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  *	.pushsection .rodata
114  *	"10:
115  *	.ascii "mov r0, r7"	@ text title for test case
116  *	.byte	0
117  *	.popsection
118  *	@ start of inline data...
119  *	.word	10b		@ pointer to title in .rodata section
120  *
121  *	@ TEST_ARG_REG
122  *	.byte	ARG_TYPE_REG
123  *	.byte	7
124  *	.short	0
125  *	.word	0x1234567
126  *
127  *	@ TEST_ARG_END
128  *	.byte	ARG_TYPE_END
129  *	.byte	TEST_ISA	@ flags, including ISA being tested
130  *	.short	50f-0f		@ offset of 'test_before'
131  *	.short	2f-0f		@ offset of 'test_after2' (if relevent)
132  *	.short	99f-0f		@ offset of 'test_done'
133  *	@ start of test case code...
134  *	0:
135  *	.code	TEST_ISA	@ switch to ISA being tested
136  *
137  *	@ TEST_INSTRUCTION
138  *	50:	nop		@ location for 'test_before' probe
139  *	1:	mov r0, r7	@ the test case instruction 'test_insn'
140  *		nop		@ location for 'test_after' probe
141  *
142  *	// TESTCASE_END
143  *	2:
144  *	99:	bl __kprobes_test_case_end_##TEST_ISA
145  *	.code	NONMAL_ISA
146  *
147  * When the above is execute the following happens...
148  *
149  * __kprobes_test_case_start() is an assembler wrapper which sets up space
150  * for a stack buffer and calls the C function kprobes_test_case_start().
151  * This C function will do some initial processing of the inline data and
152  * setup some global state. It then inserts the test_before and test_after
153  * kprobes and returns a value which causes the assembler wrapper to jump
154  * to the start of the test case code, (local label '0').
155  *
156  * When the test case code executes, the test_before probe will be hit and
157  * test_before_post_handler will call setup_test_context(). This fills the
158  * stack buffer and CPU registers with a test pattern and then processes
159  * the test case arguments. In our example there is one TEST_ARG_REG which
160  * indicates that R7 should be loaded with the value 0x12345678.
161  *
162  * When the test_before probe ends, the test case continues and executes
163  * the "mov r0, r7" instruction. It then hits the test_after probe and the
164  * pre-handler for this (test_after_pre_handler) will save a copy of the
165  * CPU register context. This should now have R0 holding the same value as
166  * R7.
167  *
168  * Finally we get to the call to __kprobes_test_case_end_{32,16}. This is
169  * an assembler wrapper which switches back to the ISA used by the test
170  * code and calls the C function kprobes_test_case_end().
171  *
172  * For each run through the test case, test_case_run_count is incremented
173  * by one. For even runs, kprobes_test_case_end() saves a copy of the
174  * register and stack buffer contents from the test case just run. It then
175  * inserts a kprobe on the test case instruction 'test_insn' and returns a
176  * value to cause the test case code to be re-run.
177  *
178  * For odd numbered runs, kprobes_test_case_end() compares the register and
179  * stack buffer contents to those that were saved on the previous even
180  * numbered run (the one without the kprobe on test_insn). These should be
181  * the same if the kprobe instruction simulation routine is correct.
182  *
183  * The pair of test case runs is repeated with different combinations of
184  * flag values in CPSR and, for Thumb, different ITState. This is
185  * controlled by test_context_cpsr().
186  *
187  * BUILDING TEST CASES
188  * -------------------
189  *
190  *
191  * As an aid to building test cases, the stack buffer is initialised with
192  * some special values:
193  *
194  *   [SP+13*4]	Contains SP+120. This can be used to test instructions
195  *		which load a value into SP.
196  *
197  *   [SP+15*4]	When testing branching instructions using TEST_BRANCH_{F,B},
198  *		this holds the target address of the branch, 'test_after2'.
199  *		This can be used to test instructions which load a PC value
200  *		from memory.
201  */
202 
203 #include <linux/kernel.h>
204 #include <linux/module.h>
205 #include <linux/slab.h>
206 #include <linux/sched/clock.h>
207 #include <linux/kprobes.h>
208 #include <linux/errno.h>
209 #include <linux/stddef.h>
210 #include <linux/bug.h>
211 #include <asm/opcodes.h>
212 
213 #include "core.h"
214 #include "test-core.h"
215 #include "../decode-arm.h"
216 #include "../decode-thumb.h"
217 
218 
219 #define BENCHMARKING	1
220 
221 
222 /*
223  * Test basic API
224  */
225 
226 static bool test_regs_ok;
227 static int test_func_instance;
228 static int pre_handler_called;
229 static int post_handler_called;
230 static int kretprobe_handler_called;
231 static int tests_failed;
232 
233 #define FUNC_ARG1 0x12345678
234 #define FUNC_ARG2 0xabcdef
235 
236 
237 #ifndef CONFIG_THUMB2_KERNEL
238 
239 #define RET(reg)	"mov	pc, "#reg
240 
241 long arm_func(long r0, long r1);
242 
243 static void __used __naked __arm_kprobes_test_func(void)
244 {
245 	__asm__ __volatile__ (
246 		".arm					\n\t"
247 		".type arm_func, %%function		\n\t"
248 		"arm_func:				\n\t"
249 		"adds	r0, r0, r1			\n\t"
250 		"mov	pc, lr				\n\t"
251 		".code "NORMAL_ISA	 /* Back to Thumb if necessary */
252 		: : : "r0", "r1", "cc"
253 	);
254 }
255 
256 #else /* CONFIG_THUMB2_KERNEL */
257 
258 #define RET(reg)	"bx	"#reg
259 
260 long thumb16_func(long r0, long r1);
261 long thumb32even_func(long r0, long r1);
262 long thumb32odd_func(long r0, long r1);
263 
264 static void __used __naked __thumb_kprobes_test_funcs(void)
265 {
266 	__asm__ __volatile__ (
267 		".type thumb16_func, %%function		\n\t"
268 		"thumb16_func:				\n\t"
269 		"adds.n	r0, r0, r1			\n\t"
270 		"bx	lr				\n\t"
271 
272 		".align					\n\t"
273 		".type thumb32even_func, %%function	\n\t"
274 		"thumb32even_func:			\n\t"
275 		"adds.w	r0, r0, r1			\n\t"
276 		"bx	lr				\n\t"
277 
278 		".align					\n\t"
279 		"nop.n					\n\t"
280 		".type thumb32odd_func, %%function	\n\t"
281 		"thumb32odd_func:			\n\t"
282 		"adds.w	r0, r0, r1			\n\t"
283 		"bx	lr				\n\t"
284 
285 		: : : "r0", "r1", "cc"
286 	);
287 }
288 
289 #endif /* CONFIG_THUMB2_KERNEL */
290 
291 
292 static int call_test_func(long (*func)(long, long), bool check_test_regs)
293 {
