test-core.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * arch/arm/kernel/kprobes-test.c
   4 *
   5 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
   6 */
   7
   8/*
   9 * This file contains test code for ARM kprobes.
  10 *
  11 * The top level function run_all_tests() executes tests for all of the
  12 * supported instruction sets: ARM, 16-bit Thumb, and 32-bit Thumb. These tests
  13 * fall into two categories; run_api_tests() checks basic functionality of the
  14 * kprobes API, and run_test_cases() is a comprehensive test for kprobes
  15 * instruction decoding and simulation.
  16 *
  17 * run_test_cases() first checks the kprobes decoding table for self consistency
  18 * (using table_test()) then executes a series of test cases for each of the CPU
  19 * instruction forms. coverage_start() and coverage_end() are used to verify
  20 * that these test cases cover all of the possible combinations of instructions
  21 * described by the kprobes decoding tables.
  22 *
  23 * The individual test cases are in kprobes-test-arm.c and kprobes-test-thumb.c
  24 * which use the macros defined in kprobes-test.h. The rest of this
  25 * documentation will describe the operation of the framework used by these
  26 * test cases.
  27 */
  28
  29/*
  30 * TESTING METHODOLOGY
  31 * -------------------
  32 *
  33 * The methodology used to test an ARM instruction 'test_insn' is to use
  34 * inline assembler like:
  35 *
  36 * test_before: nop
  37 * test_case:	test_insn
  38 * test_after:	nop
  39 *
  40 * When the test case is run a kprobe is placed of each nop. The
  41 * post-handler of the test_before probe is used to modify the saved CPU
  42 * register context to that which we require for the test case. The
  43 * pre-handler of the of the test_after probe saves a copy of the CPU
  44 * register context. In this way we can execute test_insn with a specific
  45 * register context and see the results afterwards.
  46 *
  47 * To actually test the kprobes instruction emulation we perform the above
  48 * step a second time but with an additional kprobe on the test_case
  49 * instruction itself. If the emulation is accurate then the results seen
  50 * by the test_after probe will be identical to the first run which didn't
  51 * have a probe on test_case.
  52 *
  53 * Each test case is run several times with a variety of variations in the
  54 * flags value of stored in CPSR, and for Thumb code, different ITState.
  55 *
  56 * For instructions which can modify PC, a second test_after probe is used
  57 * like this:
  58 *
  59 * test_before: nop
  60 * test_case:	test_insn
  61 * test_after:	nop
  62 *		b test_done
  63 * test_after2: nop
  64 * test_done:
  65 *
  66 * The test case is constructed such that test_insn branches to
  67 * test_after2, or, if testing a conditional instruction, it may just
  68 * continue to test_after. The probes inserted at both locations let us
  69 * determine which happened. A similar approach is used for testing
  70 * backwards branches...
  71 *
  72 *		b test_before
  73 *		b test_done  @ helps to cope with off by 1 branches
  74 * test_after2: nop
  75 *		b test_done
  76 * test_before: nop
  77 * test_case:	test_insn
  78 * test_after:	nop
  79 * test_done:
  80 *
  81 * The macros used to generate the assembler instructions describe above
  82 * are TEST_INSTRUCTION, TEST_BRANCH_F (branch forwards) and TEST_BRANCH_B
  83 * (branch backwards). In these, the local variables numbered 1, 50, 2 and
  84 * 99 represent: test_before, test_case, test_after2 and test_done.
  85 *
  86 * FRAMEWORK
  87 * ---------
  88 *
  89 * Each test case is wrapped between the pair of macros TESTCASE_START and
  90 * TESTCASE_END. As well as performing the inline assembler boilerplate,
  91 * these call out to the kprobes_test_case_start() and
  92 * kprobes_test_case_end() functions which drive the execution of the test
  93 * case. The specific arguments to use for each test case are stored as
  94 * inline data constructed using the various TEST_ARG_* macros. Putting
  95 * this all together, a simple test case may look like:
  96 *
  97 *	TESTCASE_START("Testing mov r0, r7")
  98 *	TEST_ARG_REG(7, 0x12345678) // Set r7=0x12345678
  99 *	TEST_ARG_END("")
 100 *	TEST_INSTRUCTION("mov r0, r7")
 101 *	TESTCASE_END
 102 *
 103 * Note, in practice the single convenience macro TEST_R would be used for this
 104 * instead.
 105 *
 106 * The above would expand to assembler looking something like:
 107 *
 108 *	@ TESTCASE_START
 109 *	bl	__kprobes_test_case_start
 110 *	.pushsection .rodata
 111 *	"10:
 112 *	.ascii "mov r0, r7"	@ text title for test case
 113 *	.byte	0
 114 *	.popsection
 115 *	@ start of inline data...
