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;
228 static int tests_failed;
230 #define FUNC_ARG1 0x12345678
231 #define FUNC_ARG2 0xabcdef
234 #ifndef CONFIG_THUMB2_KERNEL
236 long arm_func(long r0, long r1);
238 static void __used __naked __arm_kprobes_test_func(void)
240 __asm__ __volatile__ (
242 ".type arm_func, %%function \n\t"
244 "adds r0, r0, r1 \n\t"
246 ".code "NORMAL_ISA /* Back to Thumb if necessary */
247 : : : "r0", "r1", "cc"
251 #else /* CONFIG_THUMB2_KERNEL */
253 long thumb16_func(long r0, long r1);
254 long thumb32even_func(long r0, long r1);
255 long thumb32odd_func(long r0, long r1);
257 static void __used __naked __thumb_kprobes_test_funcs(void)
259 __asm__ __volatile__ (
260 ".type thumb16_func, %%function \n\t"
262 "adds.n r0, r0, r1 \n\t"
266 ".type thumb32even_func, %%function \n\t"
267 "thumb32even_func: \n\t"
268 "adds.w r0, r0, r1 \n\t"
273 ".type thumb32odd_func, %%function \n\t"
274 "thumb32odd_func: \n\t"
275 "adds.w r0, r0, r1 \n\t"
278 : : : "r0", "r1", "cc"
282 #endif /* CONFIG_THUMB2_KERNEL */
285 static int call_test_func(long (*func)(long, long), bool check_test_regs)
289 ++test_func_instance;
290 test_regs_ok = false;
292 ret = (*func)(FUNC_ARG1, FUNC_ARG2);
293 if (ret != FUNC_ARG1 + FUNC_ARG2) {
294 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
298 if (check_test_regs && !test_regs_ok) {
299 pr_err("FAIL: test regs not OK\n");
306 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
308 pre_handler_called = test_func_instance;
309 if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
314 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
317 post_handler_called = test_func_instance;
318 if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
319 test_regs_ok = false;
322 static struct kprobe the_kprobe = {
324 .pre_handler = pre_handler,
325 .post_handler = post_handler
328 static int test_kprobe(long (*func)(long, long))
332 the_kprobe.addr = (kprobe_opcode_t *)func;
333 ret = register_kprobe(&the_kprobe);
335 pr_err("FAIL: register_kprobe failed with %d\n", ret);
339 ret = call_test_func(func, true);
341 unregister_kprobe(&the_kprobe);
342 the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
346 if (pre_handler_called != test_func_instance) {
347 pr_err("FAIL: kprobe pre_handler not called\n");
350 if (post_handler_called != test_func_instance) {
351 pr_err("FAIL: kprobe post_handler not called\n");
354 if (!call_test_func(func, false))
356 if (pre_handler_called == test_func_instance ||
357 post_handler_called == test_func_instance) {
358 pr_err("FAIL: probe called after unregistering\n");
365 static void __kprobes jprobe_func(long r0, long r1)
367 jprobe_func_called = test_func_instance;
368 if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
373 static struct jprobe the_jprobe = {
374 .entry = jprobe_func,
377 static int test_jprobe(long (*func)(long, long))
381 the_jprobe.kp.addr = (kprobe_opcode_t *)func;
382 ret = register_jprobe(&the_jprobe);
384 pr_err("FAIL: register_jprobe failed with %d\n", ret);
388 ret = call_test_func(func, true);
390 unregister_jprobe(&the_jprobe);
391 the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
