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 jprobe_func_called; 231 static int kretprobe_handler_called; 232 static int tests_failed; 233 234 #define FUNC_ARG1 0x12345678 235 #define FUNC_ARG2 0xabcdef 236 237 238 #ifndef CONFIG_THUMB2_KERNEL 239 240 #define RET(reg) "mov pc, "#reg 241 242 long arm_func(long r0, long r1); 243 244 static void __used __naked __arm_kprobes_test_func(void) 245 { 246 __asm__ __volatile__ ( 247 ".arm \n\t" 248 ".type arm_func, %%function \n\t" 249 "arm_func: \n\t" 250 "adds r0, r0, r1 \n\t" 251 "mov pc, lr \n\t" 252 ".code "NORMAL_ISA /* Back to Thumb if necessary */ 253 : : : "r0", "r1", "cc" 254 ); 255 } 256 257 #else /* CONFIG_THUMB2_KERNEL */ 258 259 #define RET(reg) "bx "#reg 260 261 long thumb16_func(long r0, long r1); 262 long thumb32even_func(long r0, long r1); 263 long thumb32odd_func(long r0, long r1); 264 265 static void __used __naked __thumb_kprobes_test_funcs(void) 266 { 267 __asm__ __volatile__ ( 268 ".type thumb16_func, %%function \n\t" 269 "thumb16_func: \n\t" 270 "adds.n r0, r0, r1 \n\t" 271 "bx lr \n\t" 272 273 ".align \n\t" 274 ".type thumb32even_func, %%function \n\t" 275 "thumb32even_func: \n\t" 276 "adds.w r0, r0, r1 \n\t" 277 "bx lr \n\t" 278 279 ".align \n\t" 280 "nop.n \n\t" 281 ".type thumb32odd_func, %%function \n\t" 282 "thumb32odd_func: \n\t" 283 "adds.w r0, r0, r1 \n\t" 284 "bx lr \n\t" 285 286 : : : "r0", "r1", "cc" 287 ); 288 } 289 290 #endif /* CONFIG_THUMB2_KERNEL */ 291 292 293 static int call_test_func(long (*func)(long, long), bool check_test_regs) 294 { 295 long ret; 296 297 ++test_func_instance; 298 test_regs_ok = false; 299 300 ret = (*func)(FUNC_ARG1, FUNC_ARG2); 301 if (ret != FUNC_ARG1 + FUNC_ARG2) { 302 pr_err("FAIL: call_test_func: func returned %lx\n", ret); 303 return false; 304 } 305 306 if (check_test_regs && !test_regs_ok) { 307 pr_err("FAIL: test regs not OK\n"); 308 return false; 309 } 310 311 return true; 312 } 313 314 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs) 315 { 316 pre_handler_called = test_func_instance; 317 if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2) 318 test_regs_ok = true; 319 return 0; 320 } 321 322 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs, 323 unsigned long flags) 324 { 325 post_handler_called = test_func_instance; 326 if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2) 327 test_regs_ok = false; 328 } 329 330 static struct kprobe the_kprobe = { 331 .addr = 0, 332 .pre_handler = pre_handler, 333 .post_handler = post_handler 334 }; 335 336 static int test_kprobe(long (*func)(long, long)) 337 { 338 int ret; 339 340 the_kprobe.addr = (kprobe_opcode_t *)func; 341 ret = register_kprobe(&the_kprobe); 342 if (ret < 0) { 343 pr_err("FAIL: register_kprobe failed with %d\n", ret); 344 return ret; 345 } 346 347 ret = call_test_func(func, true); 348 349 unregister_kprobe(&the_kprobe); 350 the_kprobe.flags = 0; /* Clear disable flag to allow reuse */ 351 352 if (!ret) 353 return -EINVAL; 354 if (pre_handler_called != test_func_instance) { 355 pr_err("FAIL: kprobe pre_handler not called\n"); 356 return -EINVAL; 357 } 358 if (post_handler_called != test_func_instance) { 359 pr_err("FAIL: kprobe post_handler not called\n"); 360 return -EINVAL; 361 } 362 if (!call_test_func(func, false)) 363 return -EINVAL; 364 if (pre_handler_called == test_func_instance || 365 post_handler_called == test_func_instance) { 366 pr_err("FAIL: probe called after unregistering\n"); 367 return -EINVAL; 368 } 369 370 return 0; 371 } 372 373 static void __kprobes jprobe_func(long r0, long r1) 374 { 375 jprobe_func_called = test_func_instance; 376 if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2) 377 test_regs_ok = true; 378 jprobe_return(); 379 } 380 381 static struct jprobe the_jprobe = { 382 .entry = jprobe_func, 383 }; 384 385 static int test_jprobe(long (*func)(long, long)) 386 { 387 int ret; 388 389 the_jprobe.kp.addr = (kprobe_opcode_t *)func; 390 ret = register_jprobe(&the_jprobe); 391 if (ret < 0) { 392 pr_err("FAIL: register_jprobe failed with %d\n", ret); 393 return ret; 394 } 395 396 ret = call_test_func(func, true); 397 398 unregister_jprobe(&the_jprobe); 399 the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */ 400 401 if (!ret) 402 return -EINVAL; 403 if (jprobe_func_called != test_func_instance) { 404 pr_err("FAIL: jprobe handler function not called\n"); 405 return -EINVAL; 406 } 407 if (!call_test_func(func, false)) 408 return -EINVAL; 409 if (jprobe_func_called == test_func_instance) { 410 pr_err("FAIL: probe called after unregistering\n"); 411 return -EINVAL; 412 } 413 414 return 0; 415 } 416 417 static int __kprobes 418 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs) 419 { 420 kretprobe_handler_called = test_func_instance; 421 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2) 422 test_regs_ok = true; 423 return 0; 424 } 425 426 static struct kretprobe the_kretprobe = { 427 .handler = kretprobe_handler, 428 }; 429 430 static int test_kretprobe(long (*func)(long, long)) 431 { 432 int ret; 433 434 the_kretprobe.kp.addr = (kprobe_opcode_t *)func; 435 ret = register_kretprobe(&the_kretprobe); 436 if (ret < 0) { 437 pr_err("FAIL: register_kretprobe failed with %d\n", ret); 438 return ret; 439 } 440 441 ret = call_test_func(func, true); 442 443 unregister_kretprobe(&the_kretprobe); 444 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */ 445 446 if (!ret) 447 return -EINVAL; 448 if (kretprobe_handler_called != test_func_instance) { 449 pr_err("FAIL: kretprobe handler not called\n"); 450 return -EINVAL; 451 } 452 if (!call_test_func(func, false)) 453 return -EINVAL; 454 if (jprobe_func_called == test_func_instance) { 455 pr_err("FAIL: kretprobe called after unregistering\n"); 456 return -EINVAL; 457 } 458 459 return 0; 460 } 461 462 static int run_api_tests(long (*func)(long, long)) 463 { 464 int ret; 465 466 pr_info(" kprobe\n"); 467 ret = test_kprobe(func); 468 if (ret < 0) 469 return ret; 470 471 pr_info(" jprobe\n"); 472 ret = test_jprobe(func); 473 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE) 474 if (ret == -EINVAL) { 475 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n"); 476 tests_failed = ret; 477 ret = 0; 478 } 479 #endif 480 if (ret < 0) 481 return ret; 482 483 pr_info(" kretprobe\n"); 484 ret = test_kretprobe(func); 485 if (ret < 0) 486 return ret; 487 488 return 0; 489 } 490 491 492 /* 493 * Benchmarking 494 */ 495 496 #if BENCHMARKING 497 498 static void __naked benchmark_nop(void) 499 { 500 __asm__ __volatile__ ( 501 "nop \n\t" 502 RET(lr)" \n\t" 503 ); 504 } 505 506 #ifdef CONFIG_THUMB2_KERNEL 507 #define wide ".w" 508 #else 509 #define wide 510 #endif 511 512 static void __naked benchmark_pushpop1(void) 513 { 514 __asm__ __volatile__ ( 515 "stmdb"wide" sp!, {r3-r11,lr} \n\t" 516 "ldmia"wide" sp!, {r3-r11,pc}" 517 ); 518 } 519 520 static void __naked benchmark_pushpop2(void) 521 { 522 __asm__ __volatile__ ( 523 "stmdb"wide" sp!, {r0-r8,lr} \n\t" 524 "ldmia"wide" sp!, {r0-r8,pc}" 525 ); 526 } 527 528 static void __naked benchmark_pushpop3(void) 529 { 530 __asm__ __volatile__ ( 531 "stmdb"wide" sp!, {r4,lr} \n\t" 532 "ldmia"wide" sp!, {r4,pc}" 533 ); 534 } 535 536 static void __naked benchmark_pushpop4(void) 537 { 538 __asm__ __volatile__ ( 539 "stmdb"wide" sp!, {r0,lr} \n\t" 540 "ldmia"wide" sp!, {r0,pc}" 541 ); 542 } 543 544 545 #ifdef CONFIG_THUMB2_KERNEL 546 547 static void __naked benchmark_pushpop_thumb(void) 548 { 549 __asm__ __volatile__ ( 550 "push.n {r0-r7,lr} \n\t" 551 "pop.n {r0-r7,pc}" 552 ); 553 } 554 555 #endif 556 557 static int __kprobes 558 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs) 559 { 560 return 0; 561 } 562 563 static int benchmark(void(*fn)(void)) 564 { 565 unsigned n, i, t, t0; 566 567 for (n = 1000; ; n *= 2) { 568 t0 = sched_clock(); 569 for (i = n; i > 0; --i) 570 fn(); 571 t = sched_clock() - t0; 572 if (t >= 250000000) 573 break; /* Stop once we took more than 0.25 seconds */ 574 } 575 return t / n; /* Time for one iteration in nanoseconds */ 576 }; 577 578 static int kprobe_benchmark(void(*fn)(void), unsigned offset) 579 { 580 struct kprobe k = { 581 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset), 582 .pre_handler = benchmark_pre_handler, 583 }; 584 585 int ret = register_kprobe(&k); 586 if (ret < 0) { 587 pr_err("FAIL: register_kprobe failed with %d\n", ret); 588 return ret; 589 } 590 591 ret = benchmark(fn); 592 593 unregister_kprobe(&k); 594 return ret; 595 }; 596 597 struct benchmarks { 598 void (*fn)(void); 599 unsigned offset; 600 const char *title; 601 }; 602 603 static int run_benchmarks(void) 604 { 605 int ret; 606 struct benchmarks list[] = { 607 {&benchmark_nop, 0, "nop"}, 608 /* 609 * benchmark_pushpop{1,3} will have the optimised 610 * instruction emulation, whilst benchmark_pushpop{2,4} will 611 * be the equivalent unoptimised instructions. 612 */ 613 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"}, 614 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"}, 615 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"}, 616 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"}, 617 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"}, 618 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"}, 619 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"}, 620 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"}, 621 #ifdef CONFIG_THUMB2_KERNEL 622 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"}, 623 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"}, 624 #endif 625 {0} 626 }; 627 628 struct benchmarks *b; 629 for (b = list; b->fn; ++b) { 630 ret = kprobe_benchmark(b->fn, b->offset); 631 if (ret < 0) 632 return ret; 633 pr_info(" %dns for kprobe %s\n", ret, b->title); 634 } 635 636 pr_info("\n"); 637 return 0; 638 } 639 640 #endif /* BENCHMARKING */ 641 642 643 /* 644 * Decoding table self-consistency tests 645 */ 646 647 static const int