294 	long ret;
295 
296 	++test_func_instance;
297 	test_regs_ok = false;
298 
299 	ret = (*func)(FUNC_ARG1, FUNC_ARG2);
300 	if (ret != FUNC_ARG1 + FUNC_ARG2) {
301 		pr_err("FAIL: call_test_func: func returned %lx\n", ret);
302 		return false;
303 	}
304 
305 	if (check_test_regs && !test_regs_ok) {
306 		pr_err("FAIL: test regs not OK\n");
307 		return false;
308 	}
309 
310 	return true;
311 }
312 
313 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
314 {
315 	pre_handler_called = test_func_instance;
316 	if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
317 		test_regs_ok = true;
318 	return 0;
319 }
320 
321 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
322 				unsigned long flags)
323 {
324 	post_handler_called = test_func_instance;
325 	if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
326 		test_regs_ok = false;
327 }
328 
329 static struct kprobe the_kprobe = {
330 	.addr		= 0,
331 	.pre_handler	= pre_handler,
332 	.post_handler	= post_handler
333 };
334 
335 static int test_kprobe(long (*func)(long, long))
336 {
337 	int ret;
338 
339 	the_kprobe.addr = (kprobe_opcode_t *)func;
340 	ret = register_kprobe(&the_kprobe);
341 	if (ret < 0) {
342 		pr_err("FAIL: register_kprobe failed with %d\n", ret);
343 		return ret;
344 	}
345 
346 	ret = call_test_func(func, true);
347 
348 	unregister_kprobe(&the_kprobe);
349 	the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
350 
351 	if (!ret)
352 		return -EINVAL;
353 	if (pre_handler_called != test_func_instance) {
354 		pr_err("FAIL: kprobe pre_handler not called\n");
355 		return -EINVAL;
356 	}
357 	if (post_handler_called != test_func_instance) {
358 		pr_err("FAIL: kprobe post_handler not called\n");
359 		return -EINVAL;
360 	}
361 	if (!call_test_func(func, false))
362 		return -EINVAL;
363 	if (pre_handler_called == test_func_instance ||
364 				post_handler_called == test_func_instance) {
365 		pr_err("FAIL: probe called after unregistering\n");
366 		return -EINVAL;
367 	}
368 
369 	return 0;
370 }
371 
372 static int __kprobes
373 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
374 {
375 	kretprobe_handler_called = test_func_instance;
376 	if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
377 		test_regs_ok = true;
378 	return 0;
379 }
380 
381 static struct kretprobe the_kretprobe = {
382 	.handler	= kretprobe_handler,
383 };
384 
385 static int test_kretprobe(long (*func)(long, long))
386 {
387 	int ret;
388 
389 	the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
390 	ret = register_kretprobe(&the_kretprobe);
391 	if (ret < 0) {
392 		pr_err("FAIL: register_kretprobe failed with %d\n", ret);
393 		return ret;
394 	}
395 
396 	ret = call_test_func(func, true);
397 
398 	unregister_kretprobe(&the_kretprobe);
399 	the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
400 
401 	if (!ret)
402 		return -EINVAL;
403 	if (kretprobe_handler_called != test_func_instance) {
404 		pr_err("FAIL: kretprobe handler not called\n");
405 		return -EINVAL;
406 	}
407 	if (!call_test_func(func, false))
408 		return -EINVAL;
409 	if (kretprobe_handler_called == test_func_instance) {
410 		pr_err("FAIL: kretprobe called after unregistering\n");
411 		return -EINVAL;
412 	}
413 
414 	return 0;
415 }
416 
417 static int run_api_tests(long (*func)(long, long))
418 {
419 	int ret;
420 
421 	pr_info("    kprobe\n");
422 	ret = test_kprobe(func);
423 	if (ret < 0)
424 		return ret;
425 
426 	pr_info("    kretprobe\n");
427 	ret = test_kretprobe(func);
428 	if (ret < 0)
429 		return ret;
430 
431 	return 0;
432 }
433 
434 
435 /*
436  * Benchmarking
437  */
438 
439 #if BENCHMARKING
440 
441 static void __naked benchmark_nop(void)
442 {
443 	__asm__ __volatile__ (
444 		"nop		\n\t"
445 		RET(lr)"	\n\t"
446 	);
447 }
448 
449 #ifdef CONFIG_THUMB2_KERNEL
450 #define wide ".w"
451 #else
452 #define wide
453 #endif
454 
455 static void __naked benchmark_pushpop1(void)
456 {
457 	__asm__ __volatile__ (
458 		"stmdb"wide"	sp!, {r3-r11,lr}  \n\t"
459 		"ldmia"wide"	sp!, {r3-r11,pc}"
460 	);
461 }
462 
463 static void __naked benchmark_pushpop2(void)
464 {
465 	__asm__ __volatile__ (
466 		"stmdb"wide"	sp!, {r0-r8,lr}  \n\t"
467 		"ldmia"wide"	sp!, {r0-r8,pc}"
468 	);
469 }
470 
471 static void __naked benchmark_pushpop3(void)
472 {
473 	__asm__ __volatile__ (
474 		"stmdb"wide"	sp!, {r4,lr}  \n\t"
475 		"ldmia"wide"	sp!, {r4,pc}"
476 	);
477 }
478 
479 static void __naked benchmark_pushpop4(void)
480 {
481 	__asm__ __volatile__ (
482 		"stmdb"wide"	sp!, {r0,lr}  \n\t"
483 		"ldmia"wide"	sp!, {r0,pc}"
484 	);
485 }
486 
487 
488 #ifdef CONFIG_THUMB2_KERNEL
489 
490 static void __naked benchmark_pushpop_thumb(void)
491 {
492 	__asm__ __volatile__ (
493 		"push.n	{r0-r7,lr}  \n\t"
494 		"pop.n	{r0-r7,pc}"
495 	);
496 }
497 
498 #endif
499 
500 static int __kprobes
501 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
502 {
503 	return 0;
504 }
505 
506 static int benchmark(void(*fn)(void))
507 {
508 	unsigned n, i, t, t0;
509 
510 	for (n = 1000; ; n *= 2) {
511 		t0 = sched_clock();
512 		for (i = n; i > 0; --i)
513 			fn();
514 		t = sched_clock() - t0;
515 		if (t >= 250000000)
516 			break; /* Stop once we took more than 0.25 seconds */
517 	}
518 	return t / n; /* Time for one iteration in nanoseconds */
519 };
520 
521 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
522 {
523 	struct kprobe k = {
524 		.addr		= (kprobe_opcode_t *)((uintptr_t)fn + offset),
525 		.pre_handler	= benchmark_pre_handler,
526 	};
527 
528 	int ret = register_kprobe(&k);
529 	if (ret < 0) {
530 		pr_err("FAIL: register_kprobe failed with %d\n", ret);
531 		return ret;
532 	}
533 
534 	ret = benchmark(fn);
535 
536 	unregister_kprobe(&k);
537 	return ret;
538 };
539 
540 struct benchmarks {
541 	void		(*fn)(void);
542 	unsigned	offset;
543 	const char	*title;
544 };
545 
546 static int run_benchmarks(void)
547 {
548 	int ret;
549 	struct benchmarks list[] = {
550 		{&benchmark_nop, 0, "nop"},
551 		/*
552 		 * benchmark_pushpop{1,3} will have the optimised
553 		 * instruction emulation, whilst benchmark_pushpop{2,4} will
554 		 * be the equivalent unoptimised instructions.