 116 *	.word	10b		@ pointer to title in .rodata section
 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/sched/clock.h>
 204#include <linux/kprobes.h>
 205#include <linux/errno.h>
 206#include <linux/stddef.h>
 207#include <linux/bug.h>
 208#include <asm/opcodes.h>
 209
 210#include "core.h"
 211#include "test-core.h"
 212#include "../decode-arm.h"
 213#include "../decode-thumb.h"
 214
 215
 216#define BENCHMARKING	1
 217
 218
 219/*
 220 * Test basic API
 221 */
 222
 223static bool test_regs_ok;
 224static int test_func_instance;
 225static int pre_handler_called;
 226static int post_handler_called;
 227static int kretprobe_handler_called;
 228static int tests_failed;
 229
 230#define FUNC_ARG1 0x12345678
 231#define FUNC_ARG2 0xabcdef
 232
 233
 234#ifndef CONFIG_THUMB2_KERNEL
 235
 236#define RET(reg)	"mov	pc, "#reg
 237
 238long arm_func(long r0, long r1);
 239
 240static void __used __naked __arm_kprobes_test_func(void)
 241{
 242	__asm__ __volatile__ (
 243		".arm					\n\t"
 244		".type arm_func, %%function		\n\t"
 245		"arm_func:				\n\t"
 246		"adds	r0, r0, r1			\n\t"
 247		"mov	pc, lr				\n\t"
 248		".code "NORMAL_ISA	 /* Back to Thumb if necessary */
 249		: : : "r0", "r1", "cc"
 250	);
 251}
 252
 253#else /* CONFIG_THUMB2_KERNEL */
 254
 255#define RET(reg)	"bx	"#reg
 256
 257long thumb16_func(long r0, long r1);
 258long thumb32even_func(long r0, long r1);
 259long thumb32odd_func(long r0, long r1);
 260
 261static void __used __naked __thumb_kprobes_test_funcs(void)
 262{
 263	__asm__ __volatile__ (
 264		".type thumb16_func, %%function		\n\t"
 265		"thumb16_func:				\n\t"
 266		"adds.n	r0, r0, r1			\n\t"
 267		"bx	lr				\n\t"
 268
 269		".align					\n\t"
 270		".type thumb32even_func, %%function	\n\t"
 271		"thumb32even_func:			\n\t"
 272		"adds.w	r0, r0, r1			\n\t"
 273		"bx	lr				\n\t"
 274
 275		".align					\n\t"
 276		"nop.n					\n\t"
 277		".type thumb32odd_func, %%function	\n\t"
 278		"thumb32odd_func:			\n\t"
 279		"adds.w	r0, r0, r1			\n\t"
 280		"bx	lr				\n\t"
 281
 282		: : : "r0", "r1", "cc"
 283	);
 284}
 285
 286#endif /* CONFIG_THUMB2_KERNEL */
 287
 288
 289static int call_test_func(long (*func)(long, long), bool check_test_regs)
 290{
 291	long ret;
 292
 293	++test_func_instance;
 294	test_regs_ok = false;
 295
 296	ret = (*func)(FUNC_ARG1, FUNC_ARG2);
 297	if (ret != FUNC_ARG1 + FUNC_ARG2) {
 298		pr_err("FAIL: call_test_func: func returned %lx\n", ret);
 299		return false;
 300	}
 301
 302	if (check_test_regs && !test_regs_ok) {
 303		pr_err("FAIL: test regs not OK\n");
 304		return false;
 305	}
 306
 307	return true;
 308}
 309
 310static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
 311{
 312	pre_handler_called = test_func_instance;
 313	if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
 314		test_regs_ok = true;
 315	return 0;
 316}
 317
 318static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
 319				unsigned long flags)
 320{
 321	post_handler_called = test_func_instance;
 322	if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
 323		test_regs_ok = false;
 324}
 325
 326static struct kprobe the_kprobe = {
 327	.addr		= 0,
 328	.pre_handler	= pre_handler,
 329	.post_handler	= post_handler
 330};
 331
 332static int test_kprobe(long (*func)(long, long))
 333{
 334	int ret;
 335
 336	the_kprobe.addr = (kprobe_opcode_t *)func;
 337	ret = register_kprobe(&the_kprobe);
 338	if (ret < 0) {
 339		pr_err("FAIL: register_kprobe failed with %d\n", ret);
 340		return ret;
 341	}
 342
 343	ret = call_test_func(func, true);
 344
 345	unregister_kprobe(&the_kprobe);
 346	the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
 347
 348	if (!ret)
 349		return -EINVAL;
 350	if (pre_handler_called != test_func_instance) {
 351		pr_err("FAIL: kprobe pre_handler not called\n");
 352		return -EINVAL;
 353	}
 354	if (post_handler_called != test_func_instance) {
 355		pr_err("FAIL: kprobe post_handler not called\n");
 356		return -EINVAL;
 357	}
 358	if (!call_test_func(func, false))
 359		return -EINVAL;
 360	if (pre_handler_called == test_func_instance ||
 361				post_handler_called == test_func_instance) {
 362		pr_err("FAIL: probe called after unregistering\n");
 363		return -EINVAL;
 364	}
 365
 366	return 0;
 367}
 368
 369static int __kprobes
 370kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 371{
 372	kretprobe_handler_called = test_func_instance;
 373	if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
 374		test_regs_ok = true;
 375	return 0;
 376}
 377
 378static struct kretprobe the_kretprobe = {
 379	.handler	= kretprobe_handler,
 380};
 381
 382static int test_kretprobe(long (*func)(long, long))
 383{
 384	int ret;
 385
 386	the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
 387	ret = register_kretprobe(&the_kretprobe);
 388	if (ret < 0) {
 389		pr_err("FAIL: register_kretprobe failed with %d\n", ret);
 390		return ret;
 391	}
 392
 393	ret = call_test_func(func, true);
 394
 395	unregister_kretprobe(&the_kretprobe);
 396	the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
 397
 398	if (!ret)
 399		return -EINVAL;
 400	if (kretprobe_handler_called != test_func_instance) {
 401		pr_err("FAIL: kretprobe handler not called\n");
 402		return -EINVAL;
 403	}
 404	if (!call_test_func(func, false))
 405		return -EINVAL;
 406	if (kretprobe_handler_called == test_func_instance) {
 407		pr_err("FAIL: kretprobe called after unregistering\n");
 408		return -EINVAL;
 409	}
 410
 411	return 0;
 412}
 413
 414static int run_api_tests(long (*func)(long, long))
 415{
 416	int ret;
 417
 418	pr_info("    kprobe\n");
 419	ret = test_kprobe(func);
 420	if (ret < 0)
 421		return ret;
 422
 423	pr_info("    kretprobe\n");
 424	ret = test_kretprobe(func);
 425	if (ret < 0)
 426		return ret;
 427
 428	return 0;
 429}
 430
 431
 432/*
 433 * Benchmarking
 434 */
 435
 436#if BENCHMARKING
 437
 438static void __naked benchmark_nop(void)
 439{
 440	__asm__ __volatile__ (
 441		"nop		\n\t"
 442		RET(lr)"	\n\t"
 443	);
 444}
 445
 446#ifdef CONFIG_THUMB2_KERNEL
 447#define wide ".w"
 448#else
