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 jprobe_func_called;
 231 static int kretprobe_handler_called;
 232 static int tests_failed;
 233
 234 #define FUNC_ARG1 0x12345678
 235 #define FUNC_ARG2 0xabcdef
 236
 237
 238 #ifndef CONFIG_THUMB2_KERNEL
 239
 240 #define RET(reg)        "mov    pc, "#reg
 241
 242 long arm_func(long r0, long r1);
 243
 244 static void __used __naked __arm_kprobes_test_func(void)
 245 {
 246         __asm__ __volatile__ (
 247                 ".arm                                   \n\t"
 248                 ".type arm_func, %%function             \n\t"
 249                 "arm_func:                              \n\t"
 250                 "adds   r0, r0, r1                      \n\t"
 251                 "mov    pc, lr                          \n\t"
 252                 ".code "NORMAL_ISA       /* Back to Thumb if necessary */
 253                 : : : "r0", "r1", "cc"
 254         );
 255 }
 256
 257 #else /* CONFIG_THUMB2_KERNEL */
 258
 259 #define RET(reg)        "bx     "#reg
 260
 261 long thumb16_func(long r0, long r1);
 262 long thumb32even_func(long r0, long r1);
 263 long thumb32odd_func(long r0, long r1);
 264
 265 static void __used __naked __thumb_kprobes_test_funcs(void)
 266 {
 267         __asm__ __volatile__ (
 268                 ".type thumb16_func, %%function         \n\t"
 269                 "thumb16_func:                          \n\t"
 270                 "adds.n r0, r0, r1                      \n\t"
 271                 "bx     lr                              \n\t"
 272
 273                 ".align                                 \n\t"
 274                 ".type thumb32even_func, %%function     \n\t"
 275                 "thumb32even_func:                      \n\t"
 276                 "adds.w r0, r0, r1                      \n\t"
 277                 "bx     lr                              \n\t"
 278
 279                 ".align                                 \n\t"
 280                 "nop.n                                  \n\t"
 281                 ".type thumb32odd_func, %%function      \n\t"
 282                 "thumb32odd_func:                       \n\t"
 283                 "adds.w r0, r0, r1                      \n\t"
 284                 "bx     lr                              \n\t"
 285
 286                 : : : "r0", "r1", "cc"
 287         );
 288 }
 289
 290 #endif /* CONFIG_THUMB2_KERNEL */
 291
 292
 293 static int call_test_func(long (*func)(long, long), bool check_test_regs)
 294 {
 295         long ret;
 296
 297         ++test_func_instance;
 298         test_regs_ok = false;
 299
 300         ret = (*func)(FUNC_ARG1, FUNC_ARG2);
 301         if (ret != FUNC_ARG1 + FUNC_ARG2) {
 302                 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
 303                 return false;
 304         }
 305
 306         if (check_test_regs && !test_regs_ok) {
 307                 pr_err("FAIL: test regs not OK\n");
 308                 return false;
 309         }
 310
 311         return true;
 312 }
 313
 314 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
 315 {
 316         pre_handler_called = test_func_instance;
 317         if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
 318                 test_regs_ok = true;
 319         return 0;
 320 }
 321
 322 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
 323                                 unsigned long flags)
 324 {
 325         post_handler_called = test_func_instance;
 326         if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
 327                 test_regs_ok = false;
 328 }
 329
 330 static struct kprobe the_kprobe = {
 331         .addr           = 0,
 332         .pre_handler    = pre_handler,
 333         .post_handler   = post_handler
 334 };
 335
 336 static int test_kprobe(long (*func)(long, long))
 337 {
 338         int ret;
 339
 340         the_kprobe.addr = (kprobe_opcode_t *)func;
 341         ret = register_kprobe(&the_kprobe);
 342         if (ret < 0) {
 343                 pr_err("FAIL: register_kprobe failed with %d\n", ret);
 344                 return ret;
 345         }
 346
 347         ret = call_test_func(func, true);
 348
 349         unregister_kprobe(&the_kprobe);
 350         the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
 351
 352         if (!ret)
 353                 return -EINVAL;
 354         if (pre_handler_called != test_func_instance) {
 355                 pr_err("FAIL: kprobe pre_handler not called\n");
 356                 return -EINVAL;
 357         }
 358         if (post_handler_called != test_func_instance) {
 359                 pr_err("FAIL: kprobe post_handler not called\n");
 360                 return -EINVAL;
 361         }
 362         if (!call_test_func(func, false))
 363                 return -EINVAL;
 364         if (pre_handler_called == test_func_instance ||
 365                                 post_handler_called == test_func_instance) {
 366                 pr_err("FAIL: probe called after unregistering\n");
 367                 return -EINVAL;
 368         }
 369
 370         return 0;
 371 }
 372
 373 static void __kprobes jprobe_func(long r0, long r1)
 374 {
 375         jprobe_func_called = test_func_instance;
 376         if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
 377                 test_regs_ok = true;
 378         jprobe_return();
 379 }
 380
 381 static struct jprobe the_jprobe = {
 382         .entry          = jprobe_func,
 383 };
 384
 385 static int test_jprobe(long (*func)(long, long))
 386 {
 387         int ret;
 388
 389         the_jprobe.kp.addr = (kprobe_opcode_t *)func;
 390         ret = register_jprobe(&the_jprobe);
 391         if (ret < 0) {
 392                 pr_err("FAIL: register_jprobe failed with %d\n", ret);
 393                 return ret;
 394         }
 395
 396         ret = call_test_func(func, true);
 397
 398         unregister_jprobe(&the_jprobe);
 399         the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
 400
 401         if (!ret)
 402                 return -EINVAL;
 403         if (jprobe_func_called != test_func_instance) {