555 		 */
556 		{&benchmark_pushpop1, 0, "stmdb	sp!, {r3-r11,lr}"},
557 		{&benchmark_pushpop1, 4, "ldmia	sp!, {r3-r11,pc}"},
558 		{&benchmark_pushpop2, 0, "stmdb	sp!, {r0-r8,lr}"},
559 		{&benchmark_pushpop2, 4, "ldmia	sp!, {r0-r8,pc}"},
560 		{&benchmark_pushpop3, 0, "stmdb	sp!, {r4,lr}"},
561 		{&benchmark_pushpop3, 4, "ldmia	sp!, {r4,pc}"},
562 		{&benchmark_pushpop4, 0, "stmdb	sp!, {r0,lr}"},
563 		{&benchmark_pushpop4, 4, "ldmia	sp!, {r0,pc}"},
564 #ifdef CONFIG_THUMB2_KERNEL
565 		{&benchmark_pushpop_thumb, 0, "push.n	{r0-r7,lr}"},
566 		{&benchmark_pushpop_thumb, 2, "pop.n	{r0-r7,pc}"},
567 #endif
568 		{0}
569 	};
570 
571 	struct benchmarks *b;
572 	for (b = list; b->fn; ++b) {
573 		ret = kprobe_benchmark(b->fn, b->offset);
574 		if (ret < 0)
575 			return ret;
576 		pr_info("    %dns for kprobe %s\n", ret, b->title);
577 	}
578 
579 	pr_info("\n");
580 	return 0;
581 }
582 
583 #endif /* BENCHMARKING */
584 
585 
586 /*
587  * Decoding table self-consistency tests
588  */
589 
590 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
591 	[DECODE_TYPE_TABLE]	= sizeof(struct decode_table),
592 	[DECODE_TYPE_CUSTOM]	= sizeof(struct decode_custom),
593 	[DECODE_TYPE_SIMULATE]	= sizeof(struct decode_simulate),
594 	[DECODE_TYPE_EMULATE]	= sizeof(struct decode_emulate),
595 	[DECODE_TYPE_OR]	= sizeof(struct decode_or),
596 	[DECODE_TYPE_REJECT]	= sizeof(struct decode_reject)
597 };
598 
599 static int table_iter(const union decode_item *table,
600 			int (*fn)(const struct decode_header *, void *),
601 			void *args)
602 {
603 	const struct decode_header *h = (struct decode_header *)table;
604 	int result;
605 
606 	for (;;) {
607 		enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
608 
609 		if (type == DECODE_TYPE_END)
610 			return 0;
611 
612 		result = fn(h, args);
613 		if (result)
614 			return result;
615 
616 		h = (struct decode_header *)
617 			((uintptr_t)h + decode_struct_sizes[type]);
618 
619 	}
620 }
621 
622 static int table_test_fail(const struct decode_header *h, const char* message)
623 {
624 
625 	pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
626 					message, h->mask.bits, h->value.bits);
627 	return -EINVAL;
628 }
629 
630 struct table_test_args {
631 	const union decode_item *root_table;
632 	u32			parent_mask;
633 	u32			parent_value;
634 };
635 
636 static int table_test_fn(const struct decode_header *h, void *args)
637 {
638 	struct table_test_args *a = (struct table_test_args *)args;
639 	enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
640 
641 	if (h->value.bits & ~h->mask.bits)
642 		return table_test_fail(h, "Match value has bits not in mask");
643 
644 	if ((h->mask.bits & a->parent_mask) != a->parent_mask)
645 		return table_test_fail(h, "Mask has bits not in parent mask");
646 
647 	if ((h->value.bits ^ a->parent_value) & a->parent_mask)
648 		return table_test_fail(h, "Value is inconsistent with parent");
649 
650 	if (type == DECODE_TYPE_TABLE) {
651 		struct decode_table *d = (struct decode_table *)h;
652 		struct table_test_args args2 = *a;
653 		args2.parent_mask = h->mask.bits;
654 		args2.parent_value = h->value.bits;
655 		return table_iter(d->table.table, table_test_fn, &args2);
656 	}
657 
658 	return 0;
659 }
660 
661 static int table_test(const union decode_item *table)
662 {
663 	struct table_test_args args = {
664 		.root_table	= table,
665 		.parent_mask	= 0,
666 		.parent_value	= 0
667 	};
668 	return table_iter(args.root_table, table_test_fn, &args);
669 }
670 
671 
672 /*
673  * Decoding table test coverage analysis
674  *
675  * coverage_start() builds a coverage_table which contains a list of
676  * coverage_entry's to match each entry in the specified kprobes instruction
677  * decoding table.
678  *
679  * When test cases are run, coverage_add() is called to process each case.
680  * This looks up the corresponding entry in the coverage_table and sets it as
681  * being matched, as well as clearing the regs flag appropriate for the test.
