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/kprobes.h>
 207 #include <linux/errno.h>
 208 #include <linux/stddef.h>
 209 #include <linux/bug.h>
 210 #include <asm/opcodes.h>
 211
 212 #include "core.h"
 213 #include "test-core.h"
 214 #include "../decode-arm.h"
 215 #include "../decode-thumb.h"
 216
 217
 218 #define BENCHMARKING    1
 219
 220
 221 /*
 222  * Test basic API
 223  */
 224
 225 static bool test_regs_ok;
 226 static int test_func_instance;
 227 static int pre_handler_called;
 228 static int post_handler_called;
 229 static int jprobe_func_called;
 230 static int kretprobe_handler_called;
 231 static int tests_failed;
 232
 233 #define FUNC_ARG1 0x12345678
 234 #define FUNC_ARG2 0xabcdef
 235
 236
 237 #ifndef CONFIG_THUMB2_KERNEL
 238
 239 #define RET(reg)        "mov    pc, "#reg
 240
 241 long arm_func(long r0, long r1);
 242
 243 static void __used __naked __arm_kprobes_test_func(void)
 244 {
 245         __asm__ __volatile__ (
 246                 ".arm                                   \n\t"
 247                 ".type arm_func, %%function             \n\t"
 248                 "arm_func:                              \n\t"
 249                 "adds   r0, r0, r1                      \n\t"
 250                 "mov    pc, lr                          \n\t"
 251                 ".code "NORMAL_ISA       /* Back to Thumb if necessary */
 252                 : : : "r0", "r1", "cc"
 253         );
 254 }
 255
 256 #else /* CONFIG_THUMB2_KERNEL */
 257
 258 #define RET(reg)        "bx     "#reg
 259
 260 long thumb16_func(long r0, long r1);
 261 long thumb32even_func(long r0, long r1);
 262 long thumb32odd_func(long r0, long r1);
 263
 264 static void __used __naked __thumb_kprobes_test_funcs(void)
 265 {
 266         __asm__ __volatile__ (
 267                 ".type thumb16_func, %%function         \n\t"
 268                 "thumb16_func:                          \n\t"
 269                 "adds.n r0, r0, r1                      \n\t"
 270                 "bx     lr                              \n\t"
 271
 272                 ".align                                 \n\t"
 273                 ".type thumb32even_func, %%function     \n\t"
 274                 "thumb32even_func:                      \n\t"
 275                 "adds.w r0, r0, r1                      \n\t"
 276                 "bx     lr                              \n\t"
 277
 278                 ".align                                 \n\t"
 279                 "nop.n                                  \n\t"
 280                 ".type thumb32odd_func, %%function      \n\t"
 281                 "thumb32odd_func:                       \n\t"
 282                 "adds.w r0, r0, r1                      \n\t"
 283                 "bx     lr                              \n\t"
 284
 285                 : : : "r0", "r1", "cc"
 286         );
 287 }
 288
 289 #endif /* CONFIG_THUMB2_KERNEL */
 290
 291
 292 static int call_test_func(long (*func)(long, long), bool check_test_regs)
 293 {
 294         long ret;
 295
 296         ++test_func_instance;
 297         test_regs_ok = false;
 298
 299         ret = (*func)(FUNC_ARG1, FUNC_ARG2);
 300         if (ret != FUNC_ARG1 + FUNC_ARG2) {
 301                 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
 302                 return false;
 303         }
 304
 305         if (check_test_regs && !test_regs_ok) {
 306                 pr_err("FAIL: test regs not OK\n");
 307                 return false;
 308         }
 309
 310         return true;
 311 }
 312
 313 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
 314 {
 315         pre_handler_called = test_func_instance;
 316         if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
 317                 test_regs_ok = true;
 318         return 0;
 319 }
 320
 321 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
 322                                 unsigned long flags)
 323 {
 324         post_handler_called = test_func_instance;
 325         if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
 326                 test_regs_ok = false;
 327 }
 328
 329 static struct kprobe the_kprobe = {
 330         .addr           = 0,
 331         .pre_handler    = pre_handler,
 332         .post_handler   = post_handler
 333 };
 334
 335 static int test_kprobe(long (*func)(long, long))
 336 {
 337         int ret;
 338
 339         the_kprobe.addr = (kprobe_opcode_t *)func;
 340         ret = register_kprobe(&the_kprobe);
 341         if (ret < 0) {
 342                 pr_err("FAIL: register_kprobe failed with %d\n", ret);
 343                 return ret;
 344         }
 345
 346         ret = call_test_func(func, true);
 347
 348         unregister_kprobe(&the_kprobe);
 349         the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
 350
 351         if (!ret)
 352                 return -EINVAL;
 353         if (pre_handler_called != test_func_instance) {
 354                 pr_err("FAIL: kprobe pre_handler not called\n");
 355                 return -EINVAL;
 356         }
 357         if (post_handler_called != test_func_instance) {
 358                 pr_err("FAIL: kprobe post_handler not called\n");
 359                 return -EINVAL;
 360         }
 361         if (!call_test_func(func, false))
 362                 return -EINVAL;
 363         if (pre_handler_called == test_func_instance ||
 364                                 post_handler_called == test_func_instance) {
 365                 pr_err("FAIL: probe called after unregistering\n");
 366                 return -EINVAL;
 367         }
 368
 369         return 0;
 370 }
 371
 372 static void __kprobes jprobe_func(long r0, long r1)
 373 {
 374         jprobe_func_called = test_func_instance;
 375         if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
 376                 test_regs_ok = true;
 377         jprobe_return();
 378 }
 379
 380 static struct jprobe the_jprobe = {
 381         .entry          = jprobe_func,
 382 };
 383
 384 static int test_jprobe(long (*func)(long, long))
 385 {
 386         int ret;
 387
 388         the_jprobe.kp.addr = (kprobe_opcode_t *)func;
 389         ret = register_jprobe(&the_jprobe);
 390         if (ret < 0) {
 391                 pr_err("FAIL: register_jprobe failed with %d\n", ret);
 392                 return ret;
 393         }
 394
 395         ret = call_test_func(func, true);