 449#define wide
 450#endif
 451
 452static void __naked benchmark_pushpop1(void)
 453{
 454	__asm__ __volatile__ (
 455		"stmdb"wide"	sp!, {r3-r11,lr}  \n\t"
 456		"ldmia"wide"	sp!, {r3-r11,pc}"
 457	);
 458}
 459
 460static void __naked benchmark_pushpop2(void)
 461{
 462	__asm__ __volatile__ (
 463		"stmdb"wide"	sp!, {r0-r8,lr}  \n\t"
 464		"ldmia"wide"	sp!, {r0-r8,pc}"
 465	);
 466}
 467
 468static void __naked benchmark_pushpop3(void)
 469{
 470	__asm__ __volatile__ (
 471		"stmdb"wide"	sp!, {r4,lr}  \n\t"
 472		"ldmia"wide"	sp!, {r4,pc}"
 473	);
 474}
 475
 476static void __naked benchmark_pushpop4(void)
 477{
 478	__asm__ __volatile__ (
 479		"stmdb"wide"	sp!, {r0,lr}  \n\t"
 480		"ldmia"wide"	sp!, {r0,pc}"
 481	);
 482}
 483
 484
 485#ifdef CONFIG_THUMB2_KERNEL
 486
 487static void __naked benchmark_pushpop_thumb(void)
 488{
 489	__asm__ __volatile__ (
 490		"push.n	{r0-r7,lr}  \n\t"
 491		"pop.n	{r0-r7,pc}"
 492	);
 493}
 494
 495#endif
 496
 497static int __kprobes
 498benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
 499{
 500	return 0;
 501}
 502
 503static int benchmark(void(*fn)(void))
 504{
 505	unsigned n, i, t, t0;
 506
 507	for (n = 1000; ; n *= 2) {
 508		t0 = sched_clock();
 509		for (i = n; i > 0; --i)
 510			fn();
 511		t = sched_clock() - t0;
 512		if (t >= 250000000)
 513			break; /* Stop once we took more than 0.25 seconds */
 514	}
 515	return t / n; /* Time for one iteration in nanoseconds */
 516};
 517
 518static int kprobe_benchmark(void(*fn)(void), unsigned offset)
 519{
 520	struct kprobe k = {
 521		.addr		= (kprobe_opcode_t *)((uintptr_t)fn + offset),
 522		.pre_handler	= benchmark_pre_handler,
 523	};
 524
 525	int ret = register_kprobe(&k);
 526	if (ret < 0) {
 527		pr_err("FAIL: register_kprobe failed with %d\n", ret);
 528		return ret;
 529	}
 530
 531	ret = benchmark(fn);
 532
 533	unregister_kprobe(&k);
 534	return ret;
 535};
 536
 537struct benchmarks {
 538	void		(*fn)(void);
 539	unsigned	offset;
 540	const char	*title;
 541};
 542
 543static int run_benchmarks(void)
 544{
 545	int ret;
 546	struct benchmarks list[] = {
 547		{&benchmark_nop, 0, "nop"},
 548		/*
 549		 * benchmark_pushpop{1,3} will have the optimised
 550		 * instruction emulation, whilst benchmark_pushpop{2,4} will
 551		 * be the equivalent unoptimised instructions.
 552		 */
 553		{&benchmark_pushpop1, 0, "stmdb	sp!, {r3-r11,lr}"},
 554		{&benchmark_pushpop1, 4, "ldmia	sp!, {r3-r11,pc}"},
 555		{&benchmark_pushpop2, 0, "stmdb	sp!, {r0-r8,lr}"},
 556		{&benchmark_pushpop2, 4, "ldmia	sp!, {r0-r8,pc}"},
 557		{&benchmark_pushpop3, 0, "stmdb	sp!, {r4,lr}"},
 558		{&benchmark_pushpop3, 4, "ldmia	sp!, {r4,pc}"},
 559		{&benchmark_pushpop4, 0, "stmdb	sp!, {r0,lr}"},
 560		{&benchmark_pushpop4, 4, "ldmia	sp!, {r0,pc}"},
 561#ifdef CONFIG_THUMB2_KERNEL
 562		{&benchmark_pushpop_thumb, 0, "push.n	{r0-r7,lr}"},
 563		{&benchmark_pushpop_thumb, 2, "pop.n	{r0-r7,pc}"},
 564#endif
 565		{0}
 566	};
 567
 568	struct benchmarks *b;
 569	for (b = list; b->fn; ++b) {
 570		ret = kprobe_benchmark(b->fn, b->offset);
 571		if (ret < 0)
 572			return ret;
 573		pr_info("    %dns for kprobe %s\n", ret, b->title);
 574	}
 575
 576	pr_info("\n");
 577	return 0;
 578}
 579
 580#endif /* BENCHMARKING */
 581
 582
 583/*
 584 * Decoding table self-consistency tests
 585 */
 586
 587static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 588	[DECODE_TYPE_TABLE]	= sizeof(struct decode_table),
 589	[DECODE_TYPE_CUSTOM]	= sizeof(struct decode_custom),
 590	[DECODE_TYPE_SIMULATE]	= sizeof(struct decode_simulate),
 591	[DECODE_TYPE_EMULATE]	= sizeof(struct decode_emulate),
 592	[DECODE_TYPE_OR]	= sizeof(struct decode_or),
 593	[DECODE_TYPE_REJECT]	= sizeof(struct decode_reject)
 594};
 595
 596static int table_iter(const union decode_item *table,
 597			int (*fn)(const struct decode_header *, void *),
 598			void *args)
 599{
 600	const struct decode_header *h = (struct decode_header *)table;
 601	int result;
 602
 603	for (;;) {
 604		enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 605
 606		if (type == DECODE_TYPE_END)
 607			return 0;
 608
 609		result = fn(h, args);
 610		if (result)
 611			return result;
 612
 613		h = (struct decode_header *)
 614			((uintptr_t)h + decode_struct_sizes[type]);
 615
 616	}
 617}
 618
 619static int table_test_fail(const struct decode_header *h, const char* message)
 620{
 621
 622	pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
 623					message, h->mask.bits, h->value.bits);
 624	return -EINVAL;
 625}
 626
 627struct table_test_args {
 628	const union decode_item *root_table;
 629	u32			parent_mask;
 630	u32			parent_value;
 631};
 632
 633static int table_test_fn(const struct decode_header *h, void *args)
 634{
 635	struct table_test_args *a = (struct table_test_args *)args;
 636	enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 637
 638	if (h->value.bits & ~h->mask.bits)
 639		return table_test_fail(h, "Match value has bits not in mask");
 640
 641	if ((h->mask.bits & a->parent_mask) != a->parent_mask)
 642		return table_test_fail(h, "Mask has bits not in parent mask");
 643
 644	if ((h->value.bits ^ a->parent_value) & a->parent_mask)
 645		return table_test_fail(h, "Value is inconsistent with parent");
 646
 647	if (type == DECODE_TYPE_TABLE) {
 648		struct decode_table *d = (struct decode_table *)h;
 649		struct table_test_args args2 = *a;
 650		args2.parent_mask = h->mask.bits;
 651		args2.parent_value = h->value.bits;
 652		return table_iter(d->table.table, table_test_fn, &args2);
 653	}
 654
 655	return 0;
 656}
 657
 658static int table_test(const union decode_item *table)
 659{
 660	struct table_test_args args = {
 661		.root_table	= table,
 662		.parent_mask	= 0,
 663		.parent_value	= 0
 664	};
 665	return table_iter(args.root_table, table_test_fn, &args);
 666}
 667
 668
 669/*
 670 * Decoding table test coverage analysis
 671 *
 672 * coverage_start() builds a coverage_table which contains a list of
 673 * coverage_entry's to match each entry in the specified kprobes instruction
 674 * decoding table.