682  *
683  * After all test cases have been run, coverage_end() is called to check that
684  * all entries in coverage_table have been matched and that all regs flags are
685  * cleared. I.e. that all possible combinations of instructions described by
686  * the kprobes decoding tables have had a test case executed for them.
687  */
688 
689 bool coverage_fail;
690 
691 #define MAX_COVERAGE_ENTRIES 256
692 
693 struct coverage_entry {
694 	const struct decode_header	*header;
695 	unsigned			regs;
696 	unsigned			nesting;
697 	char				matched;
698 };
699 
700 struct coverage_table {
701 	struct coverage_entry	*base;
702 	unsigned		num_entries;
703 	unsigned		nesting;
704 };
705 
706 struct coverage_table coverage;
707 
708 #define COVERAGE_ANY_REG	(1<<0)
709 #define COVERAGE_SP		(1<<1)
710 #define COVERAGE_PC		(1<<2)
711 #define COVERAGE_PCWB		(1<<3)
712 
713 static const char coverage_register_lookup[16] = {
714 	[REG_TYPE_ANY]		= COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
715 	[REG_TYPE_SAMEAS16]	= COVERAGE_ANY_REG,
716 	[REG_TYPE_SP]		= COVERAGE_SP,
717 	[REG_TYPE_PC]		= COVERAGE_PC,
718 	[REG_TYPE_NOSP]		= COVERAGE_ANY_REG | COVERAGE_SP,
719 	[REG_TYPE_NOSPPC]	= COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
720 	[REG_TYPE_NOPC]		= COVERAGE_ANY_REG | COVERAGE_PC,
721 	[REG_TYPE_NOPCWB]	= COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
722 	[REG_TYPE_NOPCX]	= COVERAGE_ANY_REG,
723 	[REG_TYPE_NOSPPCX]	= COVERAGE_ANY_REG | COVERAGE_SP,
724 };
725 
726 unsigned coverage_start_registers(const struct decode_header *h)
727 {
728 	unsigned regs = 0;
729 	int i;
730 	for (i = 0; i < 20; i += 4) {
731 		int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
732 		regs |= coverage_register_lookup[r] << i;
733 	}
734 	return regs;
735 }
736 
737 static int coverage_start_fn(const struct decode_header *h, void *args)
738 {
739 	struct coverage_table *coverage = (struct coverage_table *)args;
740 	enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
741 	struct coverage_entry *entry = coverage->base + coverage->num_entries;
742 
743 	if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
744 		pr_err("FAIL: Out of space for test coverage data");
745 		return -ENOMEM;
746 	}
747 
748 	++coverage->num_entries;
749 
750 	entry->header = h;
751 	entry->regs = coverage_start_registers(h);
752 	entry->nesting = coverage->nesting;
753 	entry->matched = false;
754 
755 	if (type == DECODE_TYPE_TABLE) {
756 		struct decode_table *d = (struct decode_table *)h;
757 		int ret;
758 		++coverage->nesting;
759 		ret = table_iter(d->table.table, coverage_start_fn, coverage);
760 		--coverage->nesting;
761 		return ret;
762 	}
763 
764 	return 0;
765 }
766 
767 static int coverage_start(const union decode_item *table)
768 {
769 	coverage.base = kmalloc_array(MAX_COVERAGE_ENTRIES,
770 				      sizeof(struct coverage_entry),
771 				      GFP_KERNEL);
772 	coverage.num_entries = 0;
773 	coverage.nesting = 0;
774 	return table_iter(table, coverage_start_fn, &coverage);
775 }
776 
777 static void
778 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
779 {
780 	int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
781 	int i;
782 	for (i = 0; i < 20; i += 4) {
783 		enum decode_reg_type reg_type = (regs >> i) & 0xf;
784 		int reg = (insn >> i) & 0xf;
785 		int flag;
786 
787 		if (!reg_type)
788 			continue;
789 
790 		if (reg == 13)
791 			flag = COVERAGE_SP;
792 		else if (reg == 15)
793 			flag = COVERAGE_PC;
794 		else
795 			flag = COVERAGE_ANY_REG;
796 		entry->regs &= ~(flag << i);
797 
798 		switch (reg_type) {
799 
800 		case REG_TYPE_NONE:
801 		case REG_TYPE_ANY:
802 		case REG_TYPE_SAMEAS16:
803 			break;
804 
805 		case REG_TYPE_SP:
806 			if (reg != 13)
807 				return;
808 			break;
809 
810 		case REG_TYPE_PC:
811 			if (reg != 15)
812 				return;
813 			break;
814 
815 		case REG_TYPE_NOSP:
816 			if (reg == 13)
817 				return;
818 			break;
819 
820 		case REG_TYPE_NOSPPC:
821 		case REG_TYPE_NOSPPCX:
822 			if (reg == 13 || reg == 15)
823 				return;
824 			break;
825 
826 		case REG_TYPE_NOPCWB:
827 			if (!is_writeback(insn))
828 				break;
829 			if (reg == 15) {
830 				entry->regs &= ~(COVERAGE_PCWB << i);
831 				return;
832 			}
833 			break;
834 
835 		case REG_TYPE_NOPC:
836 		case REG_TYPE_NOPCX:
837 			if (reg == 15)
838 				return;
839 			break;
840 		}
841 
842 	}
843 }
844 
845 static void coverage_add(kprobe_opcode_t insn)
846 {
847 	struct coverage_entry *entry = coverage.base;
848 	struct coverage_entry *end = coverage.base + coverage.num_entries;
849 	bool matched = false;
850 	unsigned nesting = 0;
851 
852 	for (; entry < end; ++entry) {
853 		const struct decode_header *h = entry->header;
854 		enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
855 
856 		if (entry->nesting > nesting)
857 			continue; /* Skip sub-table we didn't match */
858 
859 		if (entry->nesting < nesting)
860 			break; /* End of sub-table we were scanning */
861 
862 		if (!matched) {
863 			if ((insn & h->mask.bits) != h->value.bits)
864 				continue;
865 			entry->matched = true;
866 		}
867 
868 		switch (type) {
869 
870 		case DECODE_TYPE_TABLE:
871 			++nesting;
872 			break;
873 
874 		case DECODE_TYPE_CUSTOM:
875 		case DECODE_TYPE_SIMULATE:
876 		case DECODE_TYPE_EMULATE:
877 			coverage_add_registers(entry, insn);
878 			return;
879 
880 		case DECODE_TYPE_OR:
881 			matched = true;
882 			break;
883 
884 		case DECODE_TYPE_REJECT:
885 		default:
886 			return;
887 		}
888 
889 	}
890 }
891 
892 static void coverage_end(void)
893 {
894 	struct coverage_entry *entry = coverage.base;
895 	struct coverage_entry *end = coverage.base + coverage.num_entries;
896 
897 	for (; entry < end; ++entry) {
898 		u32 mask = entry->header->mask.bits;
899 		u32 value = entry->header->value.bits;
900 
901 		if (entry->regs) {
902 			pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
903 				mask, value, entry->regs);
904 			coverage_fail = true;
905 		}
