arch/arm/probes/kprobes/test-core.c

   1 /*
   2  * arch/arm/kernel/kprobes-test.c
   3  *
   4  * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 /*
  12  * This file contains test code for ARM kprobes.
  13  *
  14  * The top level function run_all_tests() executes tests for all of the
  15  * supported instruction sets: ARM, 16-bit Thumb, and 32-bit Thumb. These tests
  16  * fall into two categories; run_api_tests() checks basic functionality of the
  17  * kprobes API, and run_test_cases() is a comprehensive test for kprobes
  18  * instruction decoding and simulation.
  19  *
  20  * run_test_cases() first checks the kprobes decoding table for self consistency
  21  * (using table_test()) then executes a series of test cases for each of the CPU
  22  * instruction forms. coverage_start() and coverage_end() are used to verify
  23  * that these test cases cover all of the possible combinations of instructions
  24  * described by the kprobes decoding tables.
  25  *
  26  * The individual test cases are in kprobes-test-arm.c and kprobes-test-thumb.c
  27  * which use the macros defined in kprobes-test.h. The rest of this
  28  * documentation will describe the operation of the framework used by these
  29  * test cases.
  30  */
  31
  32 /*
  33  * TESTING METHODOLOGY
  34  * -------------------
  35  *
  36  * The methodology used to test an ARM instruction 'test_insn' is to use
  37  * inline assembler like:
  38  *
  39  * test_before: nop
  40  * test_case:   test_insn
  41  * test_after:  nop
  42  *
  43  * When the test case is run a kprobe is placed of each nop. The
  44  * post-handler of the test_before probe is used to modify the saved CPU
  45  * register context to that which we require for the test case. The
  46  * pre-handler of the of the test_after probe saves a copy of the CPU
  47  * register context. In this way we can execute test_insn with a specific
  48  * register context and see the results afterwards.
  49  *
  50  * To actually test the kprobes instruction emulation we perform the above
  51  * step a second time but with an additional kprobe on the test_case
  52  * instruction itself. If the emulation is accurate then the results seen
  53  * by the test_after probe will be identical to the first run which didn't
  54  * have a probe on test_case.
  55  *
  56  * Each test case is run several times with a variety of variations in the
  57  * flags value of stored in CPSR, and for Thumb code, different ITState.
  58  *
  59  * For instructions which can modify PC, a second test_after probe is used
  60  * like this:
  61  *
  62  * test_before: nop
  63  * test_case:   test_insn
  64  * test_after:  nop
  65  *              b test_done
  66  * test_after2: nop
  67  * test_done:
  68  *
  69  * The test case is constructed such that test_insn branches to
  70  * test_after2, or, if testing a conditional instruction, it may just
  71  * continue to test_after. The probes inserted at both locations let us
  72  * determine which happened. A similar approach is used for testing
  73  * backwards branches...
  74  *
  75  *              b test_before
  76  *              b test_done  @ helps to cope with off by 1 branches
  77  * test_after2: nop
  78  *              b test_done
  79  * test_before: nop
  80  * test_case:   test_insn
  81  * test_after:  nop
  82  * test_done:
  83  *
  84  * The macros used to generate the assembler instructions describe above
  85  * are TEST_INSTRUCTION, TEST_BRANCH_F (branch forwards) and TEST_BRANCH_B
  86  * (branch backwards). In these, the local variables numbered 1, 50, 2 and
  87  * 99 represent: test_before, test_case, test_after2 and test_done.
  88  *
  89  * FRAMEWORK
  90  * ---------
  91  *
  92  * Each test case is wrapped between the pair of macros TESTCASE_START and
  93  * TESTCASE_END. As well as performing the inline assembler boilerplate,
  94  * these call out to the kprobes_test_case_start() and
  95  * kprobes_test_case_end() functions which drive the execution of the test
  96  * case. The specific arguments to use for each test case are stored as
  97  * inline data constructed using the various TEST_ARG_* macros. Putting
  98  * this all together, a simple test case may look like:
  99  *
 100  *      TESTCASE_START("Testing mov r0, r7")
 101  *      TEST_ARG_REG(7, 0x12345678) // Set r7=0x12345678
 102  *      TEST_ARG_END("")
 103  *      TEST_INSTRUCTION("mov r0, r7")
 104  *      TESTCASE_END
 105  *
 106  * Note, in practice the single convenience macro TEST_R would be used for this
 107  * instead.
 108  *
 109  * The above would expand to assembler looking something like:
 110  *
 111  *      @ TESTCASE_START
 112  *      bl      __kprobes_test_case_start
 113  *      .pushsection .rodata
 114  *      "10:
 115  *      .ascii "mov r0, r7"     @ text title for test case
 116  *      .byte   0
 117  *      .popsection
 118  *      @ start of inline data...
 119  *      .word   10b             @ pointer to title in .rodata section
 120  *
 121  *      @ TEST_ARG_REG
 122  *      .byte   ARG_TYPE_REG
 123  *      .byte   7
 124  *      .short  0
 125  *      .word   0x1234567
 126  *
 127  *      @ TEST_ARG_END
 128  *      .byte   ARG_TYPE_END
 129  *      .byte   TEST_ISA        @ flags, including ISA being tested
 130  *      .short  50f-0f          @ offset of 'test_before'
 131  *      .short  2f-0f           @ offset of 'test_after2' (if relevent)
 132  *      .short  99f-0f          @ offset of 'test_done'
 133  *      @ start of test case code...
 134  *      0:
 135  *      .code   TEST_ISA        @ switch to ISA being tested
 136  *
 137  *      @ TEST_INSTRUCTION
 138  *      50:     nop             @ location for 'test_before' probe
 139  *      1:      mov r0, r7      @ the test case instruction 'test_insn'
 140  *              nop             @ location for 'test_after' probe
 141  *
 142  *      // TESTCASE_END
 143  *      2:
 144  *      99:     bl __kprobes_test_case_end_##TEST_ISA
 145  *      .code   NONMAL_ISA
 146  *
 147  * When the above is execute the following happens...
 148  *
 149  * __kprobes_test_case_start() is an assembler wrapper which sets up space
 150  * for a stack buffer and calls the C function kprobes_test_case_start().
 151  * This C function will do some initial processing of the inline data and
 152  * setup some global state. It then inserts the test_before and test_after
 153  * kprobes and returns a value which causes the assembler wrapper to jump
 154  * to the start of the test case code, (local label '0').
 155  *
 156  * When the test case code executes, the test_before probe will be hit and
 157  * test_before_post_handler will call setup_test_context(). This fills the
 158  * stack buffer and CPU registers with a test pattern and then processes
 159  * the test case arguments. In our example there is one TEST_ARG_REG which
 160  * indicates that R7 should be loaded with the value 0x12345678.
 161  *
 162  * When the test_before probe ends, the test case continues and executes
 163  * the "mov r0, r7" instruction. It then hits the test_after probe and the
 164  * pre-handler for this (test_after_pre_handler) will save a copy of the
 165  * CPU register context. This should now have R0 holding the same value as
 166  * R7.
