2 * arch/arm/kernel/kprobes-test.c
4 * Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
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.
12 * This file contains test code for ARM kprobes.
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.
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.
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
36 * The methodology used to test an ARM instruction 'test_insn' is to use
37 * inline assembler like:
40 * test_case: test_insn
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.
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.
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.
59 * For instructions which can modify PC, a second test_after probe is used
63 * test_case: test_insn
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...
76 * b test_done @ helps to cope with off by 1 branches
80 * test_case: test_insn
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.
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:
100 * TESTCASE_START("Testing mov r0, r7")
101 * TEST_ARG_REG(7, 0x12345678) // Set r7=0x12345678
103 * TEST_INSTRUCTION("mov r0, r7")
106 * Note, in practice the single convenience macro TEST_R would be used for this
109 * The above would expand to assembler looking something like:
112 * bl __kprobes_test_case_start
113 * @ start of inline data...
114 * .ascii "mov r0, r7" @ text title for test case
126 * .byte TEST_ISA @ flags, including ISA being tested
127 * .short 50f-0f @ offset of 'test_before'
128 * .short 2f-0f @ offset of 'test_after2' (if relevent)
129 * .short 99f-0f @ offset of 'test_done'
130 * @ start of test case code...
132 * .code TEST_ISA @ switch to ISA being tested
135 * 50: nop @ location for 'test_before' probe
136 * 1: mov r0, r7 @ the test case instruction 'test_insn'
137 * nop @ location for 'test_after' probe
141 * 99: bl __kprobes_test_case_end_##TEST_ISA
144 * When the above is execute the following happens...
146 * __kprobes_test_case_start() is an assembler wrapper which sets up space
147 * for a stack buffer and calls the C function kprobes_test_case_start().
148 * This C function will do some initial processing of the inline data and
149 * setup some global state. It then inserts the test_before and test_after
150 * kprobes and returns a value which causes the assembler wrapper to jump
151 * to the start of the test case code, (local label '0').
153 * When the test case code executes, the test_before probe will be hit and
154 * test_before_post_handler will call setup_test_context(). This fills the
155 * stack buffer and CPU registers with a test pattern and then processes
156 * the test case arguments. In our example there is one TEST_ARG_REG which
157 * indicates that R7 should be loaded with the value 0x12345678.
159 * When the test_before probe ends, the test case continues and executes
160 * the "mov r0, r7" instruction. It then hits the test_after probe and the
161 * pre-handler for this (test_after_pre_handler) will save a copy of the
162 * CPU register context. This should now have R0 holding the same value as
165 * Finally we get to the call to __kprobes_test_case_end_{32,16}. This is
166 * an assembler wrapper which switches back to the ISA used by the test
167 * code and calls the C function kprobes_test_case_end().
169 * For each run through the test case, test_case_run_count is incremented
170 * by one. For even runs, kprobes_test_case_end() saves a copy of the
171 * register and stack buffer contents from the test case just run. It then
172 * inserts a kprobe on the test case instruction 'test_insn' and returns a
173 * value to cause the test case code to be re-run.
175 * For odd numbered runs, kprobes_test_case_end() compares the register and
176 * stack buffer contents to those that were saved on the previous even
177 * numbered run (the one without the kprobe on test_insn). These should be
178 * the same if the kprobe instruction simulation routine is correct.
180 * The pair of test case runs is repeated with different combinations of
181 * flag values in CPSR and, for Thumb, different ITState. This is
182 * controlled by test_context_cpsr().
184 * BUILDING TEST CASES
185 * -------------------
188 * As an aid to building test cases, the stack buffer is initialised with
189 * some special values:
191 * [SP+13*4] Contains SP+120. This can be used to test instructions
192 * which load a value into SP.
194 * [SP+15*4] When testing branching instructions using TEST_BRANCH_{F,B},
195 * this holds the target address of the branch, 'test_after2'.