 396
 397         unregister_jprobe(&the_jprobe);
 398         the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
 399
 400         if (!ret)
 401                 return -EINVAL;
 402         if (jprobe_func_called != test_func_instance) {
 403                 pr_err("FAIL: jprobe handler function not called\n");
 404                 return -EINVAL;
 405         }
 406         if (!call_test_func(func, false))
 407                 return -EINVAL;
 408         if (jprobe_func_called == test_func_instance) {
 409                 pr_err("FAIL: probe called after unregistering\n");
 410                 return -EINVAL;
 411         }
 412
 413         return 0;
 414 }
 415
 416 static int __kprobes
 417 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
 418 {
 419         kretprobe_handler_called = test_func_instance;
 420         if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
 421                 test_regs_ok = true;
 422         return 0;
 423 }
 424
 425 static struct kretprobe the_kretprobe = {
 426         .handler        = kretprobe_handler,
 427 };
 428
 429 static int test_kretprobe(long (*func)(long, long))
 430 {
 431         int ret;
 432
 433         the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
 434         ret = register_kretprobe(&the_kretprobe);
 435         if (ret < 0) {
 436                 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
 437                 return ret;
 438         }
 439
 440         ret = call_test_func(func, true);
 441
 442         unregister_kretprobe(&the_kretprobe);
 443         the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
 444
 445         if (!ret)
 446                 return -EINVAL;
 447         if (kretprobe_handler_called != test_func_instance) {
 448                 pr_err("FAIL: kretprobe handler not called\n");
 449                 return -EINVAL;
 450         }
 451         if (!call_test_func(func, false))
 452                 return -EINVAL;
 453         if (jprobe_func_called == test_func_instance) {
 454                 pr_err("FAIL: kretprobe called after unregistering\n");
 455                 return -EINVAL;
 456         }
 457
 458         return 0;
 459 }
 460
 461 static int run_api_tests(long (*func)(long, long))
 462 {
 463         int ret;
 464
 465         pr_info("    kprobe\n");
 466         ret = test_kprobe(func);
 467         if (ret < 0)
 468                 return ret;
 469
 470         pr_info("    jprobe\n");
 471         ret = test_jprobe(func);
 472 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE)
 473         if (ret == -EINVAL) {
 474                 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n");
 475                 tests_failed = ret;
 476                 ret = 0;
 477         }
 478 #endif
 479         if (ret < 0)
 480                 return ret;
 481
 482         pr_info("    kretprobe\n");
 483         ret = test_kretprobe(func);
 484         if (ret < 0)
 485                 return ret;
 486
 487         return 0;
 488 }
 489
 490
 491 /*
 492  * Benchmarking
 493  */
 494
 495 #if BENCHMARKING
 496
 497 static void __naked benchmark_nop(void)
 498 {
 499         __asm__ __volatile__ (
 500                 "nop            \n\t"
 501                 RET(lr)"        \n\t"
 502         );
 503 }
 504
 505 #ifdef CONFIG_THUMB2_KERNEL
 506 #define wide ".w"
 507 #else
 508 #define wide
 509 #endif
 510
 511 static void __naked benchmark_pushpop1(void)
 512 {
 513         __asm__ __volatile__ (
 514                 "stmdb"wide"    sp!, {r3-r11,lr}  \n\t"
 515                 "ldmia"wide"    sp!, {r3-r11,pc}"
 516         );
 517 }
 518
 519 static void __naked benchmark_pushpop2(void)
 520 {
 521         __asm__ __volatile__ (
 522                 "stmdb"wide"    sp!, {r0-r8,lr}  \n\t"
 523                 "ldmia"wide"    sp!, {r0-r8,pc}"
 524         );
 525 }
 526
 527 static void __naked benchmark_pushpop3(void)
 528 {
 529         __asm__ __volatile__ (
 530                 "stmdb"wide"    sp!, {r4,lr}  \n\t"
 531                 "ldmia"wide"    sp!, {r4,pc}"
 532         );
 533 }
 534
 535 static void __naked benchmark_pushpop4(void)
 536 {
 537         __asm__ __volatile__ (
 538                 "stmdb"wide"    sp!, {r0,lr}  \n\t"
 539                 "ldmia"wide"    sp!, {r0,pc}"
 540         );
 541 }
 542
 543
 544 #ifdef CONFIG_THUMB2_KERNEL
 545
 546 static void __naked benchmark_pushpop_thumb(void)
 547 {
 548         __asm__ __volatile__ (
 549                 "push.n {r0-r7,lr}  \n\t"
 550                 "pop.n  {r0-r7,pc}"
 551         );
 552 }
 553
 554 #endif
 555
 556 static int __kprobes
 557 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
 558 {
 559         return 0;
 560 }
 561
 562 static int benchmark(void(*fn)(void))
 563 {
 564         unsigned n, i, t, t0;
 565
 566         for (n = 1000; ; n *= 2) {
 567                 t0 = sched_clock();
 568                 for (i = n; i > 0; --i)
 569                         fn();
 570                 t = sched_clock() - t0;
 571                 if (t >= 250000000)
 572                         break; /* Stop once we took more than 0.25 seconds */
 573         }
 574         return t / n; /* Time for one iteration in nanoseconds */
 575 };
 576
 577 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
 578 {
 579         struct kprobe k = {
 580                 .addr           = (kprobe_opcode_t *)((uintptr_t)fn + offset),
 581                 .pre_handler    = benchmark_pre_handler,
 582         };
 583
 584         int ret = register_kprobe(&k);
 585         if (ret < 0) {
 586                 pr_err("FAIL: register_kprobe failed with %d\n", ret);
 587                 return ret;
 588         }
 589
 590         ret = benchmark(fn);
 591
 592         unregister_kprobe(&k);
 593         return ret;
 594 };
 595
 596 struct benchmarks {
 597         void            (*fn)(void);
 598         unsigned        offset;
 599         const char      *title;
 600 };
 601
 602 static int run_benchmarks(void)
 603 {
 604         int ret;
 605         struct benchmarks list[] = {
 606                 {&benchmark_nop, 0, "nop"},
 607                 /*
 608                  * benchmark_pushpop{1,3} will have the optimised
 609                  * instruction emulation, whilst benchmark_pushpop{2,4} will
 610                  * be the equivalent unoptimised instructions.