906 		if (!entry->matched) {
907 			pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
908 				mask, value);
909 			coverage_fail = true;
910 		}
911 	}
912 
913 	kfree(coverage.base);
914 }
915 
916 
917 /*
918  * Framework for instruction set test cases
919  */
920 
921 void __naked __kprobes_test_case_start(void)
922 {
923 	__asm__ __volatile__ (
924 		"mov	r2, sp					\n\t"
925 		"bic	r3, r2, #7				\n\t"
926 		"mov	sp, r3					\n\t"
927 		"stmdb	sp!, {r2-r11}				\n\t"
928 		"sub	sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
929 		"bic	r0, lr, #1  @ r0 = inline data		\n\t"
930 		"mov	r1, sp					\n\t"
931 		"bl	kprobes_test_case_start			\n\t"
932 		RET(r0)"					\n\t"
933 	);
934 }
935 
936 #ifndef CONFIG_THUMB2_KERNEL
937 
938 void __naked __kprobes_test_case_end_32(void)
939 {
940 	__asm__ __volatile__ (
941 		"mov	r4, lr					\n\t"
942 		"bl	kprobes_test_case_end			\n\t"
943 		"cmp	r0, #0					\n\t"
944 		"movne	pc, r0					\n\t"
945 		"mov	r0, r4					\n\t"
946 		"add	sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
947 		"ldmia	sp!, {r2-r11}				\n\t"
948 		"mov	sp, r2					\n\t"
949 		"mov	pc, r0					\n\t"
950 	);
951 }
952 
953 #else /* CONFIG_THUMB2_KERNEL */
954 
955 void __naked __kprobes_test_case_end_16(void)
956 {
957 	__asm__ __volatile__ (
958 		"mov	r4, lr					\n\t"
959 		"bl	kprobes_test_case_end			\n\t"
960 		"cmp	r0, #0					\n\t"
961 		"bxne	r0					\n\t"
962 		"mov	r0, r4					\n\t"
963 		"add	sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
964 		"ldmia	sp!, {r2-r11}				\n\t"
965 		"mov	sp, r2					\n\t"
966 		"bx	r0					\n\t"
967 	);
968 }
969 
970 void __naked __kprobes_test_case_end_32(void)
971 {
972 	__asm__ __volatile__ (
973 		".arm						\n\t"
974 		"orr	lr, lr, #1  @ will return to Thumb code	\n\t"
975 		"ldr	pc, 1f					\n\t"
976 		"1:						\n\t"
977 		".word	__kprobes_test_case_end_16		\n\t"
978 	);
979 }
980 
981 #endif
982 
983 
984 int kprobe_test_flags;
985 int kprobe_test_cc_position;
986 
987 static int test_try_count;
988 static int test_pass_count;
989 static int test_fail_count;
990 
991 static struct pt_regs initial_regs;
992 static struct pt_regs expected_regs;
993 static struct pt_regs result_regs;
994 
995 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
996 
997 static const char *current_title;
998 static struct test_arg *current_args;
999 static u32 *current_stack;
1000 static uintptr_t current_branch_target;
1001 
1002 static uintptr_t current_code_start;
1003 static kprobe_opcode_t current_instruction;
1004 
1005 
1006 #define TEST_CASE_PASSED -1
1007 #define TEST_CASE_FAILED -2
1008 
1009 static int test_case_run_count;
1010 static bool test_case_is_thumb;
1011 static int test_instance;
1012 
1013 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1014 {
1015 	int ret = arm_check_condition(cc << 28, cpsr);
1016 
1017 	return (ret != ARM_OPCODE_CONDTEST_FAIL);
1018 }
1019 
1020 static int is_last_scenario;
1021 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1022 static int memory_needs_checking;
1023 
1024 static unsigned long test_context_cpsr(int scenario)
1025 {
1026 	unsigned long cpsr;
1027 
1028 	probe_should_run = 1;
1029 
1030 	/* Default case is that we cycle through 16 combinations of flags */
1031 	cpsr  = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1032 	cpsr |= (scenario & 0xf) << 16; /* GE flags */
1033 	cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1034 
1035 	if (!test_case_is_thumb) {
1036 		/* Testing ARM code */
1037 		int cc = current_instruction >> 28;
1038 
1039 		probe_should_run = test_check_cc(cc, cpsr) != 0;
1040 		if (scenario == 15)
1041 			is_last_scenario = true;
1042 
1043 	} else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1044 		/* Testing Thumb code without setting ITSTATE */
1045 		if (kprobe_test_cc_position) {
1046 			int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1047 			probe_should_run = test_check_cc(cc, cpsr) != 0;
1048 		}
1049 
1050 		if (scenario == 15)
1051 			is_last_scenario = true;
1052 
1053 	} else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1054 		/* Testing Thumb code with all combinations of ITSTATE */
1055 		unsigned x = (scenario >> 4);
1056 		unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1057 		unsigned mask = x / 7 + 2;  /* ITSTATE<4:0>, bits reversed */
1058 
1059 		if (mask > 0x1f) {
1060 			/* Finish by testing state from instruction 'itt al' */
1061 			cond_base = 7;
1062 			mask = 0x4;
1063 			if ((scenario & 0xf) == 0xf)
1064 				is_last_scenario = true;
1065 		}
1066 
1067 		cpsr |= cond_base << 13;	/* ITSTATE<7:5> */
1068 		cpsr |= (mask & 0x1) << 12;	/* ITSTATE<4> */
1069 		cpsr |= (mask & 0x2) << 10;	/* ITSTATE<3> */
1070 		cpsr |= (mask & 0x4) << 8;	/* ITSTATE<2> */
1071 		cpsr |= (mask & 0x8) << 23;	/* ITSTATE<1> */
1072 		cpsr |= (mask & 0x10) << 21;	/* ITSTATE<0> */
1073 
1074 		probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1075 
1076 	} else {
1077 		/* Testing Thumb code with several combinations of ITSTATE */
1078 		switch (scenario) {
1079 		case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1080 			cpsr = 0x00000800;
1081 			probe_should_run = 0;
1082 			break;
1083 		case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1084 			cpsr = 0xf0007800;
1085 			probe_should_run = 0;
1086 			break;
1087 		case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1088 			cpsr = 0x00009800;
1089 			break;
1090 		case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1091 			cpsr = 0xf0002800;
1092 			is_last_scenario = true;
1093 			break;
1094 		}
1095 	}
1096 
1097 	return cpsr;
1098 }
1099 
1100 static void setup_test_context(struct pt_regs *regs)
1101 {
1102 	int scenario = test_case_run_count>>1;
1103 	unsigned long val;
1104 	struct test_arg *args;
1105 	int i;
1106 
1107 	is_last_scenario = false;
1108 	memory_needs_checking = false;
1109 
1110 	/* Initialise test memory on stack */
1111 	val = (scenario & 1) ? VALM : ~VALM;
1112 	for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1113 		current_stack[i] = val + (i << 8);