 167  *
 168  * Finally we get to the call to __kprobes_test_case_end_{32,16}. This is
 169  * an assembler wrapper which switches back to the ISA used by the test
 170  * code and calls the C function kprobes_test_case_end().
 171  *
 172  * For each run through the test case, test_case_run_count is incremented
 173  * by one. For even runs, kprobes_test_case_end() saves a copy of the
 174  * register and stack buffer contents from the test case just run. It then
 175  * inserts a kprobe on the test case instruction 'test_insn' and returns a
 176  * value to cause the test case code to be re-run.
 177  *
 178  * For odd numbered runs, kprobes_test_case_end() compares the register and
 179  * stack buffer contents to those that were saved on the previous even
 180  * numbered run (the one without the kprobe on test_insn). These should be
 181  * the same if the kprobe instruction simulation routine is correct.
 182  *
 183  * The pair of test case runs is repeated with different combinations of
 184  * flag values in CPSR and, for Thumb, different ITState. This is
 185  * controlled by test_context_cpsr().
 186  *
 187  * BUILDING TEST CASES
 188  * -------------------
 189  *
 190  *
 191  * As an aid to building test cases, the stack buffer is initialised with
 192  * some special values:
 193  *
 194  *   [SP+13*4]  Contains SP+120. This can be used to test instructions
 195  *              which load a value into SP.
 196  *
 197  *   [SP+15*4]  When testing branching instructions using TEST_BRANCH_{F,B},
 198  *              this holds the target address of the branch, 'test_after2'.
 199  *              This can be used to test instructions which load a PC value
 200  *              from memory.
 201  */
 202
 203 #include <linux/kernel.h>
 204 #include <linux/module.h>
 205 #include <linux/slab.h>
 206 #include <linux/sched/clock.h>
 207 #include <linux/kprobes.h>
 208 #include <linux/errno.h>
 209 #include <linux/stddef.h>
 210 #include <linux/bug.h>
 211 #include <asm/opcodes.h>
 212
 213 #include "core.h"
 214 #include "test-core.h"
 215 #include "../decode-arm.h"
 216 #include "../decode-thumb.h"
 217
 218
 219 #define BENCHMARKING    1
 220
 221
 222 /*
 223  * Test basic API
 224  */
 225
 226 static bool test_regs_ok;
 227 static int test_func_instance;
 228 static int pre_handler_called;
 229 static int post_handler_called;
 230 static int kretprobe_handler_called;
 231 static int tests_failed;
 232
 233 #define FUNC_ARG1 0x12345678
 234 #define FUNC_ARG2 0xabcdef
 235
 236
 237 #ifndef CONFIG_THUMB2_KERNEL
 238
 239 #define RET(reg)        "mov    pc, "#reg
 240
 241 long arm_func(long r0, long r1);
 242
 243 static void __used __naked __arm_kprobes_test_func(void)
 244 {
 245         __asm__ __volatile__ (
 246                 ".arm                                   \n\t"
 247                 ".type arm_func, %%function             \n\t"
 248                 "arm_func:                              \n\t"
 249                 "adds   r0, r0, r1                      \n\t"
 250                 "mov    pc, lr                          \n\t"
 251                 ".code "NORMAL_ISA       /* Back to Thumb if necessary */
 252                 : : : "r0", "r1", "cc"
 253         );
 254 }
 255
 256 #else /* CONFIG_THUMB2_KERNEL */
 257
 258 #define RET(reg)        "bx     "#reg
 259
 260 long thumb16_func(long r0, long r1);
 261 long thumb32even_func(long r0, long r1);
 262 long thumb32odd_func(long r0, long r1);
 263
 264 static void __used __naked __thumb_kprobes_test_funcs(void)
 265 {
 266         __asm__ __volatile__ (
 267                 ".type thumb16_func, %%function         \n\t"
 268                 "thumb16_func:                          \n\t"
 269                 "adds.n r0, r0, r1                      \n\t"
 270                 "bx     lr                              \n\t"
 271
 272                 ".align                                 \n\t"
 273                 ".type thumb32even_func, %%function     \n\t"
 274                 "thumb32even_func:                      \n\t"
 275                 "adds.w r0, r0, r1                      \n\t"
 276                 "bx     lr                              \n\t"
 277
 278                 ".align                                 \n\t"
 279                 "nop.n                                  \n\t"
 280                 ".type thumb32odd_func, %%function      \n\t"
 281                 "thumb32odd_func:                       \n\t"
 282                 "adds.w r0, r0, r1                      \n\t"
 283                 "bx     lr                              \n\t"
 284
 285                 : : : "r0", "r1", "cc"
 286         );
 287 }
 288
 289 #endif /* CONFIG_THUMB2_KERNEL */
 290
 291
 292 static int call_test_func(long (*func)(long, long), bool check_test_regs)
 293 {
 294         long ret;
 295
 296         ++test_func_instance;
 297         test_regs_ok = false;
 298
 299         ret = (*func)(FUNC_ARG1, FUNC_ARG2);
 300         if (ret != FUNC_ARG1 + FUNC_ARG2) {
 301                 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
 302                 return false;
 303         }
 304
 305         if (check_test_regs && !test_regs_ok) {
 306                 pr_err("FAIL: test regs not OK\n");
 307                 return false;
 308         }
 309
 310         return true;
 311 }
 312
 313 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
 314 {
 315         pre_handler_called = test_func_instance;
 316         if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
 317                 test_regs_ok = true;
 318         return 0;
 319 }
 320
 321 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
 322                                 unsigned long flags)
 323 {
 324         post_handler_called = test_func_instance;
 325         if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
 326                 test_regs_ok = false;
 327 }
 328
 329 static struct kprobe the_kprobe = {
 330         .addr           = 0,
 331         .pre_handler    = pre_handler,
 332         .post_handler   = post_handler
 333 };
 334
 335 static int test_kprobe(long (*func)(long, long))
 336 {
 337         int ret;
 338
 339         the_kprobe.addr = (kprobe_opcode_t *)func;
 340         ret = register_kprobe(&the_kprobe);
 341         if (ret < 0) {
 342                 pr_err("FAIL: register_kprobe failed with %d\n", ret);