 611                  */
 612                 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
 613                 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
 614                 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
 615                 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
 616                 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
 617                 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
 618                 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
 619                 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
 620 #ifdef CONFIG_THUMB2_KERNEL
 621                 {&benchmark_pushpop_thumb, 0, "push.n   {r0-r7,lr}"},
 622                 {&benchmark_pushpop_thumb, 2, "pop.n    {r0-r7,pc}"},
 623 #endif
 624                 {0}
 625         };
 626
 627         struct benchmarks *b;
 628         for (b = list; b->fn; ++b) {
 629                 ret = kprobe_benchmark(b->fn, b->offset);
 630                 if (ret < 0)
 631                         return ret;
 632                 pr_info("    %dns for kprobe %s\n", ret, b->title);
 633         }
 634
 635         pr_info("\n");
 636         return 0;
 637 }
 638
 639 #endif /* BENCHMARKING */
 640
 641
 642 /*
 643  * Decoding table self-consistency tests
 644  */
 645
 646 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
 647         [DECODE_TYPE_TABLE]     = sizeof(struct decode_table),
 648         [DECODE_TYPE_CUSTOM]    = sizeof(struct decode_custom),
 649         [DECODE_TYPE_SIMULATE]  = sizeof(struct decode_simulate),
 650         [DECODE_TYPE_EMULATE]   = sizeof(struct decode_emulate),
 651         [DECODE_TYPE_OR]        = sizeof(struct decode_or),
 652         [DECODE_TYPE_REJECT]    = sizeof(struct decode_reject)
 653 };
 654
 655 static int table_iter(const union decode_item *table,
 656                         int (*fn)(const struct decode_header *, void *),
 657                         void *args)
 658 {
 659         const struct decode_header *h = (struct decode_header *)table;
 660         int result;
 661
 662         for (;;) {
 663                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 664
 665                 if (type == DECODE_TYPE_END)
 666                         return 0;
 667
 668                 result = fn(h, args);
 669                 if (result)
 670                         return result;
 671
 672                 h = (struct decode_header *)
 673                         ((uintptr_t)h + decode_struct_sizes[type]);
 674
 675         }
 676 }
 677
 678 static int table_test_fail(const struct decode_header *h, const char* message)
 679 {
 680
 681         pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
 682                                         message, h->mask.bits, h->value.bits);
 683         return -EINVAL;
 684 }
 685
 686 struct table_test_args {
 687         const union decode_item *root_table;
 688         u32                     parent_mask;
 689         u32                     parent_value;
 690 };
 691
 692 static int table_test_fn(const struct decode_header *h, void *args)
 693 {
 694         struct table_test_args *a = (struct table_test_args *)args;
 695         enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 696
 697         if (h->value.bits & ~h->mask.bits)
 698                 return table_test_fail(h, "Match value has bits not in mask");
 699
 700         if ((h->mask.bits & a->parent_mask) != a->parent_mask)
 701                 return table_test_fail(h, "Mask has bits not in parent mask");
 702
 703         if ((h->value.bits ^ a->parent_value) & a->parent_mask)
 704                 return table_test_fail(h, "Value is inconsistent with parent");
 705
 706         if (type == DECODE_TYPE_TABLE) {
 707                 struct decode_table *d = (struct decode_table *)h;
 708                 struct table_test_args args2 = *a;
 709                 args2.parent_mask = h->mask.bits;
 710                 args2.parent_value = h->value.bits;
 711                 return table_iter(d->table.table, table_test_fn, &args2);
 712         }
 713
 714         return 0;
 715 }
 716
 717 static int table_test(const union decode_item *table)
 718 {
 719         struct table_test_args args = {
 720                 .root_table     = table,
 721                 .parent_mask    = 0,
 722                 .parent_value   = 0
 723         };
 724         return table_iter(args.root_table, table_test_fn, &args);
 725 }
 726
 727
 728 /*
 729  * Decoding table test coverage analysis
 730  *
 731  * coverage_start() builds a coverage_table which contains a list of
 732  * coverage_entry's to match each entry in the specified kprobes instruction
 733  * decoding table.
 734  *
 735  * When test cases are run, coverage_add() is called to process each case.
 736  * This looks up the corresponding entry in the coverage_table and sets it as
 737  * being matched, as well as clearing the regs flag appropriate for the test.
 738  *
 739  * After all test cases have been run, coverage_end() is called to check that
 740  * all entries in coverage_table have been matched and that all regs flags are
 741  * cleared. I.e. that all possible combinations of instructions described by
 742  * the kprobes decoding tables have had a test case executed for them.