 404                 pr_err("FAIL: jprobe handler function not called\n");
 405                 return -EINVAL;
 406         }
 407         if (!call_test_func(func, false))
 408                 return -EINVAL;
 409         if (jprobe_func_called == test_func_instance) {
 410                 pr_err("FAIL: probe called after unregistering\n");
 411                 return -EINVAL;
 412         }
 413
 414         return 0;
 415 }
 416
 417 static int __kprobes
 418 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 419 {
 420         kretprobe_handler_called = test_func_instance;
 421         if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
 422                 test_regs_ok = true;
 423         return 0;
 424 }
 425
 426 static struct kretprobe the_kretprobe = {
 427         .handler        = kretprobe_handler,
 428 };
 429
 430 static int test_kretprobe(long (*func)(long, long))
 431 {
 432         int ret;
 433
 434         the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
 435         ret = register_kretprobe(&the_kretprobe);
 436         if (ret < 0) {
 437                 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
 438                 return ret;
 439         }
 440
 441         ret = call_test_func(func, true);
 442
 443         unregister_kretprobe(&the_kretprobe);
 444         the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
 445
 446         if (!ret)
 447                 return -EINVAL;
 448         if (kretprobe_handler_called != test_func_instance) {
 449                 pr_err("FAIL: kretprobe handler not called\n");
 450                 return -EINVAL;
 451         }
 452         if (!call_test_func(func, false))
 453                 return -EINVAL;
 454         if (jprobe_func_called == test_func_instance) {
 455                 pr_err("FAIL: kretprobe called after unregistering\n");
 456                 return -EINVAL;
 457         }
 458
 459         return 0;
 460 }
 461
 462 static int run_api_tests(long (*func)(long, long))
 463 {
 464         int ret;
 465
 466         pr_info("    kprobe\n");
 467         ret = test_kprobe(func);
 468         if (ret < 0)
 469                 return ret;
 470
 471         pr_info("    jprobe\n");
 472         ret = test_jprobe(func);
 473 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE)
 474         if (ret == -EINVAL) {
 475                 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n");
 476                 tests_failed = ret;
 477                 ret = 0;
 478         }
 479 #endif
 480         if (ret < 0)
 481                 return ret;
 482
 483         pr_info("    kretprobe\n");
 484         ret = test_kretprobe(func);
 485         if (ret < 0)
 486                 return ret;
 487
 488         return 0;
 489 }
 490
 491
 492 /*
 493  * Benchmarking
 494  */
 495
 496 #if BENCHMARKING
 497
 498 static void __naked benchmark_nop(void)
 499 {
 500         __asm__ __volatile__ (
 501                 "nop            \n\t"
 502                 RET(lr)"        \n\t"
 503         );
 504 }
 505
 506 #ifdef CONFIG_THUMB2_KERNEL
 507 #define wide ".w"
 508 #else
 509 #define wide
 510 #endif
 511
 512 static void __naked benchmark_pushpop1(void)
 513 {
 514         __asm__ __volatile__ (
 515                 "stmdb"wide"    sp!, {r3-r11,lr}  \n\t"
 516                 "ldmia"wide"    sp!, {r3-r11,pc}"
 517         );
 518 }
 519
 520 static void __naked benchmark_pushpop2(void)
 521 {
 522         __asm__ __volatile__ (
 523                 "stmdb"wide"    sp!, {r0-r8,lr}  \n\t"
 524                 "ldmia"wide"    sp!, {r0-r8,pc}"
 525         );
 526 }
 527
 528 static void __naked benchmark_pushpop3(void)
 529 {
 530         __asm__ __volatile__ (
 531                 "stmdb"wide"    sp!, {r4,lr}  \n\t"
 532                 "ldmia"wide"    sp!, {r4,pc}"
 533         );
 534 }
 535
 536 static void __naked benchmark_pushpop4(void)
 537 {
 538         __asm__ __volatile__ (
 539                 "stmdb"wide"    sp!, {r0,lr}  \n\t"
 540                 "ldmia"wide"    sp!, {r0,pc}"
 541         );
 542 }
 543
 544
 545 #ifdef CONFIG_THUMB2_KERNEL
 546
 547 static void __naked benchmark_pushpop_thumb(void)
 548 {
 549         __asm__ __volatile__ (
 550                 "push.n {r0-r7,lr}  \n\t"
 551                 "pop.n  {r0-r7,pc}"
 552         );
 553 }
 554
 555 #endif
 556
 557 static int __kprobes
 558 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
 559 {
 560         return 0;
 561 }
 562
 563 static int benchmark(void(*fn)(void))
 564 {
 565         unsigned n, i, t, t0;
 566
 567         for (n = 1000; ; n *= 2) {
 568                 t0 = sched_clock();
 569                 for (i = n; i > 0; --i)
 570                         fn();
 571                 t = sched_clock() - t0;
 572                 if (t >= 250000000)
 573                         break; /* Stop once we took more than 0.25 seconds */
 574         }
 575         return t / n; /* Time for one iteration in nanoseconds */
 576 };
 577
 578 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
 579 {
 580         struct kprobe k = {
 581                 .addr           = (kprobe_opcode_t *)((uintptr_t)fn + offset),
 582                 .pre_handler    = benchmark_pre_handler,
 583         };
 584
 585         int ret = register_kprobe(&k);
 586         if (ret < 0) {
 587                 pr_err("FAIL: register_kprobe failed with %d\n", ret);
 588                 return ret;
 589         }
 590
 591         ret = benchmark(fn);
 592
 593         unregister_kprobe(&k);
 594         return ret;
 595 };
 596
 597 struct benchmarks {
 598         void            (*fn)(void);
 599         unsigned        offset;
 600         const char      *title;
 601 };
 602
 603 static int run_benchmarks(void)
 604 {
 605         int ret;
 606         struct benchmarks list[] = {
 607                 {&benchmark_nop, 0, "nop"},
 608                 /*
 609                  * benchmark_pushpop{1,3} will have the optimised
 610                  * instruction emulation, whilst benchmark_pushpop{2,4} will
 611                  * be the equivalent unoptimised instructions.