 343                 return ret;
 344         }
 345
 346         ret = call_test_func(func, true);
 347
 348         unregister_kprobe(&the_kprobe);
 349         the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
 350
 351         if (!ret)
 352                 return -EINVAL;
 353         if (pre_handler_called != test_func_instance) {
 354                 pr_err("FAIL: kprobe pre_handler not called\n");
 355                 return -EINVAL;
 356         }
 357         if (post_handler_called != test_func_instance) {
 358                 pr_err("FAIL: kprobe post_handler not called\n");
 359                 return -EINVAL;
 360         }
 361         if (!call_test_func(func, false))
 362                 return -EINVAL;
 363         if (pre_handler_called == test_func_instance ||
 364                                 post_handler_called == test_func_instance) {
 365                 pr_err("FAIL: probe called after unregistering\n");
 366                 return -EINVAL;
 367         }
 368
 369         return 0;
 370 }
 371
 372 static int __kprobes
 373 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 374 {
 375         kretprobe_handler_called = test_func_instance;
 376         if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
 377                 test_regs_ok = true;
 378         return 0;
 379 }
 380
 381 static struct kretprobe the_kretprobe = {
 382         .handler        = kretprobe_handler,
 383 };
 384
 385 static int test_kretprobe(long (*func)(long, long))
 386 {
 387         int ret;
 388
 389         the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
 390         ret = register_kretprobe(&the_kretprobe);
 391         if (ret < 0) {
 392                 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
 393                 return ret;
 394         }
 395
 396         ret = call_test_func(func, true);
 397
 398         unregister_kretprobe(&the_kretprobe);
 399         the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
 400
 401         if (!ret)
 402                 return -EINVAL;
 403         if (kretprobe_handler_called != test_func_instance) {
 404                 pr_err("FAIL: kretprobe handler not called\n");
 405                 return -EINVAL;
 406         }
 407         if (!call_test_func(func, false))
 408                 return -EINVAL;
 409         if (kretprobe_handler_called == test_func_instance) {
 410                 pr_err("FAIL: kretprobe called after unregistering\n");
 411                 return -EINVAL;
 412         }
 413
 414         return 0;
 415 }
 416
 417 static int run_api_tests(long (*func)(long, long))
 418 {
 419         int ret;
 420
 421         pr_info("    kprobe\n");
 422         ret = test_kprobe(func);
 423         if (ret < 0)
 424                 return ret;
 425
 426         pr_info("    kretprobe\n");
 427         ret = test_kretprobe(func);
 428         if (ret < 0)
 429                 return ret;
 430
 431         return 0;
 432 }
 433
 434
 435 /*
 436  * Benchmarking
 437  */
 438
 439 #if BENCHMARKING
 440
 441 static void __naked benchmark_nop(void)
 442 {
 443         __asm__ __volatile__ (
 444                 "nop            \n\t"
 445                 RET(lr)"        \n\t"
 446         );
 447 }
 448
 449 #ifdef CONFIG_THUMB2_KERNEL
 450 #define wide ".w"
 451 #else
 452 #define wide
 453 #endif
 454
 455 static void __naked benchmark_pushpop1(void)
 456 {
 457         __asm__ __volatile__ (
 458                 "stmdb"wide"    sp!, {r3-r11,lr}  \n\t"
 459                 "ldmia"wide"    sp!, {r3-r11,pc}"
 460         );
 461 }
 462
 463 static void __naked benchmark_pushpop2(void)
 464 {
 465         __asm__ __volatile__ (
 466                 "stmdb"wide"    sp!, {r0-r8,lr}  \n\t"
 467                 "ldmia"wide"    sp!, {r0-r8,pc}"
 468         );
 469 }
 470
 471 static void __naked benchmark_pushpop3(void)
 472 {
 473         __asm__ __volatile__ (
 474                 "stmdb"wide"    sp!, {r4,lr}  \n\t"
 475                 "ldmia"wide"    sp!, {r4,pc}"
 476         );
 477 }
 478
 479 static void __naked benchmark_pushpop4(void)
 480 {
 481         __asm__ __volatile__ (
 482                 "stmdb"wide"    sp!, {r0,lr}  \n\t"
 483                 "ldmia"wide"    sp!, {r0,pc}"
 484         );
 485 }
 486
 487
 488 #ifdef CONFIG_THUMB2_KERNEL
 489
 490 static void __naked benchmark_pushpop_thumb(void)
 491 {
 492         __asm__ __volatile__ (
 493                 "push.n {r0-r7,lr}  \n\t"
 494                 "pop.n  {r0-r7,pc}"
 495         );
 496 }
 497
 498 #endif
 499
 500 static int __kprobes
 501 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
 502 {
 503         return 0;
 504 }
 505
 506 static int benchmark(void(*fn)(void))
 507 {
 508         unsigned n, i, t, t0;
 509
 510         for (n = 1000; ; n *= 2) {
 511                 t0 = sched_clock();
 512                 for (i = n; i > 0; --i)
 513                         fn();
 514                 t = sched_clock() - t0;
 515                 if (t >= 250000000)
 516                         break; /* Stop once we took more than 0.25 seconds */
 517         }
 518         return t / n; /* Time for one iteration in nanoseconds */
 519 };
 520
 521 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
 522 {
 523         struct kprobe k = {
 524                 .addr           = (kprobe_opcode_t *)((uintptr_t)fn + offset),
 525                 .pre_handler    = benchmark_pre_handler,
 526         };
 527
 528         int ret = register_kprobe(&k);
 529         if (ret < 0) {
 530                 pr_err("FAIL: register_kprobe failed with %d\n", ret);
 531                 return ret;
 532         }
 533
 534         ret = benchmark(fn);
 535
 536         unregister_kprobe(&k);
 537         return ret;
 538 };
 539
 540 struct benchmarks {
 541         void            (*fn)(void);
 542         unsigned        offset;
 543         const char      *title;
 544 };
 545
 546 static int run_benchmarks(void)
 547 {
 548         int ret;
 549         struct benchmarks list[] = {
 550                 {&benchmark_nop, 0, "nop"},
 551                 /*
 552                  * benchmark_pushpop{1,3} will have the optimised
 553                  * instruction emulation, whilst benchmark_pushpop{2,4} will
 554                  * be the equivalent unoptimised instructions.