 743  */
 744
 745 bool coverage_fail;
 746
 747 #define MAX_COVERAGE_ENTRIES 256
 748
 749 struct coverage_entry {
 750         const struct decode_header      *header;
 751         unsigned                        regs;
 752         unsigned                        nesting;
 753         char                            matched;
 754 };
 755
 756 struct coverage_table {
 757         struct coverage_entry   *base;
 758         unsigned                num_entries;
 759         unsigned                nesting;
 760 };
 761
 762 struct coverage_table coverage;
 763
 764 #define COVERAGE_ANY_REG        (1<<0)
 765 #define COVERAGE_SP             (1<<1)
 766 #define COVERAGE_PC             (1<<2)
 767 #define COVERAGE_PCWB           (1<<3)
 768
 769 static const char coverage_register_lookup[16] = {
 770         [REG_TYPE_ANY]          = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 771         [REG_TYPE_SAMEAS16]     = COVERAGE_ANY_REG,
 772         [REG_TYPE_SP]           = COVERAGE_SP,
 773         [REG_TYPE_PC]           = COVERAGE_PC,
 774         [REG_TYPE_NOSP]         = COVERAGE_ANY_REG | COVERAGE_SP,
 775         [REG_TYPE_NOSPPC]       = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
 776         [REG_TYPE_NOPC]         = COVERAGE_ANY_REG | COVERAGE_PC,
 777         [REG_TYPE_NOPCWB]       = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
 778         [REG_TYPE_NOPCX]        = COVERAGE_ANY_REG,
 779         [REG_TYPE_NOSPPCX]      = COVERAGE_ANY_REG | COVERAGE_SP,
 780 };
 781
 782 unsigned coverage_start_registers(const struct decode_header *h)
 783 {
 784         unsigned regs = 0;
 785         int i;
 786         for (i = 0; i < 20; i += 4) {
 787                 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
 788                 regs |= coverage_register_lookup[r] << i;
 789         }
 790         return regs;
 791 }
 792
 793 static int coverage_start_fn(const struct decode_header *h, void *args)
 794 {
 795         struct coverage_table *coverage = (struct coverage_table *)args;
 796         enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 797         struct coverage_entry *entry = coverage->base + coverage->num_entries;
 798
 799         if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
 800                 pr_err("FAIL: Out of space for test coverage data");
 801                 return -ENOMEM;
 802         }
 803
 804         ++coverage->num_entries;
 805
 806         entry->header = h;
 807         entry->regs = coverage_start_registers(h);
 808         entry->nesting = coverage->nesting;
 809         entry->matched = false;
 810
 811         if (type == DECODE_TYPE_TABLE) {
 812                 struct decode_table *d = (struct decode_table *)h;
 813                 int ret;
 814                 ++coverage->nesting;
 815                 ret = table_iter(d->table.table, coverage_start_fn, coverage);
 816                 --coverage->nesting;
 817                 return ret;
 818         }
 819
 820         return 0;
 821 }
 822
 823 static int coverage_start(const union decode_item *table)
 824 {
 825         coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
 826                                 sizeof(struct coverage_entry), GFP_KERNEL);
 827         coverage.num_entries = 0;
 828         coverage.nesting = 0;
 829         return table_iter(table, coverage_start_fn, &coverage);
 830 }
 831
 832 static void
 833 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
 834 {
 835         int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
 836         int i;
 837         for (i = 0; i < 20; i += 4) {
 838                 enum decode_reg_type reg_type = (regs >> i) & 0xf;
 839                 int reg = (insn >> i) & 0xf;
 840                 int flag;
 841
 842                 if (!reg_type)
 843                         continue;
 844
 845                 if (reg == 13)
 846                         flag = COVERAGE_SP;
 847                 else if (reg == 15)
 848                         flag = COVERAGE_PC;
 849                 else
 850                         flag = COVERAGE_ANY_REG;
 851                 entry->regs &= ~(flag << i);
 852
 853                 switch (reg_type) {
 854
 855                 case REG_TYPE_NONE:
 856                 case REG_TYPE_ANY:
 857                 case REG_TYPE_SAMEAS16:
 858                         break;
 859
 860                 case REG_TYPE_SP:
 861                         if (reg != 13)
 862                                 return;
 863                         break;
 864
 865                 case REG_TYPE_PC:
 866                         if (reg != 15)
 867                                 return;
 868                         break;
 869
 870                 case REG_TYPE_NOSP:
 871                         if (reg == 13)
 872                                 return;
 873                         break;
 874
 875                 case REG_TYPE_NOSPPC:
 876                 case REG_TYPE_NOSPPCX:
 877                         if (reg == 13 || reg == 15)
 878                                 return;
 879                         break;
 880
 881                 case REG_TYPE_NOPCWB:
 882                         if (!is_writeback(insn))
 883                                 break;
 884                         if (reg == 15) {
 885                                 entry->regs &= ~(COVERAGE_PCWB << i);
 886                                 return;
 887                         }
 888                         break;
 889
 890                 case REG_TYPE_NOPC:
 891                 case REG_TYPE_NOPCX:
 892                         if (reg == 15)
 893                                 return;
 894                         break;
 895                 }
 896
 897         }
 898 }
 899
 900 static void coverage_add(kprobe_opcode_t insn)
 901 {
 902         struct coverage_entry *entry = coverage.base;
 903         struct coverage_entry *end = coverage.base + coverage.num_entries;
 904         bool matched = false;
 905         unsigned nesting = 0;
 906
 907         for (; entry < end; ++entry) {
 908                 const struct decode_header *h = entry->header;
 909                 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
 910
 911                 if (entry->nesting > nesting)
 912                         continue; /* Skip sub-table we didn't match */
 913
 914                 if (entry->nesting < nesting)
 915                         break; /* End of sub-table we were scanning */
 916
 917                 if (!matched) {
 918                         if ((insn & h->mask.bits) != h->value.bits)
 919                                 continue;
 920                         entry->matched = true;
 921                 }
 922
 923                 switch (type) {
 924
 925                 case DECODE_TYPE_TABLE:
 926                         ++nesting;
 927                         break;
 928
 929                 case DECODE_TYPE_CUSTOM:
 930                 case DECODE_TYPE_SIMULATE:
 931                 case DECODE_TYPE_EMULATE:
 932                         coverage_add_registers(entry, insn);
 933                         return;
 934
 935                 case DECODE_TYPE_OR:
 936                         matched = true;
 937                         break;
 938
 939                 case DECODE_TYPE_REJECT:
 940                 default:
 941                         return;
 942                 }
 943
 944         }
 945 }
 946
 947 static void coverage_end(void)
 948 {
 949         struct coverage_entry *entry = coverage.base;
 950         struct coverage_entry *end = coverage.base + coverage.num_entries;
 951
 952         for (; entry < end; ++entry) {
 953                 u32 mask = entry->header->mask.bits;
 954                 u32 value = entry->header->value.bits;
 955
 956                 if (entry->regs) {
