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

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  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 '').
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
1734 

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