1114 	/* Put target of branch on stack for tests which load PC from memory */
1115 	if (current_branch_target)
1116 		current_stack[15] = current_branch_target;
1117 	/* Put a value for SP on stack for tests which load SP from memory */
1118 	current_stack[13] = (u32)current_stack + 120;
1119 
1120 	/* Initialise register values to their default state */
1121 	val = (scenario & 2) ? VALR : ~VALR;
1122 	for (i = 0; i < 13; ++i)
1123 		regs->uregs[i] = val ^ (i << 8);
1124 	regs->ARM_lr = val ^ (14 << 8);
1125 	regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1126 	regs->ARM_cpsr |= test_context_cpsr(scenario);
1127 
1128 	/* Perform testcase specific register setup  */
1129 	args = current_args;
1130 	for (; args[0].type != ARG_TYPE_END; ++args)
1131 		switch (args[0].type) {
1132 		case ARG_TYPE_REG: {
1133 			struct test_arg_regptr *arg =
1134 				(struct test_arg_regptr *)args;
1135 			regs->uregs[arg->reg] = arg->val;
1136 			break;
1137 		}
1138 		case ARG_TYPE_PTR: {
1139 			struct test_arg_regptr *arg =
1140 				(struct test_arg_regptr *)args;
1141 			regs->uregs[arg->reg] =
1142 				(unsigned long)current_stack + arg->val;
1143 			memory_needs_checking = true;
1144 			/*
1145 			 * Test memory at an address below SP is in danger of
1146 			 * being altered by an interrupt occurring and pushing
1147 			 * data onto the stack. Disable interrupts to stop this.
1148 			 */
1149 			if (arg->reg == 13)
1150 				regs->ARM_cpsr |= PSR_I_BIT;
1151 			break;
1152 		}
1153 		case ARG_TYPE_MEM: {
1154 			struct test_arg_mem *arg = (struct test_arg_mem *)args;
1155 			current_stack[arg->index] = arg->val;
1156 			break;
1157 		}
1158 		default:
1159 			break;
1160 		}
1161 }
1162 
1163 struct test_probe {
1164 	struct kprobe	kprobe;
1165 	bool		registered;
1166 	int		hit;
1167 };
1168 
1169 static void unregister_test_probe(struct test_probe *probe)
1170 {
1171 	if (probe->registered) {
1172 		unregister_kprobe(&probe->kprobe);
1173 		probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1174 	}
1175 	probe->registered = false;
1176 }
1177 
1178 static int register_test_probe(struct test_probe *probe)
1179 {
1180 	int ret;
1181 
1182 	if (probe->registered)
1183 		BUG();
1184 
1185 	ret = register_kprobe(&probe->kprobe);
1186 	if (ret >= 0) {
1187 		probe->registered = true;
1188 		probe->hit = -1;
1189 	}
1190 	return ret;
1191 }
1192 
1193 static int __kprobes
1194 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1195 {
1196 	container_of(p, struct test_probe, kprobe)->hit = test_instance;
1197 	return 0;
1198 }
1199 
1200 static void __kprobes
1201 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1202 							unsigned long flags)
1203 {
1204 	setup_test_context(regs);
1205 	initial_regs = *regs;
1206 	initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1207 }
1208 
1209 static int __kprobes
1210 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1211 {
1212 	container_of(p, struct test_probe, kprobe)->hit = test_instance;
1213 	return 0;
1214 }
1215 
1216 static int __kprobes
1217 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1218 {
1219 	struct test_arg *args;
1220 
1221 	if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1222 		return 0; /* Already run for this test instance */
1223 
1224 	result_regs = *regs;
1225 
1226 	/* Mask out results which are indeterminate */
1227 	result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1228 	for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
1229 		if (args[0].type == ARG_TYPE_REG_MASKED) {
1230 			struct test_arg_regptr *arg =
1231 				(struct test_arg_regptr *)args;
1232 			result_regs.uregs[arg->reg] &= arg->val;
1233 		}
1234 
1235 	/* Undo any changes done to SP by the test case */
1236 	regs->ARM_sp = (unsigned long)current_stack;
1237 	/* Enable interrupts in case setup_test_context disabled them */
1238 	regs->ARM_cpsr &= ~PSR_I_BIT;
1239 
1240 	container_of(p, struct test_probe, kprobe)->hit = test_instance;
1241 	return 0;
1242 }
1243 
1244 static struct test_probe test_before_probe = {
1245 	.kprobe.pre_handler	= test_before_pre_handler,
1246 	.kprobe.post_handler	= test_before_post_handler,
1247 };
1248 
1249 static struct test_probe test_case_probe = {
1250 	.kprobe.pre_handler	= test_case_pre_handler,
1251 };
1252 
1253 static struct test_probe test_after_probe = {
1254 	.kprobe.pre_handler	= test_after_pre_handler,
1255 };
1256 
1257 static struct test_probe test_after2_probe = {
1258 	.kprobe.pre_handler	= test_after_pre_handler,
1259 };
1260 
1261 static void test_case_cleanup(void)
1262 {
1263 	unregister_test_probe(&test_before_probe);
1264 	unregister_test_probe(&test_case_probe);
1265 	unregister_test_probe(&test_after_probe);
1266 	unregister_test_probe(&test_after2_probe);
1267 }
1268 
1269 static void print_registers(struct pt_regs *regs)
1270 {
1271 	pr_err("r0  %08lx | r1  %08lx | r2  %08lx | r3  %08lx\n",
1272 		regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1273 	pr_err("r4  %08lx | r5  %08lx | r6  %08lx | r7  %08lx\n",
1274 		regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1275 	pr_err("r8  %08lx | r9  %08lx | r10 %08lx | r11 %08lx\n",
1276 		regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1277 	pr_err("r12 %08lx | sp  %08lx | lr  %08lx | pc  %08lx\n",
1278 		regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1279 	pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1280 }
1281 
1282 static void print_memory(u32 *mem, size_t size)
1283 {
1284 	int i;
1285 	for (i = 0; i < size / sizeof(u32); i += 4)
1286 		pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1287 						mem[i+2], mem[i+3]);
1288 }
1289 
1290 static size_t expected_memory_size(u32 *sp)
1291 {
1292 	size_t size = sizeof(expected_memory);
1293 	int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1294 	if (offset > 0)
1295 		size -= offset;
1296 	return size;
1297 }
1298 
1299 static void test_case_failed(const char *message)
1300 {