395 if (jprobe_func_called != test_func_instance) {
396 pr_err("FAIL: jprobe handler function not called\n");
399 if (!call_test_func(func, false))
401 if (jprobe_func_called == test_func_instance) {
402 pr_err("FAIL: probe called after unregistering\n");
410 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
412 kretprobe_handler_called = test_func_instance;
413 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
418 static struct kretprobe the_kretprobe = {
419 .handler = kretprobe_handler,
422 static int test_kretprobe(long (*func)(long, long))
426 the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
427 ret = register_kretprobe(&the_kretprobe);
429 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
433 ret = call_test_func(func, true);
435 unregister_kretprobe(&the_kretprobe);
436 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
440 if (kretprobe_handler_called != test_func_instance) {
441 pr_err("FAIL: kretprobe handler not called\n");
444 if (!call_test_func(func, false))
446 if (jprobe_func_called == test_func_instance) {
447 pr_err("FAIL: kretprobe called after unregistering\n");
454 static int run_api_tests(long (*func)(long, long))
458 pr_info(" kprobe\n");
459 ret = test_kprobe(func);
463 pr_info(" jprobe\n");
464 ret = test_jprobe(func);
465 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE)
466 if (ret == -EINVAL) {
467 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n");
475 pr_info(" kretprobe\n");
476 ret = test_kretprobe(func);
490 static void __naked benchmark_nop(void)
492 __asm__ __volatile__ (
498 #ifdef CONFIG_THUMB2_KERNEL
504 static void __naked benchmark_pushpop1(void)
506 __asm__ __volatile__ (
507 "stmdb"wide" sp!, {r3-r11,lr} \n\t"
508 "ldmia"wide" sp!, {r3-r11,pc}"
512 static void __naked benchmark_pushpop2(void)
514 __asm__ __volatile__ (
515 "stmdb"wide" sp!, {r0-r8,lr} \n\t"
516 "ldmia"wide" sp!, {r0-r8,pc}"
520 static void __naked benchmark_pushpop3(void)
522 __asm__ __volatile__ (
523 "stmdb"wide" sp!, {r4,lr} \n\t"
524 "ldmia"wide" sp!, {r4,pc}"
528 static void __naked benchmark_pushpop4(void)
530 __asm__ __volatile__ (
531 "stmdb"wide" sp!, {r0,lr} \n\t"
532 "ldmia"wide" sp!, {r0,pc}"
537 #ifdef CONFIG_THUMB2_KERNEL
539 static void __naked benchmark_pushpop_thumb(void)
541 __asm__ __volatile__ (
542 "push.n {r0-r7,lr} \n\t"
550 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
555 static int benchmark(void(*fn)(void))
557 unsigned n, i, t, t0;
559 for (n = 1000; ; n *= 2) {
561 for (i = n; i > 0; --i)
563 t = sched_clock() - t0;
565 break; /* Stop once we took more than 0.25 seconds */
567 return t / n; /* Time for one iteration in nanoseconds */
570 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
573 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset),
574 .pre_handler = benchmark_pre_handler,
577 int ret = register_kprobe(&k);
579 pr_err("FAIL: register_kprobe failed with %d\n", ret);
585 unregister_kprobe(&k);
595 static int run_benchmarks(void)
598 struct benchmarks list[] = {
599 {&benchmark_nop, 0, "nop"},
601 * benchmark_pushpop{1,3} will have the optimised
602 * instruction emulation, whilst benchmark_pushpop{2,4} will
603 * be the equivalent unoptimised instructions.
