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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 "kprobes.h"
206#include "kprobes-test.h"
207
208
209#define BENCHMARKING 1
210
211
212/*
213 * Test basic API
214 */
215
216static bool test_regs_ok;
217static int test_func_instance;
218static int pre_handler_called;
219static int post_handler_called;
220static int jprobe_func_called;
221static int kretprobe_handler_called;
222
223#define FUNC_ARG1 0x12345678
224#define FUNC_ARG2 0xabcdef
225
226
227#ifndef CONFIG_THUMB2_KERNEL
228
229long arm_func(long r0, long r1);
230
231static void __used __naked __arm_kprobes_test_func(void)
232{
233 __asm__ __volatile__ (
234 ".arm \n\t"
235 ".type arm_func, %%function \n\t"
236 "arm_func: \n\t"
237 "adds r0, r0, r1 \n\t"
238 "bx lr \n\t"
239 ".code "NORMAL_ISA /* Back to Thumb if necessary */
240 : : : "r0", "r1", "cc"
241 );
242}
243
244#else /* CONFIG_THUMB2_KERNEL */
245
246long thumb16_func(long r0, long r1);
247long thumb32even_func(long r0, long r1);
248long thumb32odd_func(long r0, long r1);
249
250static void __used __naked __thumb_kprobes_test_funcs(void)
251{
252 __asm__ __volatile__ (
253 ".type thumb16_func, %%function \n\t"
254 "thumb16_func: \n\t"
255 "adds.n r0, r0, r1 \n\t"
256 "bx lr \n\t"
257
258 ".align \n\t"
259 ".type thumb32even_func, %%function \n\t"
260 "thumb32even_func: \n\t"
261 "adds.w r0, r0, r1 \n\t"
262 "bx lr \n\t"
263
264 ".align \n\t"
265 "nop.n \n\t"
266 ".type thumb32odd_func, %%function \n\t"
267 "thumb32odd_func: \n\t"
268 "adds.w r0, r0, r1 \n\t"
269 "bx lr \n\t"
270
271 : : : "r0", "r1", "cc"
272 );
273}
274
275#endif /* CONFIG_THUMB2_KERNEL */
276
277
278static int call_test_func(long (*func)(long, long), bool check_test_regs)
279{
280 long ret;
281
282 ++test_func_instance;
283 test_regs_ok = false;
284
285 ret = (*func)(FUNC_ARG1, FUNC_ARG2);
286 if (ret != FUNC_ARG1 + FUNC_ARG2) {
287 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
288 return false;
289 }
290
291 if (check_test_regs && !test_regs_ok) {
292 pr_err("FAIL: test regs not OK\n");
293 return false;
294 }
295
296 return true;
297}
298
299static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
300{
301 pre_handler_called = test_func_instance;
302 if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
303 test_regs_ok = true;
304 return 0;
305}
306
307static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
308 unsigned long flags)
309{
310 post_handler_called = test_func_instance;
311 if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
312 test_regs_ok = false;
313}
314
315static struct kprobe the_kprobe = {
316 .addr = 0,
317 .pre_handler = pre_handler,
318 .post_handler = post_handler
319};
320
321static int test_kprobe(long (*func)(long, long))
322{
323 int ret;
324
325 the_kprobe.addr = (kprobe_opcode_t *)func;
326 ret = register_kprobe(&the_kprobe);
327 if (ret < 0) {
328 pr_err("FAIL: register_kprobe failed with %d\n", ret);
329 return ret;
330 }
331
332 ret = call_test_func(func, true);
333
334 unregister_kprobe(&the_kprobe);
335 the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
336
337 if (!ret)
338 return -EINVAL;
339 if (pre_handler_called != test_func_instance) {
340 pr_err("FAIL: kprobe pre_handler not called\n");
341 return -EINVAL;
342 }
343 if (post_handler_called != test_func_instance) {
344 pr_err("FAIL: kprobe post_handler not called\n");
345 return -EINVAL;
346 }
347 if (!call_test_func(func, false))
348 return -EINVAL;
349 if (pre_handler_called == test_func_instance ||
350 post_handler_called == test_func_instance) {
351 pr_err("FAIL: probe called after unregistering\n");
352 return -EINVAL;
353 }
354
355 return 0;
356}
357
358static void __kprobes jprobe_func(long r0, long r1)
359{
360 jprobe_func_called = test_func_instance;
361 if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
362 test_regs_ok = true;
363 jprobe_return();
364}
365
366static struct jprobe the_jprobe = {
367 .entry = jprobe_func,
368};
369
370static int test_jprobe(long (*func)(long, long))
371{
372 int ret;
373
374 the_jprobe.kp.addr = (kprobe_opcode_t *)func;
375 ret = register_jprobe(&the_jprobe);
376 if (ret < 0) {
377 pr_err("FAIL: register_jprobe failed with %d\n", ret);
378 return ret;
379 }
380
381 ret = call_test_func(func, true);
382
383 unregister_jprobe(&the_jprobe);
384 the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
