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/kprobes.h> 207 #include <linux/errno.h> 208 #include <linux/stddef.h> 209 #include <linux/bug.h> 210 #include <asm/opcodes.h> 211 212 #include "core.h" 213 #include "test-core.h" 214 #include "../decode-arm.h" 215 #include "../decode-thumb.h" 216 217 218 #define BENCHMARKING 1 219 220 221 /* 222 * Test basic API 223 */ 224 225 static bool test_regs_ok; 226 static int test_func_instance; 227 static int pre_handler_called; 228 static int post_handler_called; 229 static int jprobe_func_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 void __kprobes jprobe_func(long r0, long r1) 373 { 374 jprobe_func_called = test_func_instance; 375 if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2) 376 test_regs_ok = true; 377 jprobe_return(); 378 } 379 380 static struct jprobe the_jprobe = { 381 .entry = jprobe_func, 382 }; 383 384 static int test_jprobe(long (*func)(long, long)) 385 { 386 int ret; 387 388 the_jprobe.kp.addr = (kprobe_opcode_t *)func; 389 ret = register_jprobe(&the_jprobe); 390 if (ret < 0) { 391 pr_err("FAIL: register_jprobe failed with %d\n", ret); 392 return ret; 393 } 394 395 ret = call_test_func(func, true); 396 397 unregister_jprobe(&the_jprobe); 398 the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */ 399 400 if (!ret) 401 return -EINVAL; 402 if (jprobe_func_called != test_func_instance) { 403 pr_err("FAIL: jprobe handler function not called\n"); 404 return -EINVAL; 405 } 406 if (!call_test_func(func, false)) 407 return -EINVAL; 408 if (jprobe_func_called == test_func_instance) { 409 pr_err("FAIL: probe called after unregistering\n"); 410 return -EINVAL; 411 } 412 413 return 0; 414 } 415 416 static int __kprobes 417 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs) 418 { 419 kretprobe_handler_called = test_func_instance; 420 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2) 421 test_regs_ok = true; 422 return 0; 423 } 424 425 static struct kretprobe the_kretprobe = { 426 .handler = kretprobe_handler, 427 }; 428 429 static int test_kretprobe(long (*func)(long, long)) 430 { 431 int ret; 432 433 the_kretprobe.kp.addr = (kprobe_opcode_t *)func; 434 ret = register_kretprobe(&the_kretprobe); 435 if (ret < 0) { 436 pr_err("FAIL: register_kretprobe failed with %d\n", ret); 437 return ret; 438 } 439 440 ret = call_test_func(func, true); 441 442 unregister_kretprobe(&the_kretprobe); 443 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */ 444 445 if (!ret) 446 return -EINVAL; 447 if (kretprobe_handler_called != test_func_instance) { 448 pr_err("FAIL: kretprobe handler not called\n"); 449 return -EINVAL; 450 } 451 if (!call_test_func(func, false)) 452 return -EINVAL; 453 if (jprobe_func_called == test_func_instance) { 454 pr_err("FAIL: kretprobe called after unregistering\n"); 455 return -EINVAL; 456 } 457 458 return 0; 459 } 460 461 static int run_api_tests(long (*func)(long, long)) 462 { 463 int ret; 464 465 pr_info(" kprobe\n"); 466 ret = test_kprobe(func); 467 if (ret < 0) 468 return ret; 469 470 pr_info(" jprobe\n"); 471 ret = test_jprobe(func); 472 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE) 473 if (ret == -EINVAL) { 474 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n"); 475 tests_failed = ret; 476 ret = 0; 477 } 478 #endif 479 if (ret < 0) 480 return ret; 481 482 pr_info(" kretprobe\n"); 483 ret = test_kretprobe(func); 484 if (ret < 0) 485 return ret; 486 487 return 0; 488 } 489 490 491 /* 492 * Benchmarking 493 */ 494 495 #if BENCHMARKING 496 497 static void __naked benchmark_nop(void) 498 { 499 __asm__ __volatile__ ( 500 "nop \n\t" 501 RET(lr)" \n\t" 502 ); 503 } 504 505 #ifdef CONFIG_THUMB2_KERNEL 506 #define wide ".w" 507 #else 508 #define wide 509 #endif 510 511 static void __naked benchmark_pushpop1(void) 512 { 513 __asm__ __volatile__ ( 514 "stmdb"wide" sp!, {r3-r11,lr} \n\t" 515 "ldmia"wide" sp!, {r3-r11,pc}" 516 ); 517 } 518 519 static void __naked benchmark_pushpop2(void) 520 { 521 __asm__ __volatile__ ( 522 "stmdb"wide" sp!, {r0-r8,lr} \n\t" 523 "ldmia"wide" sp!, {r0-r8,pc}" 524 ); 525 } 526 527 static void __naked benchmark_pushpop3(void) 528 { 529 __asm__ __volatile__ ( 530 "stmdb"wide" sp!, {r4,lr} \n\t" 531 "ldmia"wide" sp!, {r4,pc}" 532 ); 533 } 534 535 static void __naked benchmark_pushpop4(void) 536 { 537 __asm__ __volatile__ ( 538 "stmdb"wide" sp!, {r0,lr} \n\t" 539 "ldmia"wide" sp!, {r0,pc}" 540 ); 541 } 542 543 544 #ifdef CONFIG_THUMB2_KERNEL 545 546 static void __naked benchmark_pushpop_thumb(void) 547 { 548 __asm__ __volatile__ ( 549 "push.n {r0-r7,lr} \n\t" 550 "pop.n {r0-r7,pc}" 551 ); 552 } 553 554 #endif 555 556 static int __kprobes 557 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs) 558 { 559 return 0; 560 } 561 562 static int benchmark(void(*fn)(void)) 563 { 564 unsigned n, i, t, t0; 565 566 for (n = 1000; ; n *= 2) { 567 t0 = sched_clock(); 568 for (i = n; i > 0; --i) 569 fn(); 570 t = sched_clock() - t0; 571 if (t >= 250000000) 572 break; /* Stop once we took more than 0.25 seconds */ 573 } 574 return t / n; /* Time for one iteration in nanoseconds */ 575 }; 576 577 static int kprobe_benchmark(void(*fn)(void), unsigned offset) 578 { 579 struct kprobe k = { 580 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset), 581 .pre_handler = benchmark_pre_handler, 582 }; 583 584 int ret = register_kprobe(&k); 585 if (ret < 0) { 586 pr_err("FAIL: register_kprobe failed with %d\n", ret); 587 return ret; 588 } 589 590 ret = benchmark(fn); 591 592 unregister_kprobe(&k); 593 return ret; 594 }; 595 596 struct benchmarks { 597 void (*fn)(void); 598 unsigned offset; 599 const char *title; 600 }; 601 602 static int run_benchmarks(void) 603 { 604 int ret; 605 struct benchmarks list[] = { 606 {&benchmark_nop, 0, "nop"}, 607 /* 608 * benchmark_pushpop{1,3} will have the optimised 609 * instruction emulation, whilst benchmark_pushpop{2,4} will 610 * be the equivalent unoptimised instructions. 611 */ 612 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"}, 613 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"}, 614 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"}, 615 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"}, 616 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"}, 617 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"}, 618 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"}, 619 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"}, 620 #ifdef CONFIG_THUMB2_KERNEL 621 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"}, 622 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"}, 623 #endif 624 {0} 625 }; 626 627 struct benchmarks *b; 628 for (b = list; b->fn; ++b) { 629 ret = kprobe_benchmark(b->fn, b->offset); 630 if (ret < 0) 631 return ret; 632 pr_info(" %dns for kprobe %s\n", ret, b->title); 633 } 634 635 pr_info("\n"); 636 return 0; 637 } 638 639 #endif /* BENCHMARKING */ 640 641 642 /* 643 * Decoding table self-consistency tests 644 */ 645 646 static const int decode_struct_sizes[NUM_DECODE_TYPES] = { 647 [DECODE_TYPE_TABLE] = sizeof(struct decode_table), 648 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom), 649 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate), 650 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate), 651 [DECODE_TYPE_OR] = sizeof(struct decode_or), 652 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject) 653 }; 654 655 static int table_iter(const union decode_item *table, 656 int (*fn)(const struct decode_header *, void *), 657 void *args) 658 { 659 const struct decode_header *h = (struct decode_header *)table; 660 int result; 661 662 for (;;) { 663 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 664 665 if (type == DECODE_TYPE_END) 666 return 0; 667 668 result = fn(h, args); 669 if (result) 670 return result; 671 672 h = (struct decode_header *) 673 ((uintptr_t)h + decode_struct_sizes[type]); 674 675 } 676 } 677 678 static int table_test_fail(const struct decode_header *h, const char* message) 679 { 680 681 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n", 682 message, h->mask.bits, h->value.bits); 683 return -EINVAL; 684 } 685 686 struct table_test_args { 687 const union decode_item *root_table; 688 u32 parent_mask; 689 u32 parent_value; 690 }; 691 692 static int table_test_fn(const struct decode_header *h, void *args) 693 { 694 struct table_test_args *a = (struct table_test_args *)args; 695 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 696 697 if (h->value.bits & ~h->mask.bits) 698 return table_test_fail(h, "Match value has bits not in mask"); 699 700 if ((h->mask.bits & a->parent_mask) != a->parent_mask) 701 return table_test_fail(h, "Mask has bits not in parent mask"); 702 703 if ((h->value.bits ^ a->parent_value) & a->parent_mask) 704 return table_test_fail(h, "Value is inconsistent with parent"); 705 706 if (type == DECODE_TYPE_TABLE) { 707 struct decode_table *d = (struct decode_table *)h; 708 struct table_test_args args2 = *a; 709 args2.parent_mask = h->mask.bits; 710 args2.parent_value = h->value.bits; 711 return table_iter(d->table.table, table_test_fn, &args2); 712 } 713 714 return 0; 715 } 716 717 static int table_test(const union decode_item *table) 718 { 719 struct table_test_args args = { 720 .root_table = table, 721 .parent_mask = 0, 722 .parent_value = 0 723 }; 724 return table_iter(args.root_table, table_test_fn, &args); 725 } 726 727 728 /* 729 * Decoding table test coverage analysis 730 * 731 * coverage_start() builds a coverage_table which contains a list of 732 * coverage_entry's to match each entry in the specified kprobes instruction 733 * decoding table. 