196 * This can be used to test instructions which load a PC value
200 #include <linux/kernel.h>
201 #include <linux/module.h>
202 #include <linux/slab.h>
203 #include <linux/kprobes.h>
204 #include <linux/errno.h>
205 #include <linux/stddef.h>
206 #include <linux/bug.h>
207 #include <asm/opcodes.h>
210 #include "probes-arm.h"
211 #include "probes-thumb.h"
212 #include "kprobes-test.h"
215 #define BENCHMARKING 1
222 static bool test_regs_ok;
223 static int test_func_instance;
224 static int pre_handler_called;
225 static int post_handler_called;
226 static int jprobe_func_called;
227 static int kretprobe_handler_called;
229 #define FUNC_ARG1 0x12345678
230 #define FUNC_ARG2 0xabcdef
233 #ifndef CONFIG_THUMB2_KERNEL
235 long arm_func(long r0, long r1);
237 static void __used __naked __arm_kprobes_test_func(void)
239 __asm__ __volatile__ (
241 ".type arm_func, %%function \n\t"
243 "adds r0, r0, r1 \n\t"
245 ".code "NORMAL_ISA /* Back to Thumb if necessary */
246 : : : "r0", "r1", "cc"
250 #else /* CONFIG_THUMB2_KERNEL */
252 long thumb16_func(long r0, long r1);
253 long thumb32even_func(long r0, long r1);
254 long thumb32odd_func(long r0, long r1);
256 static void __used __naked __thumb_kprobes_test_funcs(void)
258 __asm__ __volatile__ (
259 ".type thumb16_func, %%function \n\t"
261 "adds.n r0, r0, r1 \n\t"
265 ".type thumb32even_func, %%function \n\t"
266 "thumb32even_func: \n\t"
267 "adds.w r0, r0, r1 \n\t"
272 ".type thumb32odd_func, %%function \n\t"
273 "thumb32odd_func: \n\t"
274 "adds.w r0, r0, r1 \n\t"
277 : : : "r0", "r1", "cc"
281 #endif /* CONFIG_THUMB2_KERNEL */
284 static int call_test_func(long (*func)(long, long), bool check_test_regs)
288 ++test_func_instance;
289 test_regs_ok = false;
291 ret = (*func)(FUNC_ARG1, FUNC_ARG2);
292 if (ret != FUNC_ARG1 + FUNC_ARG2) {
293 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
297 if (check_test_regs && !test_regs_ok) {
298 pr_err("FAIL: test regs not OK\n");
305 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
307 pre_handler_called = test_func_instance;
308 if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
313 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
316 post_handler_called = test_func_instance;
317 if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
318 test_regs_ok = false;
321 static struct kprobe the_kprobe = {
323 .pre_handler = pre_handler,
324 .post_handler = post_handler
327 static int test_kprobe(long (*func)(long, long))
331 the_kprobe.addr = (kprobe_opcode_t *)func;
332 ret = register_kprobe(&the_kprobe);
334 pr_err("FAIL: register_kprobe failed with %d\n", ret);
338 ret = call_test_func(func, true);
340 unregister_kprobe(&the_kprobe);
341 the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
345 if (pre_handler_called != test_func_instance) {
346 pr_err("FAIL: kprobe pre_handler not called\n");
349 if (post_handler_called != test_func_instance) {
350 pr_err("FAIL: kprobe post_handler not called\n");
353 if (!call_test_func(func, false))
355 if (pre_handler_called == test_func_instance ||
356 post_handler_called == test_func_instance) {
357 pr_err("FAIL: probe called after unregistering\n");
364 static void __kprobes jprobe_func(long r0, long r1)
366 jprobe_func_called = test_func_instance;
367 if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
372 static struct jprobe the_jprobe = {
373 .entry = jprobe_func,
376 static int test_jprobe(long (*func)(long, long))
380 the_jprobe.kp.addr = (kprobe_opcode_t *)func;
381 ret = register_jprobe(&the_jprobe);
383 pr_err("FAIL: register_jprobe failed with %d\n", ret);
387 ret = call_test_func(func, true);
389 unregister_jprobe(&the_jprobe);
390 the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
394 if (jprobe_func_called != test_func_instance) {
395 pr_err("FAIL: jprobe handler function not called\n");
398 if (!call_test_func(func, false))
400 if (jprobe_func_called == test_func_instance) {
401 pr_err("FAIL: probe called after unregistering\n");
409 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
411 kretprobe_handler_called = test_func_instance;
412 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
417 static struct kretprobe the_kretprobe = {
418 .handler = kretprobe_handler,
421 static int test_kretprobe(long (*func)(long, long))
425 the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
426 ret = register_kretprobe(&the_kretprobe);
428 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
432 ret = call_test_func(func, true);
434 unregister_kretprobe(&the_kretprobe);
435 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
439 if (kretprobe_handler_called != test_func_instance) {
440 pr_err("FAIL: kretprobe handler not called\n");
443 if (!call_test_func(func, false))
445 if (jprobe_func_called == test_func_instance) {
446 pr_err("FAIL: kretprobe called after unregistering\n");
453 static int run_api_tests(long (*func)(long, long))
457 pr_info(" kprobe\n");
458 ret = test_kprobe(func);
