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

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