385
386 if (!ret)
387 return -EINVAL;
388 if (jprobe_func_called != test_func_instance) {
389 pr_err("FAIL: jprobe handler function not called\n");
390 return -EINVAL;
391 }
392 if (!call_test_func(func, false))
393 return -EINVAL;
394 if (jprobe_func_called == test_func_instance) {
395 pr_err("FAIL: probe called after unregistering\n");
396 return -EINVAL;
397 }
398
399 return 0;
400}
401
402static int __kprobes
403kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
404{
405 kretprobe_handler_called = test_func_instance;
406 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
407 test_regs_ok = true;
408 return 0;
409}
410
411static struct kretprobe the_kretprobe = {
412 .handler = kretprobe_handler,
413};
414
415static int test_kretprobe(long (*func)(long, long))
416{
417 int ret;
418
419 the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
420 ret = register_kretprobe(&the_kretprobe);
421 if (ret < 0) {
422 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
423 return ret;
424 }
425
426 ret = call_test_func(func, true);
427
428 unregister_kretprobe(&the_kretprobe);
429 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
430
431 if (!ret)
432 return -EINVAL;
433 if (kretprobe_handler_called != test_func_instance) {
434 pr_err("FAIL: kretprobe handler not called\n");
435 return -EINVAL;
436 }
437 if (!call_test_func(func, false))
438 return -EINVAL;
439 if (jprobe_func_called == test_func_instance) {
440 pr_err("FAIL: kretprobe called after unregistering\n");
441 return -EINVAL;
442 }
443
444 return 0;
445}
446
447static int run_api_tests(long (*func)(long, long))
448{
449 int ret;
450
451 pr_info(" kprobe\n");
452 ret = test_kprobe(func);
453 if (ret < 0)
454 return ret;
455
456 pr_info(" jprobe\n");
457 ret = test_jprobe(func);
458 if (ret < 0)
459 return ret;
460
461 pr_info(" kretprobe\n");
462 ret = test_kretprobe(func);
463 if (ret < 0)
464 return ret;
465
466 return 0;
467}
468
469
470/*
471 * Benchmarking
472 */
473
474#if BENCHMARKING
475
476static void __naked benchmark_nop(void)
477{
478 __asm__ __volatile__ (
479 "nop \n\t"
480 "bx lr"
481 );
482}
483
484#ifdef CONFIG_THUMB2_KERNEL
485#define wide ".w"
486#else
487#define wide
488#endif
489
490static void __naked benchmark_pushpop1(void)
491{
492 __asm__ __volatile__ (
493 "stmdb"wide" sp!, {r3-r11,lr} \n\t"
494 "ldmia"wide" sp!, {r3-r11,pc}"
495 );
496}
497
498static void __naked benchmark_pushpop2(void)
499{
500 __asm__ __volatile__ (
501 "stmdb"wide" sp!, {r0-r8,lr} \n\t"
502 "ldmia"wide" sp!, {r0-r8,pc}"
503 );
504}
505
506static void __naked benchmark_pushpop3(void)
507{
508 __asm__ __volatile__ (
509 "stmdb"wide" sp!, {r4,lr} \n\t"
510 "ldmia"wide" sp!, {r4,pc}"
511 );
512}
513
514static void __naked benchmark_pushpop4(void)
515{
516 __asm__ __volatile__ (
517 "stmdb"wide" sp!, {r0,lr} \n\t"
518 "ldmia"wide" sp!, {r0,pc}"
519 );
520}
521
522
523#ifdef CONFIG_THUMB2_KERNEL
524
525static void __naked benchmark_pushpop_thumb(void)
526{
527 __asm__ __volatile__ (
528 "push.n {r0-r7,lr} \n\t"
529 "pop.n {r0-r7,pc}"
530 );
531}
532
533#endif
534
535static int __kprobes
536benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
537{
538 return 0;
539}
540
541static int benchmark(void(*fn)(void))
542{
543 unsigned n, i, t, t0;
544
545 for (n = 1000; ; n *= 2) {
546 t0 = sched_clock();
547 for (i = n; i > 0; --i)
548 fn();
549 t = sched_clock() - t0;
550 if (t >= 250000000)
551 break; /* Stop once we took more than 0.25 seconds */
552 }
553 return t / n; /* Time for one iteration in nanoseconds */
554};
555
556static int kprobe_benchmark(void(*fn)(void), unsigned offset)
557{
558 struct kprobe k = {
559 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset),
560 .pre_handler = benchmark_pre_handler,
561 };
562
563 int ret = register_kprobe(&k);
564 if (ret < 0) {
565 pr_err("FAIL: register_kprobe failed with %d\n", ret);
566 return ret;
567 }
568
569 ret = benchmark(fn);
570
571 unregister_kprobe(&k);
572 return ret;
573};
574
575struct benchmarks {
576 void (*fn)(void);
577 unsigned offset;
578 const char *title;
579};
580
581static int run_benchmarks(void)
582{
583 int ret;
584 struct benchmarks list[] = {
585 {&benchmark_nop, 0, "nop"},
586 /*
587 * benchmark_pushpop{1,3} will have the optimised
588 * instruction emulation, whilst benchmark_pushpop{2,4} will
589 * be the equivalent unoptimised instructions.