 612                  */
 613                 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
 614                 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
 615                 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
 616                 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
 617                 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
 618                 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
 619                 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
 620                 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
 621 #ifdef CONFIG_THUMB2_KERNEL
 622                 {&benchmark_pushpop_thumb, 0, "push.n   {r0-r7,lr}"},
 623                 {&benchmark_pushpop_thumb, 2, "pop.n    {r0-r7,pc}"},
 624 #endif
 625                 {0}
 626         };
 627
 628         struct benchmarks *b;
 629         for (b = list; b->fn; ++b) {
 630                 ret = kprobe_benchmark(b->fn, b->offset);
 631                 if (ret < 0)
 632                         return ret;
 633                 pr_info("    %dns for kprobe %s\n", ret, b->title);
 634         }
 635
 636         pr_info("\n");
 637         return 0;
 638 }
 639
 640 #endif /* BENCHMARKING */
 641
 642
 643 /*
 644  * Decoding table self-consistency tests
 645  */
 646
 647 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 648         [DECODE_TYPE_TABLE]     = sizeof(struct decode_table),
 649         [DECODE_TYPE_CUSTOM]    = sizeof(struct decode_custom),
 650         [DECODE_TYPE_SIMULATE]  = sizeof(struct decode_simulate),
 651         [DECODE_TYPE_EMULATE]   = sizeof(struct decode_emulate),
 652         [DECODE_TYPE_OR]        = sizeof(struct decode_or),
 653         [DECODE_TYPE_REJECT]    = sizeof(struct decode_reject)
 654 };
 655
 656 static int table_iter(const union decode_item *table,
 657                         int (*fn)(const struct decode_header *, void *),
 658                         void *args)
 659 {
 660         const struct decode_header *h = (struct decode_header *)table;
 661         int result;
 662
 663         for (;;) {
 664                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 665
 666                 if (type == DECODE_TYPE_END)
 667                         return 0;
 668
 669                 result = fn(h, args);
 670                 if (result)
 671                         return result;
 672
 673                 h = (struct decode_header *)
 674                         ((uintptr_t)h + decode_struct_sizes[type]);
 675
 676         }
 677 }
 678
 679 static int table_test_fail(const struct decode_header *h, const char* message)
 680 {
 681
 682         pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
 683                                         message, h->mask.bits, h->value.bits);
 684         return -EINVAL;
 685 }
 686
 687 struct table_test_args {
 688         const union decode_item *root_table;
 689         u32                     parent_mask;
 690         u32                     parent_value;
 691 };
 692
 693 static int table_test_fn(const struct decode_header *h, void *args)
 694 {
 695         struct table_test_args *a = (struct table_test_args *)args;
 696         enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 697
 698         if (h->value.bits & ~h->mask.bits)
 699                 return table_test_fail(h, "Match value has bits not in mask");
 700
 701         if ((h->mask.bits & a->parent_mask) != a->parent_mask)
 702                 return table_test_fail(h, "Mask has bits not in parent mask");
 703
 704         if ((h->value.bits ^ a->parent_value) & a->parent_mask)
 705                 return table_test_fail(h, "Value is inconsistent with parent");
 706
 707         if (type == DECODE_TYPE_TABLE) {
 708                 struct decode_table *d = (struct decode_table *)h;
 709                 struct table_test_args args2 = *a;
 710                 args2.parent_mask = h->mask.bits;
 711                 args2.parent_value = h->value.bits;
 712                 return table_iter(d->table.table, table_test_fn, &args2);
 713         }
 714
 715         return 0;
 716 }
 717
 718 static int table_test(const union decode_item *table)
 719 {
 720         struct table_test_args args = {
 721                 .root_table     = table,
 722                 .parent_mask    = 0,
 723                 .parent_value   = 0
 724         };
 725         return table_iter(args.root_table, table_test_fn, &args);
 726 }
 727
 728
 729 /*
 730  * Decoding table test coverage analysis
 731  *
 732  * coverage_start() builds a coverage_table which contains a list of
 733  * coverage_entry's to match each entry in the specified kprobes instruction
 734  * decoding table.
 735  *
 736  * When test cases are run, coverage_add() is called to process each case.
 737  * This looks up the corresponding entry in the coverage_table and sets it as
 738  * being matched, as well as clearing the regs flag appropriate for the test.
 739  *
 740  * After all test cases have been run, coverage_end() is called to check that
 741  * all entries in coverage_table have been matched and that all regs flags are
 742  * cleared. I.e. that all possible combinations of instructions described by
 743  * the kprobes decoding tables have had a test case executed for them.