734 * 735 * When test cases are run, coverage_add() is called to process each case. 736 * This looks up the corresponding entry in the coverage_table and sets it as 737 * being matched, as well as clearing the regs flag appropriate for the test. 738 * 739 * After all test cases have been run, coverage_end() is called to check that 740 * all entries in coverage_table have been matched and that all regs flags are 741 * cleared. I.e. that all possible combinations of instructions described by 742 * the kprobes decoding tables have had a test case executed for them. 743 */ 744 745 bool coverage_fail; 746 747 #define MAX_COVERAGE_ENTRIES 256 748 749 struct coverage_entry { 750 const struct decode_header *header; 751 unsigned regs; 752 unsigned nesting; 753 char matched; 754 }; 755 756 struct coverage_table { 757 struct coverage_entry *base; 758 unsigned num_entries; 759 unsigned nesting; 760 }; 761 762 struct coverage_table coverage; 763 764 #define COVERAGE_ANY_REG (1<<0) 765 #define COVERAGE_SP (1<<1) 766 #define COVERAGE_PC (1<<2) 767 #define COVERAGE_PCWB (1<<3) 768 769 static const char coverage_register_lookup[16] = { 770 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC, 771 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG, 772 [REG_TYPE_SP] = COVERAGE_SP, 773 [REG_TYPE_PC] = COVERAGE_PC, 774 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP, 775 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC, 776 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC, 777 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB, 778 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG, 779 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP, 780 }; 781 782 unsigned coverage_start_registers(const struct decode_header *h) 783 { 784 unsigned regs = 0; 785 int i; 786 for (i = 0; i < 20; i += 4) { 787 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf; 788 regs |= coverage_register_lookup[r] << i; 789 } 790 return regs; 791 } 792 793 static int coverage_start_fn(const struct decode_header *h, void *args) 794 { 795 struct coverage_table *coverage = (struct coverage_table *)args; 796 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 797 struct coverage_entry *entry = coverage->base + coverage->num_entries; 798 799 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) { 800 pr_err("FAIL: Out of space for test coverage data"); 801 return -ENOMEM; 802 } 803 804 ++coverage->num_entries; 805 806 entry->header = h; 807 entry->regs = coverage_start_registers(h); 808 entry->nesting = coverage->nesting; 809 entry->matched = false; 810 811 if (type == DECODE_TYPE_TABLE) { 812 struct decode_table *d = (struct decode_table *)h; 813 int ret; 814 ++coverage->nesting; 815 ret = table_iter(d->table.table, coverage_start_fn, coverage); 816 --coverage->nesting; 817 return ret; 818 } 819 820 return 0; 821 } 822 823 static int coverage_start(const union decode_item *table) 824 { 825 coverage.base = kmalloc(MAX_COVERAGE_ENTRIES * 826 sizeof(struct coverage_entry), GFP_KERNEL); 827 coverage.num_entries = 0; 828 coverage.nesting = 0; 829 return table_iter(table, coverage_start_fn, &coverage); 830 } 831 832 static void 833 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn) 834 { 835 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS; 836 int i; 837 for (i = 0; i < 20; i += 4) { 838 enum decode_reg_type reg_type = (regs >> i) & 0xf; 839 int reg = (insn >> i) & 0xf; 840 int flag; 841 842 if (!reg_type) 843 continue; 844 845 if (reg == 13) 846 flag = COVERAGE_SP; 847 else if (reg == 15) 848 flag = COVERAGE_PC; 849 else 850 flag = COVERAGE_ANY_REG; 851 entry->regs &= ~(flag << i); 852 853 switch (reg_type) { 854 855 case REG_TYPE_NONE: 856 case REG_TYPE_ANY: 857 case REG_TYPE_SAMEAS16: 858 break; 859 860 case REG_TYPE_SP: 861 if (reg != 13) 862 return; 863 break; 864 865 case REG_TYPE_PC: 866 if (reg != 15) 867 return; 868 break; 869 870 case REG_TYPE_NOSP: 871 if (reg == 13) 872 return; 873 break; 874 875 case REG_TYPE_NOSPPC: 876 case REG_TYPE_NOSPPCX: 877 if (reg == 13 || reg == 15) 878 return; 879 break; 880 881 case REG_TYPE_NOPCWB: 882 if (!is_writeback(insn)) 883 break; 