1301 	test_case_cleanup();
1302 
1303 	pr_err("FAIL: %s\n", message);
1304 	pr_err("FAIL: Test %s\n", current_title);
1305 	pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1306 }
1307 
1308 static unsigned long next_instruction(unsigned long pc)
1309 {
1310 #ifdef CONFIG_THUMB2_KERNEL
1311 	if ((pc & 1) &&
1312 	    !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1313 		return pc + 2;
1314 	else
1315 #endif
1316 	return pc + 4;
1317 }
1318 
1319 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1320 {
1321 	struct test_arg *args;
1322 	struct test_arg_end *end_arg;
1323 	unsigned long test_code;
1324 
1325 	current_title = *title++;
1326 	args = (struct test_arg *)title;
1327 	current_args = args;
1328 	current_stack = stack;
1329 
1330 	++test_try_count;
1331 
1332 	while (args->type != ARG_TYPE_END)
1333 		++args;
1334 	end_arg = (struct test_arg_end *)args;
1335 
1336 	test_code = (unsigned long)(args + 1); /* Code starts after args */
1337 
1338 	test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1339 	if (test_case_is_thumb)
1340 		test_code |= 1;
1341 
1342 	current_code_start = test_code;
1343 
1344 	current_branch_target = 0;
1345 	if (end_arg->branch_offset != end_arg->end_offset)
1346 		current_branch_target = test_code + end_arg->branch_offset;
1347 
1348 	test_code += end_arg->code_offset;
1349 	test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1350 
1351 	test_code = next_instruction(test_code);
1352 	test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1353 
1354 	if (test_case_is_thumb) {
1355 		u16 *p = (u16 *)(test_code & ~1);
1356 		current_instruction = __mem_to_opcode_thumb16(p[0]);
1357 		if (is_wide_instruction(current_instruction)) {
1358 			u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1359 			current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1360 		}
1361 	} else {
1362 		current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1363 	}
1364 
1365 	if (current_title[0] == '.')
1366 		verbose("%s\n", current_title);
1367 	else
1368 		verbose("%s\t@ %0*x\n", current_title,
1369 					test_case_is_thumb ? 4 : 8,
1370 					current_instruction);
1371 
1372 	test_code = next_instruction(test_code);
1373 	test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1374 
1375 	if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1376 		if (!test_case_is_thumb ||
1377 			is_wide_instruction(current_instruction)) {
1378 				test_case_failed("expected 16-bit instruction");
1379 				goto fail;
1380 		}
1381 	} else {
1382 		if (test_case_is_thumb &&
1383 			!is_wide_instruction(current_instruction)) {
1384 				test_case_failed("expected 32-bit instruction");
1385 				goto fail;
1386 		}
1387 	}
1388 
1389 	coverage_add(current_instruction);
1390 
1391 	if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1392 		if (register_test_probe(&test_case_probe) < 0)
1393 			goto pass;
1394 		test_case_failed("registered probe for unsupported instruction");
1395 		goto fail;
1396 	}
1397 
1398 	if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1399 		if (register_test_probe(&test_case_probe) >= 0)
1400 			goto pass;
1401 		test_case_failed("couldn't register probe for supported instruction");
1402 		goto fail;
1403 	}
1404 
1405 	if (register_test_probe(&test_before_probe) < 0) {
1406 		test_case_failed("register test_before_probe failed");
1407 		goto fail;
1408 	}
1409 	if (register_test_probe(&test_after_probe) < 0) {
1410 		test_case_failed("register test_after_probe failed");
1411 		goto fail;
1412 	}
1413 	if (current_branch_target) {
1414 		test_after2_probe.kprobe.addr =
1415 				(kprobe_opcode_t *)current_branch_target;
1416 		if (register_test_probe(&test_after2_probe) < 0) {
1417 			test_case_failed("register test_after2_probe failed");
1418 			goto fail;
1419 		}
1420 	}
1421 
1422 	/* Start first run of test case */
1423 	test_case_run_count = 0;
1424 	++test_instance;
1425 	return current_code_start;
1426 pass:
1427 	test_case_run_count = TEST_CASE_PASSED;
1428 	return (uintptr_t)test_after_probe.kprobe.addr;
1429 fail:
1430 	test_case_run_count = TEST_CASE_FAILED;
1431 	return (uintptr_t)test_after_probe.kprobe.addr;
1432 }
1433 
1434 static bool check_test_results(void)
1435 {
1436 	size_t mem_size = 0;
1437 	u32 *mem = 0;
1438 
1439 	if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1440 		test_case_failed("registers differ");
1441 		goto fail;
1442 	}
1443 
1444 	if (memory_needs_checking) {
1445 		mem = (u32 *)result_regs.ARM_sp;
1446 		mem_size = expected_memory_size(mem);
1447 		if (memcmp(expected_memory, mem, mem_size)) {
1448 			test_case_failed("test memory differs");
1449 			goto fail;
1450 		}
1451 	}
1452 
1453 	return true;
1454 
1455 fail:
1456 	pr_err("initial_regs:\n");
1457 	print_registers(&initial_regs);
1458 	pr_err("expected_regs:\n");
1459 	print_registers(&expected_regs);
1460 	pr_err("result_regs:\n");
1461 	print_registers(&result_regs);
1462 
1463 	if (mem) {
1464 		pr_err("expected_memory:\n");
1465 		print_memory(expected_memory, mem_size);
1466 		pr_err("result_memory:\n");
1467 		print_memory(mem, mem_size);
1468 	}
1469 
1470 	return false;
1471 }
1472 
1473 static uintptr_t __used kprobes_test_case_end(void)
1474 {
1475 	if (test_case_run_count < 0) {
1476 		if (test_case_run_count == TEST_CASE_PASSED)
1477 			/* kprobes_test_case_start did all the needed testing */
1478 			goto pass;
1479 		else
1480 			/* kprobes_test_case_start failed */
1481 			goto fail;
1482 	}
1483 
1484 	if (test_before_probe.hit != test_instance) {
1485 		test_case_failed("test_before_handler not run");
1486 		goto fail;
1487 	}
1488 
1489 	if (test_after_probe.hit != test_instance &&
1490 				test_after2_probe.hit != test_instance) {
1491 		test_case_failed("test_after_handler not run");
1492 		goto fail;
1493 	}
1494 
1495 	/*
1496 	 * Even numbered test runs ran without a probe on the test case so
1497 	 * we can gather reference results. The subsequent odd numbered run
1498 	 * will have the probe inserted.