 675 *
 676 * When test cases are run, coverage_add() is called to process each case.
 677 * This looks up the corresponding entry in the coverage_table and sets it as
 678 * being matched, as well as clearing the regs flag appropriate for the test.
 679 *
 680 * After all test cases have been run, coverage_end() is called to check that
 681 * all entries in coverage_table have been matched and that all regs flags are
 682 * cleared. I.e. that all possible combinations of instructions described by
 683 * the kprobes decoding tables have had a test case executed for them.
 684 */
 685
 686bool coverage_fail;
 687
 688#define MAX_COVERAGE_ENTRIES 256
 689
 690struct coverage_entry {
 691	const struct decode_header	*header;
 692	unsigned			regs;
 693	unsigned			nesting;
 694	char				matched;
 695};
 696
 697struct coverage_table {
 698	struct coverage_entry	*base;
 699	unsigned		num_entries;
 700	unsigned		nesting;
 701};
 702
 703struct coverage_table coverage;
 704
 705#define COVERAGE_ANY_REG	(1<<0)
 706#define COVERAGE_SP		(1<<1)
 707#define COVERAGE_PC		(1<<2)
 708#define COVERAGE_PCWB		(1<<3)
 709
 710static const char coverage_register_lookup[16] = {
 711	[REG_TYPE_ANY]		= COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 712	[REG_TYPE_SAMEAS16]	= COVERAGE_ANY_REG,
 713	[REG_TYPE_SP]		= COVERAGE_SP,
 714	[REG_TYPE_PC]		= COVERAGE_PC,
 715	[REG_TYPE_NOSP]		= COVERAGE_ANY_REG | COVERAGE_SP,
 716	[REG_TYPE_NOSPPC]	= COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 717	[REG_TYPE_NOPC]		= COVERAGE_ANY_REG | COVERAGE_PC,
 718	[REG_TYPE_NOPCWB]	= COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
 719	[REG_TYPE_NOPCX]	= COVERAGE_ANY_REG,
 720	[REG_TYPE_NOSPPCX]	= COVERAGE_ANY_REG | COVERAGE_SP,
 721};
 722
 723static unsigned coverage_start_registers(const struct decode_header *h)
 724{
 725	unsigned regs = 0;
 726	int i;
 727	for (i = 0; i < 20; i += 4) {
 728		int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
 729		regs |= coverage_register_lookup[r] << i;
 730	}
 731	return regs;
 732}
 733
 734static int coverage_start_fn(const struct decode_header *h, void *args)
 735{
 736	struct coverage_table *coverage = (struct coverage_table *)args;
 737	enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 738	struct coverage_entry *entry = coverage->base + coverage->num_entries;
 739
 740	if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
 741		pr_err("FAIL: Out of space for test coverage data");
 742		return -ENOMEM;
 743	}
 744
 745	++coverage->num_entries;
 746
 747	entry->header = h;
 748	entry->regs = coverage_start_registers(h);
 749	entry->nesting = coverage->nesting;
 750	entry->matched = false;
 751
 752	if (type == DECODE_TYPE_TABLE) {
 753		struct decode_table *d = (struct decode_table *)h;
 754		int ret;
 755		++coverage->nesting;
 756		ret = table_iter(d->table.table, coverage_start_fn, coverage);
 757		--coverage->nesting;
 758		return ret;
 759	}
 760
 761	return 0;
 762}
 763
 764static int coverage_start(const union decode_item *table)
 765{
 766	coverage.base = kmalloc_array(MAX_COVERAGE_ENTRIES,
 767				      sizeof(struct coverage_entry),
 768				      GFP_KERNEL);
 769	coverage.num_entries = 0;
 770	coverage.nesting = 0;
 771	return table_iter(table, coverage_start_fn, &coverage);
 772}
 773
 774static void
 775coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
 776{
 777	int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
 778	int i;
 779	for (i = 0; i < 20; i += 4) {
 780		enum decode_reg_type reg_type = (regs >> i) & 0xf;
 781		int reg = (insn >> i) & 0xf;
 782		int flag;
 783
 784		if (!reg_type)
 785			continue;
 786
 787		if (reg == 13)
 788			flag = COVERAGE_SP;
 789		else if (reg == 15)
 790			flag = COVERAGE_PC;
 791		else
 792			flag = COVERAGE_ANY_REG;
 793		entry->regs &= ~(flag << i);
 794
 795		switch (reg_type) {
 796
 797		case REG_TYPE_NONE:
 798		case REG_TYPE_ANY:
 799		case REG_TYPE_SAMEAS16:
 800			break;
 801
 802		case REG_TYPE_SP:
 803			if (reg != 13)
 804				return;
 805			break;
 806
 807		case REG_TYPE_PC:
 808			if (reg != 15)
 809				return;
 810			break;
 811
 812		case REG_TYPE_NOSP:
 813			if (reg == 13)
 814				return;
 815			break;
 816
 817		case REG_TYPE_NOSPPC:
 818		case REG_TYPE_NOSPPCX:
 819			if (reg == 13 || reg == 15)
 820				return;
 821			break;
 822
 823		case REG_TYPE_NOPCWB:
 824			if (!is_writeback(insn))
 825				break;
 826			if (reg == 15) {
 827				entry->regs &= ~(COVERAGE_PCWB << i);
 828				return;
 829			}
 830			break;
 831
 832		case REG_TYPE_NOPC:
 833		case REG_TYPE_NOPCX:
 834			if (reg == 15)
 835				return;
 836			break;
 837		}
 838
 839	}
 840}
 841
 842static void coverage_add(kprobe_opcode_t insn)
 843{
 844	struct coverage_entry *entry = coverage.base;
 845	struct coverage_entry *end = coverage.base + coverage.num_entries;
 846	bool matched = false;
 847	unsigned nesting = 0;
 848
 849	for (; entry < end; ++entry) {
 850		const struct decode_header *h = entry->header;
 851		enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 852
 853		if (entry->nesting > nesting)
 854			continue; /* Skip sub-table we didn't match */
 855
 856		if (entry->nesting < nesting)
 857			break; /* End of sub-table we were scanning */
 858
 859		if (!matched) {
 860			if ((insn & h->mask.bits) != h->value.bits)
 861				continue;
 862			entry->matched = true;
 863		}
 864
 865		switch (type) {
 866
 867		case DECODE_TYPE_TABLE:
 868			++nesting;
 869			break;
 870
 871		case DECODE_TYPE_CUSTOM:
 872		case DECODE_TYPE_SIMULATE:
 873		case DECODE_TYPE_EMULATE:
 874			coverage_add_registers(entry, insn);
 875			return;
 876
 877		case DECODE_TYPE_OR:
 878			matched = true;
 879			break;
 880
 881		case DECODE_TYPE_REJECT:
 882		default:
 883			return;
 884		}
 885
 886	}
 887}
 888
 889static void coverage_end(void)
 890{
 891	struct coverage_entry *entry = coverage.base;
 892	struct coverage_entry *end = coverage.base + coverage.num_entries;