 744  */
 745
 746 bool coverage_fail;
 747
 748 #define MAX_COVERAGE_ENTRIES 256
 749
 750 struct coverage_entry {
 751         const struct decode_header      *header;
 752         unsigned                        regs;
 753         unsigned                        nesting;
 754         char                            matched;
 755 };
 756
 757 struct coverage_table {
 758         struct coverage_entry   *base;
 759         unsigned                num_entries;
 760         unsigned                nesting;
 761 };
 762
 763 struct coverage_table coverage;
 764
 765 #define COVERAGE_ANY_REG        (1<<0)
 766 #define COVERAGE_SP             (1<<1)
 767 #define COVERAGE_PC             (1<<2)
 768 #define COVERAGE_PCWB           (1<<3)
 769
 770 static const char coverage_register_lookup[16] = {
 771         [REG_TYPE_ANY]          = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 772         [REG_TYPE_SAMEAS16]     = COVERAGE_ANY_REG,
 773         [REG_TYPE_SP]           = COVERAGE_SP,
 774         [REG_TYPE_PC]           = COVERAGE_PC,
 775         [REG_TYPE_NOSP]         = COVERAGE_ANY_REG | COVERAGE_SP,
 776         [REG_TYPE_NOSPPC]       = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 777         [REG_TYPE_NOPC]         = COVERAGE_ANY_REG | COVERAGE_PC,
 778         [REG_TYPE_NOPCWB]       = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
 779         [REG_TYPE_NOPCX]        = COVERAGE_ANY_REG,
 780         [REG_TYPE_NOSPPCX]      = COVERAGE_ANY_REG | COVERAGE_SP,
 781 };
 782
 783 unsigned coverage_start_registers(const struct decode_header *h)
 784 {
 785         unsigned regs = 0;
 786         int i;
 787         for (i = 0; i < 20; i += 4) {
 788                 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
 789                 regs |= coverage_register_lookup[r] << i;
 790         }
 791         return regs;
 792 }
 793
 794 static int coverage_start_fn(const struct decode_header *h, void *args)
 795 {
 796         struct coverage_table *coverage = (struct coverage_table *)args;
 797         enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 798         struct coverage_entry *entry = coverage->base + coverage->num_entries;
 799
 800         if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
 801                 pr_err("FAIL: Out of space for test coverage data");
 802                 return -ENOMEM;
 803         }
 804
 805         ++coverage->num_entries;
 806
 807         entry->header = h;
 808         entry->regs = coverage_start_registers(h);
 809         entry->nesting = coverage->nesting;
 810         entry->matched = false;
 811
 812         if (type == DECODE_TYPE_TABLE) {
 813                 struct decode_table *d = (struct decode_table *)h;
 814                 int ret;
 815                 ++coverage->nesting;
 816                 ret = table_iter(d->table.table, coverage_start_fn, coverage);
 817                 --coverage->nesting;
 818                 return ret;
 819         }
 820
 821         return 0;
 822 }
 823
 824 static int coverage_start(const union decode_item *table)
 825 {
 826         coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
 827                                 sizeof(struct coverage_entry), GFP_KERNEL);
 828         coverage.num_entries = 0;
 829         coverage.nesting = 0;
 830         return table_iter(table, coverage_start_fn, &coverage);
 831 }
 832
 833 static void
 834 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
 835 {
 836         int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
 837         int i;
 838         for (i = 0; i < 20; i += 4) {
 839                 enum decode_reg_type reg_type = (regs >> i) & 0xf;
 840                 int reg = (insn >> i) & 0xf;
 841                 int flag;
 842
 843                 if (!reg_type)
 844                         continue;
 845
 846                 if (reg == 13)
 847                         flag = COVERAGE_SP;
 848                 else if (reg == 15)
 849                         flag = COVERAGE_PC;
 850                 else
 851                         flag = COVERAGE_ANY_REG;
 852                 entry->regs &= ~(flag << i);
 853
 854                 switch (reg_type) {
 855
 856                 case REG_TYPE_NONE:
 857                 case REG_TYPE_ANY:
 858                 case REG_TYPE_SAMEAS16:
 859                         break;
 860
 861                 case REG_TYPE_SP:
 862                         if (reg != 13)
 863                                 return;
 864                         break;
 865
 866                 case REG_TYPE_PC:
 867                         if (reg != 15)
 868                                 return;
 869                         break;
 870
 871                 case REG_TYPE_NOSP:
 872                         if (reg == 13)
 873                                 return;
 874                         break;
 875
 876                 case REG_TYPE_NOSPPC:
 877                 case REG_TYPE_NOSPPCX:
 878                         if (reg == 13 || reg == 15)
 879                                 return;
 880                         break;
 881
 882                 case REG_TYPE_NOPCWB:
 883                         if (!is_writeback(insn))
 884                                 break;
 885                         if (reg == 15) {
 886                                 entry->regs &= ~(COVERAGE_PCWB << i);
 887                                 return;
 888                         }
 889                         break;
 890
 891                 case REG_TYPE_NOPC:
 892                 case REG_TYPE_NOPCX:
 893                         if (reg == 15)
 894                                 return;
 895                         break;
 896                 }
 897
 898         }
 899 }
 900
 901 static void coverage_add(kprobe_opcode_t insn)
 902 {
 903         struct coverage_entry *entry = coverage.base;
 904         struct coverage_entry *end = coverage.base + coverage.num_entries;
 905         bool matched = false;
 906         unsigned nesting = 0;
 907
 908         for (; entry < end; ++entry) {
 909                 const struct decode_header *h = entry->header;
 910                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 911
 912                 if (entry->nesting > nesting)
 913                         continue; /* Skip sub-table we didn't match */
 914
 915                 if (entry->nesting < nesting)
 916                         break; /* End of sub-table we were scanning */
 917
 918                 if (!matched) {
 919                         if ((insn & h->mask.bits) != h->value.bits)
 920                                 continue;
 921                         entry->matched = true;
 922                 }
 923
 924                 switch (type) {
 925
 926                 case DECODE_TYPE_TABLE:
 927                         ++nesting;
 928                         break;
 929
 930                 case DECODE_TYPE_CUSTOM:
 931                 case DECODE_TYPE_SIMULATE:
 932                 case DECODE_TYPE_EMULATE:
 933                         coverage_add_registers(entry, insn);
 934                         return;
 935
 936                 case DECODE_TYPE_OR:
 937                         matched = true;
 938                         break;
 939
 940                 case DECODE_TYPE_REJECT:
 941                 default:
 942                         return;
 943                 }
 944
 945         }
 946 }
 947
 948 static void coverage_end(void)
 949 {
 950         struct coverage_entry *entry = coverage.base;
 951         struct coverage_entry *end = coverage.base + coverage.num_entries;
 952
 953         for (; entry < end; ++entry) {
 954                 u32 mask = entry->header->mask.bits;
 955                 u32 value = entry->header->value.bits;
 956
 957                 if (entry->regs) {
 958                         pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