884 if (reg == 15) { 885 entry->regs &= ~(COVERAGE_PCWB << i); 886 return; 887 } 888 break; 889 890 case REG_TYPE_NOPC: 891 case REG_TYPE_NOPCX: 892 if (reg == 15) 893 return; 894 break; 895 } 896 897 } 898 } 899 900 static void coverage_add(kprobe_opcode_t insn) 901 { 902 struct coverage_entry *entry = coverage.base; 903 struct coverage_entry *end = coverage.base + coverage.num_entries; 904 bool matched = false; 905 unsigned nesting = 0; 906 907 for (; entry < end; ++entry) { 908 const struct decode_header *h = entry->header; 909 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK; 910 911 if (entry->nesting > nesting) 912 continue; /* Skip sub-table we didn't match */ 913 914 if (entry->nesting < nesting) 915 break; /* End of sub-table we were scanning */ 916 917 if (!matched) { 918 if ((insn & h->mask.bits) != h->value.bits) 919 continue; 920 entry->matched = true; 921 } 922 923 switch (type) { 924 925 case DECODE_TYPE_TABLE: 926 ++nesting; 927 break; 928 929 case DECODE_TYPE_CUSTOM: 930 case DECODE_TYPE_SIMULATE: 931 case DECODE_TYPE_EMULATE: 932 coverage_add_registers(entry, insn); 933 return; 934 935 case DECODE_TYPE_OR: 936 matched = true; 937 break; 938 939 case DECODE_TYPE_REJECT: 940 default: 941 return; 942 } 943 944 } 945 } 946 947 static void coverage_end(void) 948 { 949 struct coverage_entry *entry = coverage.base; 950 struct coverage_entry *end = coverage.base + coverage.num_entries; 951 952 for (; entry < end; ++entry) { 953 u32 mask = entry->header->mask.bits; 954 u32 value = entry->header->value.bits; 955 956 if (entry->regs) { 957 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n", 958 mask, value, entry->regs); 959 coverage_fail = true; 960 } 961 if (!entry->matched) { 962 pr_err("FAIL: Test coverage entry missing for %08x %08x\n", 963 mask, value); 964 coverage_fail = true; 965 } 966 } 967 968 kfree(coverage.base); 969 } 970 971 972 /* 973 * Framework for instruction set test cases 974 */ 975 976 void __naked __kprobes_test_case_start(void) 977 { 978 __asm__ __volatile__ ( 979 "stmdb sp!, {r4-r11} \n\t" 980 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" 981 "bic r0, lr, #1 @ r0 = inline data \n\t" 982 "mov r1, sp \n\t" 983 "bl kprobes_test_case_start \n\t" 984 RET(r0)" \n\t" 985 ); 986 } 987 988 #ifndef CONFIG_THUMB2_KERNEL 989 990 void __naked __kprobes_test_case_end_32(void) 991 { 992 __asm__ __volatile__ ( 993 "mov r4, lr \n\t" 994 "bl kprobes_test_case_end \n\t" 995 "cmp r0, #0 \n\t" 996 "movne pc, r0 \n\t" 997 "mov r0, r4 \n\t" 998 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" 999 "ldmia sp!, {r4-r11} \n\t" 1000 "mov pc, r0 \n\t" 1001 ); 1002 } 1003 1004 #else /* CONFIG_THUMB2_KERNEL */ 1005 1006 void __naked __kprobes_test_case_end_16(void) 1007 { 1008 __asm__ __volatile__ ( 1009 "mov r4, lr \n\t" 1010 "bl kprobes_test_case_end \n\t" 1011 "cmp r0, #0 \n\t" 1012 "bxne r0 \n\t" 1013 "mov r0, r4 \n\t" 1014 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t" 1015 "ldmia sp!, {r4-r11} \n\t" 1016 "bx r0 \n\t" 1017 ); 1018 } 1019 1020 void __naked __kprobes_test_case_end_32(void) 1021 { 1022 __asm__ __volatile__ ( 1023 ".arm \n\t" 1024 "orr lr, lr, #1 @ will return to Thumb code \n\t" 1025 "ldr pc, 1f \n\t" 1026 "1: \n\t" 1027 ".word __kprobes_test_case_end_16 \n\t" 1028 ); 1029 } 1030 1031 #endif 1032 1033 1034 int kprobe_test_flags; 1035 int kprobe_test_cc_position; 1036 1037 static int test_try_count; 1038 static int test_pass_count; 1039 static int test_fail_count; 1040 1041 static struct pt_regs initial_regs; 1042 static struct pt_regs expected_regs; 1043 static struct pt_regs result_regs; 1044 1045 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)]; 1046 1047 static const char *current_title; 1048 static struct test_arg *current_args; 1049 static u32 *current_stack; 1050 static uintptr_t current_branch_target; 1051 1052 static uintptr_t current_code_start; 1053 static kprobe_opcode_t current_instruction; 1054 1055 1056 #define TEST_CASE_PASSED -1 1057 #define TEST_CASE_FAILED -2 1058 1059 static int test_case_run_count; 1060 static bool test_case_is_thumb; 1061 static int test_instance; 1062 1063 static unsigned long test_check_cc(int cc, unsigned long cpsr) 1064 { 1065 int ret = arm_check_condition(cc << 28, cpsr); 1066 1067 return (ret != ARM_OPCODE_CONDTEST_FAIL); 1068 } 1069 1070 static int is_last_scenario; 1071 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */ 1072 static int memory_needs_checking; 1073 1074 static unsigned long test_context_cpsr(int scenario) 1075 { 1076 unsigned long cpsr; 1077 1078 probe_should_run = 1; 1079 1080 /* Default case is that we cycle through 16 combinations of flags */ 1081 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */ 1082 cpsr |= (scenario & 0xf) << 16; /* GE flags */ 1083 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */ 1084 1085 if (!test_case_is_thumb) { 1086 /* Testing ARM code */ 1087 int cc = current_instruction >> 28; 1088 1089 probe_should_run = test_check_cc(cc, cpsr) != 0; 1090 if (scenario == 15) 1091 is_last_scenario = true; 1092 1093 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) { 1094 /* Testing Thumb code without setting ITSTATE */ 1095 if (kprobe_test_cc_position) { 1096 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf; 1097 probe_should_run = test_check_cc(cc, cpsr) != 0; 1098 } 1099 1100 if (scenario == 15) 1101 is_last_scenario = true; 1102 1103 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) { 1104 /* Testing Thumb code with all combinations of ITSTATE */ 1105 unsigned x = (scenario >> 4); 1106 unsigned cond_base = x % 7; /* ITSTATE<7:5> */ 1107 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */ 1108 1109 if (mask > 0x1f) { 1110 /* Finish by testing state from instruction 'itt al' */ 1111 cond_base = 7; 1112 mask = 0x4; 1113 if ((scenario & 0xf) == 0xf) 1114 is_last_scenario = true; 1115 } 1116 1117 cpsr |= cond_base << 13; /* ITSTATE<7:5> */ 1118 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */ 1119 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */ 1120 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */ 1121 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */ 1122 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */ 1123 1124 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0; 1125 1126 } else { 1127 /* Testing Thumb code with several combinations of ITSTATE */ 1128 switch (scenario) { 1129 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */ 1130 cpsr = 0x00000800; 1131 probe_should_run = 0; 1132 break; 1133 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */ 1134 cpsr = 0xf0007800; 1135 probe_should_run = 0; 1136 break; 1137 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */ 1138 cpsr = 0x00009800; 1139 break; 1140 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */ 1141 cpsr = 0xf0002800; 1142 is_last_scenario = true; 1143 break; 1144 } 1145 } 1146 1147 return cpsr; 1148 } 1149 1150 static void setup_test_context(struct pt_regs *regs) 1151 { 1152 int scenario = test_case_run_count>>1; 1153 unsigned long val; 1154 struct test_arg *args; 1155 int i; 1156 1157 is_last_scenario = false; 1158 memory_needs_checking = false; 1159 1160 /* Initialise test memory on stack */ 1161 val = (scenario & 1) ? VALM : ~VALM; 1162 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i) 1163 current_stack[i] = val + (i << 8); 1164 /* Put target of branch on stack for tests which load PC from memory */ 1165 if (current_branch_target) 1166 current_stack[15] = current_branch_target; 1167 /* Put a value for SP on stack for tests which load SP from memory */ 1168 current_stack[13] = (u32)current_stack + 120; 1169 1170 /* Initialise register values to their default state */ 1171 val = (scenario & 2) ? VALR : ~VALR; 1172 for (i = 0; i < 13; ++i) 1173 regs->uregs[i] = val ^ (i << 8); 1174 regs->ARM_lr = val ^ (14 << 8); 1175 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK); 1176 regs->ARM_cpsr |= test_context_cpsr(scenario); 1177 1178 /* Perform testcase specific register setup */ 1179 args = current_args; 1180 for (; args[0].type != ARG_TYPE_END; ++args) 1181 switch (args[0].type) { 1182 case ARG_TYPE_REG: { 1183 struct test_arg_regptr *arg = 1184 (struct test_arg_regptr *)args; 1185 regs->uregs[arg->reg] = arg->val; 1186 break; 1187 } 1188 case ARG_TYPE_PTR: { 1189 struct test_arg_regptr *arg = 1190 (struct test_arg_regptr *)args; 1191 regs->uregs[arg->reg] = 1192 (unsigned long)current_stack + arg->val; 1193 memory_needs_checking = true; 1194 /* 1195 * Test memory at an address below SP is in danger of 1196 * being altered by an interrupt occurring and pushing 1197 * data onto the stack. Disable interrupts to stop this. 1198 */ 1199 if (arg->reg == 13) 1200 regs->ARM_cpsr |= PSR_I_BIT; 1201 break; 1202 } 1203 case ARG_TYPE_MEM: { 1204 struct test_arg_mem *arg = (struct test_arg_mem *)args; 1205 current_stack[arg->index] = arg->val; 1206 break; 1207 } 1208 default: 1209 break; 1210 } 1211 } 1212 1213 struct test_probe { 1214 struct kprobe kprobe; 1215 bool registered; 1216 int hit; 1217 }; 1218 1219 static void unregister_test_probe(struct test_probe *probe) 1220 { 1221 if (probe->registered) { 1222 