 893
 894	for (; entry < end; ++entry) {
 895		u32 mask = entry->header->mask.bits;
 896		u32 value = entry->header->value.bits;
 897
 898		if (entry->regs) {
 899			pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
 900				mask, value, entry->regs);
 901			coverage_fail = true;
 902		}
 903		if (!entry->matched) {
 904			pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
 905				mask, value);
 906			coverage_fail = true;
 907		}
 908	}
 909
 910	kfree(coverage.base);
 911}
 912
 913
 914/*
 915 * Framework for instruction set test cases
 916 */
 917
 918void __naked __kprobes_test_case_start(void)
 919{
 920	__asm__ __volatile__ (
 921		"mov	r2, sp					\n\t"
 922		"bic	r3, r2, #7				\n\t"
 923		"mov	sp, r3					\n\t"
 924		"stmdb	sp!, {r2-r11}				\n\t"
 925		"sub	sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 926		"bic	r0, lr, #1  @ r0 = inline data		\n\t"
 927		"mov	r1, sp					\n\t"
 928		"bl	kprobes_test_case_start			\n\t"
 929		RET(r0)"					\n\t"
 930	);
 931}
 932
 933#ifndef CONFIG_THUMB2_KERNEL
 934
 935void __naked __kprobes_test_case_end_32(void)
 936{
 937	__asm__ __volatile__ (
 938		"mov	r4, lr					\n\t"
 939		"bl	kprobes_test_case_end			\n\t"
 940		"cmp	r0, #0					\n\t"
 941		"movne	pc, r0					\n\t"
 942		"mov	r0, r4					\n\t"
 943		"add	sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 944		"ldmia	sp!, {r2-r11}				\n\t"
 945		"mov	sp, r2					\n\t"
 946		"mov	pc, r0					\n\t"
 947	);
 948}
 949
 950#else /* CONFIG_THUMB2_KERNEL */
 951
 952void __naked __kprobes_test_case_end_16(void)
 953{
 954	__asm__ __volatile__ (
 955		"mov	r4, lr					\n\t"
 956		"bl	kprobes_test_case_end			\n\t"
 957		"cmp	r0, #0					\n\t"
 958		"bxne	r0					\n\t"
 959		"mov	r0, r4					\n\t"
 960		"add	sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 961		"ldmia	sp!, {r2-r11}				\n\t"
 962		"mov	sp, r2					\n\t"
 963		"bx	r0					\n\t"
 964	);
 965}
 966
 967void __naked __kprobes_test_case_end_32(void)
 968{
 969	__asm__ __volatile__ (
 970		".arm						\n\t"
 971		"orr	lr, lr, #1  @ will return to Thumb code	\n\t"
 972		"ldr	pc, 1f					\n\t"
 973		"1:						\n\t"
 974		".word	__kprobes_test_case_end_16		\n\t"
 975	);
 976}
 977
 978#endif
 979
 980
 981int kprobe_test_flags;
 982int kprobe_test_cc_position;
 983
 984static int test_try_count;
 985static int test_pass_count;
 986static int test_fail_count;
 987
 988static struct pt_regs initial_regs;
 989static struct pt_regs expected_regs;
 990static struct pt_regs result_regs;
 991
 992static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
 993
 994static const char *current_title;
 995static struct test_arg *current_args;
 996static u32 *current_stack;
 997static uintptr_t current_branch_target;
 998
 999static uintptr_t current_code_start;
1000static kprobe_opcode_t current_instruction;
1001
1002
1003#define TEST_CASE_PASSED -1
1004#define TEST_CASE_FAILED -2
1005
1006static int test_case_run_count;
1007static bool test_case_is_thumb;
1008static int test_instance;
1009
1010static unsigned long test_check_cc(int cc, unsigned long cpsr)
1011{
1012	int ret = arm_check_condition(cc << 28, cpsr);
1013
1014	return (ret != ARM_OPCODE_CONDTEST_FAIL);
1015}
1016
1017static int is_last_scenario;
1018static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1019static int memory_needs_checking;
1020
1021static unsigned long test_context_cpsr(int scenario)
1022{
1023	unsigned long cpsr;
1024
1025	probe_should_run = 1;
1026
1027	/* Default case is that we cycle through 16 combinations of flags */
1028	cpsr  = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1029	cpsr |= (scenario & 0xf) << 16; /* GE flags */
1030	cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1031
1032	if (!test_case_is_thumb) {
1033		/* Testing ARM code */
1034		int cc = current_instruction >> 28;
1035
1036		probe_should_run = test_check_cc(cc, cpsr) != 0;
1037		if (scenario == 15)
1038			is_last_scenario = true;
1039
1040	} else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1041		/* Testing Thumb code without setting ITSTATE */
1042		if (kprobe_test_cc_position) {
1043			int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1044			probe_should_run = test_check_cc(cc, cpsr) != 0;
1045		}
1046
1047		if (scenario == 15)
1048			is_last_scenario = true;
1049
1050	} else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1051		/* Testing Thumb code with all combinations of ITSTATE */
1052		unsigned x = (scenario >> 4);
1053		unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1054		unsigned mask = x / 7 + 2;  /* ITSTATE<4:0>, bits reversed */
1055
1056		if (mask > 0x1f) {
1057			/* Finish by testing state from instruction 'itt al' */
1058			cond_base = 7;
1059			mask = 0x4;
1060			if ((scenario & 0xf) == 0xf)
1061				is_last_scenario = true;
1062		}
1063
1064		cpsr |= cond_base << 13;	/* ITSTATE<7:5> */
1065		cpsr |= (mask & 0x1) << 12;	/* ITSTATE<4> */
1066		cpsr |= (mask & 0x2) << 10;	/* ITSTATE<3> */
1067		cpsr |= (mask & 0x4) << 8;	/* ITSTATE<2> */
1068		cpsr |= (mask & 0x8) << 23;	/* ITSTATE<1> */
1069		cpsr |= (mask & 0x10) << 21;	/* ITSTATE<0> */
1070
1071		probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1072
1073	} else {
1074		/* Testing Thumb code with several combinations of ITSTATE */
1075		switch (scenario) {
1076		case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1077			cpsr = 0x00000800;
1078			probe_should_run = 0;
1079			break;
1080		case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1081			cpsr = 0xf0007800;
1082			probe_should_run = 0;
1083			break;
1084		case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1085			cpsr = 0x00009800;
1086			break;
1087		case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1088			cpsr = 0xf0002800;
1089			is_last_scenario = true;
1090			break;
1091		}
1092	}
1093
1094	return cpsr;
1095}
1096
1097static void setup_test_context(struct pt_regs *regs)
1098{
1099	int scenario = test_case_run_count>>1;
1100	unsigned long val;