462 pr_info(" jprobe\n");
463 ret = test_jprobe(func);
467 pr_info(" kretprobe\n");
468 ret = test_kretprobe(func);
482 static void __naked benchmark_nop(void)
484 __asm__ __volatile__ (
490 #ifdef CONFIG_THUMB2_KERNEL
496 static void __naked benchmark_pushpop1(void)
498 __asm__ __volatile__ (
499 "stmdb"wide" sp!, {r3-r11,lr} \n\t"
500 "ldmia"wide" sp!, {r3-r11,pc}"
504 static void __naked benchmark_pushpop2(void)
506 __asm__ __volatile__ (
507 "stmdb"wide" sp!, {r0-r8,lr} \n\t"
508 "ldmia"wide" sp!, {r0-r8,pc}"
512 static void __naked benchmark_pushpop3(void)
514 __asm__ __volatile__ (
515 "stmdb"wide" sp!, {r4,lr} \n\t"
516 "ldmia"wide" sp!, {r4,pc}"
520 static void __naked benchmark_pushpop4(void)
522 __asm__ __volatile__ (
523 "stmdb"wide" sp!, {r0,lr} \n\t"
524 "ldmia"wide" sp!, {r0,pc}"
529 #ifdef CONFIG_THUMB2_KERNEL
531 static void __naked benchmark_pushpop_thumb(void)
533 __asm__ __volatile__ (
534 "push.n {r0-r7,lr} \n\t"
542 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
547 static int benchmark(void(*fn)(void))
549 unsigned n, i, t, t0;
551 for (n = 1000; ; n *= 2) {
553 for (i = n; i > 0; --i)
555 t = sched_clock() - t0;
557 break; /* Stop once we took more than 0.25 seconds */
559 return t / n; /* Time for one iteration in nanoseconds */
562 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
565 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset),
566 .pre_handler = benchmark_pre_handler,
569 int ret = register_kprobe(&k);
571 pr_err("FAIL: register_kprobe failed with %d\n", ret);
577 unregister_kprobe(&k);
587 static int run_benchmarks(void)
590 struct benchmarks list[] = {
591 {&benchmark_nop, 0, "nop"},
593 * benchmark_pushpop{1,3} will have the optimised
594 * instruction emulation, whilst benchmark_pushpop{2,4} will
595 * be the equivalent unoptimised instructions.
597 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
598 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
599 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
600 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
601 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
602 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
603 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
604 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
605 #ifdef CONFIG_THUMB2_KERNEL
606 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"},
607 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"},
612 struct benchmarks *b;
613 for (b = list; b->fn; ++b) {
614 ret = kprobe_benchmark(b->fn, b->offset);
617 pr_info(" %dns for kprobe %s\n", ret, b->title);
624 #endif /* BENCHMARKING */
628 * Decoding table self-consistency tests
631 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
632 [DECODE_TYPE_TABLE] = sizeof(struct decode_table),
633 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
634 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
635 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
636 [DECODE_TYPE_OR] = sizeof(struct decode_or),
637 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
640 static int table_iter(const union decode_item *table,
641 int (*fn)(const struct decode_header *, void *),
644 const struct decode_header *h = (struct decode_header *)table;
648 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
650 if (type == DECODE_TYPE_END)
653 result = fn(h, args);
657 h = (struct decode_header *)
658 ((uintptr_t)h + decode_struct_sizes[type]);
663 static int table_test_fail(const struct decode_header *h, const char* message)
666 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
667 message, h->mask.bits, h->value.bits);
671 struct table_test_args {
672 const union decode_item *root_table;
677 static int table_test_fn(const struct decode_header *h, void *args)
679 struct table_test_args *a = (struct table_test_args *)args;
680 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
682 if (h->value.bits & ~h->mask.bits)
683 return table_test_fail(h, "Match value has bits not in mask");
685 if ((h->mask.bits & a->parent_mask) != a->parent_mask)
686 return table_test_fail(h, "Mask has bits not in parent mask");
688 if ((h->value.bits ^ a->parent_value) & a->parent_mask)
689 return table_test_fail(h, "Value is inconsistent with parent");
691 if (type == DECODE_TYPE_TABLE) {
692 struct decode_table *d = (struct decode_table *)h;
693 struct table_test_args args2 = *a;
694 args2.parent_mask = h->mask.bits;
695 args2.parent_value = h->value.bits;
696 return table_iter(d->table.table, table_test_fn, &args2);
702 static int table_test(const union decode_item *table)
704 struct table_test_args args = {
709 return table_iter(args.root_table, table_test_fn, &args);
714 * Decoding table test coverage analysis
716 * coverage_start() builds a coverage_table which contains a list of
717 * coverage_entry's to match each entry in the specified kprobes instruction
720 * When test cases are run, coverage_add() is called to process each case.