590 */
591 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
592 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
593 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
594 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
595 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
596 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
597 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
598 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
599#ifdef CONFIG_THUMB2_KERNEL
600 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"},
601 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"},
602#endif
603 {0}
604 };
605
606 struct benchmarks *b;
607 for (b = list; b->fn; ++b) {
608 ret = kprobe_benchmark(b->fn, b->offset);
609 if (ret < 0)
610 return ret;
611 pr_info(" %dns for kprobe %s\n", ret, b->title);
612 }
613
614 pr_info("\n");
615 return 0;
616}
617
618#endif /* BENCHMARKING */
619
620
621/*
622 * Decoding table self-consistency tests
623 */
624
625static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
626 [DECODE_TYPE_TABLE] = sizeof(struct decode_table),
627 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
628 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
629 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
630 [DECODE_TYPE_OR] = sizeof(struct decode_or),
631 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
632};
633
634static int table_iter(const union decode_item *table,
635 int (*fn)(const struct decode_header *, void *),
636 void *args)
637{
638 const struct decode_header *h = (struct decode_header *)table;
639 int result;
640
641 for (;;) {
642 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
643
644 if (type == DECODE_TYPE_END)
645 return 0;
646
647 result = fn(h, args);
648 if (result)
649 return result;
650
651 h = (struct decode_header *)
652 ((uintptr_t)h + decode_struct_sizes[type]);
653
654 }
655}
656
657static int table_test_fail(const struct decode_header *h, const char* message)
658{
659
660 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
661 message, h->mask.bits, h->value.bits);
662 return -EINVAL;
663}
664
665struct table_test_args {
666 const union decode_item *root_table;
667 u32 parent_mask;
668 u32 parent_value;
669};
670
671static int table_test_fn(const struct decode_header *h, void *args)
672{
673 struct table_test_args *a = (struct table_test_args *)args;
674 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
675
676 if (h->value.bits & ~h->mask.bits)
677 return table_test_fail(h, "Match value has bits not in mask");
678
679 if ((h->mask.bits & a->parent_mask) != a->parent_mask)
680 return table_test_fail(h, "Mask has bits not in parent mask");
681
682 if ((h->value.bits ^ a->parent_value) & a->parent_mask)
683 return table_test_fail(h, "Value is inconsistent with parent");
684
685 if (type == DECODE_TYPE_TABLE) {
686 struct decode_table *d = (struct decode_table *)h;
687 struct table_test_args args2 = *a;
688 args2.parent_mask = h->mask.bits;
689 args2.parent_value = h->value.bits;
690 return table_iter(d->table.table, table_test_fn, &args2);
691 }
692
693 return 0;
694}
695
696static int table_test(const union decode_item *table)
697{
698 struct table_test_args args = {
699 .root_table = table,
700 .parent_mask = 0,
701 .parent_value = 0
702 };
703 return table_iter(args.root_table, table_test_fn, &args);
704}
705
706
707/*
708 * Decoding table test coverage analysis
709 *
710 * coverage_start() builds a coverage_table which contains a list of
711 * coverage_entry's to match each entry in the specified kprobes instruction
712 * decoding table.
713 *
714 * When test cases are run, coverage_add() is called to process each case.
715 * This looks up the corresponding entry in the coverage_table and sets it as
716 * being matched, as well as clearing the regs flag appropriate for the test.
717 *
718 * After all test cases have been run, coverage_end() is called to check that
719 * all entries in coverage_table have been matched and that all regs flags are
720 * cleared. I.e. that all possible combinations of instructions described by
721 * the kprobes decoding tables have had a test case executed for them.
722 */
723
724bool coverage_fail;
725
726#define MAX_COVERAGE_ENTRIES 256
727
728struct coverage_entry {
729 const struct decode_header *header;
730 unsigned regs;
731 unsigned nesting;
732 char matched;
733};
734
735struct coverage_table {
736 struct coverage_entry *base;
737 unsigned num_entries;
738 unsigned nesting;
739};
740
741struct coverage_table coverage;
742
743#define COVERAGE_ANY_REG (1<<0)
744#define COVERAGE_SP (1<<1)
745#define COVERAGE_PC (1<<2)
746#define COVERAGE_PCWB (1<<3)
747
748static const char coverage_register_lookup[16] = {
749 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
750 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG,
751 [REG_TYPE_SP] = COVERAGE_SP,
752 [REG_TYPE_PC] = COVERAGE_PC,
753 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP,
754 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
755 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC,
756 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
757 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG,
758 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP,
759};
760
761unsigned coverage_start_registers(const struct decode_header *h)
762{
763 unsigned regs = 0;
764 int i;
765 for (i = 0; i < 20; i += 4) {
766 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
767 regs |= coverage_register_lookup[r] << i;
768 }
769 return regs;
770}
771
772static int coverage_start_fn(const struct decode_header *h, void *args)
773{
774 struct coverage_table *coverage = (struct coverage_table *)args;
775 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
776 struct coverage_entry *entry = coverage->base + coverage->num_entries;
777
778 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
779 pr_err("FAIL: Out of space for test coverage data");
780 return -ENOMEM;
781 }
782
783 ++coverage->num_entries;
784
785 entry->header = h;