decode_struct_sizes[NUM_DECODE_TYPES] = { 648 [DECODE_TYPE_TABLE] = sizeof(struct decode_table), 649 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom), 650 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate), 651 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate), 652 [DECODE_TYPE_OR] = sizeof(struct decode_or), 653 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject) 654 }; 655 656 static int table_iter(const union decode_item *table, 657 int (*fn)(const struct decode_header *, void *), 658 void *args) 659 { 660 const struct decode_header *h = (struct decode_header *)table; 661 int result; 662 663 for (;;) { 664 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 665 666 if (type == DECODE_TYPE_END) 667 return 0; 668 669 result = fn(h, args); 670 if (result) 671 return result; 672 673 h = (struct decode_header *) 674 ((uintptr_t)h + decode_struct_sizes[type]); 675 676 } 677 } 678 679 static int table_test_fail(const struct decode_header *h, const char* message) 680 { 681 682 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n", 683 message, h->mask.bits, h->value.bits); 684 return -EINVAL; 685 } 686 687 struct table_test_args { 688 const union decode_item *root_table; 689 u32 parent_mask; 690 u32 parent_value; 691 }; 692 693 static int table_test_fn(const struct decode_header *h, void *args) 694 { 695 struct table_test_args *a = (struct table_test_args *)args; 696 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 697 698 if (h->value.bits & ~h->mask.bits) 699 return table_test_fail(h, "Match value has bits not in mask"); 700 701 if ((h->mask.bits & a->parent_mask) != a->parent_mask) 702 return table_test_fail(h, "Mask has bits not in parent mask"); 703 704 if ((h->value.bits ^ a->parent_value) & a->parent_mask) 705 return table_test_fail(h, "Value is inconsistent with parent"); 706 707 if (type == DECODE_TYPE_TABLE) { 708 struct decode_table *d = (struct decode_table *)h; 709 struct table_test_args args2 = *a; 710 args2.parent_mask = h->mask.bits; 711 args2.parent_value = h->value.bits; 712 return table_iter(d->table.table, table_test_fn, &args2); 713 } 714 715 return 0; 716 } 717 718 static int table_test(const union decode_item *table) 719 { 720 struct table_test_args args = { 721 .root_table = table, 722 .parent_mask = 0, 723 .parent_value = 0 724 }; 725 return table_iter(args.root_table, table_test_fn, &args); 726 } 727 728 729 /* 730 * Decoding table test coverage analysis 731 * 732 * coverage_start() builds a coverage_table which contains a list of 733 * coverage_entry's to match each entry in the specified kprobes instruction 734 * decoding table. 735 * 736 * When test cases are run, coverage_add() is called to process each case. 737 * This looks up the corresponding entry in the coverage_table and sets it as 738 * being matched, as well as clearing the regs flag appropriate for the test. 739 * 740 * After all test cases have been run, coverage_end() is called to check that 741 * all entries in coverage_table have been matched and that all regs flags are 742 * cleared. I.e. that all possible combinations of instructions described by 743 * the kprobes decoding tables have had a test case executed for them. 744 */ 745 746 bool coverage_fail; 747 748 #define MAX_COVERAGE_ENTRIES 256 749 750 struct coverage_entry { 751 const struct decode_header *header; 752 unsigned regs; 753 unsigned nesting; 754 char matched; 755 }; 756 757 struct coverage_table { 758 struct coverage_entry *base; 759 unsigned num_entries; 760 unsigned nesting; 761 }; 762 763 struct coverage_table coverage; 764 765 #define COVERAGE_ANY_REG (1<<0) 766 #define COVERAGE_SP (1<<1) 767 #define COVERAGE_PC (1<<2) 768 #define COVERAGE_PCWB (1<<3) 769 770 static const char coverage_register_lookup[16] = { 771 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC, 772 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG, 773 [REG_TYPE_SP] = COVERAGE_SP, 774 [REG_TYPE_PC] = COVERAGE_PC, 775 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP, 776 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC, 777 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC, 778 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB, 779 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG, 780 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP, 781 }; 782 783 unsigned coverage_start_registers(const struct decode_header *h) 784 { 785 unsigned regs = 0; 786 int i; 787 for (i = 0; i < 20; i += 4) { 788 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf; 789 regs |= coverage_register_lookup[r] << i; 790 } 791 return regs; 792 } 793 794 static int coverage_start_fn(const struct decode_header *h, void *args) 795 { 796 struct coverage_table *coverage = (struct coverage_table *)args; 797 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 798 struct coverage_entry *entry = coverage->base + coverage->num_entries; 799 800 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) { 