 959                                 mask, value, entry->regs);
 960                         coverage_fail = true;
 961                 }
 962                 if (!entry->matched) {
 963                         pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
 964                                 mask, value);
 965                         coverage_fail = true;
 966                 }
 967         }
 968
 969         kfree(coverage.base);
 970 }
 971
 972
 973 /*
 974  * Framework for instruction set test cases
 975  */
 976
 977 void __naked __kprobes_test_case_start(void)
 978 {
 979         __asm__ __volatile__ (
 980                 "mov    r2, sp                                  \n\t"
 981                 "bic    r3, r2, #7                              \n\t"
 982                 "mov    sp, r3                                  \n\t"
 983                 "stmdb  sp!, {r2-r11}                           \n\t"
 984                 "sub    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 985                 "bic    r0, lr, #1  @ r0 = inline data          \n\t"
 986                 "mov    r1, sp                                  \n\t"
 987                 "bl     kprobes_test_case_start                 \n\t"
 988                 RET(r0)"                                        \n\t"
 989         );
 990 }
 991
 992 #ifndef CONFIG_THUMB2_KERNEL
 993
 994 void __naked __kprobes_test_case_end_32(void)
 995 {
 996         __asm__ __volatile__ (
 997                 "mov    r4, lr                                  \n\t"
 998                 "bl     kprobes_test_case_end                   \n\t"
 999                 "cmp    r0, #0                                  \n\t"
1000                 "movne  pc, r0                                  \n\t"
1001                 "mov    r0, r4                                  \n\t"
1002                 "add    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
1003                 "ldmia  sp!, {r2-r11}                           \n\t"
1004                 "mov    sp, r2                                  \n\t"
1005                 "mov    pc, r0                                  \n\t"
1006         );
1007 }
1008
1009 #else /* CONFIG_THUMB2_KERNEL */
1010
1011 void __naked __kprobes_test_case_end_16(void)
1012 {
1013         __asm__ __volatile__ (
1014                 "mov    r4, lr                                  \n\t"
1015                 "bl     kprobes_test_case_end                   \n\t"
1016                 "cmp    r0, #0                                  \n\t"
1017                 "bxne   r0                                      \n\t"
1018                 "mov    r0, r4                                  \n\t"
1019                 "add    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
1020                 "ldmia  sp!, {r2-r11}                           \n\t"
1021                 "mov    sp, r2                                  \n\t"
1022                 "bx     r0                                      \n\t"
1023         );
1024 }
1025
1026 void __naked __kprobes_test_case_end_32(void)
1027 {
1028         __asm__ __volatile__ (
1029                 ".arm                                           \n\t"
1030                 "orr    lr, lr, #1  @ will return to Thumb code \n\t"
1031                 "ldr    pc, 1f                                  \n\t"
1032                 "1:                                             \n\t"
1033                 ".word  __kprobes_test_case_end_16              \n\t"
1034         );
1035 }
1036
1037 #endif
1038
1039
1040 int kprobe_test_flags;
1041 int kprobe_test_cc_position;
1042
1043 static int test_try_count;
1044 static int test_pass_count;
1045 static int test_fail_count;
1046
1047 static struct pt_regs initial_regs;
1048 static struct pt_regs expected_regs;
1049 static struct pt_regs result_regs;
1050
1051 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1052
1053 static const char *current_title;
1054 static struct test_arg *current_args;
1055 static u32 *current_stack;
1056 static uintptr_t current_branch_target;
1057
1058 static uintptr_t current_code_start;
1059 static kprobe_opcode_t current_instruction;
1060
1061
1062 #define TEST_CASE_PASSED -1
1063 #define TEST_CASE_FAILED -2
1064
1065 static int test_case_run_count;
1066 static bool test_case_is_thumb;
1067 static int test_instance;
1068
1069 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1070 {
1071         int ret = arm_check_condition(cc << 28, cpsr);
1072
1073         return (ret != ARM_OPCODE_CONDTEST_FAIL);
1074 }
1075
1076 static int is_last_scenario;
1077 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1078 static int memory_needs_checking;
1079
1080 static unsigned long test_context_cpsr(int scenario)
1081 {
1082         unsigned long cpsr;
1083
1084         probe_should_run = 1;
1085
1086         /* Default case is that we cycle through 16 combinations of flags */
1087         cpsr  = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1088         cpsr |= (scenario & 0xf) << 16; /* GE flags */
1089         cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1090
1091         if (!test_case_is_thumb) {
1092                 /* Testing ARM code */
1093                 int cc = current_instruction >> 28;
1094
1095                 probe_should_run = test_check_cc(cc, cpsr) != 0;
1096                 if (scenario == 15)
1097                         is_last_scenario = true;
1098
1099         } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1100                 /* Testing Thumb code without setting ITSTATE */
1101                 if (kprobe_test_cc_position) {
1102                         int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1103                         probe_should_run = test_check_cc(cc, cpsr) != 0;
1104                 }
1105
1106                 if (scenario == 15)
1107                         is_last_scenario = true;
1108
1109         } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1110                 /* Testing Thumb code with all combinations of ITSTATE */
1111                 unsigned x = (scenario >> 4);
1112                 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1113                 unsigned mask = x / 7 + 2;  /* ITSTATE<4:0>, bits reversed */
1114
1115                 if (mask > 0x1f) {
1116                         /* Finish by testing state from instruction 'itt al' */
1117                         cond_base = 7;
1118                         mask = 0x4;
1119                         if ((scenario & 0xf) == 0xf)
1120                                 is_last_scenario = true;
1121                 }
1122
1123                 cpsr |= cond_base << 13;        /* ITSTATE<7:5> */
1124                 cpsr |= (mask & 0x1) << 12;     /* ITSTATE<4> */
1125                 cpsr |= (mask & 0x2) << 10;     /* ITSTATE<3> */
1126                 cpsr |= (mask & 0x4) << 8;      /* ITSTATE<2> */
1127                 cpsr |= (mask & 0x8) << 23;     /* ITSTATE<1> */
1128                 cpsr |= (mask & 0x10) << 21;    /* ITSTATE<0> */
1129
1130                 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1131
1132         } else {
1133                 /* Testing Thumb code with several combinations of ITSTATE */
1134                 switch (scenario) {
1135                 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1136                         cpsr = 0x00000800;
1137                         probe_should_run = 0;
1138                         break;
1139                 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1140                         cpsr = 0xf0007800;
1141                         probe_should_run = 0;
1142                         break;
1143                 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1144                         cpsr = 0x00009800;
1145                         break;
1146                 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1147                         cpsr = 0xf0002800;