786 entry->regs = coverage_start_registers(h);
787 entry->nesting = coverage->nesting;
788 entry->matched = false;
789
790 if (type == DECODE_TYPE_TABLE) {
791 struct decode_table *d = (struct decode_table *)h;
792 int ret;
793 ++coverage->nesting;
794 ret = table_iter(d->table.table, coverage_start_fn, coverage);
795 --coverage->nesting;
796 return ret;
797 }
798
799 return 0;
800}
801
802static int coverage_start(const union decode_item *table)
803{
804 coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
805 sizeof(struct coverage_entry), GFP_KERNEL);
806 coverage.num_entries = 0;
807 coverage.nesting = 0;
808 return table_iter(table, coverage_start_fn, &coverage);
809}
810
811static void
812coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
813{
814 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
815 int i;
816 for (i = 0; i < 20; i += 4) {
817 enum decode_reg_type reg_type = (regs >> i) & 0xf;
818 int reg = (insn >> i) & 0xf;
819 int flag;
820
821 if (!reg_type)
822 continue;
823
824 if (reg == 13)
825 flag = COVERAGE_SP;
826 else if (reg == 15)
827 flag = COVERAGE_PC;
828 else
829 flag = COVERAGE_ANY_REG;
830 entry->regs &= ~(flag << i);
831
832 switch (reg_type) {
833
834 case REG_TYPE_NONE:
835 case REG_TYPE_ANY:
836 case REG_TYPE_SAMEAS16:
837 break;
838
839 case REG_TYPE_SP:
840 if (reg != 13)
841 return;
842 break;
843
844 case REG_TYPE_PC:
845 if (reg != 15)
846 return;
847 break;
848
849 case REG_TYPE_NOSP:
850 if (reg == 13)
851 return;
852 break;
853
854 case REG_TYPE_NOSPPC:
855 case REG_TYPE_NOSPPCX:
856 if (reg == 13 || reg == 15)
857 return;
858 break;
859
860 case REG_TYPE_NOPCWB:
861 if (!is_writeback(insn))
862 break;
863 if (reg == 15) {
864 entry->regs &= ~(COVERAGE_PCWB << i);
865 return;
866 }
867 break;
868
869 case REG_TYPE_NOPC:
870 case REG_TYPE_NOPCX:
871 if (reg == 15)
872 return;
873 break;
874 }
875
876 }
877}
878
879static void coverage_add(kprobe_opcode_t insn)
880{
881 struct coverage_entry *entry = coverage.base;
882 struct coverage_entry *end = coverage.base + coverage.num_entries;
883 bool matched = false;
884 unsigned nesting = 0;
885
886 for (; entry < end; ++entry) {
887 const struct decode_header *h = entry->header;
888 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
889
890 if (entry->nesting > nesting)
891 continue; /* Skip sub-table we didn't match */
892
893 if (entry->nesting < nesting)
894 break; /* End of sub-table we were scanning */
895
896 if (!matched) {
897 if ((insn & h->mask.bits) != h->value.bits)
898 continue;
899 entry->matched = true;
900 }
901
902 switch (type) {
903
904 case DECODE_TYPE_TABLE:
905 ++nesting;
906 break;
907
908 case DECODE_TYPE_CUSTOM:
909 case DECODE_TYPE_SIMULATE:
910 case DECODE_TYPE_EMULATE:
911 coverage_add_registers(entry, insn);
912 return;
913
914 case DECODE_TYPE_OR:
915 matched = true;
916 break;
917
918 case DECODE_TYPE_REJECT:
919 default:
920 return;
921 }
922
923 }
924}
925
926static void coverage_end(void)
927{
928 struct coverage_entry *entry = coverage.base;
929 struct coverage_entry *end = coverage.base + coverage.num_entries;
930
931 for (; entry < end; ++entry) {
932 u32 mask = entry->header->mask.bits;
933 u32 value = entry->header->value.bits;
934
935 if (entry->regs) {
936 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
937 mask, value, entry->regs);
938 coverage_fail = true;
939 }
940 if (!entry->matched) {
941 pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
942 mask, value);
943 coverage_fail = true;
944 }
945 }
946
947 kfree(coverage.base);
948}
949
950
951/*
952 * Framework for instruction set test cases
953 */
954
955void __naked __kprobes_test_case_start(void)
956{
957 __asm__ __volatile__ (
958 "stmdb sp!, {r4-r11} \n\t"
959 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
960 "bic r0, lr, #1 @ r0 = inline title string \n\t"
961 "mov r1, sp \n\t"
962 "bl kprobes_test_case_start \n\t"
963 "bx r0 \n\t"
964 );
965}
966
967#ifndef CONFIG_THUMB2_KERNEL
968
969void __naked __kprobes_test_case_end_32(void)
970{
971 __asm__ __volatile__ (
972 "mov r4, lr \n\t"
973 "bl kprobes_test_case_end \n\t"
974 "cmp r0, #0 \n\t"
975 "movne pc, r0 \n\t"
976 "mov r0, r4 \n\t"
977 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
978 "ldmia sp!, {r4-r11} \n\t"
979 "mov pc, r0 \n\t"
980 );
981}
982
983#else /* CONFIG_THUMB2_KERNEL */
984
985void __naked __kprobes_test_case_end_16(void)
986{
987 __asm__ __volatile__ (
988 "mov r4, lr \n\t"
989 "bl kprobes_test_case_end \n\t"
990 "cmp r0, #0 \n\t"
991 "bxne r0 \n\t"
992 "mov r0, r4 \n\t"
993 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
994 "ldmia sp!, {r4-r11} \n\t"
995 "bx r0 \n\t"
996 );
997}
998
999void __naked __kprobes_test_case_end_32(void)
1000{
1001 __asm__ __volatile__ (
1002 ".arm \n\t"
1003 "orr lr, lr, #1 @ will return to Thumb code \n\t"
1004 "ldr pc, 1f \n\t"
1005 "1: \n\t"
1006 ".word __kprobes_test_case_end_16 \n\t"
1007 );
1008}
1009
1010#endif
1011
1012
1013int kprobe_test_flags;
1014int kprobe_test_cc_position;
1015
1016static int test_try_count;
1017static int test_pass_count;
1018static int test_fail_count;
1019
1020static struct pt_regs initial_regs;
1021static struct pt_regs expected_regs;
1022static struct pt_regs result_regs;
1023
1024static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1025
1026static const char *current_title;
1027static struct test_arg *current_args;
1028static u32 *current_stack;
1029static uintptr_t current_branch_target;
1030
1031static uintptr_t current_code_start;
1032static kprobe_opcode_t current_instruction;
1033
1034
1035#define TEST_CASE_PASSED -1
1036#define TEST_CASE_FAILED -2
1037
1038static int test_case_run_count;
1039static bool test_case_is_thumb;
1040static int test_instance;
1041
1042/*
1043 * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
1044 * can change randomly as the kernel doesn't take care to preserve or initialise
1045 * this across context switches. Also, with Security Extentions, the flag may
1046 * not be under control of the kernel; for this reason we ignore the state of
1047 * the FIQ disable flag CPSR.F as well.