721 * This looks up the corresponding entry in the coverage_table and sets it as
722 * being matched, as well as clearing the regs flag appropriate for the test.
724 * After all test cases have been run, coverage_end() is called to check that
725 * all entries in coverage_table have been matched and that all regs flags are
726 * cleared. I.e. that all possible combinations of instructions described by
727 * the kprobes decoding tables have had a test case executed for them.
732 #define MAX_COVERAGE_ENTRIES 256
734 struct coverage_entry {
735 const struct decode_header *header;
741 struct coverage_table {
742 struct coverage_entry *base;
743 unsigned num_entries;
747 struct coverage_table coverage;
749 #define COVERAGE_ANY_REG (1<<0)
750 #define COVERAGE_SP (1<<1)
751 #define COVERAGE_PC (1<<2)
752 #define COVERAGE_PCWB (1<<3)
754 static const char coverage_register_lookup[16] = {
755 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
756 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG,
757 [REG_TYPE_SP] = COVERAGE_SP,
758 [REG_TYPE_PC] = COVERAGE_PC,
759 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP,
760 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
761 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC,
762 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
763 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG,
764 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP,
767 unsigned coverage_start_registers(const struct decode_header *h)
771 for (i = 0; i < 20; i += 4) {
772 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
773 regs |= coverage_register_lookup[r] << i;
778 static int coverage_start_fn(const struct decode_header *h, void *args)
780 struct coverage_table *coverage = (struct coverage_table *)args;
781 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
782 struct coverage_entry *entry = coverage->base + coverage->num_entries;
784 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
785 pr_err("FAIL: Out of space for test coverage data");
789 ++coverage->num_entries;
792 entry->regs = coverage_start_registers(h);
793 entry->nesting = coverage->nesting;
794 entry->matched = false;
796 if (type == DECODE_TYPE_TABLE) {
797 struct decode_table *d = (struct decode_table *)h;
800 ret = table_iter(d->table.table, coverage_start_fn, coverage);
808 static int coverage_start(const union decode_item *table)
810 coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
811 sizeof(struct coverage_entry), GFP_KERNEL);
812 coverage.num_entries = 0;
813 coverage.nesting = 0;
814 return table_iter(table, coverage_start_fn, &coverage);
818 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
820 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
822 for (i = 0; i < 20; i += 4) {
823 enum decode_reg_type reg_type = (regs >> i) & 0xf;
824 int reg = (insn >> i) & 0xf;
835 flag = COVERAGE_ANY_REG;
836 entry->regs &= ~(flag << i);
842 case REG_TYPE_SAMEAS16:
860 case REG_TYPE_NOSPPC:
861 case REG_TYPE_NOSPPCX:
862 if (reg == 13 || reg == 15)
866 case REG_TYPE_NOPCWB:
867 if (!is_writeback(insn))
870 entry->regs &= ~(COVERAGE_PCWB << i);
885 static void coverage_add(kprobe_opcode_t insn)
887 struct coverage_entry *entry = coverage.base;