1148                         is_last_scenario = true;
1149                         break;
1150                 }
1151         }
1152
1153         return cpsr;
1154 }
1155
1156 static void setup_test_context(struct pt_regs *regs)
1157 {
1158         int scenario = test_case_run_count>>1;
1159         unsigned long val;
1160         struct test_arg *args;
1161         int i;
1162
1163         is_last_scenario = false;
1164         memory_needs_checking = false;
1165
1166         /* Initialise test memory on stack */
1167         val = (scenario & 1) ? VALM : ~VALM;
1168         for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1169                 current_stack[i] = val + (i << 8);
1170         /* Put target of branch on stack for tests which load PC from memory */
1171         if (current_branch_target)
1172                 current_stack[15] = current_branch_target;
1173         /* Put a value for SP on stack for tests which load SP from memory */
1174         current_stack[13] = (u32)current_stack + 120;
1175
1176         /* Initialise register values to their default state */
1177         val = (scenario & 2) ? VALR : ~VALR;
1178         for (i = 0; i < 13; ++i)
1179                 regs->uregs[i] = val ^ (i << 8);
1180         regs->ARM_lr = val ^ (14 << 8);
1181         regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1182         regs->ARM_cpsr |= test_context_cpsr(scenario);
1183
1184         /* Perform testcase specific register setup  */
1185         args = current_args;
1186         for (; args[0].type != ARG_TYPE_END; ++args)
1187                 switch (args[0].type) {
1188                 case ARG_TYPE_REG: {
1189                         struct test_arg_regptr *arg =
1190                                 (struct test_arg_regptr *)args;
1191                         regs->uregs[arg->reg] = arg->val;
1192                         break;
1193                 }
1194                 case ARG_TYPE_PTR: {
1195                         struct test_arg_regptr *arg =
1196                                 (struct test_arg_regptr *)args;
1197                         regs->uregs[arg->reg] =
1198                                 (unsigned long)current_stack + arg->val;
1199                         memory_needs_checking = true;
1200                         /*
1201                          * Test memory at an address below SP is in danger of
1202                          * being altered by an interrupt occurring and pushing
1203                          * data onto the stack. Disable interrupts to stop this.
1204                          */
1205                         if (arg->reg == 13)
1206                                 regs->ARM_cpsr |= PSR_I_BIT;
1207                         break;
1208                 }
1209                 case ARG_TYPE_MEM: {
1210                         struct test_arg_mem *arg = (struct test_arg_mem *)args;
1211                         current_stack[arg->index] = arg->val;
1212                         break;
1213                 }
1214                 default:
1215                         break;
1216                 }
1217 }
1218
1219 struct test_probe {
1220         struct kprobe   kprobe;
1221         bool            registered;
1222         int             hit;
1223 };
1224
1225 static void unregister_test_probe(struct test_probe *probe)
1226 {
1227         if (probe->registered) {
1228                 unregister_kprobe(&probe->kprobe);
1229                 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1230         }
1231         probe->registered = false;
1232 }
1233
1234 static int register_test_probe(struct test_probe *probe)
1235 {
1236         int ret;
1237
1238         if (probe->registered)
1239                 BUG();
1240
1241         ret = register_kprobe(&probe->kprobe);
1242         if (ret >= 0) {
1243                 probe->registered = true;
1244                 probe->hit = -1;
1245         }
1246         return ret;
1247 }
1248
1249 static int __kprobes
1250 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1251 {
1252         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1253         return 0;
1254 }
1255
1256 static void __kprobes
1257 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1258                                                         unsigned long flags)
1259 {
1260         setup_test_context(regs);
1261         initial_regs = *regs;
1262         initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1263 }
1264
1265 static int __kprobes
1266 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1267 {
1268         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1269         return 0;
1270 }
1271
1272 static int __kprobes
1273 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1274 {
1275         struct test_arg *args;
1276
1277         if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1278                 return 0; /* Already run for this test instance */
1279
1280         result_regs = *regs;
1281
1282         /* Mask out results which are indeterminate */
1283         result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1284         for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
1285                 if (args[0].type == ARG_TYPE_REG_MASKED) {
1286                         struct test_arg_regptr *arg =
1287                                 (struct test_arg_regptr *)args;
1288                         result_regs.uregs[arg->reg] &= arg->val;
1289                 }
1290
1291         /* Undo any changes done to SP by the test case */
1292         regs->ARM_sp = (unsigned long)current_stack;
1293         /* Enable interrupts in case setup_test_context disabled them */
1294         regs->ARM_cpsr &= ~PSR_I_BIT;
1295
1296         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1297         return 0;
1298 }
1299
1300 static struct test_probe test_before_probe = {
1301         .kprobe.pre_handler     = test_before_pre_handler,
1302         .kprobe.post_handler    = test_before_post_handler,
1303 };
1304
1305 static struct test_probe test_case_probe = {
1306         .kprobe.pre_handler     = test_case_pre_handler,
1307 };
1308
1309 static struct test_probe test_after_probe = {
1310         .kprobe.pre_handler     = test_after_pre_handler,
1311 };
1312
1313 static struct test_probe test_after2_probe = {
1314         .kprobe.pre_handler     = test_after_pre_handler,
1315 };
1316
1317 static void test_case_cleanup(void)
1318 {
1319         unregister_test_probe(&test_before_probe);
1320         unregister_test_probe(&test_case_probe);
1321         unregister_test_probe(&test_after_probe);
1322         unregister_test_probe(&test_after2_probe);
1323 }
1324
1325 static void print_registers(struct pt_regs *regs)
1326 {
1327         pr_err("r0  %08lx | r1  %08lx | r2  %08lx | r3  %08lx\n",
1328                 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1329         pr_err("r4  %08lx | r5  %08lx | r6  %08lx | r7  %08lx\n",
1330                 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1331         pr_err("r8  %08lx | r9  %08lx | r10 %08lx | r11 %08lx\n",
1332                 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1333         pr_err("r12 %08lx | sp  %08lx | lr  %08lx | pc  %08lx\n",
1334                 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1335         pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1336 }
1337
1338 static void print_memory(u32 *mem, size_t size)
1339 {
1340         int i;
1341         for (i = 0; i < size / sizeof(u32); i += 4)
1342                 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1343                                                 mem[i+2], mem[i+3]);
1344 }
1345
1346 static size_t expected_memory_size(u32 *sp)
1347 {
1348         size_t size = sizeof(expected_memory);
1349         int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1350         if (offset > 0)