1048 */
1049#define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
1050
1051static unsigned long test_check_cc(int cc, unsigned long cpsr)
1052{
1053 unsigned long temp;
1054
1055 switch (cc) {
1056 case 0x0: /* eq */
1057 return cpsr & PSR_Z_BIT;
1058
1059 case 0x1: /* ne */
1060 return (~cpsr) & PSR_Z_BIT;
1061
1062 case 0x2: /* cs */
1063 return cpsr & PSR_C_BIT;
1064
1065 case 0x3: /* cc */
1066 return (~cpsr) & PSR_C_BIT;
1067
1068 case 0x4: /* mi */
1069 return cpsr & PSR_N_BIT;
1070
1071 case 0x5: /* pl */
1072 return (~cpsr) & PSR_N_BIT;
1073
1074 case 0x6: /* vs */
1075 return cpsr & PSR_V_BIT;
1076
1077 case 0x7: /* vc */
1078 return (~cpsr) & PSR_V_BIT;
1079
1080 case 0x8: /* hi */
1081 cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
1082 return cpsr & PSR_C_BIT;
1083
1084 case 0x9: /* ls */
1085 cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
1086 return (~cpsr) & PSR_C_BIT;
1087
1088 case 0xa: /* ge */
1089 cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
1090 return (~cpsr) & PSR_N_BIT;
1091
1092 case 0xb: /* lt */
1093 cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
1094 return cpsr & PSR_N_BIT;
1095
1096 case 0xc: /* gt */
1097 temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
1098 temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
1099 return (~temp) & PSR_N_BIT;
1100
1101 case 0xd: /* le */
1102 temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
1103 temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
1104 return temp & PSR_N_BIT;
1105
1106 case 0xe: /* al */
1107 case 0xf: /* unconditional */
1108 return true;
1109 }
1110 BUG();
1111 return false;
1112}
1113
1114static int is_last_scenario;
1115static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1116static int memory_needs_checking;
1117
1118static unsigned long test_context_cpsr(int scenario)
1119{
1120 unsigned long cpsr;
1121
1122 probe_should_run = 1;
1123
1124 /* Default case is that we cycle through 16 combinations of flags */
1125 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1126 cpsr |= (scenario & 0xf) << 16; /* GE flags */
1127 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1128
1129 if (!test_case_is_thumb) {
1130 /* Testing ARM code */
1131 probe_should_run = test_check_cc(current_instruction >> 28, cpsr) != 0;
1132 if (scenario == 15)
1133 is_last_scenario = true;
1134
1135 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1136 /* Testing Thumb code without setting ITSTATE */
1137 if (kprobe_test_cc_position) {
1138 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1139 probe_should_run = test_check_cc(cc, cpsr) != 0;
1140 }
1141
1142 if (scenario == 15)
1143 is_last_scenario = true;
1144
1145 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1146 /* Testing Thumb code with all combinations of ITSTATE */
1147 unsigned x = (scenario >> 4);
1148 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1149 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
1150
1151 if (mask > 0x1f) {
1152 /* Finish by testing state from instruction 'itt al' */
1153 cond_base = 7;
1154 mask = 0x4;
1155 if ((scenario & 0xf) == 0xf)
1156 is_last_scenario = true;
1157 }
1158
1159 cpsr |= cond_base << 13; /* ITSTATE<7:5> */
1160 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
1161 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
1162 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
1163 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
1164 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
1165
1166 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1167
1168 } else {
1169 /* Testing Thumb code with several combinations of ITSTATE */
1170 switch (scenario) {
1171 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1172 cpsr = 0x00000800;
1173 probe_should_run = 0;
1174 break;
1175 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1176 cpsr = 0xf0007800;
1177 probe_should_run = 0;
1178 break;
1179 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1180 cpsr = 0x00009800;
1181 break;
1182 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1183 cpsr = 0xf0002800;
1184 is_last_scenario = true;
1185 break;
1186 }
1187 }
1188
1189 return cpsr;
1190}
1191
1192static void setup_test_context(struct pt_regs *regs)
1193{
1194 int scenario = test_case_run_count>>1;
1195 unsigned long val;
1196 struct test_arg *args;
1197 int i;
1198
1199 is_last_scenario = false;
1200 memory_needs_checking = false;
1201
1202 /* Initialise test memory on stack */
1203 val = (scenario & 1) ? VALM : ~VALM;
1204 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1205 current_stack[i] = val + (i << 8);
1206 /* Put target of branch on stack for tests which load PC from memory */
1207 if (current_branch_target)
1208 current_stack[15] = current_branch_target;
1209 /* Put a value for SP on stack for tests which load SP from memory */
1210 current_stack[13] = (u32)current_stack + 120;
1211
1212 /* Initialise register values to their default state */
1213 val = (scenario & 2) ? VALR : ~VALR;
1214 for (i = 0; i < 13; ++i)
1215 regs->uregs[i] = val ^ (i << 8);
1216 regs->ARM_lr = val ^ (14 << 8);
1217 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1218 regs->ARM_cpsr |= test_context_cpsr(scenario);
1219
1220 /* Perform testcase specific register setup */
1221 args = current_args;
1222 for (; args[0].type != ARG_TYPE_END; ++args)
1223 switch (args[0].type) {
1224 case ARG_TYPE_REG: {
1225 struct test_arg_regptr *arg =
1226 (struct test_arg_regptr *)args;
1227 regs->uregs[arg->reg] = arg->val;
1228 break;
1229 }
1230 case ARG_TYPE_PTR: {
1231 struct test_arg_regptr *arg =
1232 (struct test_arg_regptr *)args;
1233 regs->uregs[arg->reg] =