 555                  */
 556                 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
 557                 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
 558                 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
 559                 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
 560                 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
 561                 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
 562                 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
 563                 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
 564 #ifdef CONFIG_THUMB2_KERNEL
 565                 {&benchmark_pushpop_thumb, 0, "push.n   {r0-r7,lr}"},
 566                 {&benchmark_pushpop_thumb, 2, "pop.n    {r0-r7,pc}"},
 567 #endif
 568                 {0}
 569         };
 570
 571         struct benchmarks *b;
 572         for (b = list; b->fn; ++b) {
 573                 ret = kprobe_benchmark(b->fn, b->offset);
 574                 if (ret < 0)
 575                         return ret;
 576                 pr_info("    %dns for kprobe %s\n", ret, b->title);
 577         }
 578
 579         pr_info("\n");
 580         return 0;
 581 }
 582
 583 #endif /* BENCHMARKING */
 584
 585
 586 /*
 587  * Decoding table self-consistency tests
 588  */
 589
 590 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 591         [DECODE_TYPE_TABLE]     = sizeof(struct decode_table),
 592         [DECODE_TYPE_CUSTOM]    = sizeof(struct decode_custom),
 593         [DECODE_TYPE_SIMULATE]  = sizeof(struct decode_simulate),
 594         [DECODE_TYPE_EMULATE]   = sizeof(struct decode_emulate),
 595         [DECODE_TYPE_OR]        = sizeof(struct decode_or),
 596         [DECODE_TYPE_REJECT]    = sizeof(struct decode_reject)
 597 };
 598
 599 static int table_iter(const union decode_item *table,
 600                         int (*fn)(const struct decode_header *, void *),
 601                         void *args)
 602 {
 603         const struct decode_header *h = (struct decode_header *)table;
 604         int result;
 605
 606         for (;;) {
 607                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 608
 609                 if (type == DECODE_TYPE_END)
 610                         return 0;
 611
 612                 result = fn(h, args);
 613                 if (result)
 614                         return result;
 615
 616                 h = (struct decode_header *)
 617                         ((uintptr_t)h + decode_struct_sizes[type]);
 618
 619         }
 620 }
 621
 622 static int table_test_fail(const struct decode_header *h, const char* message)
 623 {
 624
 625         pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
 626                                         message, h->mask.bits, h->value.bits);
 627         return -EINVAL;
 628 }
 629
 630 struct table_test_args {
 631         const union decode_item *root_table;
 632         u32                     parent_mask;
 633         u32                     parent_value;
 634 };
 635
 636 static int table_test_fn(const struct decode_header *h, void *args)
 637 {
 638         struct table_test_args *a = (struct table_test_args *)args;
 639         enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 640
 641         if (h->value.bits & ~h->mask.bits)
 642                 return table_test_fail(h, "Match value has bits not in mask");
 643
 644         if ((h->mask.bits & a->parent_mask) != a->parent_mask)
 645                 return table_test_fail(h, "Mask has bits not in parent mask");
 646
 647         if ((h->value.bits ^ a->parent_value) & a->parent_mask)
 648                 return table_test_fail(h, "Value is inconsistent with parent");
 649
 650         if (type == DECODE_TYPE_TABLE) {
 651                 struct decode_table *d = (struct decode_table *)h;
 652                 struct table_test_args args2 = *a;
 653                 args2.parent_mask = h->mask.bits;
 654                 args2.parent_value = h->value.bits;
 655                 return table_iter(d->table.table, table_test_fn, &args2);
 656         }
 657
 658         return 0;
 659 }
 660
 661 static int table_test(const union decode_item *table)
 662 {
 663         struct table_test_args args = {
 664                 .root_table     = table,
 665                 .parent_mask    = 0,
 666                 .parent_value   = 0
 667         };
 668         return table_iter(args.root_table, table_test_fn, &args);
 669 }
 670
 671
 672 /*
 673  * Decoding table test coverage analysis
 674  *
 675  * coverage_start() builds a coverage_table which contains a list of
 676  * coverage_entry's to match each entry in the specified kprobes instruction
 677  * decoding table.
 678  *
 679  * When test cases are run, coverage_add() is called to process each case.
 680  * This looks up the corresponding entry in the coverage_table and sets it as
 681  * being matched, as well as clearing the regs flag appropriate for the test.
 682  *
 683  * After all test cases have been run, coverage_end() is called to check that
 684  * all entries in coverage_table have been matched and that all regs flags are
 685  * cleared. I.e. that all possible combinations of instructions described by
 686  * the kprobes decoding tables have had a test case executed for them.
 687  */
 688
 689 bool coverage_fail;
 690
 691 #define MAX_COVERAGE_ENTRIES 256
 692
 693 struct coverage_entry {
 694         const struct decode_header      *header;
 695         unsigned                        regs;
 696         unsigned                        nesting;
 697         char                            matched;
 698 };
 699
 700 struct coverage_table {
 701         struct coverage_entry   *base;
 702         unsigned                num_entries;
 703         unsigned                nesting;
 704 };
 705
 706 struct coverage_table coverage;
 707
 708 #define COVERAGE_ANY_REG        (1<<0)
 709 #define COVERAGE_SP             (1<<1)
 710 #define COVERAGE_PC             (1<<2)
 711 #define COVERAGE_PCWB           (1<<3)
 712
 713 static const char coverage_register_lookup[16] = {
 714         [REG_TYPE_ANY]          = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 715         [REG_TYPE_SAMEAS16]     = COVERAGE_ANY_REG,
 716         [REG_TYPE_SP]           = COVERAGE_SP,
 717         [REG_TYPE_PC]           = COVERAGE_PC,
 718         [REG_TYPE_NOSP]         = COVERAGE_ANY_REG | COVERAGE_SP,
 719         [REG_TYPE_NOSPPC]       = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 720         [REG_TYPE_NOPC]         = COVERAGE_ANY_REG | COVERAGE_PC,
 721         [REG_TYPE_NOPCWB]       = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
 722         [REG_TYPE_NOPCX]        = COVERAGE_ANY_REG,
 723         [REG_TYPE_NOSPPCX]      = COVERAGE_ANY_REG | COVERAGE_SP,
 724 };
 725
 726 unsigned coverage_start_registers(const struct decode_header *h)
 727 {
 728         unsigned regs = 0;
 729         int i;
 730         for (i = 0; i < 20; i += 4) {
 731                 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
 732                 regs |= coverage_register_lookup[r] << i;
 733         }
 734         return regs;
 735 }
 736
 737 static int coverage_start_fn(const struct decode_header *h, void *args)
 738 {
 739         struct coverage_table *coverage = (struct coverage_table *)args;
 740         enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 741         struct coverage_entry *entry = coverage->base + coverage->num_entries;
 742
 743         if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
 744                 pr_err("FAIL: Out of space for test coverage data");
 745                 return -ENOMEM;
 746         }
 747
 748         ++coverage->num_entries;
 749
 750         entry->header = h;
 751         entry->regs = coverage_start_registers(h);
 752         entry->nesting = coverage->nesting;