888 struct coverage_entry *end = coverage.base + coverage.num_entries;
889 bool matched = false;
890 unsigned nesting = 0;
892 for (; entry < end; ++entry) {
893 const struct decode_header *h = entry->header;
894 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
896 if (entry->nesting > nesting)
897 continue; /* Skip sub-table we didn't match */
899 if (entry->nesting < nesting)
900 break; /* End of sub-table we were scanning */
903 if ((insn & h->mask.bits) != h->value.bits)
905 entry->matched = true;
910 case DECODE_TYPE_TABLE:
914 case DECODE_TYPE_CUSTOM:
915 case DECODE_TYPE_SIMULATE:
916 case DECODE_TYPE_EMULATE:
917 coverage_add_registers(entry, insn);
924 case DECODE_TYPE_REJECT:
932 static void coverage_end(void)
934 struct coverage_entry *entry = coverage.base;
935 struct coverage_entry *end = coverage.base + coverage.num_entries;
937 for (; entry < end; ++entry) {
938 u32 mask = entry->header->mask.bits;
939 u32 value = entry->header->value.bits;
942 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
943 mask, value, entry->regs);
944 coverage_fail = true;
946 if (!entry->matched) {
947 pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
949 coverage_fail = true;
953 kfree(coverage.base);
958 * Framework for instruction set test cases
961 void __naked __kprobes_test_case_start(void)
963 __asm__ __volatile__ (
964 "stmdb sp!, {r4-r11} \n\t"
965 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
966 "bic r0, lr, #1 @ r0 = inline title string \n\t"
968 "bl kprobes_test_case_start \n\t"
973 #ifndef CONFIG_THUMB2_KERNEL
975 void __naked __kprobes_test_case_end_32(void)
977 __asm__ __volatile__ (
979 "bl kprobes_test_case_end \n\t"
983 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
984 "ldmia sp!, {r4-r11} \n\t"
989 #else /* CONFIG_THUMB2_KERNEL */
991 void __naked __kprobes_test_case_end_16(void)
993 __asm__ __volatile__ (
995 "bl kprobes_test_case_end \n\t"
999 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
1000 "ldmia sp!, {r4-r11} \n\t"
1005 void __naked __kprobes_test_case_end_32(void)
1007 __asm__ __volatile__ (
1009 "orr lr, lr, #1 @ will return to Thumb code \n\t"
1012 ".word __kprobes_test_case_end_16 \n\t"
1019 int kprobe_test_flags;
1020 int kprobe_test_cc_position;
1022 static int test_try_count;
1023 static int test_pass_count;
1024 static int test_fail_count;
1026 static struct pt_regs initial_regs;
1027 static struct pt_regs expected_regs;
1028 static struct pt_regs result_regs;
1030 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1032 static const char *current_title;
1033 static struct test_arg *current_args;
1034 static u32 *current_stack;
1035 static uintptr_t current_branch_target;
1037 static uintptr_t current_code_start;
1038 static kprobe_opcode_t current_instruction;
1041 #define TEST_CASE_PASSED -1
1042 #define TEST_CASE_FAILED -2
1044 static int test_case_run_count;
1045 static bool test_case_is_thumb;
1046 static int test_instance;
1049 * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
1050 * can change randomly as the kernel doesn't take care to preserve or initialise
1051 * this across context switches. Also, with Security Extentions, the flag may
1052 * not be under control of the kernel; for this reason we ignore the state of
1053 * the FIQ disable flag CPSR.F as well.