 957                         pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
 958                                 mask, value, entry->regs);
 959                         coverage_fail = true;
 960                 }
 961                 if (!entry->matched) {
 962                         pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
 963                                 mask, value);
 964                         coverage_fail = true;
 965                 }
 966         }
 967
 968         kfree(coverage.base);
 969 }
 970
 971
 972 /*
 973  * Framework for instruction set test cases
 974  */
 975
 976 void __naked __kprobes_test_case_start(void)
 977 {
 978         __asm__ __volatile__ (
 979                 "stmdb  sp!, {r4-r11}                           \n\t"
 980                 "sub    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 981                 "bic    r0, lr, #1  @ r0 = inline data          \n\t"
 982                 "mov    r1, sp                                  \n\t"
 983                 "bl     kprobes_test_case_start                 \n\t"
 984                 RET(r0)"                                        \n\t"
 985         );
 986 }
 987
 988 #ifndef CONFIG_THUMB2_KERNEL
 989
 990 void __naked __kprobes_test_case_end_32(void)
 991 {
 992         __asm__ __volatile__ (
 993                 "mov    r4, lr                                  \n\t"
 994                 "bl     kprobes_test_case_end                   \n\t"
 995                 "cmp    r0, #0                                  \n\t"
 996                 "movne  pc, r0                                  \n\t"
 997                 "mov    r0, r4                                  \n\t"
 998                 "add    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
 999                 "ldmia  sp!, {r4-r11}                           \n\t"
1000                 "mov    pc, r0                                  \n\t"
1001         );
1002 }
1003
1004 #else /* CONFIG_THUMB2_KERNEL */
1005
1006 void __naked __kprobes_test_case_end_16(void)
1007 {
1008         __asm__ __volatile__ (
1009                 "mov    r4, lr                                  \n\t"
1010                 "bl     kprobes_test_case_end                   \n\t"
1011                 "cmp    r0, #0                                  \n\t"
1012                 "bxne   r0                                      \n\t"
1013                 "mov    r0, r4                                  \n\t"
1014                 "add    sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
1015                 "ldmia  sp!, {r4-r11}                           \n\t"
1016                 "bx     r0                                      \n\t"
1017         );
1018 }
1019
1020 void __naked __kprobes_test_case_end_32(void)
1021 {
1022         __asm__ __volatile__ (
1023                 ".arm                                           \n\t"
1024                 "orr    lr, lr, #1  @ will return to Thumb code \n\t"
1025                 "ldr    pc, 1f                                  \n\t"
1026                 "1:                                             \n\t"
1027                 ".word  __kprobes_test_case_end_16              \n\t"
1028         );
1029 }
1030
1031 #endif
1032
1033
1034 int kprobe_test_flags;
1035 int kprobe_test_cc_position;
1036
1037 static int test_try_count;
1038 static int test_pass_count;
1039 static int test_fail_count;
1040
1041 static struct pt_regs initial_regs;
1042 static struct pt_regs expected_regs;
1043 static struct pt_regs result_regs;
1044
1045 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1046
1047 static const char *current_title;
1048 static struct test_arg *current_args;
1049 static u32 *current_stack;
1050 static uintptr_t current_branch_target;
1051
1052 static uintptr_t current_code_start;
1053 static kprobe_opcode_t current_instruction;
1054
1055
1056 #define TEST_CASE_PASSED -1
1057 #define TEST_CASE_FAILED -2
1058
1059 static int test_case_run_count;
1060 static bool test_case_is_thumb;
1061 static int test_instance;
1062
1063 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1064 {
1065         int ret = arm_check_condition(cc << 28, cpsr);
1066
1067         return (ret != ARM_OPCODE_CONDTEST_FAIL);
1068 }
1069
1070 static int is_last_scenario;
1071 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1072 static int memory_needs_checking;
1073
1074 static unsigned long test_context_cpsr(int scenario)
1075 {
1076         unsigned long cpsr;
1077
1078         probe_should_run = 1;
1079
1080         /* Default case is that we cycle through 16 combinations of flags */
1081         cpsr  = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1082         cpsr |= (scenario & 0xf) << 16; /* GE flags */
1083         cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1084
1085         if (!test_case_is_thumb) {
1086                 /* Testing ARM code */
1087                 int cc = current_instruction >> 28;
1088
1089                 probe_should_run = test_check_cc(cc, cpsr) != 0;
1090                 if (scenario == 15)
1091                         is_last_scenario = true;
1092
1093         } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1094                 /* Testing Thumb code without setting ITSTATE */
1095                 if (kprobe_test_cc_position) {
1096                         int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1097                         probe_should_run = test_check_cc(cc, cpsr) != 0;
1098                 }
1099
1100                 if (scenario == 15)
1101                         is_last_scenario = true;
1102
1103         } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1104                 /* Testing Thumb code with all combinations of ITSTATE */
1105                 unsigned x = (scenario >> 4);
1106                 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1107                 unsigned mask = x / 7 + 2;  /* ITSTATE<4:0>, bits reversed */
1108
1109                 if (mask > 0x1f) {
1110                         /* Finish by testing state from instruction 'itt al' */
1111                         cond_base = 7;
1112                         mask = 0x4;
1113                         if ((scenario & 0xf) == 0xf)
1114                                 is_last_scenario = true;
1115                 }
1116
1117                 cpsr |= cond_base << 13;        /* ITSTATE<7:5> */
1118                 cpsr |= (mask & 0x1) << 12;     /* ITSTATE<4> */
1119                 cpsr |= (mask & 0x2) << 10;     /* ITSTATE<3> */
1120                 cpsr |= (mask & 0x4) << 8;      /* ITSTATE<2> */
1121                 cpsr |= (mask & 0x8) << 23;     /* ITSTATE<1> */
1122                 cpsr |= (mask & 0x10) << 21;    /* ITSTATE<0> */
1123
1124                 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1125
1126         } else {
1127                 /* Testing Thumb code with several combinations of ITSTATE */
1128                 switch (scenario) {
1129                 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1130                         cpsr = 0x00000800;
1131                         probe_should_run = 0;
1132                         break;
1133                 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1134                         cpsr = 0xf0007800;
1135                         probe_should_run = 0;
1136                         break;
1137                 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1138                         cpsr = 0x00009800;
1139                         break;
1140                 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1141                         cpsr = 0xf0002800;
1142                         is_last_scenario = true;
1143                         break;
1144                 }
1145         }
1146
1147         return cpsr;