 753         entry->matched = false;
 754
 755         if (type == DECODE_TYPE_TABLE) {
 756                 struct decode_table *d = (struct decode_table *)h;
 757                 int ret;
 758                 ++coverage->nesting;
 759                 ret = table_iter(d->table.table, coverage_start_fn, coverage);
 760                 --coverage->nesting;
 761                 return ret;
 762         }
 763
 764         return 0;
 765 }
 766
 767 static int coverage_start(const union decode_item *table)
 768 {
 769         coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
 770                                 sizeof(struct coverage_entry), GFP_KERNEL);
 771         coverage.num_entries = 0;
 772         coverage.nesting = 0;
 773         return table_iter(table, coverage_start_fn, &coverage);
 774 }
 775
 776 static void
 777 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
 778 {
 779         int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
 780         int i;
 781         for (i = 0; i < 20; i += 4) {
 782                 enum decode_reg_type reg_type = (regs >> i) & 0xf;
 783                 int reg = (insn >> i) & 0xf;
 784                 int flag;
 785
 786                 if (!reg_type)
 787                         continue;
 788
 789                 if (reg == 13)
 790                         flag = COVERAGE_SP;
 791                 else if (reg == 15)
 792                         flag = COVERAGE_PC;
 793                 else
 794                         flag = COVERAGE_ANY_REG;
 795                 entry->regs &= ~(flag << i);
 796
 797                 switch (reg_type) {
 798
 799                 case REG_TYPE_NONE:
 800                 case REG_TYPE_ANY:
 801                 case REG_TYPE_SAMEAS16:
 802                         break;
 803
 804                 case REG_TYPE_SP:
 805                         if (reg != 13)
 806                                 return;
 807                         break;
 808
 809                 case REG_TYPE_PC:
 810                         if (reg != 15)
 811                                 return;
 812                         break;
 813
 814                 case REG_TYPE_NOSP:
 815                         if (reg == 13)
 816                                 return;
 817                         break;
 818
 819                 case REG_TYPE_NOSPPC:
 820                 case REG_TYPE_NOSPPCX:
 821                         if (reg == 13 || reg == 15)
 822                                 return;
 823                         break;
 824
 825                 case REG_TYPE_NOPCWB:
 826                         if (!is_writeback(insn))
 827                                 break;
 828                         if (reg == 15) {
 829                                 entry->regs &= ~(COVERAGE_PCWB << i);
 830                                 return;
 831                         }
 832                         break;
 833
 834                 case REG_TYPE_NOPC:
 835                 case REG_TYPE_NOPCX:
 836                         if (reg == 15)
 837                                 return;
 838                         break;
 839                 }
 840
 841         }
 842 }
 843
 844 static void coverage_add(kprobe_opcode_t insn)
 845 {
 846         struct coverage_entry *entry = coverage.base;
 847         struct coverage_entry *end = coverage.base + coverage.num_entries;
 848         bool matched = false;
 849         unsigned nesting = 0;
 850
 851         for (; entry < end; ++entry) {
 852                 const struct decode_header *h = entry->header;
 853                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 854
 855                 if (entry->nesting > nesting)
 856                         continue; /* Skip sub-table we didn't match */
 857
 858                 if (entry->nesting < nesting)
 859                         break; /* End of sub-table we were scanning */
 860
 861                 if (!matched) {
 862                         if ((insn & h->mask.bits) != h->value.bits)
 863                                 continue;
 864                         entry->matched = true;
 865                 }
 866
 867                 switch (type) {
 868
 869                 case DECODE_TYPE_TABLE:
 870                         ++nesting;
 871                         break;
 872
 873                 case DECODE_TYPE_CUSTOM:
 874                 case DECODE_TYPE_SIMULATE:
 875                 case DECODE_TYPE_EMULATE:
 876                         coverage_add_registers(entry, insn);
 877                         return;
 878
 879                 case DECODE_TYPE_OR:
 880                         matched = true;
 881                         break;
 882
 883                 case DECODE_TYPE_REJECT:
 884                 default:
 885                         return;
 886                 }
 887
 888         }
 889 }
 890
 891 static void coverage_end(void)
 892 {
 893         struct coverage_entry *entry = coverage.base;
 894         struct coverage_entry *end = coverage.base + coverage.num_entries;
 895
 896         for (; entry < end; ++entry) {
 897                 u32 mask = entry->header->mask.bits;
 898                 u32 value = entry->header->value.bits;
 899
 900                 if (entry->regs) {
 901                         pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
 902                                 mask, value, entry->regs);
 903                         coverage_fail = true;
 904                 }
 905                 if (!entry->matched) {
 906                         pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
 907                                 mask, value);
 908                         coverage_fail = true;
 909                 }
 910         }
 911
 912         kfree(coverage.base);
 913 }
 914
 915
 916 /*
 917  * Framework for instruction set test cases
 918  */
 919
 920 void __naked __kprobes_test_case_start(void)
 921 {
 922         __asm__ __volatile__ (
 923                 "mov    r2, sp                                  \n\t"
 924                 "bic    r3, r2, #7                              \n\t"
 925                 "mov    sp, r3                                  \n\t"
 926                 "stmdb  sp!, {r2-r11}                           \n\t"
 927                 "sub    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 928                 "bic    r0, lr, #1  @ r0 = inline data          \n\t"
 929                 "mov    r1, sp                                  \n\t"
 930                 "bl     kprobes_test_case_start                 \n\t"
 931                 RET(r0)"                                        \n\t"
 932         );
 933 }
 934
 935 #ifndef CONFIG_THUMB2_KERNEL
 936
 937 void __naked __kprobes_test_case_end_32(void)
 938 {
 939         __asm__ __volatile__ (
 940                 "mov    r4, lr                                  \n\t"
 941                 "bl     kprobes_test_case_end                   \n\t"
 942                 "cmp    r0, #0                                  \n\t"
 943                 "movne  pc, r0                                  \n\t"
 944                 "mov    r0, r4                                  \n\t"
 945                 "add    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 946                 "ldmia  sp!, {r2-r11}                           \n\t"
 947                 "mov    sp, r2                                  \n\t"
 948                 "mov    pc, r0                                  \n\t"
 949         );
 950 }
 951
 952 #else /* CONFIG_THUMB2_KERNEL */
 953
 954 void __naked __kprobes_test_case_end_16(void)
 955 {
 956         __asm__ __volatile__ (
 957                 "mov    r4, lr                                  \n\t"
 958                 "bl     kprobes_test_case_end                   \n\t"
 959                 "cmp    r0, #0                                  \n\t"
 960                 "bxne   r0                                      \n\t"