1055 #define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
1057 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1059 int ret = arm_check_condition(cc << 28, cpsr);
1061 return (ret != ARM_OPCODE_CONDTEST_FAIL);
1064 static int is_last_scenario;
1065 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1066 static int memory_needs_checking;
1068 static unsigned long test_context_cpsr(int scenario)
1072 probe_should_run = 1;
1074 /* Default case is that we cycle through 16 combinations of flags */
1075 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1076 cpsr |= (scenario & 0xf) << 16; /* GE flags */
1077 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1079 if (!test_case_is_thumb) {
1080 /* Testing ARM code */
1081 int cc = current_instruction >> 28;
1083 probe_should_run = test_check_cc(cc, cpsr) != 0;
1085 is_last_scenario = true;
1087 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1088 /* Testing Thumb code without setting ITSTATE */
1089 if (kprobe_test_cc_position) {
1090 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1091 probe_should_run = test_check_cc(cc, cpsr) != 0;
1095 is_last_scenario = true;
1097 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1098 /* Testing Thumb code with all combinations of ITSTATE */
1099 unsigned x = (scenario >> 4);
1100 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1101 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
1104 /* Finish by testing state from instruction 'itt al' */
1107 if ((scenario & 0xf) == 0xf)
1108 is_last_scenario = true;
1111 cpsr |= cond_base << 13; /* ITSTATE<7:5> */
1112 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
1113 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
1114 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
1115 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
1116 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
1118 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1121 /* Testing Thumb code with several combinations of ITSTATE */
1123 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1125 probe_should_run = 0;
1127 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1129 probe_should_run = 0;
1131 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1134 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1136 is_last_scenario = true;
1144 static void setup_test_context(struct pt_regs *regs)
1146 int scenario = test_case_run_count>>1;
1148 struct test_arg *args;
1151 is_last_scenario = false;
1152 memory_needs_checking = false;
1154 /* Initialise test memory on stack */
1155 val = (scenario & 1) ? VALM : ~VALM;
1156 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1157 current_stack[i] = val + (i << 8);
1158 /* Put target of branch on stack for tests which load PC from memory */
1159 if (current_branch_target)
1160 current_stack[15] = current_branch_target;
1161 /* Put a value for SP on stack for tests which load SP from memory */
1162 current_stack[13] = (u32)current_stack + 120;
1164 /* Initialise register values to their default state */
1165 val = (scenario & 2) ? VALR : ~VALR;
1166 for (i = 0; i < 13; ++i)
1167 regs->uregs[i] = val ^ (i << 8);
1168 regs->ARM_lr = val ^ (14 << 8);
1169 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1170 regs->ARM_cpsr |= test_context_cpsr(scenario);
1172 /* Perform testcase specific register setup */
1173 args = current_args;
1174 for (; args[0].type != ARG_TYPE_END; ++args)
1175 switch (args[0].type) {
1176 case ARG_TYPE_REG: {
1177 struct test_arg_regptr *arg =
1178 (struct test_arg_regptr *)args;
1179 regs->uregs[arg->reg] = arg->val;
1182 case ARG_TYPE_PTR: {
1183 struct test_arg_regptr *arg =
1184 (struct test_arg_regptr *)args;
1185 regs->uregs[arg->reg] =
1186 (unsigned long)current_stack + arg->val;
1187 memory_needs_checking = true;
1190 case ARG_TYPE_MEM: {
1191 struct test_arg_mem *arg = (struct test_arg_mem *)args;
1192 current_stack[arg->index] = arg->val;
1201 struct kprobe kprobe;
1206 static void unregister_test_probe(struct test_probe *probe)
1208 if (probe->registered) {
1209 unregister_kprobe(&probe->kprobe);
1210 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1212 probe->registered = false;
1215 static int register_test_probe(struct test_probe *probe)
1219 if (probe->registered)
1222 ret = register_kprobe(&probe->kprobe);
1224 probe->registered = true;
1230 static int __kprobes
1231 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1233 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1237 static void __kprobes
1238 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1239 unsigned long flags)
1241 setup_test_context(regs);
1242 initial_regs = *regs;
1243 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1246 static int __kprobes
1247 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1249 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1253 static int __kprobes
1254 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1256 if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1257 return 0; /* Already run for this test instance */
1259 result_regs = *regs;
1260 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1262 /* Undo any changes done to SP by the test case */
1263 regs->ARM_sp = (unsigned long)current_stack;
1265 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1269 static struct test_probe test_before_probe = {
1270 .kprobe.pre_handler = test_before_pre_handler,
1271 .kprobe.post_handler = test_before_post_handler,
1274 static struct test_probe test_case_probe = {
1275 .kprobe.pre_handler = test_case_pre_handler,
1278 static struct test_probe test_after_probe = {
1279 .kprobe.pre_handler = test_after_pre_handler,
1282 static struct test_probe test_after2_probe = {
1283 .kprobe.pre_handler = test_after_pre_handler,
1286 static void test_case_cleanup(void)
1288 unregister_test_probe(&test_before_probe);
1289 unregister_test_probe(&test_case_probe);