1499 	*/
1500 	if ((test_case_run_count & 1) == 0) {
1501 		/* Save results from run without probe */
1502 		u32 *mem = (u32 *)result_regs.ARM_sp;
1503 		expected_regs = result_regs;
1504 		memcpy(expected_memory, mem, expected_memory_size(mem));
1505 
1506 		/* Insert probe onto test case instruction */
1507 		if (register_test_probe(&test_case_probe) < 0) {
1508 			test_case_failed("register test_case_probe failed");
1509 			goto fail;
1510 		}
1511 	} else {
1512 		/* Check probe ran as expected */
1513 		if (probe_should_run == 1) {
1514 			if (test_case_probe.hit != test_instance) {
1515 				test_case_failed("test_case_handler not run");
1516 				goto fail;
1517 			}
1518 		} else if (probe_should_run == 0) {
1519 			if (test_case_probe.hit == test_instance) {
1520 				test_case_failed("test_case_handler ran");
1521 				goto fail;
1522 			}
1523 		}
1524 
1525 		/* Remove probe for any subsequent reference run */
1526 		unregister_test_probe(&test_case_probe);
1527 
1528 		if (!check_test_results())
1529 			goto fail;
1530 
1531 		if (is_last_scenario)
1532 			goto pass;
1533 	}
1534 
1535 	/* Do next test run */
1536 	++test_case_run_count;
1537 	++test_instance;
1538 	return current_code_start;
1539 fail:
1540 	++test_fail_count;
1541 	goto end;
1542 pass:
1543 	++test_pass_count;
1544 end:
1545 	test_case_cleanup();
1546 	return 0;
1547 }
1548 
1549 
1550 /*
1551  * Top level test functions
1552  */
1553 
1554 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1555 {
1556 	int ret;
1557 
1558 	pr_info("    Check decoding tables\n");
1559 	ret = table_test(table);
1560 	if (ret)
1561 		return ret;
1562 
1563 	pr_info("    Run test cases\n");
1564 	ret = coverage_start(table);
1565 	if (ret)
1566 		return ret;
1567 
1568 	tests();
1569 
1570 	coverage_end();
1571 	return 0;
1572 }
1573 
1574 
1575 static int __init run_all_tests(void)
1576 {
1577 	int ret = 0;
1578 
1579 	pr_info("Beginning kprobe tests...\n");
1580 
1581 #ifndef CONFIG_THUMB2_KERNEL
1582 
1583 	pr_info("Probe ARM code\n");
1584 	ret = run_api_tests(arm_func);
1585 	if (ret)
1586 		goto out;
1587 
1588 	pr_info("ARM instruction simulation\n");
1589 	ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1590 	if (ret)
1591 		goto out;
1592 
1593 #else /* CONFIG_THUMB2_KERNEL */
1594 
1595 	pr_info("Probe 16-bit Thumb code\n");
1596 	ret = run_api_tests(thumb16_func);
1597 	if (ret)
1598 		goto out;
1599 
1600 	pr_info("Probe 32-bit Thumb code, even halfword\n");
1601 	ret = run_api_tests(thumb32even_func);
1602 	if (ret)
1603 		goto out;
1604 
1605 	pr_info("Probe 32-bit Thumb code, odd halfword\n");
1606 	ret = run_api_tests(thumb32odd_func);
1607 	if (ret)
1608 		goto out;
1609 
1610 	pr_info("16-bit Thumb instruction simulation\n");
1611 	ret = run_test_cases(kprobe_thumb16_test_cases,
1612 				probes_decode_thumb16_table);
1613 	if (ret)
1614 		goto out;
1615 
1616 	pr_info("32-bit Thumb instruction simulation\n");
1617 	ret = run_test_cases(kprobe_thumb32_test_cases,
1618 				probes_decode_thumb32_table);
1619 	if (ret)
1620 		goto out;
1621 #endif
1622 
1623 	pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1624 		test_try_count, test_pass_count, test_fail_count);
1625 	if (test_fail_count) {
1626 		ret = -EINVAL;
1627 		goto out;
1628 	}
1629 
1630 #if BENCHMARKING
1631 	pr_info("Benchmarks\n");
1632 	ret = run_benchmarks();
1633 	if (ret)
1634 		goto out;
1635 #endif
1636 
1637 #if __LINUX_ARM_ARCH__ >= 7
1638 	/* We are able to run all test cases so coverage should be complete */
1639 	if (coverage_fail) {
1640 		pr_err("FAIL: Test coverage checks failed\n");
1641 		ret = -EINVAL;
1642 		goto out;
1643 	}
1644 #endif
1645 
1646 out:
1647 	if (ret == 0)
1648 		ret = tests_failed;
1649 	if (ret == 0)
1650 		pr_info("Finished kprobe tests OK\n");
1651 	else
1652 		pr_err("kprobe tests failed\n");
1653 
1654 	return ret;
1655 }
1656 
1657 
1658 /*
1659  * Module setup
1660  */
1661 
1662 #ifdef MODULE
1663 
1664 static void __exit kprobe_test_exit(void)
1665 {
1666 }
1667 
1668 module_init(run_all_tests)
1669 module_exit(kprobe_test_exit)
1670 MODULE_LICENSE("GPL");
1671 
1672 #else /* !MODULE */
1673 
1674 late_initcall(run_all_tests);
1675 
1676 #endif
1677