unregister_kprobe(&probe->kprobe); 1223 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */ 1224 } 1225 probe->registered = false; 1226 } 1227 1228 static int register_test_probe(struct test_probe *probe) 1229 { 1230 int ret; 1231 1232 if (probe->registered) 1233 BUG(); 1234 1235 ret = register_kprobe(&probe->kprobe); 1236 if (ret >= 0) { 1237 probe->registered = true; 1238 probe->hit = -1; 1239 } 1240 return ret; 1241 } 1242 1243 static int __kprobes 1244 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs) 1245 { 1246 container_of(p, struct test_probe, kprobe)->hit = test_instance; 1247 return 0; 1248 } 1249 1250 static void __kprobes 1251 test_before_post_handler(struct kprobe *p, struct pt_regs *regs, 1252 unsigned long flags) 1253 { 1254 setup_test_context(regs); 1255 initial_regs = *regs; 1256 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS; 1257 } 1258 1259 static int __kprobes 1260 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs) 1261 { 1262 container_of(p, struct test_probe, kprobe)->hit = test_instance; 1263 return 0; 1264 } 1265 1266 static int __kprobes 1267 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs) 1268 { 1269 struct test_arg *args; 1270 1271 if (container_of(p, struct test_probe, kprobe)->hit == test_instance) 1272 return 0; /* Already run for this test instance */ 1273 1274 result_regs = *regs; 1275 1276 /* Mask out results which are indeterminate */ 1277 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS; 1278 for (args = current_args; args[0].type != ARG_TYPE_END; ++args) 1279 if (args[0].type == ARG_TYPE_REG_MASKED) { 1280 struct test_arg_regptr *arg = 1281 (struct test_arg_regptr *)args; 1282 result_regs.uregs[arg->reg] &= arg->val; 1283 } 1284 1285 /* Undo any changes done to SP by the test case */ 1286 regs->ARM_sp = (unsigned long)current_stack; 1287 /* Enable interrupts in case setup_test_context disabled them */ 1288 regs->ARM_cpsr &= ~PSR_I_BIT; 1289 1290 container_of(p, struct test_probe, kprobe)->hit = test_instance; 1291 return 0; 1292 } 1293 1294 static struct test_probe test_before_probe = { 1295 .kprobe.pre_handler = test_before_pre_handler, 1296 .kprobe.post_handler = test_before_post_handler, 1297 }; 1298 1299 static struct test_probe test_case_probe = { 1300 .kprobe.pre_handler = test_case_pre_handler, 1301 }; 1302 1303 static struct test_probe test_after_probe = { 1304 .kprobe.pre_handler = test_after_pre_handler, 1305 }; 1306 1307 static struct test_probe test_after2_probe = { 1308 .kprobe.pre_handler = test_after_pre_handler, 1309 }; 1310 1311 static void test_case_cleanup(void) 1312 { 1313 unregister_test_probe(&test_before_probe); 1314 unregister_test_probe(&test_case_probe); 1315 unregister_test_probe(&test_after_probe); 1316 unregister_test_probe(&test_after2_probe); 1317 } 1318 1319 static void print_registers(struct pt_regs *regs) 1320 { 1321 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n", 1322 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3); 1323 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n", 1324 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7); 1325 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n", 1326 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp); 1327 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n", 1328 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc); 1329 pr_err("cpsr %08lx\n", regs->ARM_cpsr); 1330 } 1331 1332 static void print_memory(u32 *mem, size_t size) 1333 { 1334 int i; 1335 for (i = 0; i < size / sizeof(u32); i += 4) 1336 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1], 1337 mem[i+2], mem[i+3]); 1338 } 1339 1340 static size_t expected_memory_size(u32 *sp) 1341 { 1342 size_t size = sizeof(expected_memory); 1343 int offset = (uintptr_t)sp - (uintptr_t)current_stack; 1344 if (offset > 0) 1345 size -= offset; 1346 return size; 1347 } 1348 1349 static void test_case_failed(const char *message) 1350 { 1351 test_case_cleanup(); 1352 1353 pr_err("FAIL: %s\n", message); 1354 pr_err("FAIL: Test %s\n", current_title); 1355 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1); 1356 } 1357 1358 static unsigned long next_instruction(unsigned long pc) 1359 { 1360 #ifdef CONFIG_THUMB2_KERNEL 1361 if ((pc & 1) && 1362 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1)))) 1363 return pc + 2; 1364 else 1365 #endif 1366 return pc + 4; 1367 } 1368 1369 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack) 1370 { 1371 struct test_arg *args; 1372 struct test_arg_end *end_arg; 1373 unsigned long test_code; 1374 1375 current_title = *title++; 1376 