801 pr_err("FAIL: Out of space for test coverage data"); 802 return -ENOMEM; 803 } 804 805 ++coverage->num_entries; 806 807 entry->header = h; 808 entry->regs = coverage_start_registers(h); 809 entry->nesting = coverage->nesting; 810 entry->matched = false; 811 812 if (type == DECODE_TYPE_TABLE) { 813 struct decode_table *d = (struct decode_table *)h; 814 int ret; 815 ++coverage->nesting; 816 ret = table_iter(d->table.table, coverage_start_fn, coverage); 817 --coverage->nesting; 818 return ret; 819 } 820 821 return 0; 822 } 823 824 static int coverage_start(const union decode_item *table) 825 { 826 coverage.base = kmalloc(MAX_COVERAGE_ENTRIES * 827 sizeof(struct coverage_entry), GFP_KERNEL); 828 coverage.num_entries = 0; 829 coverage.nesting = 0; 830 return table_iter(table, coverage_start_fn, &coverage); 831 } 832 833 static void 834 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn) 835 { 836 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS; 837 int i; 838 for (i = 0; i < 20; i += 4) { 839 enum decode_reg_type reg_type = (regs >> i) & 0xf; 840 int reg = (insn >> i) & 0xf; 841 int flag; 842 843 if (!reg_type) 844 continue; 845 846 if (reg == 13) 847 flag = COVERAGE_SP; 848 else if (reg == 15) 849 flag = COVERAGE_PC; 850 else 851 flag = COVERAGE_ANY_REG; 852 entry->regs &= ~(flag << i); 853 854 switch (reg_type) { 855 856 case REG_TYPE_NONE: 857 case REG_TYPE_ANY: 858 case REG_TYPE_SAMEAS16: 859 break; 860 861 case REG_TYPE_SP: 862 if (reg != 13) 863 return; 864 break; 865 866 case REG_TYPE_PC: 867 if (reg != 15) 868 return; 869 break; 870 871 case REG_TYPE_NOSP: 872 if (reg == 13) 873 return; 874 break; 875 876 case REG_TYPE_NOSPPC: 877 case REG_TYPE_NOSPPCX: 878 if (reg == 13 || reg == 15) 879 return; 880 break; 881 882 case REG_TYPE_NOPCWB: 883 if (!is_writeback(insn)) 884 break; 885 if (reg == 15) { 886 entry->regs &= ~(COVERAGE_PCWB << i); 887 return; 888 } 889 break; 890 891 case REG_TYPE_NOPC: 892 case REG_TYPE_NOPCX: 893 if (reg == 15) 894 return; 895 break; 896 } 897 898 } 899 } 900 901 static void coverage_add(kprobe_opcode_t insn) 902 { 903 struct coverage_entry *entry = coverage.base; 904 struct coverage_entry *end = coverage.base + coverage.num_entries; 905 bool matched = false; 906 unsigned nesting = 0; 907 908 for (; entry < end; ++entry) { 909 const struct decode_header *h = entry->header; 910 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 911 912 if (entry->nesting > nesting) 913 continue; /* Skip sub-table we didn't match */ 914 915 if (entry->nesting < nesting) 916 break; /* End of sub-table we were scanning */ 917 918 if (!matched) { 919 if ((insn & h->mask.bits) != h->value.bits) 920 continue; 921 entry->matched = true; 922 } 923 924 switch (type) { 925 926 case DECODE_TYPE_TABLE: 927 ++nesting; 928 break; 929 930 case DECODE_TYPE_CUSTOM: 931 case DECODE_TYPE_SIMULATE: 932 case DECODE_TYPE_EMULATE: 933 coverage_add_registers(entry, insn); 934 return; 935 936 case DECODE_TYPE_OR: 937 matched = true; 938 break; 939 940 case DECODE_TYPE_REJECT: 941 default: 942 return; 943 } 944 945 } 946 } 947 948 static void coverage_end(void) 949 { 950 struct coverage_entry *entry = coverage.base; 951 struct coverage_entry *end = coverage.base + coverage.num_entries; 952 953 for (; entry < end; ++entry) { 954 u32 mask = entry->header->mask.bits; 955 u32 value = entry->header->value.bits; 956 957 if (entry->regs) { 958 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n", 959 mask, value, entry->regs); 960 coverage_fail = true; 961 } 962 if (!entry->matched) { 963 pr_err("FAIL: Test coverage entry missing for %08x %08x\n", 964 mask, value); 965 coverage_fail = true; 966 } 967 } 968 969 kfree(coverage.base); 970 } 971 972 973 /* 974 * Framework for instruction set test cases 975 */ 976 977 void __naked __kprobes_test_case_start(void) 978 { 979 __asm__ __volatile__ ( 980 "stmdb sp!, {r4-r11} \n\t" 981 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" 982 "bic r0, lr, #1 @ r0 = inline data \n\t" 983 "mov r1, sp \n\t" 984 "bl kprobes_test_case_start \n\t" 985 RET(r0)" \n\t" 986 ); 987 } 988 989 #ifndef CONFIG_THUMB2_KERNEL 990 991 void __naked __kprobes_test_case_end_32(void) 992 { 993 __asm__ __volatile__ ( 994 "mov r4, lr \n\t" 995 "bl kprobes_test_case_end \n\t" 996 "cmp r0, #0 \n\t" 997 "movne pc, r0 \n\t" 998 "mov r0, r4 \n\t" 999 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" 1000 "ldmia sp!, {r4-r11} \n\t" 1001 "mov pc, r0 \n\t" 1002 ); 1003 } 1004 1005 #else /* CONFIG_THUMB2_KERNEL */ 1006 1007 void __naked __kprobes_test_case_end_16(void) 1008 { 1009 __asm__ __volatile__ ( 1010 "mov r4, lr \n\t" 1011 "bl kprobes_test_case_end \n\t" 1012 "cmp r0, #0 \n\t" 1013 "bxne r0 \n\t" 1014 "mov r0, r4 \n\t" 1015 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" 1016 "ldmia sp!, {r4-r11} \n\t" 1017 "bx r0 \n\t" 1018 ); 1019 } 1020 1021 void __naked __kprobes_test_case_end_32(void) 1022 { 1023 __asm__ __volatile__ ( 1024 ".arm \n\t" 1025 "orr lr, lr, #1 @ will return to Thumb code \n\t" 1026 "ldr pc, 1f \n\t" 1027 "1: \n\t" 1028 ".word __kprobes_test_case_end_16 \n\t" 1029 ); 1030 } 1031 1032 #endif 1033 1034 1035 int kprobe_test_flags; 1036 int kprobe_test_cc_position; 1037 1038 static int test_try_count; 1039 static int test_pass_count; 1040 static int test_fail_count; 1041 1042 static struct pt_regs initial_regs; 1043 static struct pt_regs expected_regs; 1044 static struct pt_regs result_regs; 1045 1046 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)]; 1047 1048 static const char *current_title; 1049 static struct test_arg *current_args; 1050 static u32 *current_stack; 1051 static uintptr_t current_branch_target; 1052 1053 static uintptr_t current_code_start; 1054 static kprobe_opcode_t current_instruction; 1055 1056 1057 #define TEST_CASE_PASSED -1 1058 #define TEST_CASE_FAILED -2 1059 1060 static int test_case_run_count; 1061 static bool test_case_is_thumb; 1062 static int test_instance; 1063 1064 static unsigned long test_check_cc(int cc, unsigned long cpsr) 1065 { 1066 int ret = arm_check_condition(cc << 28, cpsr); 1067 1068 return (ret != ARM_OPCODE_CONDTEST_FAIL); 1069 } 1070 1071 static int is_last_scenario; 1072 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */ 1073 static int memory_needs_checking; 1074 1075 static unsigned long test_context_cpsr(int scenario) 1076 { 1077 unsigned long cpsr; 1078 1079 probe_should_run = 1; 1080 1081 /* Default case is that we cycle through 16 combinations of flags */ 1082 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */ 1083 cpsr |= (scenario & 0xf) << 16; /* GE flags */ 1084 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */ 1085 1086 if (!test_case_is_thumb) { 1087 /* Testing ARM code */ 1088 int cc = current_instruction >> 28; 1089 1090 probe_should_run = test_check_cc(cc, cpsr) != 0; 1091 if (scenario == 15) 1092 is_last_scenario = true; 1093 1094 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) { 1095 /* Testing Thumb code without setting ITSTATE */ 1096 if (kprobe_test_cc_position) { 1097 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf; 1098 probe_should_run = test_check_cc(cc, cpsr) != 0; 1099 } 1100 1101 if (scenario == 15) 1102 is_last_scenario = true; 1103 1104 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) { 1105 /* Testing Thumb code with all combinations of ITSTATE */ 1106 unsigned x = (scenario >> 4); 1107 unsigned cond_base = x % 7; /* ITSTATE<7:5> */ 1108 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */ 1109 1110 if (mask > 0x1f) { 1111 /* Finish by testing state from instruction 'itt al' */ 1112 cond_base = 7; 1113 mask = 0x4; 1114 if ((scenario & 0xf) == 0xf) 1115 is_last_scenario = true; 1116 } 1117 1118 cpsr |= cond_base << 13; /* ITSTATE<7:5> */ 1119 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */ 1120 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */ 1121 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */ 1122 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */ 1123 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */ 1124 1125 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0; 1126 1127 } else { 1128 /* Testing Thumb code with several combinations of ITSTATE */ 1129 switch (scenario) { 1130 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */ 1131 cpsr = 0x00000800; 1132 probe_should_run = 0; 1133 break; 1134 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */ 1135 cpsr = 0xf0007800; 1136 probe_should_run = 0; 1137 break; 1138 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */ 1139 cpsr = 0x00009800; 1140 break; 1141 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */ 1142 cpsr = 0xf0002800; 1143 is_last_scenario = true; 1144 break; 1145 } 1146 } 1147 1148 return cpsr; 1149 } 1150 1151 static void setup_test_context(struct pt_regs *regs) 1152 { 1153 int scenario = test_case_run_count>>1; 1154 unsigned long val; 1155 struct test_arg *args; 1156 int i; 1157 1158 is_last_scenario = false; 1159 memory_needs_checking = false; 1160 1161 /* Initialise test memory on stack */ 1162 val = (scenario & 1) ? VALM : ~VALM; 1163 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i) 1164 current_stack[i] = val + (i << 8); 1165 /* Put target of branch on stack for tests which load PC from memory */ 1166 if (current_branch_target) 1167 current_stack[15] = current_branch_target; 1168 /* Put a value for SP on stack for tests which load SP from memory */ 1169 current_stack[13] = (u32)current_stack + 120; 1170 1171 /* Initialise register values to their default state */ 1172 val = (scenario & 2) ? VALR : ~VALR; 1173 for (i = 0; i < 13; ++i) 1174 regs->uregs[i] = val ^ (i << 8); 1175 regs->ARM_lr = val ^ (14 << 8); 1176 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK); 1177 regs->ARM_cpsr |= test_context_cpsr(scenario); 1178 1179 /* Perform testcase specific register setup */ 1180 args = current_args; 1181 for (; args[0].type != ARG_TYPE_END; ++args) 1182 switch (args[0].type) { 1183 case ARG_TYPE_REG: { 1184 struct test_arg_regptr *arg = 1185 (struct test_arg_regptr *)args; 1186 regs->uregs[arg->reg] = arg->val; 1187 break; 1188 } 1189 case ARG_TYPE_PTR: { 1190 struct test_arg_regptr *arg = 1191 (struct test_arg_regptr *)args; 1192 regs->uregs[arg->reg] = 1193 (unsigned long)current_stack + arg->val; 1194 memory_needs_checking = true; 1195 /* 1196 * Test memory at an address below SP is in danger of 1197 * being altered by an interrupt occurring and pushing 1198 * data onto the stack. Disable interrupts to stop this. 1199 */ 1200 if (arg->reg == 13) 1201 regs->ARM_cpsr |= PSR_I_BIT; 1202 break; 1203 } 1204 case ARG_TYPE_MEM: { 1205 struct test_arg_mem *arg = (struct test_arg_mem *)args; 1206 current_stack[arg->index] = arg->val; 1207 break; 1208 } 1209 default: 1210 break; 1211 } 1212 } 1213 1214 struct test_probe { 1215 struct kprobe kprobe; 1216 bool registered; 1217 int hit; 1218 }; 1219 1220 static void unregister_test_probe(struct test_probe *probe) 1221 { 1222 if (probe->registered) { 1223 unregister_kprobe(&probe->kprobe); 1224 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */ 1225 } 1226 probe->registered = false; 1227 } 1228 1229 static int register_test_probe(struct test_probe *probe) 1230 { 1231 int ret; 1232 1233 if (probe->registered) 1234 BUG(); 1235 1236 ret = register_kprobe(&probe->kprobe); 1237 if (ret >= 0) { 1238 probe->registered = true; 1239 probe->hit = -1; 1240 } 1241 return ret; 1242 } 1243 1244 static int __kprobes 1245 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs) 1246 { 1247 container_of(p, struct test_probe, kprobe)->hit = test_instance; 1248 return 0; 1249 } 1250 1251 static void __kprobes 1252 test_before_post_handler(struct kprobe *p, struct pt_regs *regs, 1253 unsigned long flags) 1254 { 1255 setup_test_context(regs); 1256 initial_regs = *regs; 1257 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS; 1258 } 1259 1260 static int __kprobes 1261 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs) 1262 { 1263 container_of(p, struct test_probe, kprobe)->hit = test_instance; 1264 return 0; 1265 } 1266 1267 static int __kprobes 1268 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs) 1269 { 1270 struct test_arg *args; 1271 1272 if (container_of(p, struct test_probe, kprobe)->hit == test_instance) 1273 return 0; /* Already run for this test instance */ 1274 1275 result_regs = *regs; 1276 1277 /* Mask out results which are indeterminate */ 1278 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS; 1279 for (args = current_args; args[0].type != ARG_TYPE_END; ++args) 1280 if (args[0].type == ARG_TYPE_REG_MASKED) { 1281 struct test_arg_regptr *arg = 1282 (struct test_arg_regptr *)args; 1283 result_regs.uregs[arg->reg] &= arg->val; 1284 } 1285 1286 /* Undo any changes done to SP by the test case */ 1287 regs->ARM_sp = (unsigned long)current_stack; 1288 /* Enable interrupts in case setup_test_context disabled them */ 1289 regs->ARM_cpsr &= ~PSR_I_BIT; 1290 1291 container_of(p, struct test_probe, kprobe)->hit = test_instance; 1292 return 0; 1293 } 1294 1295 static struct test_probe test_before_probe = { 1296 .kprobe.pre_handler = test_before_pre_handler, 1297 .kprobe.post_handler = test_before_post_handler, 1298 }; 1299 1300 static struct test_probe test_case_probe = { 1301 .kprobe.pre_handler = test_case_pre_handler, 1302 }; 1303 1304 static struct test_probe test_after_probe = { 1305 .kprobe.pre_handler = test_after_pre_handler, 1306 }; 1307 1308 static struct test_probe test_after2_probe = { 1309 .kprobe.pre_handler = test_after_pre_handler, 1310 }; 1311 1312 static void test_case_cleanup(void) 1313 { 1314 unregister_test_probe(&test_before_probe); 1315 unregister_test_probe(&test_case_probe); 1316 unregister_test_probe(&test_after_probe); 1317 unregister_test_probe(&test_after2_probe); 1318 } 1319 1320 static void print_registers(struct pt_regs *regs) 1321 { 1322 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n", 1323 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3); 1324 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n", 1325 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7); 1326 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n", 1327 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp); 1328 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n", 1329 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc); 1330 pr_err("cpsr %08lx\n", regs->ARM_cpsr); 1331 } 1332 1333 static void print_memory(u32 *mem, size_t size) 1334 { 1335 int i; 1336 for (i = 0; i < size / sizeof(u32); i += 4) 1337 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1], 1338 mem[i+2], mem[i+3]); 1339 } 1340 1341 static size_t expected_memory_size(u32 *sp) 1342 { 1343 size_t size = sizeof(expected_memory); 1344 int offset = (uintptr_t)sp - (uintptr_t)current_stack; 1345 if (offset > 0) 1346 size -= offset; 1347 return size; 