1234 (unsigned long)current_stack + arg->val;
1235 memory_needs_checking = true;
1236 break;
1237 }
1238 case ARG_TYPE_MEM: {
1239 struct test_arg_mem *arg = (struct test_arg_mem *)args;
1240 current_stack[arg->index] = arg->val;
1241 break;
1242 }
1243 default:
1244 break;
1245 }
1246}
1247
1248struct test_probe {
1249 struct kprobe kprobe;
1250 bool registered;
1251 int hit;
1252};
1253
1254static void unregister_test_probe(struct test_probe *probe)
1255{
1256 if (probe->registered) {
1257 unregister_kprobe(&probe->kprobe);
1258 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1259 }
1260 probe->registered = false;
1261}
1262
1263static int register_test_probe(struct test_probe *probe)
1264{
1265 int ret;
1266
1267 if (probe->registered)
1268 BUG();
1269
1270 ret = register_kprobe(&probe->kprobe);
1271 if (ret >= 0) {
1272 probe->registered = true;
1273 probe->hit = -1;
1274 }
1275 return ret;
1276}
1277
1278static int __kprobes
1279test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1280{
1281 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1282 return 0;
1283}
1284
1285static void __kprobes
1286test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1287 unsigned long flags)
1288{
1289 setup_test_context(regs);
1290 initial_regs = *regs;
1291 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1292}
1293
1294static int __kprobes
1295test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1296{
1297 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1298 return 0;
1299}
1300
1301static int __kprobes
1302test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1303{
1304 if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1305 return 0; /* Already run for this test instance */
1306
1307 result_regs = *regs;
1308 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1309
1310 /* Undo any changes done to SP by the test case */
1311 regs->ARM_sp = (unsigned long)current_stack;
1312
1313 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1314 return 0;
1315}
1316
1317static struct test_probe test_before_probe = {
1318 .kprobe.pre_handler = test_before_pre_handler,
1319 .kprobe.post_handler = test_before_post_handler,
1320};
1321
1322static struct test_probe test_case_probe = {
1323 .kprobe.pre_handler = test_case_pre_handler,
1324};
1325
1326static struct test_probe test_after_probe = {
1327 .kprobe.pre_handler = test_after_pre_handler,
1328};
1329
1330static struct test_probe test_after2_probe = {
1331 .kprobe.pre_handler = test_after_pre_handler,
1332};
1333
1334static void test_case_cleanup(void)
1335{
1336 unregister_test_probe(&test_before_probe);
1337 unregister_test_probe(&test_case_probe);
1338 unregister_test_probe(&test_after_probe);
1339 unregister_test_probe(&test_after2_probe);
1340}
1341
1342static void print_registers(struct pt_regs *regs)
1343{
1344 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1345 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1346 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1347 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1348 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1349 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1350 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1351 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1352 pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1353}
1354
1355static void print_memory(u32 *mem, size_t size)
1356{
1357 int i;
1358 for (i = 0; i < size / sizeof(u32); i += 4)
1359 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1360 mem[i+2], mem[i+3]);
1361}
1362
1363static size_t expected_memory_size(u32 *sp)
1364{
1365 size_t size = sizeof(expected_memory);
1366 int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1367 if (offset > 0)
1368 size -= offset;
1369 return size;
1370}
1371
1372static void test_case_failed(const char *message)
1373{
1374 test_case_cleanup();
1375
1376 pr_err("FAIL: %s\n", message);
1377 pr_err("FAIL: Test %s\n", current_title);
1378 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1379}
1380
1381static unsigned long next_instruction(unsigned long pc)
1382{
1383#ifdef CONFIG_THUMB2_KERNEL
1384 if ((pc & 1) && !is_wide_instruction(*(u16 *)(pc - 1)))
1385 return pc + 2;
1386 else
1387#endif
1388 return pc + 4;
1389}
1390
1391static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
1392{
1393 struct test_arg *args;
1394 struct test_arg_end *end_arg;
1395 unsigned long test_code;
1396
1397 args = (struct test_arg *)PTR_ALIGN(title + strlen(title) + 1, 4);
1398
1399 current_title = title;
1400 current_args = args;
1401 current_stack = stack;
1402
1403 ++test_try_count;
1404
1405 while (args->type != ARG_TYPE_END)
1406 ++args;
1407 end_arg = (struct test_arg_end *)args;
1408
1409 test_code = (unsigned long)(args + 1); /* Code starts after args */
1410
1411 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1412 if (test_case_is_thumb)
1413 test_code |= 1;
1414
1415 current_code_start = test_code;
1416
1417 current_branch_target = 0;
1418 if (end_arg->branch_offset != end_arg->end_offset)
1419 current_branch_target = test_code + end_arg->branch_offset;
1420
1421 test_code += end_arg->code_offset;
1422 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1423
1424 test_code = next_instruction(test_code);
1425 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1426
1427 if (test_case_is_thumb) {
1428 u16 *p = (u16 *)(test_code & ~1);
1429 current_instruction = p[0];
1430 if (is_wide_instruction(current_instruction)) {
1431 current_instruction <<= 16;
1432 current_instruction |= p[1];
1433 }
1434 } else {
1435 current_instruction = *(u32 *)test_code;
1436 }
1437
1438 if (current_title[0] == '.')