1148 }
1149
1150 static void setup_test_context(struct pt_regs *regs)
1151 {
1152         int scenario = test_case_run_count>>1;
1153         unsigned long val;
1154         struct test_arg *args;
1155         int i;
1156
1157         is_last_scenario = false;
1158         memory_needs_checking = false;
1159
1160         /* Initialise test memory on stack */
1161         val = (scenario & 1) ? VALM : ~VALM;
1162         for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1163                 current_stack[i] = val + (i << 8);
1164         /* Put target of branch on stack for tests which load PC from memory */
1165         if (current_branch_target)
1166                 current_stack[15] = current_branch_target;
1167         /* Put a value for SP on stack for tests which load SP from memory */
1168         current_stack[13] = (u32)current_stack + 120;
1169
1170         /* Initialise register values to their default state */
1171         val = (scenario & 2) ? VALR : ~VALR;
1172         for (i = 0; i < 13; ++i)
1173                 regs->uregs[i] = val ^ (i << 8);
1174         regs->ARM_lr = val ^ (14 << 8);
1175         regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1176         regs->ARM_cpsr |= test_context_cpsr(scenario);
1177
1178         /* Perform testcase specific register setup  */
1179         args = current_args;
1180         for (; args[0].type != ARG_TYPE_END; ++args)
1181                 switch (args[0].type) {
1182                 case ARG_TYPE_REG: {
1183                         struct test_arg_regptr *arg =
1184                                 (struct test_arg_regptr *)args;
1185                         regs->uregs[arg->reg] = arg->val;
1186                         break;
1187                 }
1188                 case ARG_TYPE_PTR: {
1189                         struct test_arg_regptr *arg =
1190                                 (struct test_arg_regptr *)args;
1191                         regs->uregs[arg->reg] =
1192                                 (unsigned long)current_stack + arg->val;
1193                         memory_needs_checking = true;
1194                         /*
1195                          * Test memory at an address below SP is in danger of
1196                          * being altered by an interrupt occurring and pushing
1197                          * data onto the stack. Disable interrupts to stop this.
1198                          */
1199                         if (arg->reg == 13)
1200                                 regs->ARM_cpsr |= PSR_I_BIT;
1201                         break;
1202                 }
1203                 case ARG_TYPE_MEM: {
1204                         struct test_arg_mem *arg = (struct test_arg_mem *)args;
1205                         current_stack[arg->index] = arg->val;
1206                         break;
1207                 }
1208                 default:
1209                         break;
1210                 }
1211 }
1212
1213 struct test_probe {
1214         struct kprobe   kprobe;
1215         bool            registered;
1216         int             hit;
1217 };
1218
1219 static void unregister_test_probe(struct test_probe *probe)
1220 {
1221         if (probe->registered) {
1222                 unregister_kprobe(&probe->kprobe);
1223                 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1224         }
1225         probe->registered = false;
1226 }
1227
1228 static int register_test_probe(struct test_probe *probe)
1229 {
1230         int ret;
1231
1232         if (probe->registered)
1233                 BUG();
1234
1235         ret = register_kprobe(&probe->kprobe);
1236         if (ret >= 0) {
1237                 probe->registered = true;
1238                 probe->hit = -1;
1239         }
1240         return ret;
1241 }
1242
1243 static int __kprobes
1244 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1245 {
1246         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1247         return 0;
1248 }
1249
1250 static void __kprobes
1251 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1252                                                         unsigned long flags)
1253 {
1254         setup_test_context(regs);
1255         initial_regs = *regs;
1256         initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1257 }
1258
1259 static int __kprobes
1260 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1261 {
1262         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1263         return 0;
1264 }
1265
1266 static int __kprobes
1267 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1268 {
1269         struct test_arg *args;
1270
1271         if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1272                 return 0; /* Already run for this test instance */
1273
1274         result_regs = *regs;
1275
1276         /* Mask out results which are indeterminate */
1277         result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1278         for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
1279                 if (args[0].type == ARG_TYPE_REG_MASKED) {
1280                         struct test_arg_regptr *arg =
1281                                 (struct test_arg_regptr *)args;
1282                         result_regs.uregs[arg->reg] &= arg->val;
1283                 }
1284
1285         /* Undo any changes done to SP by the test case */
1286         regs->ARM_sp = (unsigned long)current_stack;
1287         /* Enable interrupts in case setup_test_context disabled them */
1288         regs->ARM_cpsr &= ~PSR_I_BIT;
1289
1290         container_of(p, struct test_probe, kprobe)->hit = test_instance;
1291         return 0;
1292 }
1293
1294 static struct test_probe test_before_probe = {
1295         .kprobe.pre_handler     = test_before_pre_handler,
1296         .kprobe.post_handler    = test_before_post_handler,
1297 };
1298
1299 static struct test_probe test_case_probe = {
1300         .kprobe.pre_handler     = test_case_pre_handler,
1301 };
1302
1303 static struct test_probe test_after_probe = {
1304         .kprobe.pre_handler     = test_after_pre_handler,
1305 };
1306
1307 static struct test_probe test_after2_probe = {
1308         .kprobe.pre_handler     = test_after_pre_handler,
1309 };
1310
1311 static void test_case_cleanup(void)
1312 {
1313         unregister_test_probe(&test_before_probe);
1314         unregister_test_probe(&test_case_probe);
1315         unregister_test_probe(&test_after_probe);
1316         unregister_test_probe(&test_after2_probe);
1317 }
1318
1319 static void print_registers(struct pt_regs *regs)
1320 {
1321         pr_err("r0  %08lx | r1  %08lx | r2  %08lx | r3  %08lx\n",
1322                 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1323         pr_err("r4  %08lx | r5  %08lx | r6  %08lx | r7  %08lx\n",
1324                 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1325         pr_err("r8  %08lx | r9  %08lx | r10 %08lx | r11 %08lx\n",
1326                 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1327         pr_err("r12 %08lx | sp  %08lx | lr  %08lx | pc  %08lx\n",
1328                 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1329         pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1330 }
1331
1332 static void print_memory(u32 *mem, size_t size)
1333 {
1334         int i;
1335         for (i = 0; i < size / sizeof(u32); i += 4)
1336                 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1337                                                 mem[i+2], mem[i+3]);
1338 }
1339
1340 static size_t expected_memory_size(u32 *sp)
1341 {
1342         size_t size = sizeof(expected_memory);
1343         int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1344         if (offset > 0)
1345                 size -= offset;
1346         return size;