1348 } 1349 1350 static void test_case_failed(const char *message) 1351 { 1352 test_case_cleanup(); 1353 1354 pr_err("FAIL: %s\n", message); 1355 pr_err("FAIL: Test %s\n", current_title); 1356 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1); 1357 } 1358 1359 static unsigned long next_instruction(unsigned long pc) 1360 { 1361 #ifdef CONFIG_THUMB2_KERNEL 1362 if ((pc & 1) && 1363 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1)))) 1364 return pc + 2; 1365 else 1366 #endif 1367 return pc + 4; 1368 } 1369 1370 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack) 1371 { 1372 struct test_arg *args; 1373 struct test_arg_end *end_arg; 1374 unsigned long test_code; 1375 1376 current_title = *title++; 1377 args = (struct test_arg *)title; 1378 current_args = args; 1379 current_stack = stack; 1380 1381 ++test_try_count; 1382 1383 while (args->type != ARG_TYPE_END) 1384 ++args; 1385 end_arg = (struct test_arg_end *)args; 1386 1387 test_code = (unsigned long)(args + 1); /* Code starts after args */ 1388 1389 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB; 1390 if (test_case_is_thumb) 1391 test_code |= 1; 1392 1393 current_code_start = test_code; 1394 1395 current_branch_target = 0; 1396 if (end_arg->branch_offset != end_arg->end_offset) 1397 current_branch_target = test_code + end_arg->branch_offset; 1398 1399 test_code += end_arg->code_offset; 1400 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code; 1401 1402 test_code = next_instruction(test_code); 1403 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code; 1404 1405 if (test_case_is_thumb) { 1406 u16 *p = (u16 *)(test_code & ~1); 1407 current_instruction = __mem_to_opcode_thumb16(p[0]); 1408 if (is_wide_instruction(current_instruction)) { 1409 u16 instr2 = __mem_to_opcode_thumb16(p[1]); 1410 current_instruction = __opcode_thumb32_compose(current_instruction, instr2); 1411 } 1412 } else { 1413 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code); 1414 } 1415 1416 if (current_title[0] == '.') 1417 verbose("%s\n", current_title); 1418 else 1419 verbose("%s\t@ %0*x\n", current_title, 1420 test_case_is_thumb ? 4 : 8, 1421 current_instruction); 1422 1423 test_code = next_instruction(test_code); 1424 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code; 1425 1426 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) { 1427 if (!test_case_is_thumb || 1428 is_wide_instruction(current_instruction)) { 1429 test_case_failed("expected 16-bit instruction"); 1430 goto fail; 1431 } 1432 } else { 1433 if (test_case_is_thumb && 1434 !is_wide_instruction(current_instruction)) { 1435 test_case_failed("expected 32-bit instruction"); 1436 goto fail; 1437 } 1438 } 1439 1440 coverage_add(current_instruction); 1441 1442 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) { 1443 if (register_test_probe(&test_case_probe) < 0) 1444 goto pass; 1445 test_case_failed("registered probe for unsupported instruction"); 1446 goto fail; 1447 } 1448 1449 if (end_arg->flags & ARG_FLAG_SUPPORTED) { 1450 if (register_test_probe(&test_case_probe) >= 0) 1451 goto pass; 1452 test_case_failed("couldn't register probe for supported instruction"); 1453 goto fail; 1454 } 1455 1456 if (register_test_probe(&test_before_probe) < 0) { 1457 test_case_failed("register test_before_probe failed"); 1458 goto fail; 1459 } 1460 if (register_test_probe(&test_after_probe) < 0) { 1461 test_case_failed("register test_after_probe failed"); 1462 goto fail; 1463 } 1464 if (current_branch_target) { 1465 test_after2_probe.kprobe.addr = 1466 (kprobe_opcode_t *)current_branch_target; 1467 if (register_test_probe(&test_after2_probe) < 0) { 1468 test_case_failed("register test_after2_probe failed"); 1469 goto fail; 1470 } 1471 } 1472 1473 /* Start first run of test case */ 1474 test_case_run_count = 0; 1475 ++test_instance; 1476 return current_code_start; 1477 pass: 1478 test_case_run_count = TEST_CASE_PASSED; 1479 return (uintptr_t)test_after_probe.kprobe.addr; 1480 fail: 1481 test_case_run_count = TEST_CASE_FAILED; 1482 return (uintptr_t)test_after_probe.kprobe.addr; 1483 } 1484 1485 static bool check_test_results(void) 1486 { 1487 size_t mem_size = 0; 1488 u32 *mem = 0; 1489 1490 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) { 1491 test_case_failed("registers differ"); 1492 goto fail; 1493 } 1494 1495 if (memory_needs_checking) { 1496 mem = (u32 *)result_regs.ARM_sp; 1497 mem_size = expected_memory_size(mem); 1498 if (memcmp(expected_memory, mem, mem_size)) { 1499 test_case_failed("test memory differs"); 1500 goto fail; 1501 } 1502 } 1503 1504 return true; 1505 1506 fail: 1507 pr_err("initial_regs:\n"); 1508 print_registers(&initial_regs); 1509 pr_err("expected_regs:\n"); 1510 print_registers(&expected_regs); 1511 pr_err("result_regs:\n"); 1512 print_registers(&result_regs); 1513 1514 if (mem) { 1515 pr_err("current_stack=%p\n", current_stack); 1516 pr_err("expected_memory:\n"); 1517 print_memory(expected_memory, mem_size); 