1290 unregister_test_probe(&test_after_probe);
1291 unregister_test_probe(&test_after2_probe);
1294 static void print_registers(struct pt_regs *regs)
1296 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1297 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1298 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1299 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1300 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1301 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1302 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1303 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1304 pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1307 static void print_memory(u32 *mem, size_t size)
1310 for (i = 0; i < size / sizeof(u32); i += 4)
1311 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1312 mem[i+2], mem[i+3]);
1315 static size_t expected_memory_size(u32 *sp)
1317 size_t size = sizeof(expected_memory);
1318 int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1324 static void test_case_failed(const char *message)
1326 test_case_cleanup();
1328 pr_err("FAIL: %s\n", message);
1329 pr_err("FAIL: Test %s\n", current_title);
1330 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1333 static unsigned long next_instruction(unsigned long pc)
1335 #ifdef CONFIG_THUMB2_KERNEL
1337 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1344 static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
1346 struct test_arg *args;
1347 struct test_arg_end *end_arg;
1348 unsigned long test_code;
1350 args = (struct test_arg *)PTR_ALIGN(title + strlen(title) + 1, 4);
1352 current_title = title;
1353 current_args = args;
1354 current_stack = stack;
1358 while (args->type != ARG_TYPE_END)
1360 end_arg = (struct test_arg_end *)args;
1362 test_code = (unsigned long)(args + 1); /* Code starts after args */
1364 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1365 if (test_case_is_thumb)
1368 current_code_start = test_code;
1370 current_branch_target = 0;
1371 if (end_arg->branch_offset != end_arg->end_offset)
1372 current_branch_target = test_code + end_arg->branch_offset;
1374 test_code += end_arg->code_offset;
1375 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1377 test_code = next_instruction(test_code);
1378 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1380 if (test_case_is_thumb) {
1381 u16 *p = (u16 *)(test_code & ~1);
1382 current_instruction = __mem_to_opcode_thumb16(p[0]);
1383 if (is_wide_instruction(current_instruction)) {
1384 u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1385 current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1388 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1391 if (current_title[0] == '.')
1392 verbose("%s\n", current_title);
1394 verbose("%s\t@ %0*x\n", current_title,
1395 test_case_is_thumb ? 4 : 8,
1396 current_instruction);
1398 test_code = next_instruction(test_code);
1399 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1401 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1402 if (!test_case_is_thumb ||
1403 is_wide_instruction(current_instruction)) {
1404 test_case_failed("expected 16-bit instruction");
1408 if (test_case_is_thumb &&
1409 !is_wide_instruction(current_instruction)) {
1410 test_case_failed("expected 32-bit instruction");
1415 coverage_add(current_instruction);
1417 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1418 if (register_test_probe(&test_case_probe) < 0)
1420 test_case_failed("registered probe for unsupported instruction");
1424 if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1425 if (register_test_probe(&test_case_probe) >= 0)
1427 test_case_failed("couldn't register probe for supported instruction");
1431 if (register_test_probe(&test_before_probe) < 0) {
1432 test_case_failed("register test_before_probe failed");
1435 if (register_test_probe(&test_after_probe) < 0) {
1436 test_case_failed("register test_after_probe failed");
1439 if (current_branch_target) {
1440 test_after2_probe.kprobe.addr =
1441 (kprobe_opcode_t *)current_branch_target;
1442 if (register_test_probe(&test_after2_probe) < 0) {
1443 test_case_failed("register test_after2_probe failed");
1448 /* Start first run of test case */
1449 test_case_run_count = 0;
1451 return current_code_start;
1453 test_case_run_count = TEST_CASE_PASSED;
1454 return (uintptr_t)test_after_probe.kprobe.addr;
1456 test_case_run_count = TEST_CASE_FAILED;
1457 return (uintptr_t)test_after_probe.kprobe.addr;
1460 static bool check_test_results(void)
1462 size_t mem_size = 0;
1465 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1466 test_case_failed("registers differ");
1470 if (memory_needs_checking) {
1471 mem = (u32 *)result_regs.ARM_sp;
1472 mem_size = expected_memory_size(mem);
1473 if (memcmp(expected_memory, mem, mem_size)) {
1474 test_case_failed("test memory differs");
1482 pr_err("initial_regs:\n");
1483 print_registers(&initial_regs);
1484 pr_err("expected_regs:\n");
1485 print_registers(&expected_regs);
1486 pr_err("result_regs:\n");
1487 print_registers(&result_regs);
1490 pr_err("current_stack=%p\n", current_stack);
1491 pr_err("expected_memory:\n");
1492 print_memory(expected_memory, mem_size);
1493 pr_err("result_memory:\n");
1494 print_memory(mem, mem_size);
1500 static uintptr_t __used kprobes_test_case_end(void)
1502 if (test_case_run_count < 0) {
1503 if (test_case_run_count == TEST_CASE_PASSED)
1504 /* kprobes_test_case_start did all the needed testing */
1507 /* kprobes_test_case_start failed */
1511 if (test_before_probe.hit != test_instance) {
1512 test_case_failed("test_before_handler not run");
1516 if (test_after_probe.hit != test_instance &&
1517 test_after2_probe.hit != test_instance) {
1518 test_case_failed("test_after_handler not run");
1523 * Even numbered test runs ran without a probe on the test case so
1524 * we can gather reference results. The subsequent odd numbered run
1525 * will have the probe inserted.
