kprobe_decode_thumb32_table);
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
1668out:
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
1684static void __exit kprobe_test_exit(void)
1685{
1686}
1687
1688module_init(run_all_tests)
1689module_exit(kprobe_test_exit)
1690MODULE_LICENSE("GPL");
1691
1692#else /* !MODULE */
1693
1694late_initcall(run_all_tests);
1695
1696#endif