1518 pr_err("result_memory:\n"); 1519 print_memory(mem, mem_size); 1520 } 1521 1522 return false; 1523 } 1524 1525 static uintptr_t __used kprobes_test_case_end(void) 1526 { 1527 if (test_case_run_count < 0) { 1528 if (test_case_run_count == TEST_CASE_PASSED) 1529 /* kprobes_test_case_start did all the needed testing */ 1530 goto pass; 1531 else 1532 /* kprobes_test_case_start failed */ 1533 goto fail; 1534 } 1535 1536 if (test_before_probe.hit != test_instance) { 1537 test_case_failed("test_before_handler not run"); 1538 goto fail; 1539 } 1540 1541 if (test_after_probe.hit != test_instance && 1542 test_after2_probe.hit != test_instance) { 1543 test_case_failed("test_after_handler not run"); 1544 goto fail; 1545 } 1546 1547 /* 1548 * Even numbered test runs ran without a probe on the test case so 1549 * we can gather reference results. The subsequent odd numbered run 1550 * will have the probe inserted. 1551 */ 1552 if ((test_case_run_count & 1) == 0) { 1553 /* Save results from run without probe */ 1554 u32 *mem = (u32 *)result_regs.ARM_sp; 1555 expected_regs = result_regs; 1556 memcpy(expected_memory, mem, expected_memory_size(mem)); 1557 1558 /* Insert probe onto test case instruction */ 1559 if (register_test_probe(&test_case_probe) < 0) { 1560 test_case_failed("register test_case_probe failed"); 1561 goto fail; 1562 } 1563 } else { 1564 /* Check probe ran as expected */ 1565 if (probe_should_run == 1) { 1566 if (test_case_probe.hit != test_instance) { 1567 test_case_failed("test_case_handler not run"); 1568 goto fail; 1569 } 1570 } else if (probe_should_run == 0) { 1571 if (test_case_probe.hit == test_instance) { 1572 test_case_failed("test_case_handler ran"); 1573 goto fail; 1574 } 1575 } 1576 1577 /* Remove probe for any subsequent reference run */ 1578 unregister_test_probe(&test_case_probe); 1579 1580 if (!check_test_results()) 1581 goto fail; 1582 1583 if (is_last_scenario) 1584 goto pass; 1585 } 1586 1587 /* Do next test run */ 1588 ++test_case_run_count; 1589 ++test_instance; 1590 return current_code_start; 1591 fail: 1592 ++test_fail_count; 1593 goto end; 1594 pass: 1595 ++test_pass_count; 1596 end: 1597 test_case_cleanup(); 1598 return 0; 1599 } 1600 1601 1602 /* 1603 * Top level test functions 1604 */ 1605 1606 static int run_test_cases(void (*tests)(void), const union decode_item *table) 1607 { 1608 int ret; 1609 1610 pr_info(" Check decoding tables\n"); 1611 ret = table_test(table); 1612 if (ret) 1613 return ret; 1614 1615 pr_info(" Run test cases\n"); 1616 ret = coverage_start(table); 1617 if (ret) 1618 return ret; 1619 1620 tests(); 1621 1622 coverage_end(); 1623 return 0; 1624 } 1625 1626 1627 static int __init run_all_tests(void) 1628 { 1629 int ret = 0; 1630 1631 pr_info("Beginning kprobe tests...\n"); 1632 1633 #ifndef CONFIG_THUMB2_KERNEL 1634 1635 pr_info("Probe ARM code\n"); 1636 ret = run_api_tests(arm_func); 1637 if (ret) 1638 goto out; 1639 1640 pr_info("ARM instruction simulation\n"); 1641 ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table); 1642 if (ret) 1643 goto out; 1644 1645 #else /* CONFIG_THUMB2_KERNEL */ 1646 1647 pr_info("Probe 16-bit Thumb code\n"); 1648 ret = run_api_tests(thumb16_func); 1649 if (ret) 1650 goto out; 1651 1652 pr_info("Probe 32-bit Thumb code, even halfword\n"); 1653 ret = run_api_tests(thumb32even_func); 1654 if (ret) 1655 goto out; 1656 1657 pr_info("Probe 32-bit Thumb code, odd halfword\n"); 1658 ret = run_api_tests(thumb32odd_func); 1659 if (ret) 1660 goto out; 1661 1662 pr_info("16-bit Thumb instruction simulation\n"); 1663 ret = run_test_cases(kprobe_thumb16_test_cases, 1664 probes_decode_thumb16_table); 1665 if (ret) 1666 goto out; 1667 1668 pr_info("32-bit Thumb instruction simulation\n"); 1669 ret = run_test_cases(kprobe_thumb32_test_cases, 1670 probes_decode_thumb32_table); 1671 if (ret) 1672 goto out; 1673 #endif 1674 1675 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n", 1676 test_try_count, test_pass_count, test_fail_count); 1677 if (test_fail_count) { 1678 ret = -EINVAL; 1679 goto out; 1680 } 1681 1682 #if BENCHMARKING 1683 pr_info("Benchmarks\n"); 1684 ret = run_benchmarks(); 1685 if (ret) 1686 goto out; 1687 #endif 1688 1689 #if __LINUX_ARM_ARCH__ >= 7 1690 /* We are able to run all test cases so coverage should be complete */ 1691 if (coverage_fail) { 1692 pr_err("FAIL: Test coverage checks failed\n"); 1693 ret = -EINVAL; 1694 goto out; 1695 } 1696 #endif 1697 1698 out: 1699 if (ret == 0) 1700 ret = tests_failed; 1701 if (ret == 0) 1702 pr_info("Finished kprobe tests OK\n"); 1703 else 1704 pr_err("kprobe tests failed\n"); 1705 1706 return ret; 1707 } 1708 1709 1710 /* 1711 * Module setup 1712 */ 1713 1714 #ifdef MODULE 1715 1716 static void __exit kprobe_test_exit(void) 1717 { 1718 } 1719 1720 module_init(run_all_tests) 1721 module_exit(kprobe_test_exit) 1722 MODULE_LICENSE("GPL"); 1723 1724 #else /* !MODULE */ 1725 1726 late_initcall(run_all_tests); 1727 1728 #endif 1729