1101	struct test_arg *args;
1102	int i;
1103
1104	is_last_scenario = false;
1105	memory_needs_checking = false;
1106
1107	/* Initialise test memory on stack */
1108	val = (scenario & 1) ? VALM : ~VALM;
1109	for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1110		current_stack[i] = val + (i << 8);
1111	/* Put target of branch on stack for tests which load PC from memory */
1112	if (current_branch_target)
1113		current_stack[15] = current_branch_target;
1114	/* Put a value for SP on stack for tests which load SP from memory */
1115	current_stack[13] = (u32)current_stack + 120;
1116
1117	/* Initialise register values to their default state */
1118	val = (scenario & 2) ? VALR : ~VALR;
1119	for (i = 0; i < 13; ++i)
1120		regs->uregs[i] = val ^ (i << 8);
1121	regs->ARM_lr = val ^ (14 << 8);
1122	regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1123	regs->ARM_cpsr |= test_context_cpsr(scenario);
1124
1125	/* Perform testcase specific register setup  */
1126	args = current_args;
1127	for (; args[0].type != ARG_TYPE_END; ++args)
1128		switch (args[0].type) {
1129		case ARG_TYPE_REG: {
1130			struct test_arg_regptr *arg =
1131				(struct test_arg_regptr *)args;
1132			regs->uregs[arg->reg] = arg->val;
1133			break;
1134		}
1135		case ARG_TYPE_PTR: {
1136			struct test_arg_regptr *arg =
1137				(struct test_arg_regptr *)args;
1138			regs->uregs[arg->reg] =
1139				(unsigned long)current_stack + arg->val;
1140			memory_needs_checking = true;
1141			/*
1142			 * Test memory at an address below SP is in danger of
1143			 * being altered by an interrupt occurring and pushing
1144			 * data onto the stack. Disable interrupts to stop this.
1145			 */
1146			if (arg->reg == 13)
1147				regs->ARM_cpsr |= PSR_I_BIT;
1148			break;
1149		}
1150		case ARG_TYPE_MEM: {
1151			struct test_arg_mem *arg = (struct test_arg_mem *)args;
1152			current_stack[arg->index] = arg->val;
1153			break;
1154		}
1155		default:
1156			break;
1157		}
1158}
1159
1160struct test_probe {
1161	struct kprobe	kprobe;
1162	bool		registered;
1163	int		hit;
1164};
1165
1166static void unregister_test_probe(struct test_probe *probe)
1167{
1168	if (probe->registered) {
1169		unregister_kprobe(&probe->kprobe);
1170		probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1171	}
1172	probe->registered = false;
1173}
1174
1175static int register_test_probe(struct test_probe *probe)
1176{
1177	int ret;
1178
1179	if (probe->registered)
1180		BUG();
1181
1182	ret = register_kprobe(&probe->kprobe);
1183	if (ret >= 0) {
1184		probe->registered = true;
1185		probe->hit = -1;
1186	}
1187	return ret;
1188}
1189
1190static int __kprobes
1191test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1192{
1193	container_of(p, struct test_probe, kprobe)->hit = test_instance;
1194	return 0;
1195}
1196
1197static void __kprobes
1198test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1199							unsigned long flags)
1200{
1201	setup_test_context(regs);
1202	initial_regs = *regs;
1203	initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1204}
1205
1206static int __kprobes
1207test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1208{
1209	container_of(p, struct test_probe, kprobe)->hit = test_instance;
1210	return 0;
1211}
1212
1213static int __kprobes
1214test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1215{
1216	struct test_arg *args;
1217
1218	if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1219		return 0; /* Already run for this test instance */
1220
1221	result_regs = *regs;
1222
1223	/* Mask out results which are indeterminate */
1224	result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1225	for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
1226		if (args[0].type == ARG_TYPE_REG_MASKED) {
1227			struct test_arg_regptr *arg =
1228				(struct test_arg_regptr *)args;
1229			result_regs.uregs[arg->reg] &= arg->val;
1230		}
1231
1232	/* Undo any changes done to SP by the test case */
1233	regs->ARM_sp = (unsigned long)current_stack;
1234	/* Enable interrupts in case setup_test_context disabled them */
1235	regs->ARM_cpsr &= ~PSR_I_BIT;
1236
1237	container_of(p, struct test_probe, kprobe)->hit = test_instance;
1238	return 0;
1239}
1240
1241static struct test_probe test_before_probe = {
1242	.kprobe.pre_handler	= test_before_pre_handler,
1243	.kprobe.post_handler	= test_before_post_handler,
1244};
1245
1246static struct test_probe test_case_probe = {
1247	.kprobe.pre_handler	= test_case_pre_handler,
1248};
1249
1250static struct test_probe test_after_probe = {
1251	.kprobe.pre_handler	= test_after_pre_handler,
1252};
1253
1254static struct test_probe test_after2_probe = {
1255	.kprobe.pre_handler	= test_after_pre_handler,
1256};
1257
1258static void test_case_cleanup(void)
1259{
1260	unregister_test_probe(&test_before_probe);
1261	unregister_test_probe(&test_case_probe);
1262	unregister_test_probe(&test_after_probe);
1263	unregister_test_probe(&test_after2_probe);
1264}
1265
1266static void print_registers(struct pt_regs *regs)
1267{
1268	pr_err("r0  %08lx | r1  %08lx | r2  %08lx | r3  %08lx\n",
1269		regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1270	pr_err("r4  %08lx | r5  %08lx | r6  %08lx | r7  %08lx\n",
1271		regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1272	pr_err("r8  %08lx | r9  %08lx | r10 %08lx | r11 %08lx\n",
1273		regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1274	pr_err("r12 %08lx | sp  %08lx | lr  %08lx | pc  %08lx\n",
1275		regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1276	pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1277}
1278
1279static void print_memory(u32 *mem, size_t size)
1280{
1281	int i;
1282	for (i = 0; i < size / sizeof(u32); i += 4)
1283		pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1284						mem[i+2], mem[i+3]);
1285}
1286
1287static size_t expected_memory_size(u32 *sp)
1288{
1289	size_t size = sizeof(expected_memory);
1290	int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1291	if (offset > 0)