 961                 "mov    r0, r4                                  \n\t"
 962                 "add    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 963                 "ldmia  sp!, {r2-r11}                           \n\t"
 964                 "mov    sp, r2                                  \n\t"
 965                 "bx     r0                                      \n\t"
 966         );
 967 }
 968
 969 void __naked __kprobes_test_case_end_32(void)
 970 {
 971         __asm__ __volatile__ (
 972                 ".arm                                           \n\t"
 973                 "orr    lr, lr, #1  @ will return to Thumb code \n\t"
 974                 "ldr    pc, 1f                                  \n\t"
 975                 "1:                                             \n\t"
 976                 ".word  __kprobes_test_case_end_16              \n\t"
 977         );
 978 }
 979
 980 #endif
 981
 982
 983 int kprobe_test_flags;
 984 int kprobe_test_cc_position;
 985
 986 static int test_try_count;
 987 static int test_pass_count;
 988 static int test_fail_count;
 989
 990 static struct pt_regs initial_regs;
 991 static struct pt_regs expected_regs;
 992 static struct pt_regs result_regs;
 993
 994 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
 995
 996 static const char *current_title;
 997 static struct test_arg *current_args;
 998 static u32 *current_stack;
 999 static uintptr_t current_branch_target;
1000
1001 static uintptr_t current_code_start;
1002 static kprobe_opcode_t current_instruction;
1003
1004
1005 #define TEST_CASE_PASSED -1
1006 #define TEST_CASE_FAILED -2
1007
1008 static int test_case_run_count;
1009 static bool test_case_is_thumb;
1010 static int test_instance;
1011
1012 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1013 {
1014         int ret = arm_check_condition(cc << 28, cpsr);
1015
1016         return (ret != ARM_OPCODE_CONDTEST_FAIL);
1017 }
1018
1019 static int is_last_scenario;
1020 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1021 static int memory_needs_checking;
1022
1023 static unsigned long test_context_cpsr(int scenario)
1024 {
1025         unsigned long cpsr;
1026
1027         probe_should_run = 1;
1028
1029         /* Default case is that we cycle through 16 combinations of flags */
1030         cpsr  = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1031         cpsr |= (scenario & 0xf) << 16; /* GE flags */
1032         cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1033
1034         if (!test_case_is_thumb) {
1035                 /* Testing ARM code */
1036                 int cc = current_instruction >> 28;
1037
1038                 probe_should_run = test_check_cc(cc, cpsr) != 0;
1039                 if (scenario == 15)
1040                         is_last_scenario = true;
1041
1042         } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1043                 /* Testing Thumb code without setting ITSTATE */
1044                 if (kprobe_test_cc_position) {
1045                         int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1046                         probe_should_run = test_check_cc(cc, cpsr) != 0;
1047                 }
1048
1049                 if (scenario == 15)
1050                         is_last_scenario = true;
1051
1052         } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1053                 /* Testing Thumb code with all combinations of ITSTATE */
1054                 unsigned x = (scenario >> 4);
1055                 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1056                 unsigned mask = x / 7 + 2;  /* ITSTATE<4:0>, bits reversed */
1057
1058                 if (mask > 0x1f) {
1059                         /* Finish by testing state from instruction 'itt al' */
1060                         cond_base = 7;
1061                         mask = 0x4;
1062                         if ((scenario & 0xf) == 0xf)
1063                                 is_last_scenario = true;
1064                 }
1065
1066                 cpsr |= cond_base << 13;        /* ITSTATE<7:5> */
1067                 cpsr |= (mask & 0x1) << 12;     /* ITSTATE<4> */
1068                 cpsr |= (mask & 0x2) << 10;     /* ITSTATE<3> */
1069                 cpsr |= (mask & 0x4) << 8;      /* ITSTATE<2> */
1070                 cpsr |= (mask & 0x8) << 23;     /* ITSTATE<1> */
1071                 cpsr |= (mask & 0x10) << 21;    /* ITSTATE<0> */
1072
1073                 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1074
1075         } else {
1076                 /* Testing Thumb code with several combinations of ITSTATE */
1077                 switch (scenario) {
1078                 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1079                         cpsr = 0x00000800;
1080                         probe_should_run = 0;
1081                         break;
1082                 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1083                         cpsr = 0xf0007800;
1084                         probe_should_run = 0;
1085                         break;
1086                 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1087                         cpsr = 0x00009800;
1088                         break;
1089                 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1090                         cpsr = 0xf0002800;
1091                         is_last_scenario = true;
1092                         break;
1093                 }
1094         }
1095
1096         return cpsr;
1097 }
1098
1099 static void setup_test_context(struct pt_regs *regs)
1100 {
1101         int scenario = test_case_run_count>>1;
1102         unsigned long val;
1103         struct test_arg *args;
1104         int i;
1105
1106         is_last_scenario = false;
1107         memory_needs_checking = false;
1108
1109         /* Initialise test memory on stack */
1110         val = (scenario & 1) ? VALM : ~VALM;
1111         for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1112                 current_stack[i] = val + (i << 8);
1113         /* Put target of branch on stack for tests which load PC from memory */
1114         if (current_branch_target)
1115                 current_stack[15] = current_branch_target;
1116         /* Put a value for SP on stack for tests which load SP from memory */
1117         current_stack[13] = (u32)current_stack + 120;
1118
1119         /* Initialise register values to their default state */
1120         val = (scenario & 2) ? VALR : ~VALR;
1121         for (i = 0; i < 13; ++i)
1122                 regs->uregs[i] = val ^ (i << 8);
1123         regs->ARM_lr = val ^ (14 << 8);
1124         regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1125         regs->ARM_cpsr |= test_context_cpsr(scenario);
1126
1127         /* Perform testcase specific register setup  */
1128         args = current_args;
1129         for (; args[0].type != ARG_TYPE_END; ++args)
1130                 switch (args[0].type) {
1131                 case ARG_TYPE_REG: {
1132                         struct test_arg_regptr *arg =
1133                                 (struct test_arg_regptr *)args;
1134                         regs->uregs[arg->reg] = arg->val;
1135                         break;
1136                 }
1137                 case ARG_TYPE_PTR: {
1138                         struct test_arg_regptr *arg =
1139                                 (struct test_arg_regptr *)args;
1140                         regs->uregs[arg->reg] =
1141                                 (unsigned long)current_stack + arg->val;
1142                         memory_needs_checking = true;
1143                         /*
1144                          * Test memory at an address below SP is in danger of
1145                          * being altered by an interrupt occurring and pushing
1146                          * data onto the stack. Disable interrupts to stop this.