args = (struct test_arg *)title; 1377 current_args = args; 1378 current_stack = stack; 1379 1380 ++test_try_count; 1381 1382 while (args->type != ARG_TYPE_END) 1383 ++args; 1384 end_arg = (struct test_arg_end *)args; 1385 1386 test_code = (unsigned long)(args + 1); /* Code starts after args */ 1387 1388 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB; 1389 if (test_case_is_thumb) 1390 test_code |= 1; 1391 1392 current_code_start = test_code; 1393 1394 current_branch_target = 0; 1395 if (end_arg->branch_offset != end_arg->end_offset) 1396 current_branch_target = test_code + end_arg->branch_offset; 1397 1398 test_code += end_arg->code_offset; 1399 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code; 1400 1401 test_code = next_instruction(test_code); 1402 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code; 1403 1404 if (test_case_is_thumb) { 1405 u16 *p = (u16 *)(test_code & ~1); 1406 current_instruction = __mem_to_opcode_thumb16(p[0]); 1407 if (is_wide_instruction(current_instruction)) { 1408 u16 instr2 = __mem_to_opcode_thumb16(p[1]); 1409 current_instruction = __opcode_thumb32_compose(current_instruction, instr2); 1410 } 1411 } else { 1412 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code); 1413 } 1414 1415 if (current_title[0] == '.') 1416 verbose("%s\n", current_title); 1417 else 1418 verbose("%s\t@ %0*x\n", current_title, 1419 test_case_is_thumb ? 4 : 8, 1420 current_instruction); 1421 1422 test_code = next_instruction(test_code); 1423 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code; 1424 1425 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) { 1426 if (!test_case_is_thumb || 1427 is_wide_instruction(current_instruction)) { 1428 test_case_failed("expected 16-bit instruction"); 1429 goto fail; 1430 } 1431 } else { 1432 if (test_case_is_thumb && 1433 !is_wide_instruction(current_instruction)) { 1434 test_case_failed("expected 32-bit instruction"); 1435 goto fail; 1436 } 1437 } 1438 1439 coverage_add(current_instruction); 1440 1441 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) { 1442 if (register_test_probe(&test_case_probe) < 0) 1443 goto pass; 1444 test_case_failed("registered probe for unsupported instruction"); 1445 goto fail; 1446 } 1447 1448 if (end_arg->flags & ARG_FLAG_SUPPORTED) { 1449 if (register_test_probe(&test_case_probe) >= 0) 1450 goto pass; 1451 test_case_failed("couldn't register probe for supported instruction"); 1452 goto fail; 1453 } 1454 1455 if (register_test_probe(&test_before_probe) < 0) { 1456 test_case_failed("register test_before_probe failed"); 1457 goto fail; 1458 } 1459 if (register_test_probe(&test_after_probe) < 0) { 1460 test_case_failed("register test_after_probe failed"); 1461 goto fail; 1462 } 1463 if (current_branch_target) { 1464 test_after2_probe.kprobe.addr = 1465 (kprobe_opcode_t *)current_branch_target; 1466 if (register_test_probe(&test_after2_probe) < 0) { 1467 test_case_failed("register test_after2_probe failed"); 1468 goto fail; 1469 } 1470 } 1471 1472 /* Start first run of test case */ 1473 test_case_run_count = 0; 1474 ++test_instance; 1475 return current_code_start; 1476 pass: 1477 test_case_run_count = TEST_CASE_PASSED; 1478 return (uintptr_t)test_after_probe.kprobe.addr; 1479 fail: 1480 test_case_run_count = TEST_CASE_FAILED; 1481 return (uintptr_t)test_after_probe.kprobe.addr; 1482 } 1483 1484 static bool check_test_results(void) 1485 { 1486 size_t mem_size = 0; 1487 u32 *mem = 0; 1488 1489 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) { 1490 test_case_failed("registers differ"); 1491 goto fail; 1492 } 1493 1494 if (memory_needs_checking) { 1495 mem = (u32 *)result_regs.ARM_sp; 1496 mem_size = expected_memory_size(mem); 1497 if (memcmp(expected_memory, mem, mem_size)) { 1498 test_case_failed("test memory differs"); 1499 goto fail; 1500 } 1501 } 1502 1503 return true; 1504 1505 fail: 1506 pr_err("initial_regs:\n"); 1507 print_registers(&initial_regs); 1508 pr_err("expected_regs:\n"); 1509 print_registers(&expected_regs); 1510 pr_err("result_regs:\n"); 1511 print_registers(&result_regs); 1512 1513 if (mem) { 1514 pr_err("current_stack=%p\n", current_stack); 1515 pr_err("expected_memory:\n"); 1516 print_memory(expected_memory, mem_size); 1517 pr_err("result_memory:\n"); 1518 print_memory(mem, mem_size); 1519 } 1520 1521 return false; 1522 } 1523 1524 static uintptr_t __used kprobes_test_case_end(void) 1525 { 1526 if (test_case_run_count < 0) { 1527 if (test_case_run_count == TEST_CASE_PASSED) 1528 /* kprobes_test_case_start did all the needed testing */ 1529 goto pass; 1530 else 1531 /* kprobes_test_case_start failed */ 1532 goto fail; 1533 } 1534 1535 if (test_before_probe.hit != test_instance) { 1536 test_case_failed("test_before_handler not run"); 1537 goto fail; 1538 } 1539 1540 if (test_after_probe.hit != test_instance && 1541 test_after2_probe.hit != test_instance) { 1542 test_case_failed("test_after_handler not run"); 1543 goto fail; 1544 } 1545 1546 /* 1547 * Even numbered test runs ran without a probe on the test case so 1548 * we can gather reference results. The subsequent odd numbered run 1549 * will have the probe inserted. 