1439 verbose("%s\n", current_title);
1440 else
1441 verbose("%s\t@ %0*x\n", current_title,
1442 test_case_is_thumb ? 4 : 8,
1443 current_instruction);
1444
1445 test_code = next_instruction(test_code);
1446 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1447
1448 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1449 if (!test_case_is_thumb ||
1450 is_wide_instruction(current_instruction)) {
1451 test_case_failed("expected 16-bit instruction");
1452 goto fail;
1453 }
1454 } else {
1455 if (test_case_is_thumb &&
1456 !is_wide_instruction(current_instruction)) {
1457 test_case_failed("expected 32-bit instruction");
1458 goto fail;
1459 }
1460 }
1461
1462 coverage_add(current_instruction);
1463
1464 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1465 if (register_test_probe(&test_case_probe) < 0)
1466 goto pass;
1467 test_case_failed("registered probe for unsupported instruction");
1468 goto fail;
1469 }
1470
1471 if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1472 if (register_test_probe(&test_case_probe) >= 0)
1473 goto pass;
1474 test_case_failed("couldn't register probe for supported instruction");
1475 goto fail;
1476 }
1477
1478 if (register_test_probe(&test_before_probe) < 0) {
1479 test_case_failed("register test_before_probe failed");
1480 goto fail;
1481 }
1482 if (register_test_probe(&test_after_probe) < 0) {
1483 test_case_failed("register test_after_probe failed");
1484 goto fail;
1485 }
1486 if (current_branch_target) {
1487 test_after2_probe.kprobe.addr =
1488 (kprobe_opcode_t *)current_branch_target;
1489 if (register_test_probe(&test_after2_probe) < 0) {
1490 test_case_failed("register test_after2_probe failed");
1491 goto fail;
1492 }
1493 }
1494
1495 /* Start first run of test case */
1496 test_case_run_count = 0;
1497 ++test_instance;
1498 return current_code_start;
1499pass:
1500 test_case_run_count = TEST_CASE_PASSED;
1501 return (uintptr_t)test_after_probe.kprobe.addr;
1502fail:
1503 test_case_run_count = TEST_CASE_FAILED;
1504 return (uintptr_t)test_after_probe.kprobe.addr;
1505}
1506
1507static bool check_test_results(void)
1508{
1509 size_t mem_size = 0;
1510 u32 *mem = 0;
1511
1512 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1513 test_case_failed("registers differ");
1514 goto fail;
1515 }
1516
1517 if (memory_needs_checking) {
1518 mem = (u32 *)result_regs.ARM_sp;
1519 mem_size = expected_memory_size(mem);
1520 if (memcmp(expected_memory, mem, mem_size)) {
1521 test_case_failed("test memory differs");
1522 goto fail;
1523 }
1524 }
1525
1526 return true;
1527
1528fail:
1529 pr_err("initial_regs:\n");
1530 print_registers(&initial_regs);
1531 pr_err("expected_regs:\n");
1532 print_registers(&expected_regs);
1533 pr_err("result_regs:\n");
1534 print_registers(&result_regs);
1535
1536 if (mem) {
1537 pr_err("current_stack=%p\n", current_stack);
1538 pr_err("expected_memory:\n");
1539 print_memory(expected_memory, mem_size);
1540 pr_err("result_memory:\n");
1541 print_memory(mem, mem_size);
1542 }
1543
1544 return false;
1545}
1546
1547static uintptr_t __used kprobes_test_case_end(void)
1548{
1549 if (test_case_run_count < 0) {
1550 if (test_case_run_count == TEST_CASE_PASSED)
1551 /* kprobes_test_case_start did all the needed testing */
1552 goto pass;
1553 else
1554 /* kprobes_test_case_start failed */
1555 goto fail;
1556 }
1557
1558 if (test_before_probe.hit != test_instance) {
1559 test_case_failed("test_before_handler not run");
1560 goto fail;
1561 }
1562
1563 if (test_after_probe.hit != test_instance &&
1564 test_after2_probe.hit != test_instance) {
1565 test_case_failed("test_after_handler not run");
1566 goto fail;
1567 }
1568
1569 /*
1570 * Even numbered test runs ran without a probe on the test case so
1571 * we can gather reference results. The subsequent odd numbered run
1572 * will have the probe inserted.