1292		size -= offset;
1293	return size;
1294}
1295
1296static void test_case_failed(const char *message)
1297{
1298	test_case_cleanup();
1299
1300	pr_err("FAIL: %s\n", message);
1301	pr_err("FAIL: Test %s\n", current_title);
1302	pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1303}
1304
1305static unsigned long next_instruction(unsigned long pc)
1306{
1307#ifdef CONFIG_THUMB2_KERNEL
1308	if ((pc & 1) &&
1309	    !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1310		return pc + 2;
1311	else
1312#endif
1313	return pc + 4;
1314}
1315
1316static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1317{
1318	struct test_arg *args;
1319	struct test_arg_end *end_arg;
1320	unsigned long test_code;
1321
1322	current_title = *title++;
1323	args = (struct test_arg *)title;
1324	current_args = args;
1325	current_stack = stack;
1326
1327	++test_try_count;
1328
1329	while (args->type != ARG_TYPE_END)
1330		++args;
1331	end_arg = (struct test_arg_end *)args;
1332
1333	test_code = (unsigned long)(args + 1); /* Code starts after args */
1334
1335	test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1336	if (test_case_is_thumb)
1337		test_code |= 1;
1338
1339	current_code_start = test_code;
1340
1341	current_branch_target = 0;
1342	if (end_arg->branch_offset != end_arg->end_offset)
1343		current_branch_target = test_code + end_arg->branch_offset;
1344
1345	test_code += end_arg->code_offset;
1346	test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1347
1348	test_code = next_instruction(test_code);
1349	test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1350
1351	if (test_case_is_thumb) {
1352		u16 *p = (u16 *)(test_code & ~1);
1353		current_instruction = __mem_to_opcode_thumb16(p[0]);
1354		if (is_wide_instruction(current_instruction)) {
1355			u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1356			current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1357		}
1358	} else {
1359		current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1360	}
1361
1362	if (current_title[0] == '.')
1363		verbose("%s\n", current_title);
1364	else
1365		verbose("%s\t@ %0*x\n", current_title,
1366					test_case_is_thumb ? 4 : 8,
1367					current_instruction);
1368
1369	test_code = next_instruction(test_code);
1370	test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1371
1372	if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1373		if (!test_case_is_thumb ||
1374			is_wide_instruction(current_instruction)) {
1375				test_case_failed("expected 16-bit instruction");
1376				goto fail;
1377		}
1378	} else {
1379		if (test_case_is_thumb &&
1380			!is_wide_instruction(current_instruction)) {
1381				test_case_failed("expected 32-bit instruction");
1382				goto fail;
1383		}
1384	}
1385
1386	coverage_add(current_instruction);
1387
1388	if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1389		if (register_test_probe(&test_case_probe) < 0)
1390			goto pass;
1391		test_case_failed("registered probe for unsupported instruction");
1392		goto fail;
1393	}
1394
1395	if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1396		if (register_test_probe(&test_case_probe) >= 0)
1397			goto pass;
1398		test_case_failed("couldn't register probe for supported instruction");
1399		goto fail;
1400	}
1401
1402	if (register_test_probe(&test_before_probe) < 0) {
1403		test_case_failed("register test_before_probe failed");
1404		goto fail;
1405	}
1406	if (register_test_probe(&test_after_probe) < 0) {
1407		test_case_failed("register test_after_probe failed");
1408		goto fail;
1409	}
1410	if (current_branch_target) {
1411		test_after2_probe.kprobe.addr =
1412				(kprobe_opcode_t *)current_branch_target;
1413		if (register_test_probe(&test_after2_probe) < 0) {
1414			test_case_failed("register test_after2_probe failed");
1415			goto fail;
1416		}
1417	}
1418
1419	/* Start first run of test case */
1420	test_case_run_count = 0;
1421	++test_instance;
1422	return current_code_start;
1423pass:
1424	test_case_run_count = TEST_CASE_PASSED;
1425	return (uintptr_t)test_after_probe.kprobe.addr;
1426fail:
1427	test_case_run_count = TEST_CASE_FAILED;
1428	return (uintptr_t)test_after_probe.kprobe.addr;
1429}
1430
1431static bool check_test_results(void)
1432{
1433	size_t mem_size = 0;
1434	u32 *mem = 0;
1435
1436	if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1437		test_case_failed("registers differ");
1438		goto fail;
1439	}
1440
1441	if (memory_needs_checking) {
1442		mem = (u32 *)result_regs.ARM_sp;
1443		mem_size = expected_memory_size(mem);
1444		if (memcmp(expected_memory, mem, mem_size)) {
1445			test_case_failed("test memory differs");
1446			goto fail;
1447		}
1448	}
1449
1450	return true;
1451
1452fail:
1453	pr_err("initial_regs:\n");
1454	print_registers(&initial_regs);
1455	pr_err("expected_regs:\n");
1456	print_registers(&expected_regs);
1457	pr_err("result_regs:\n");
1458	print_registers(&result_regs);
1459
1460	if (mem) {
1461		pr_err("expected_memory:\n");
1462		print_memory(expected_memory, mem_size);
1463		pr_err("result_memory:\n");
1464		print_memory(mem, mem_size);
1465	}
1466
1467	return false;
1468}
1469
1470static uintptr_t __used kprobes_test_case_end(void)
1471{
1472	if (test_case_run_count < 0) {
1473		if (test_case_run_count == TEST_CASE_PASSED)
1474			/* kprobes_test_case_start did all the needed testing */
1475			goto pass;
1476		else
1477			/* kprobes_test_case_start failed */
1478			goto fail;
1479	}
1480
1481	if (test_before_probe.hit != test_instance) {
1482		test_case_failed("test_before_handler not run");
1483		goto fail;
1484	}
1485
1486	if (test_after_probe.hit != test_instance &&
1487				test_after2_probe.hit != test_instance) {
1488		test_case_failed("test_after_handler not run");
1489		goto fail;
1490	}
1491
1492	/*
1493	 * Even numbered test runs ran without a probe on the test case so
1494	 * we can gather reference results. The subsequent odd numbered run
1495	 * will have the probe inserted.