1147                          */
1148                         if (arg->reg == 13)
1149                                 regs->ARM_cpsr |= PSR_I_BIT;
1150                         break;
1151                 }
1152                 case ARG_TYPE_MEM: {
1153                         struct test_arg_mem *arg = (struct test_arg_mem *)args;
1154                         current_stack[arg->index] = arg->val;
1155                         break;
1156                 }
1157                 default:
1158                         break;
1159                 }
1160 }
1161
1162 struct test_probe {
1163         struct kprobe   kprobe;
1164         bool            registered;
1165         int             hit;
1166 };
1167
1168 static void unregister_test_probe(struct test_probe *probe)
1169 {
1170         if (probe->registered) {
1171                 unregister_kprobe(&probe->kprobe);
1172                 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1173         }
1174         probe->registered = false;
1175 }
1176
1177 static int register_test_probe(struct test_probe *probe)
1178 {
1179         int ret;
1180
1181         if (probe->registered)
1182                 BUG();
1183
1184         ret = register_kprobe(&probe->kprobe);
1185         if (ret >= 0) {
1186                 probe->registered = true;
1187                 probe->hit = -1;
1188         }
1189         return ret;
1190 }
1191
1192 static int __kprobes
1193 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1194 {
1195         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1196         return 0;
1197 }
1198
1199 static void __kprobes
1200 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1201                                                         unsigned long flags)
1202 {
1203         setup_test_context(regs);
1204         initial_regs = *regs;
1205         initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1206 }
1207
1208 static int __kprobes
1209 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1210 {
1211         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1212         return 0;
1213 }
1214
1215 static int __kprobes
1216 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1217 {
1218         struct test_arg *args;
1219
1220         if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1221                 return 0; /* Already run for this test instance */
1222
1223         result_regs = *regs;
1224
1225         /* Mask out results which are indeterminate */
1226         result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1227         for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
1228                 if (args[0].type == ARG_TYPE_REG_MASKED) {
1229                         struct test_arg_regptr *arg =
1230                                 (struct test_arg_regptr *)args;
1231                         result_regs.uregs[arg->reg] &= arg->val;
1232                 }
1233
1234         /* Undo any changes done to SP by the test case */
1235         regs->ARM_sp = (unsigned long)current_stack;
1236         /* Enable interrupts in case setup_test_context disabled them */
1237         regs->ARM_cpsr &= ~PSR_I_BIT;
1238
1239         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1240         return 0;
1241 }
1242
1243 static struct test_probe test_before_probe = {
1244         .kprobe.pre_handler     = test_before_pre_handler,
1245         .kprobe.post_handler    = test_before_post_handler,
1246 };
1247
1248 static struct test_probe test_case_probe = {
1249         .kprobe.pre_handler     = test_case_pre_handler,
1250 };
1251
1252 static struct test_probe test_after_probe = {
1253         .kprobe.pre_handler     = test_after_pre_handler,
1254 };
1255
1256 static struct test_probe test_after2_probe = {
1257         .kprobe.pre_handler     = test_after_pre_handler,
1258 };
1259
1260 static void test_case_cleanup(void)
1261 {
1262         unregister_test_probe(&test_before_probe);
1263         unregister_test_probe(&test_case_probe);
1264         unregister_test_probe(&test_after_probe);
1265         unregister_test_probe(&test_after2_probe);
1266 }
1267
1268 static void print_registers(struct pt_regs *regs)
1269 {
1270         pr_err("r0  %08lx | r1  %08lx | r2  %08lx | r3  %08lx\n",
1271                 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1272         pr_err("r4  %08lx | r5  %08lx | r6  %08lx | r7  %08lx\n",
1273                 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1274         pr_err("r8  %08lx | r9  %08lx | r10 %08lx | r11 %08lx\n",
1275                 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1276         pr_err("r12 %08lx | sp  %08lx | lr  %08lx | pc  %08lx\n",
1277                 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1278         pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1279 }
1280
1281 static void print_memory(u32 *mem, size_t size)
1282 {
1283         int i;
1284         for (i = 0; i < size / sizeof(u32); i += 4)
1285                 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1286                                                 mem[i+2], mem[i+3]);
1287 }
1288
1289 static size_t expected_memory_size(u32 *sp)
1290 {
1291         size_t size = sizeof(expected_memory);
1292         int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1293         if (offset > 0)
1294                 size -= offset;
1295         return size;
1296 }
1297
1298 static void test_case_failed(const char *message)
1299 {
1300         test_case_cleanup();
1301
1302         pr_err("FAIL: %s\n", message);
1303         pr_err("FAIL: Test %s\n", current_title);
1304         pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1305 }
1306
1307 static unsigned long next_instruction(unsigned long pc)
1308 {
1309 #ifdef CONFIG_THUMB2_KERNEL
1310         if ((pc & 1) &&
1311             !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1312                 return pc + 2;
1313         else
1314 #endif
1315         return pc + 4;
1316 }
1317
1318 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1319 {
1320         struct test_arg *args;
1321         struct test_arg_end *end_arg;
1322         unsigned long test_code;
1323
1324         current_title = *title++;
1325         args = (struct test_arg *)title;
1326         current_args = args;
1327         current_stack = stack;
1328
1329         ++test_try_count;
1330
1331         while (args->type != ARG_TYPE_END)
1332                 ++args;
1333         end_arg = (struct test_arg_end *)args;
1334
1335         test_code = (unsigned long)(args + 1); /* Code starts after args */
1336
1337         test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1338         if (test_case_is_thumb)
1339                 test_code |= 1;
1340
1341         current_code_start = test_code;
1342
1343         current_branch_target = 0;
1344         if (end_arg->branch_offset != end_arg->end_offset)
1345                 current_branch_target = test_code + end_arg->branch_offset;
1346
1347         test_code += end_arg->code_offset;
1348         test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1349
1350         test_code = next_instruction(test_code);
1351         test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1352
1353         if (test_case_is_thumb) {
1354                 u16 *p = (u16 *)(test_code & ~1);
1355                 current_instruction = __mem_to_opcode_thumb16(p[0]);
1356                 if (is_wide_instruction(current_instruction)) {
1357                         u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1358                         current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1359                 }
1360         } else {
1361                 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1362         }
1363
1364         if (current_title[0] == '.')
1365                 verbose("%s\n", current_title);
1366         else
1367                 verbose("%s\t@ %0*x\n", current_title,
1368                                         test_case_is_thumb ? 4 : 8,
1369                                         current_instruction);
1370
1371         test_code = next_instruction(test_code);
1372         test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1373
1374         if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1375                 if (!test_case_is_thumb ||
1376                         is_wide_instruction(current_instruction)) {
1377                                 test_case_failed("expected 16-bit instruction");
1378                                 goto fail;
1379                 }
1380         } else {
1381                 if (test_case_is_thumb &&
1382                         !is_wide_instruction(current_instruction)) {
1383                                 test_case_failed("expected 32-bit instruction");
1384                                 goto fail;
1385                 }
1386         }
1387
1388         coverage_add(current_instruction);
1389
1390         if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1391                 if (register_test_probe(&test_case_probe) < 0)
1392                         goto pass;
1393                 test_case_failed("registered probe for unsupported instruction");
1394                 goto fail;
1395         }
1396
1397         if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1398                 if (register_test_probe(&test_case_probe) >= 0)
1399                         goto pass;
1400                 test_case_failed("couldn't register probe for supported instruction");
1401                 goto fail;
1402         }
1403
1404         if (register_test_probe(&test_before_probe) < 0) {
1405                 test_case_failed("register test_before_probe failed");
1406                 goto fail;
1407         }
1408         if (register_test_probe(&test_after_probe) < 0) {
1409                 test_case_failed("register test_after_probe failed");
1410                 goto fail;
1411         }
1412         if (current_branch_target) {
1413                 test_after2_probe.kprobe.addr =
1414                                 (kprobe_opcode_t *)current_branch_target;
1415                 if (register_test_probe(&test_after2_probe) < 0) {
1416                         test_case_failed("register test_after2_probe failed");
1417                         goto fail;
1418                 }
1419         }
1420
1421         /* Start first run of test case */
1422         test_case_run_count = 0;
1423         ++test_instance;
1424         return current_code_start;
1425 pass:
1426         test_case_run_count = TEST_CASE_PASSED;
1427         return (uintptr_t)test_after_probe.kprobe.addr;
1428 fail:
1429         test_case_run_count = TEST_CASE_FAILED;
1430         return (uintptr_t)test_after_probe.kprobe.addr;
1431 }
1432
1433 static bool check_test_results(void)
1434 {
1435         size_t mem_size = 0;
1436         u32 *mem = 0;
1437
1438         if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1439                 test_case_failed("registers differ");
1440                 goto fail;
1441         }
1442
1443         if (memory_needs_checking) {
1444                 mem = (u32 *)result_regs.ARM_sp;
1445                 mem_size = expected_memory_size(mem);
1446                 if (memcmp(expected_memory, mem, mem_size)) {
1447                         test_case_failed("test memory differs");
1448                         goto fail;
1449                 }
1450         }
1451
1452         return true;
1453
1454 fail:
1455         pr_err("initial_regs:\n");
1456         print_registers(&initial_regs);
1457         pr_err("expected_regs:\n");
1458         print_registers(&expected_regs);
1459         pr_err("result_regs:\n");
1460         print_registers(&result_regs);
1461
1462         if (mem) {
1463                 pr_err("current_stack=%p\n", current_stack);
1464                 pr_err("expected_memory:\n");
1465                 print_memory(expected_memory, mem_size);
1466                 pr_err("result_memory:\n");
1467                 print_memory(mem, mem_size);
1468         }
1469
1470         return false;
1471 }
1472
1473 static uintptr_t __used kprobes_test_case_end(void)
1474 {
1475         if (test_case_run_count < 0) {
1476                 if (test_case_run_count == TEST_CASE_PASSED)
1477                         /* kprobes_test_case_start did all the needed testing */
1478                         goto pass;
1479                 else
1480                         /* kprobes_test_case_start failed */
1481                         goto fail;
1482         }
1483
1484         if (test_before_probe.hit != test_instance) {
1485                 test_case_failed("test_before_handler not run");
1486                 goto fail;
1487         }
1488
1489         if (test_after_probe.hit != test_instance &&
1490                                 test_after2_probe.hit != test_instance) {
1491                 test_case_failed("test_after_handler not run");
1492                 goto fail;
1493         }
1494
1495         /*
1496          * Even numbered test runs ran without a probe on the test case so
1497          * we can gather reference results. The subsequent odd numbered run
1498          * will have the probe inserted.