1347 }
1348
1349 static void test_case_failed(const char *message)
1350 {
1351         test_case_cleanup();
1352
1353         pr_err("FAIL: %s\n", message);
1354         pr_err("FAIL: Test %s\n", current_title);
1355         pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1356 }
1357
1358 static unsigned long next_instruction(unsigned long pc)
1359 {
1360 #ifdef CONFIG_THUMB2_KERNEL
1361         if ((pc & 1) &&
1362             !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1363                 return pc + 2;
1364         else
1365 #endif
1366         return pc + 4;
1367 }
1368
1369 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1370 {
1371         struct test_arg *args;
1372         struct test_arg_end *end_arg;
1373         unsigned long test_code;
1374
1375         current_title = *title++;
1376         args = (struct test_arg *)title;
1377         current_args = args;
1378         current_stack = stack;
1379
1380         ++test_try_count;
1381
1382         while (args->type != ARG_TYPE_END)
1383                 ++args;
1384         end_arg = (struct test_arg_end *)args;
1385
1386         test_code = (unsigned long)(args + 1); /* Code starts after args */
1387
1388         test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1389         if (test_case_is_thumb)
1390                 test_code |= 1;
1391
1392         current_code_start = test_code;
1393
1394         current_branch_target = 0;
1395         if (end_arg->branch_offset != end_arg->end_offset)
1396                 current_branch_target = test_code + end_arg->branch_offset;
1397
1398         test_code += end_arg->code_offset;
1399         test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1400
1401         test_code = next_instruction(test_code);
1402         test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1403
1404         if (test_case_is_thumb) {
1405                 u16 *p = (u16 *)(test_code & ~1);
1406                 current_instruction = __mem_to_opcode_thumb16(p[0]);
1407                 if (is_wide_instruction(current_instruction)) {
1408                         u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1409                         current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1410                 }
1411         } else {
1412                 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1413         }
1414
1415         if (current_title[0] == '.')
1416                 verbose("%s\n", current_title);
1417         else
1418                 verbose("%s\t@ %0*x\n", current_title,
1419                                         test_case_is_thumb ? 4 : 8,
1420                                         current_instruction);
1421
1422         test_code = next_instruction(test_code);
1423         test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1424
1425         if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1426                 if (!test_case_is_thumb ||
1427                         is_wide_instruction(current_instruction)) {
1428                                 test_case_failed("expected 16-bit instruction");
1429                                 goto fail;
1430                 }
1431         } else {
1432                 if (test_case_is_thumb &&
1433                         !is_wide_instruction(current_instruction)) {
1434                                 test_case_failed("expected 32-bit instruction");
1435                                 goto fail;
1436                 }
1437         }
1438
1439         coverage_add(current_instruction);
1440
1441         if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1442                 if (register_test_probe(&test_case_probe) < 0)
1443                         goto pass;
1444                 test_case_failed("registered probe for unsupported instruction");
1445                 goto fail;
1446         }
1447
1448         if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1449                 if (register_test_probe(&test_case_probe) >= 0)
1450                         goto pass;
1451                 test_case_failed("couldn't register probe for supported instruction");
1452                 goto fail;
1453         }
1454
1455         if (register_test_probe(&test_before_probe) < 0) {
1456                 test_case_failed("register test_before_probe failed");
1457                 goto fail;
1458         }
1459         if (register_test_probe(&test_after_probe) < 0) {
1460                 test_case_failed("register test_after_probe failed");
1461                 goto fail;
1462         }
1463         if (current_branch_target) {
1464                 test_after2_probe.kprobe.addr =
1465                                 (kprobe_opcode_t *)current_branch_target;
1466                 if (register_test_probe(&test_after2_probe) < 0) {
1467                         test_case_failed("register test_after2_probe failed");
1468                         goto fail;
1469                 }
1470         }
1471
1472         /* Start first run of test case */
1473         test_case_run_count = 0;
1474         ++test_instance;
1475         return current_code_start;
1476 pass:
1477         test_case_run_count = TEST_CASE_PASSED;
1478         return (uintptr_t)test_after_probe.kprobe.addr;
1479 fail:
1480         test_case_run_count = TEST_CASE_FAILED;
1481         return (uintptr_t)test_after_probe.kprobe.addr;
1482 }
1483
1484 static bool check_test_results(void)
1485 {
1486         size_t mem_size = 0;
1487         u32 *mem = 0;
1488
1489         if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1490                 test_case_failed("registers differ");
1491                 goto fail;
1492         }
1493
1494         if (memory_needs_checking) {
1495                 mem = (u32 *)result_regs.ARM_sp;
1496                 mem_size = expected_memory_size(mem);
1497                 if (memcmp(expected_memory, mem, mem_size)) {
1498                         test_case_failed("test memory differs");
1499                         goto fail;
1500                 }
1501         }
1502
1503         return true;
1504
1505 fail:
1506         pr_err("initial_regs:\n");
1507         print_registers(&initial_regs);
1508         pr_err("expected_regs:\n");
1509         print_registers(&expected_regs);
1510         pr_err("result_regs:\n");
1511         print_registers(&result_regs);
1512
1513         if (mem) {
1514                 pr_err("current_stack=%p\n", current_stack);
1515                 pr_err("expected_memory:\n");
1516                 print_memory(expected_memory, mem_size);
1517                 pr_err("result_memory:\n");
1518                 print_memory(mem, mem_size);
1519         }
1520
1521         return false;
1522 }
1523
1524 static uintptr_t __used kprobes_test_case_end(void)
1525 {
1526         if (test_case_run_count < 0) {
1527                 if (test_case_run_count == TEST_CASE_PASSED)
1528                         /* kprobes_test_case_start did all the needed testing */
1529                         goto pass;
1530                 else
1531                         /* kprobes_test_case_start failed */
1532                         goto fail;
1533         }
1534
1535         if (test_before_probe.hit != test_instance) {
1536                 test_case_failed("test_before_handler not run");
1537                 goto fail;
1538         }
1539
1540         if (test_after_probe.hit != test_instance &&
1541                                 test_after2_probe.hit != test_instance) {
1542                 test_case_failed("test_after_handler not run");
1543                 goto fail;
1544         }
1545
1546         /*
1547          * Even numbered test runs ran without a probe on the test case so
1548          * we can gather reference results. The subsequent odd numbered run
1549          * will have the probe inserted.