1351                 size -= offset;
1352         return size;
1353 }
1354
1355 static void test_case_failed(const char *message)
1356 {
1357         test_case_cleanup();
1358
1359         pr_err("FAIL: %s\n", message);
1360         pr_err("FAIL: Test %s\n", current_title);
1361         pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1362 }
1363
1364 static unsigned long next_instruction(unsigned long pc)
1365 {
1366 #ifdef CONFIG_THUMB2_KERNEL
1367         if ((pc & 1) &&
1368             !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1369                 return pc + 2;
1370         else
1371 #endif
1372         return pc + 4;
1373 }
1374
1375 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1376 {
1377         struct test_arg *args;
1378         struct test_arg_end *end_arg;
1379         unsigned long test_code;
1380
1381         current_title = *title++;
1382         args = (struct test_arg *)title;
1383         current_args = args;
1384         current_stack = stack;
1385
1386         ++test_try_count;
1387
1388         while (args->type != ARG_TYPE_END)
1389                 ++args;
1390         end_arg = (struct test_arg_end *)args;
1391
1392         test_code = (unsigned long)(args + 1); /* Code starts after args */
1393
1394         test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1395         if (test_case_is_thumb)
1396                 test_code |= 1;
1397
1398         current_code_start = test_code;
1399
1400         current_branch_target = 0;
1401         if (end_arg->branch_offset != end_arg->end_offset)
1402                 current_branch_target = test_code + end_arg->branch_offset;
1403
1404         test_code += end_arg->code_offset;
1405         test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1406
1407         test_code = next_instruction(test_code);
1408         test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1409
1410         if (test_case_is_thumb) {
1411                 u16 *p = (u16 *)(test_code & ~1);
1412                 current_instruction = __mem_to_opcode_thumb16(p[0]);
1413                 if (is_wide_instruction(current_instruction)) {
1414                         u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1415                         current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1416                 }
1417         } else {
1418                 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1419         }
1420
1421         if (current_title[0] == '.')
1422                 verbose("%s\n", current_title);
1423         else
1424                 verbose("%s\t@ %0*x\n", current_title,
1425                                         test_case_is_thumb ? 4 : 8,
1426                                         current_instruction);
1427
1428         test_code = next_instruction(test_code);
1429         test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1430
1431         if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1432                 if (!test_case_is_thumb ||
1433                         is_wide_instruction(current_instruction)) {
1434                                 test_case_failed("expected 16-bit instruction");
1435                                 goto fail;
1436                 }
1437         } else {
1438                 if (test_case_is_thumb &&
1439                         !is_wide_instruction(current_instruction)) {
1440                                 test_case_failed("expected 32-bit instruction");
1441                                 goto fail;
1442                 }
1443         }
1444
1445         coverage_add(current_instruction);
1446
1447         if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1448                 if (register_test_probe(&test_case_probe) < 0)
1449                         goto pass;
1450                 test_case_failed("registered probe for unsupported instruction");
1451                 goto fail;
1452         }
1453
1454         if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1455                 if (register_test_probe(&test_case_probe) >= 0)
1456                         goto pass;
1457                 test_case_failed("couldn't register probe for supported instruction");
1458                 goto fail;
1459         }
1460
1461         if (register_test_probe(&test_before_probe) < 0) {
1462                 test_case_failed("register test_before_probe failed");
1463                 goto fail;
1464         }
1465         if (register_test_probe(&test_after_probe) < 0) {
1466                 test_case_failed("register test_after_probe failed");
1467                 goto fail;
1468         }
1469         if (current_branch_target) {
1470                 test_after2_probe.kprobe.addr =
1471                                 (kprobe_opcode_t *)current_branch_target;
1472                 if (register_test_probe(&test_after2_probe) < 0) {
1473                         test_case_failed("register test_after2_probe failed");
1474                         goto fail;
1475                 }
1476         }
1477
1478         /* Start first run of test case */
1479         test_case_run_count = 0;
1480         ++test_instance;
1481         return current_code_start;
1482 pass:
1483         test_case_run_count = TEST_CASE_PASSED;
1484         return (uintptr_t)test_after_probe.kprobe.addr;
1485 fail:
1486         test_case_run_count = TEST_CASE_FAILED;
1487         return (uintptr_t)test_after_probe.kprobe.addr;
1488 }
1489
1490 static bool check_test_results(void)
1491 {
1492         size_t mem_size = 0;
1493         u32 *mem = 0;
1494
1495         if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1496                 test_case_failed("registers differ");
1497                 goto fail;
1498         }
1499
1500         if (memory_needs_checking) {
1501                 mem = (u32 *)result_regs.ARM_sp;
1502                 mem_size = expected_memory_size(mem);
1503                 if (memcmp(expected_memory, mem, mem_size)) {
1504                         test_case_failed("test memory differs");
1505                         goto fail;
1506                 }
1507         }
1508
1509         return true;
1510
1511 fail:
1512         pr_err("initial_regs:\n");
1513         print_registers(&initial_regs);
1514         pr_err("expected_regs:\n");
1515         print_registers(&expected_regs);
1516         pr_err("result_regs:\n");
1517         print_registers(&result_regs);
1518
1519         if (mem) {
1520                 pr_err("current_stack=%p\n", current_stack);
1521                 pr_err("expected_memory:\n");
1522                 print_memory(expected_memory, mem_size);
1523                 pr_err("result_memory:\n");
1524                 print_memory(mem, mem_size);
1525         }
1526
1527         return false;
1528 }
1529
1530 static uintptr_t __used kprobes_test_case_end(void)
1531 {
1532         if (test_case_run_count < 0) {
1533                 if (test_case_run_count == TEST_CASE_PASSED)
1534                         /* kprobes_test_case_start did all the needed testing */
1535                         goto pass;
1536                 else
1537                         /* kprobes_test_case_start failed */
1538                         goto fail;
1539         }
1540
1541         if (test_before_probe.hit != test_instance) {
1542                 test_case_failed("test_before_handler not run");
1543                 goto fail;
1544         }
1545
1546         if (test_after_probe.hit != test_instance &&
1547                                 test_after2_probe.hit != test_instance) {
1548                 test_case_failed("test_after_handler not run");
1549                 goto fail;
1550         }
1551
1552         /*
1553          * Even numbered test runs ran without a probe on the test case so
1554          * we can gather reference results. The subsequent odd numbered run
1555          * will have the probe inserted.