1550 */ 1551 if ((test_case_run_count & 1) == 0) { 1552 /* Save results from run without probe */ 1553 u32 *mem = (u32 *)result_regs.ARM_sp; 1554 expected_regs = result_regs; 1555 memcpy(expected_memory, mem, expected_memory_size(mem)); 1556 1557 /* Insert probe onto test case instruction */ 1558 if (register_test_probe(&test_case_probe) < 0) { 1559 test_case_failed("register test_case_probe failed"); 1560 goto fail; 1561 } 1562 } else { 1563 /* Check probe ran as expected */ 1564 if (probe_should_run == 1) { 1565 if (test_case_probe.hit != test_instance) { 1566 test_case_failed("test_case_handler not run"); 1567 goto fail; 1568 } 1569 } else if (probe_should_run == 0) { 1570 if (test_case_probe.hit == test_instance) { 1571 test_case_failed("test_case_handler ran"); 1572 goto fail; 1573 } 1574 } 1575 1576 /* Remove probe for any subsequent reference run */ 1577 unregister_test_probe(&test_case_probe); 1578 1579 if (!check_test_results()) 1580 goto fail; 1581 1582 if (is_last_scenario) 1583 goto pass; 1584 } 1585 1586 /* Do next test run */ 1587 ++test_case_run_count; 1588 ++test_instance; 1589 return current_code_start; 1590 fail: 1591 ++test_fail_count; 1592 goto end; 1593 pass: 1594 ++test_pass_count; 1595 end: 1596 test_case_cleanup(); 1597 return 0; 1598 } 1599 1600 1601 /* 1602 * Top level test functions 1603 */ 1604 1605 static int run_test_cases(void (*tests)(void), const union decode_item *table) 1606 { 1607 int ret; 1608 1609 pr_info(" Check decoding tables\n"); 1610 ret = table_test(table); 1611 if (ret) 1612 return ret; 1613 1614 pr_info(" Run test cases\n"); 1615 ret = coverage_start(table); 1616 if (ret) 1617 return ret; 1618 1619 tests(); 1620 1621 coverage_end(); 1622 return 0; 1623 } 1624 1625 1626 static int __init run_all_tests(void) 1627 { 1628 int ret = 0; 1629 1630 pr_info("Beginning kprobe tests...\n"); 1631 1632 #ifndef CONFIG_THUMB2_KERNEL 1633 1634 pr_info("Probe ARM code\n"); 1635 ret = run_api_tests(arm_func); 1636 if (ret) 1637 goto out; 1638 1639 pr_info("ARM instruction simulation\n"); 1640 ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table); 1641 if (ret) 1642 goto out; 1643 1644 #else /* CONFIG_THUMB2_KERNEL */ 1645 1646 pr_info("Probe 16-bit Thumb code\n"); 1647 ret = run_api_tests(thumb16_func); 1648 if (ret) 1649 goto out; 1650 1651 pr_info("Probe 32-bit Thumb code, even halfword\n"); 1652 ret = run_api_tests(thumb32even_func); 1653 if (ret) 1654 goto out; 1655 1656 pr_info("Probe 32-bit Thumb code, odd halfword\n"); 1657 ret = run_api_tests(thumb32odd_func); 1658 if (ret) 1659 goto out; 1660 1661 pr_info("16-bit Thumb instruction simulation\n"); 1662 ret = run_test_cases(kprobe_thumb16_test_cases, 1663 probes_decode_thumb16_table); 1664 if (ret) 1665 goto out; 1666 1667 pr_info("32-bit Thumb instruction simulation\n"); 1668 ret = run_test_cases(kprobe_thumb32_test_cases, 1669 probes_decode_thumb32_table); 1670 if (ret) 1671 goto out; 1672 #endif 1673 1674 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n", 1675 test_try_count, test_pass_count, test_fail_count); 1676 if (test_fail_count) { 1677 ret = -EINVAL; 1678 goto out; 1679 } 1680 1681 #if BENCHMARKING 1682 pr_info("Benchmarks\n"); 1683 ret = run_benchmarks(); 1684 if (ret) 1685 goto out; 1686 #endif 1687 1688 #if __LINUX_ARM_ARCH__ >= 7 1689 /* We are able to run all test cases so coverage should be complete */ 1690 if (coverage_fail) { 1691 pr_err("FAIL: Test coverage checks failed\n"); 1692 ret = -EINVAL; 1693 goto out; 1694 } 1695 #endif 1696 1697 out: 1698 if (ret == 0) 1699 ret = tests_failed; 1700 if (ret == 0) 1701 pr_info("Finished kprobe tests OK\n"); 1702 else 1703 pr_err("kprobe tests failed\n"); 1704 1705 return ret; 1706 } 1707 1708 1709 /* 1710 * Module setup 1711 */ 1712 1713 #ifdef MODULE 1714 1715 static void __exit kprobe_test_exit(void) 1716 { 1717 } 1718 1719 module_init(run_all_tests) 1720 module_exit(kprobe_test_exit) 1721 MODULE_LICENSE("GPL"); 1722 1723 #else /* !MODULE */ 1724 1725 late_initcall(run_all_tests); 1726 1727 #endif 1728