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