1556         */
1557         if ((test_case_run_count & 1) == 0) {
1558                 /* Save results from run without probe */
1559                 u32 *mem = (u32 *)result_regs.ARM_sp;
1560                 expected_regs = result_regs;
1561                 memcpy(expected_memory, mem, expected_memory_size(mem));
1562
1563                 /* Insert probe onto test case instruction */
1564                 if (register_test_probe(&test_case_probe) < 0) {
1565                         test_case_failed("register test_case_probe failed");
1566                         goto fail;
1567                 }
1568         } else {
1569                 /* Check probe ran as expected */
1570                 if (probe_should_run == 1) {
1571                         if (test_case_probe.hit != test_instance) {
1572                                 test_case_failed("test_case_handler not run");
1573                                 goto fail;
1574                         }
1575                 } else if (probe_should_run == 0) {
1576                         if (test_case_probe.hit == test_instance) {
1577                                 test_case_failed("test_case_handler ran");
1578                                 goto fail;
1579                         }
1580                 }
1581
1582                 /* Remove probe for any subsequent reference run */
1583                 unregister_test_probe(&test_case_probe);
1584
1585                 if (!check_test_results())
1586                         goto fail;
1587
1588                 if (is_last_scenario)
1589                         goto pass;
1590         }
1591
1592         /* Do next test run */
1593         ++test_case_run_count;
1594         ++test_instance;
1595         return current_code_start;
1596 fail:
1597         ++test_fail_count;
1598         goto end;
1599 pass:
1600         ++test_pass_count;
1601 end:
1602         test_case_cleanup();
1603         return 0;
1604 }
1605
1606
1607 /*
1608  * Top level test functions
1609  */
1610
1611 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1612 {
1613         int ret;
1614
1615         pr_info("    Check decoding tables\n");
1616         ret = table_test(table);
1617         if (ret)
1618                 return ret;
1619
1620         pr_info("    Run test cases\n");
1621         ret = coverage_start(table);
1622         if (ret)
1623                 return ret;
1624
1625         tests();
1626
1627         coverage_end();
1628         return 0;
1629 }
1630
1631
1632 static int __init run_all_tests(void)
1633 {
1634         int ret = 0;
1635
1636         pr_info("Beginning kprobe tests...\n");
1637
1638 #ifndef CONFIG_THUMB2_KERNEL
1639
1640         pr_info("Probe ARM code\n");
1641         ret = run_api_tests(arm_func);
1642         if (ret)
1643                 goto out;
1644
1645         pr_info("ARM instruction simulation\n");
1646         ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1647         if (ret)
1648                 goto out;
1649
1650 #else /* CONFIG_THUMB2_KERNEL */
1651
1652         pr_info("Probe 16-bit Thumb code\n");
1653         ret = run_api_tests(thumb16_func);
1654         if (ret)
1655                 goto out;
1656
1657         pr_info("Probe 32-bit Thumb code, even halfword\n");
1658         ret = run_api_tests(thumb32even_func);
1659         if (ret)
1660                 goto out;
1661
1662         pr_info("Probe 32-bit Thumb code, odd halfword\n");
1663         ret = run_api_tests(thumb32odd_func);
1664         if (ret)
1665                 goto out;
1666
1667         pr_info("16-bit Thumb instruction simulation\n");
1668         ret = run_test_cases(kprobe_thumb16_test_cases,
1669                                 probes_decode_thumb16_table);
1670         if (ret)
1671                 goto out;
1672
1673         pr_info("32-bit Thumb instruction simulation\n");
1674         ret = run_test_cases(kprobe_thumb32_test_cases,
1675                                 probes_decode_thumb32_table);
1676         if (ret)
1677                 goto out;
1678 #endif
1679
1680         pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1681                 test_try_count, test_pass_count, test_fail_count);
1682         if (test_fail_count) {
1683                 ret = -EINVAL;
1684                 goto out;
1685         }
1686
1687 #if BENCHMARKING
1688         pr_info("Benchmarks\n");
1689         ret = run_benchmarks();
1690         if (ret)
1691                 goto out;
1692 #endif
1693
1694 #if __LINUX_ARM_ARCH__ >= 7
1695         /* We are able to run all test cases so coverage should be complete */
1696         if (coverage_fail) {
1697                 pr_err("FAIL: Test coverage checks failed\n");
1698                 ret = -EINVAL;
1699                 goto out;
1700         }
1701 #endif
1702
1703 out:
1704         if (ret == 0)
1705                 ret = tests_failed;
1706         if (ret == 0)
1707                 pr_info("Finished kprobe tests OK\n");
1708         else
1709                 pr_err("kprobe tests failed\n");
1710
1711         return ret;
1712 }
1713
1714
1715 /*
1716  * Module setup
1717  */
1718
1719 #ifdef MODULE
1720
1721 static void __exit kprobe_test_exit(void)
1722 {
1723 }
1724
1725 module_init(run_all_tests)
1726 module_exit(kprobe_test_exit)
1727 MODULE_LICENSE("GPL");
1728
1729 #else /* !MODULE */
1730
1731 late_initcall(run_all_tests);
1732
1733 #endif