1527 if ((test_case_run_count & 1) == 0) {
1528 /* Save results from run without probe */
1529 u32 *mem = (u32 *)result_regs.ARM_sp;
1530 expected_regs = result_regs;
1531 memcpy(expected_memory, mem, expected_memory_size(mem));
1533 /* Insert probe onto test case instruction */
1534 if (register_test_probe(&test_case_probe) < 0) {
1535 test_case_failed("register test_case_probe failed");
1539 /* Check probe ran as expected */
1540 if (probe_should_run == 1) {
1541 if (test_case_probe.hit != test_instance) {
1542 test_case_failed("test_case_handler not run");
1545 } else if (probe_should_run == 0) {
1546 if (test_case_probe.hit == test_instance) {
1547 test_case_failed("test_case_handler ran");
1552 /* Remove probe for any subsequent reference run */
1553 unregister_test_probe(&test_case_probe);
1555 if (!check_test_results())
1558 if (is_last_scenario)
1562 /* Do next test run */
1563 ++test_case_run_count;
1565 return current_code_start;
1572 test_case_cleanup();
1578 * Top level test functions
1581 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1585 pr_info(" Check decoding tables\n");
1586 ret = table_test(table);
1590 pr_info(" Run test cases\n");
1591 ret = coverage_start(table);
1602 static int __init run_all_tests(void)
1606 pr_info("Beginning kprobe tests...\n");
1608 #ifndef CONFIG_THUMB2_KERNEL
1610 pr_info("Probe ARM code\n");
1611 ret = run_api_tests(arm_func);
1615 pr_info("ARM instruction simulation\n");
1616 ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1620 #else /* CONFIG_THUMB2_KERNEL */
1622 pr_info("Probe 16-bit Thumb code\n");
1623 ret = run_api_tests(thumb16_func);
1627 pr_info("Probe 32-bit Thumb code, even halfword\n");
1628 ret = run_api_tests(thumb32even_func);
1632 pr_info("Probe 32-bit Thumb code, odd halfword\n");
1633 ret = run_api_tests(thumb32odd_func);
1637 pr_info("16-bit Thumb instruction simulation\n");
1638 ret = run_test_cases(kprobe_thumb16_test_cases,
1639 probes_decode_thumb16_table);
1643 pr_info("32-bit Thumb instruction simulation\n");
1644 ret = run_test_cases(kprobe_thumb32_test_cases,
1645 probes_decode_thumb32_table);
1650 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1651 test_try_count, test_pass_count, test_fail_count);
1652 if (test_fail_count) {
1658 pr_info("Benchmarks\n");
1659 ret = run_benchmarks();
1664 #if __LINUX_ARM_ARCH__ >= 7
1665 /* We are able to run all test cases so coverage should be complete */
1666 if (coverage_fail) {
1667 pr_err("FAIL: Test coverage checks failed\n");
1675 pr_info("Finished kprobe tests OK\n");
1677 pr_err("kprobe tests failed\n");
1689 static void __exit kprobe_test_exit(void)
1693 module_init(run_all_tests)
1694 module_exit(kprobe_test_exit)
1695 MODULE_LICENSE("GPL");
1699 late_initcall(run_all_tests);