1496	*/
1497	if ((test_case_run_count & 1) == 0) {
1498		/* Save results from run without probe */
1499		u32 *mem = (u32 *)result_regs.ARM_sp;
1500		expected_regs = result_regs;
1501		memcpy(expected_memory, mem, expected_memory_size(mem));
1502
1503		/* Insert probe onto test case instruction */
1504		if (register_test_probe(&test_case_probe) < 0) {
1505			test_case_failed("register test_case_probe failed");
1506			goto fail;
1507		}
1508	} else {
1509		/* Check probe ran as expected */
1510		if (probe_should_run == 1) {
1511			if (test_case_probe.hit != test_instance) {
1512				test_case_failed("test_case_handler not run");
1513				goto fail;
1514			}
1515		} else if (probe_should_run == 0) {
1516			if (test_case_probe.hit == test_instance) {
1517				test_case_failed("test_case_handler ran");
1518				goto fail;
1519			}
1520		}
1521
1522		/* Remove probe for any subsequent reference run */
1523		unregister_test_probe(&test_case_probe);
1524
1525		if (!check_test_results())
1526			goto fail;
1527
1528		if (is_last_scenario)
1529			goto pass;
1530	}
1531
1532	/* Do next test run */
1533	++test_case_run_count;
1534	++test_instance;
1535	return current_code_start;
1536fail:
1537	++test_fail_count;
1538	goto end;
1539pass:
1540	++test_pass_count;
1541end:
1542	test_case_cleanup();
1543	return 0;
1544}
1545
1546
1547/*
1548 * Top level test functions
1549 */
1550
1551static int run_test_cases(void (*tests)(void), const union decode_item *table)
1552{
1553	int ret;
1554
1555	pr_info("    Check decoding tables\n");
1556	ret = table_test(table);
1557	if (ret)
1558		return ret;
1559
1560	pr_info("    Run test cases\n");
1561	ret = coverage_start(table);
1562	if (ret)
1563		return ret;
1564
1565	tests();
1566
1567	coverage_end();
1568	return 0;
1569}
1570
1571
1572static int __init run_all_tests(void)
1573{
1574	int ret = 0;
1575
1576	pr_info("Beginning kprobe tests...\n");
1577
1578#ifndef CONFIG_THUMB2_KERNEL
1579
1580	pr_info("Probe ARM code\n");
1581	ret = run_api_tests(arm_func);
1582	if (ret)
1583		goto out;
1584
1585	pr_info("ARM instruction simulation\n");
1586	ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1587	if (ret)
1588		goto out;
1589
1590#else /* CONFIG_THUMB2_KERNEL */
1591
1592	pr_info("Probe 16-bit Thumb code\n");
1593	ret = run_api_tests(thumb16_func);
1594	if (ret)
1595		goto out;
1596
1597	pr_info("Probe 32-bit Thumb code, even halfword\n");
1598	ret = run_api_tests(thumb32even_func);
1599	if (ret)
1600		goto out;
1601
1602	pr_info("Probe 32-bit Thumb code, odd halfword\n");
1603	ret = run_api_tests(thumb32odd_func);
1604	if (ret)
1605		goto out;
1606
1607	pr_info("16-bit Thumb instruction simulation\n");
1608	ret = run_test_cases(kprobe_thumb16_test_cases,
1609				probes_decode_thumb16_table);
1610	if (ret)
1611		goto out;
1612
1613	pr_info("32-bit Thumb instruction simulation\n");
1614	ret = run_test_cases(kprobe_thumb32_test_cases,
1615				probes_decode_thumb32_table);
1616	if (ret)
1617		goto out;
1618#endif
1619
1620	pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1621		test_try_count, test_pass_count, test_fail_count);
1622	if (test_fail_count) {
1623		ret = -EINVAL;
1624		goto out;
1625	}
1626
1627#if BENCHMARKING
1628	pr_info("Benchmarks\n");
1629	ret = run_benchmarks();
1630	if (ret)
1631		goto out;
1632#endif
1633
1634#if __LINUX_ARM_ARCH__ >= 7
1635	/* We are able to run all test cases so coverage should be complete */
1636	if (coverage_fail) {
1637		pr_err("FAIL: Test coverage checks failed\n");
1638		ret = -EINVAL;
1639		goto out;
1640	}
1641#endif
1642
1643out:
1644	if (ret == 0)
1645		ret = tests_failed;
1646	if (ret == 0)
1647		pr_info("Finished kprobe tests OK\n");
1648	else
1649		pr_err("kprobe tests failed\n");
1650
1651	return ret;
1652}
1653
1654
1655/*
1656 * Module setup
1657 */
1658
1659#ifdef MODULE
1660
1661static void __exit kprobe_test_exit(void)
1662{
1663}
1664
1665module_init(run_all_tests)
1666module_exit(kprobe_test_exit)
1667MODULE_LICENSE("GPL");
1668
1669#else /* !MODULE */
1670
1671late_initcall(run_all_tests);
1672
1673#endif