1499         */
1500         if ((test_case_run_count & 1) == 0) {
1501                 /* Save results from run without probe */
1502                 u32 *mem = (u32 *)result_regs.ARM_sp;
1503                 expected_regs = result_regs;
1504                 memcpy(expected_memory, mem, expected_memory_size(mem));
1505
1506                 /* Insert probe onto test case instruction */
1507                 if (register_test_probe(&test_case_probe) < 0) {
1508                         test_case_failed("register test_case_probe failed");
1509                         goto fail;
1510                 }
1511         } else {
1512                 /* Check probe ran as expected */
1513                 if (probe_should_run == 1) {
1514                         if (test_case_probe.hit != test_instance) {
1515                                 test_case_failed("test_case_handler not run");
1516                                 goto fail;
1517                         }
1518                 } else if (probe_should_run == 0) {
1519                         if (test_case_probe.hit == test_instance) {
1520                                 test_case_failed("test_case_handler ran");
1521                                 goto fail;
1522                         }
1523                 }
1524
1525                 /* Remove probe for any subsequent reference run */
1526                 unregister_test_probe(&test_case_probe);
1527
1528                 if (!check_test_results())
1529                         goto fail;
1530
1531                 if (is_last_scenario)
1532                         goto pass;
1533         }
1534
1535         /* Do next test run */
1536         ++test_case_run_count;
1537         ++test_instance;
1538         return current_code_start;
1539 fail:
1540         ++test_fail_count;
1541         goto end;
1542 pass:
1543         ++test_pass_count;
1544 end:
1545         test_case_cleanup();
1546         return 0;
1547 }
1548
1549
1550 /*
1551  * Top level test functions
1552  */
1553
1554 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1555 {
1556         int ret;
1557
1558         pr_info("    Check decoding tables\n");
1559         ret = table_test(table);
1560         if (ret)
1561                 return ret;
1562
1563         pr_info("    Run test cases\n");
1564         ret = coverage_start(table);
1565         if (ret)
1566                 return ret;
1567
1568         tests();
1569
1570         coverage_end();
1571         return 0;
1572 }
1573
1574
1575 static int __init run_all_tests(void)
1576 {
1577         int ret = 0;
1578
1579         pr_info("Beginning kprobe tests...\n");
1580
1581 #ifndef CONFIG_THUMB2_KERNEL
1582
1583         pr_info("Probe ARM code\n");
1584         ret = run_api_tests(arm_func);
1585         if (ret)
1586                 goto out;
1587
1588         pr_info("ARM instruction simulation\n");
1589         ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1590         if (ret)
1591                 goto out;
1592
1593 #else /* CONFIG_THUMB2_KERNEL */
1594
1595         pr_info("Probe 16-bit Thumb code\n");
1596         ret = run_api_tests(thumb16_func);
1597         if (ret)
1598                 goto out;
1599
1600         pr_info("Probe 32-bit Thumb code, even halfword\n");
1601         ret = run_api_tests(thumb32even_func);
1602         if (ret)
1603                 goto out;
1604
1605         pr_info("Probe 32-bit Thumb code, odd halfword\n");
1606         ret = run_api_tests(thumb32odd_func);
1607         if (ret)
1608                 goto out;
1609
1610         pr_info("16-bit Thumb instruction simulation\n");
1611         ret = run_test_cases(kprobe_thumb16_test_cases,
1612                                 probes_decode_thumb16_table);
1613         if (ret)
1614                 goto out;
1615
1616         pr_info("32-bit Thumb instruction simulation\n");
1617         ret = run_test_cases(kprobe_thumb32_test_cases,
1618                                 probes_decode_thumb32_table);
1619         if (ret)
1620                 goto out;
1621 #endif
1622
1623         pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1624                 test_try_count, test_pass_count, test_fail_count);
1625         if (test_fail_count) {
1626                 ret = -EINVAL;
1627                 goto out;
1628         }
1629
1630 #if BENCHMARKING
1631         pr_info("Benchmarks\n");
1632         ret = run_benchmarks();
1633         if (ret)
1634                 goto out;
1635 #endif
1636
1637 #if __LINUX_ARM_ARCH__ >= 7
1638         /* We are able to run all test cases so coverage should be complete */
1639         if (coverage_fail) {
1640                 pr_err("FAIL: Test coverage checks failed\n");
1641                 ret = -EINVAL;
1642                 goto out;
1643         }
1644 #endif
1645
1646 out:
1647         if (ret == 0)
1648                 ret = tests_failed;
1649         if (ret == 0)
1650                 pr_info("Finished kprobe tests OK\n");
1651         else
1652                 pr_err("kprobe tests failed\n");
1653
1654         return ret;
1655 }
1656
1657
1658 /*
1659  * Module setup
1660  */
1661
1662 #ifdef MODULE
1663
1664 static void __exit kprobe_test_exit(void)
1665 {
1666 }
1667
1668 module_init(run_all_tests)
1669 module_exit(kprobe_test_exit)
1670 MODULE_LICENSE("GPL");
1671
1672 #else /* !MODULE */
1673
1674 late_initcall(run_all_tests);
1675
1676 #endif