1573 */
1574 if ((test_case_run_count & 1) == 0) {
1575 /* Save results from run without probe */
1576 u32 *mem = (u32 *)result_regs.ARM_sp;
1577 expected_regs = result_regs;
1578 memcpy(expected_memory, mem, expected_memory_size(mem));
1579
1580 /* Insert probe onto test case instruction */
1581 if (register_test_probe(&test_case_probe) < 0) {
1582 test_case_failed("register test_case_probe failed");
1583 goto fail;
1584 }
1585 } else {
1586 /* Check probe ran as expected */
1587 if (probe_should_run == 1) {
1588 if (test_case_probe.hit != test_instance) {
1589 test_case_failed("test_case_handler not run");
1590 goto fail;
1591 }
1592 } else if (probe_should_run == 0) {
1593 if (test_case_probe.hit == test_instance) {
1594 test_case_failed("test_case_handler ran");
1595 goto fail;
1596 }
1597 }
1598
1599 /* Remove probe for any subsequent reference run */
1600 unregister_test_probe(&test_case_probe);
1601
1602 if (!check_test_results())
1603 goto fail;
1604
1605 if (is_last_scenario)
1606 goto pass;
1607 }
1608
1609 /* Do next test run */
1610 ++test_case_run_count;
1611 ++test_instance;
1612 return current_code_start;
1613fail:
1614 ++test_fail_count;
1615 goto end;
1616pass:
1617 ++test_pass_count;
1618end:
1619 test_case_cleanup();
1620 return 0;
1621}
1622
1623
1624/*
1625 * Top level test functions
1626 */
1627
1628static int run_test_cases(void (*tests)(void), const union decode_item *table)
1629{
1630 int ret;
1631
1632 pr_info(" Check decoding tables\n");
1633 ret = table_test(table);
1634 if (ret)
1635 return ret;
1636
1637 pr_info(" Run test cases\n");
1638 ret = coverage_start(table);
1639 if (ret)
1640 return ret;
1641
1642 tests();
1643
1644 coverage_end();
1645 return 0;
1646}
1647
1648
1649static int __init run_all_tests(void)
1650{
1651 int ret = 0;
1652
1653 pr_info("Begining kprobe tests...\n");
1654
1655#ifndef CONFIG_THUMB2_KERNEL
1656
1657 pr_info("Probe ARM code\n");
1658 ret = run_api_tests(arm_func);
1659 if (ret)
1660 goto out;
1661
1662 pr_info("ARM instruction simulation\n");
1663 ret = run_test_cases(kprobe_arm_test_cases, kprobe_decode_arm_table);
1664 if (ret)
1665 goto out;
1666
1667#else /* CONFIG_THUMB2_KERNEL */
1668
1669 pr_info("Probe 16-bit Thumb code\n");
1670 ret = run_api_tests(thumb16_func);
1671 if (ret)
1672 goto out;
1673
1674 pr_info("Probe 32-bit Thumb code, even halfword\n");
1675 ret = run_api_tests(thumb32even_func);
1676 if (ret)
1677 goto out;
1678
1679 pr_info("Probe 32-bit Thumb code, odd halfword\n");
1680 ret = run_api_tests(thumb32odd_func);
1681 if (ret)
1682 goto out;
1683
1684 pr_info("16-bit Thumb instruction simulation\n");
1685 ret = run_test_cases(kprobe_thumb16_test_cases,
1686 kprobe_decode_thumb16_table);
1687 if (ret)
1688 goto out;
1689
1690 pr_info("32-bit Thumb instruction simulation\n");
1691 ret = run_test_cases(kprobe_thumb32_test_cases,
1692 kprobe_decode_thumb32_table);
1693 if (ret)
1694 goto out;
1695#endif
1696
1697 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1698 test_try_count, test_pass_count, test_fail_count);
1699 if (test_fail_count) {
1700 ret = -EINVAL;
1701 goto out;
1702 }
1703
1704#if BENCHMARKING
1705 pr_info("Benchmarks\n");
1706 ret = run_benchmarks();
1707 if (ret)
1708 goto out;
1709#endif
1710
1711#if __LINUX_ARM_ARCH__ >= 7
1712 /* We are able to run all test cases so coverage should be complete */
1713 if (coverage_fail) {
1714 pr_err("FAIL: Test coverage checks failed\n");
1715 ret = -EINVAL;
1716 goto out;
1717 }
1718#endif
1719
1720out:
1721 if (ret == 0)
1722 pr_info("Finished kprobe tests OK\n");
1723 else
1724 pr_err("kprobe tests failed\n");
1725
1726 return ret;
1727}
1728
1729
1730/*
1731 * Module setup
1732 */
1733
1734#ifdef MODULE
1735
1736static void __exit kprobe_test_exit(void)
1737{
1738}
1739
1740module_init(run_all_tests)
1741module_exit(kprobe_test_exit)
1742MODULE_LICENSE("GPL");
1743
1744#else /* !MODULE */
1745
1746late_initcall(run_all_tests);
1747
1748#endif
generated by cgit v1.2.2 (git 2.25.0) at 2024-09-22 01:36:01 -0400