1550         */
1551         if ((test_case_run_count & 1) == 0) {
1552                 /* Save results from run without probe */
1553                 u32 *mem = (u32 *)result_regs.ARM_sp;
1554                 expected_regs = result_regs;
1555                 memcpy(expected_memory, mem, expected_memory_size(mem));
1556
1557                 /* Insert probe onto test case instruction */
1558                 if (register_test_probe(&test_case_probe) < 0) {
1559                         test_case_failed("register test_case_probe failed");
1560                         goto fail;
1561                 }
1562         } else {
1563                 /* Check probe ran as expected */
1564                 if (probe_should_run == 1) {
1565                         if (test_case_probe.hit != test_instance) {
1566                                 test_case_failed("test_case_handler not run");
1567                                 goto fail;
1568                         }
1569                 } else if (probe_should_run == 0) {
1570                         if (test_case_probe.hit == test_instance) {
1571                                 test_case_failed("test_case_handler ran");
1572                                 goto fail;
1573                         }
1574                 }
1575
1576                 /* Remove probe for any subsequent reference run */
1577                 unregister_test_probe(&test_case_probe);
1578
1579                 if (!check_test_results())
1580                         goto fail;
1581
1582                 if (is_last_scenario)
1583                         goto pass;
1584         }
1585
1586         /* Do next test run */
1587         ++test_case_run_count;
1588         ++test_instance;
1589         return current_code_start;
1590 fail:
1591         ++test_fail_count;
1592         goto end;
1593 pass:
1594         ++test_pass_count;
1595 end:
1596         test_case_cleanup();
1597         return 0;
1598 }
1599
1600
1601 /*
1602  * Top level test functions
1603  */
1604
1605 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1606 {
1607         int ret;
1608
1609         pr_info("    Check decoding tables\n");
1610         ret = table_test(table);
1611         if (ret)
1612                 return ret;
1613
1614         pr_info("    Run test cases\n");
1615         ret = coverage_start(table);
1616         if (ret)
1617                 return ret;
1618
1619         tests();
1620
1621         coverage_end();
1622         return 0;
1623 }
1624
1625
1626 static int __init run_all_tests(void)
1627 {
1628         int ret = 0;
1629
1630         pr_info("Beginning kprobe tests...\n");
1631
1632 #ifndef CONFIG_THUMB2_KERNEL
1633
1634         pr_info("Probe ARM code\n");
1635         ret = run_api_tests(arm_func);
1636         if (ret)
1637                 goto out;
1638
1639         pr_info("ARM instruction simulation\n");
1640         ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1641         if (ret)
1642                 goto out;
1643
1644 #else /* CONFIG_THUMB2_KERNEL */
1645
1646         pr_info("Probe 16-bit Thumb code\n");
1647         ret = run_api_tests(thumb16_func);
1648         if (ret)
1649                 goto out;
1650
1651         pr_info("Probe 32-bit Thumb code, even halfword\n");
1652         ret = run_api_tests(thumb32even_func);
1653         if (ret)
1654                 goto out;
1655
1656         pr_info("Probe 32-bit Thumb code, odd halfword\n");
1657         ret = run_api_tests(thumb32odd_func);
1658         if (ret)
1659                 goto out;
1660
1661         pr_info("16-bit Thumb instruction simulation\n");
1662         ret = run_test_cases(kprobe_thumb16_test_cases,
1663                                 probes_decode_thumb16_table);
1664         if (ret)
1665                 goto out;
1666
1667         pr_info("32-bit Thumb instruction simulation\n");
1668         ret = run_test_cases(kprobe_thumb32_test_cases,
1669                                 probes_decode_thumb32_table);
1670         if (ret)
1671                 goto out;
1672 #endif
1673
1674         pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1675                 test_try_count, test_pass_count, test_fail_count);
1676         if (test_fail_count) {
1677                 ret = -EINVAL;
1678                 goto out;
1679         }
1680
1681 #if BENCHMARKING
1682         pr_info("Benchmarks\n");
1683         ret = run_benchmarks();
1684         if (ret)
1685                 goto out;
1686 #endif
1687
1688 #if __LINUX_ARM_ARCH__ >= 7
1689         /* We are able to run all test cases so coverage should be complete */
1690         if (coverage_fail) {
1691                 pr_err("FAIL: Test coverage checks failed\n");
1692                 ret = -EINVAL;
1693                 goto out;
1694         }
1695 #endif
1696
1697 out:
1698         if (ret == 0)
1699                 ret = tests_failed;
1700         if (ret == 0)
1701                 pr_info("Finished kprobe tests OK\n");
1702         else
1703                 pr_err("kprobe tests failed\n");
1704
1705         return ret;
1706 }
1707
1708
1709 /*
1710  * Module setup
1711  */
1712
1713 #ifdef MODULE
1714
1715 static void __exit kprobe_test_exit(void)
1716 {
1717 }
1718
1719 module_init(run_all_tests)
1720 module_exit(kprobe_test_exit)
1721 MODULE_LICENSE("GPL");
1722
1723 #else /* !MODULE */
1724
1725 late_initcall(run_all_tests);
1726
1727 #endif