605 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
606 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
607 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
608 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
609 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
610 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
611 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
612 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
613 #ifdef CONFIG_THUMB2_KERNEL
614 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"},
615 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"},
620 struct benchmarks *b;
621 for (b = list; b->fn; ++b) {
622 ret = kprobe_benchmark(b->fn, b->offset);
625 pr_info(" %dns for kprobe %s\n", ret, b->title);
632 #endif /* BENCHMARKING */
636 * Decoding table self-consistency tests
639 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
640 [DECODE_TYPE_TABLE] = sizeof(struct decode_table),
641 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
642 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
643 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
644 [DECODE_TYPE_OR] = sizeof(struct decode_or),
645 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
648 static int table_iter(const union decode_item *table,
649 int (*fn)(const struct decode_header *, void *),
652 const struct decode_header *h = (struct decode_header *)table;
656 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
658 if (type == DECODE_TYPE_END)
661 result = fn(h, args);
665 h = (struct decode_header *)
666 ((uintptr_t)h + decode_struct_sizes[type]);
671 static int table_test_fail(const struct decode_header *h, const char* message)
674 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
675 message, h->mask.bits, h->value.bits);
679 struct table_test_args {
680 const union decode_item *root_table;
685 static int table_test_fn(const struct decode_header *h, void *args)
687 struct table_test_args *a = (struct table_test_args *)args;
688 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
690 if (h->value.bits & ~h->mask.bits)
691 return table_test_fail(h, "Match value has bits not in mask");
693 if ((h->mask.bits & a->parent_mask) != a->parent_mask)
694 return table_test_fail(h, "Mask has bits not in parent mask");
696 if ((h->value.bits ^ a->parent_value) & a->parent_mask)
697 return table_test_fail(h, "Value is inconsistent with parent");
699 if (type == DECODE_TYPE_TABLE) {
700 struct decode_table *d = (struct decode_table *)h;
701 struct table_test_args args2 = *a;
702 args2.parent_mask = h->mask.bits;
703 args2.parent_value = h->value.bits;
704 return table_iter(d->table.table, table_test_fn, &args2);
710 static int table_test(const union decode_item *table)
712 struct table_test_args args = {
717 return table_iter(args.root_table, table_test_fn, &args);
722 * Decoding table test coverage analysis
724 * coverage_start() builds a coverage_table which contains a list of
725 * coverage_entry's to match each entry in the specified kprobes instruction
728 * When test cases are run, coverage_add() is called to process each case.
729 * This looks up the corresponding entry in the coverage_table and sets it as
730 * being matched, as well as clearing the regs flag appropriate for the test.
732 * After all test cases have been run, coverage_end() is called to check that
733 * all entries in coverage_table have been matched and that all regs flags are
734 * cleared. I.e. that all possible combinations of instructions described by
735 * the kprobes decoding tables have had a test case executed for them.
740 #define MAX_COVERAGE_ENTRIES 256
742 struct coverage_entry {
743 const struct decode_header *header;
749 struct coverage_table {
750 struct coverage_entry *base;
751 unsigned num_entries;
755 struct coverage_table coverage;
757 #define COVERAGE_ANY_REG (1<<0)
758 #define COVERAGE_SP (1<<1)
759 #define COVERAGE_PC (1<<2)
760 #define COVERAGE_PCWB (1<<3)
762 static const char coverage_register_lookup[16] = {
763 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
764 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG,
765 [REG_TYPE_SP] = COVERAGE_SP,
766 [REG_TYPE_PC] = COVERAGE_PC,
767 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP,
768 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
769 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC,
770 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
771 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG,
772 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP,
775 unsigned coverage_start_registers(const struct decode_header *h)
779 for (i = 0; i < 20; i += 4) {
780 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
781 regs |= coverage_register_lookup[r] << i;
786 static int coverage_start_fn(const struct decode_header *h, void *args)
788 struct coverage_table *coverage = (struct coverage_table *)args;
789 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
790 struct coverage_entry *entry = coverage->base + coverage->num_entries;
792 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
793 pr_err("FAIL: Out of space for test coverage data");
797 ++coverage->num_entries;
800 entry->regs = coverage_start_registers(h);
801 entry->nesting = coverage->nesting;
802 entry->matched = false;
804 if (type == DECODE_TYPE_TABLE) {
805 struct decode_table *d = (struct decode_table *)h;
808 ret = table_iter(d->table.table, coverage_start_fn, coverage);
816 static int coverage_start(const union decode_item *table)
818 coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
819 sizeof(struct coverage_entry), GFP_KERNEL);
820 coverage.num_entries = 0;
821 coverage.nesting = 0;
822 return table_iter(table, coverage_start_fn, &coverage);
826 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
828 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
830 for (i = 0; i < 20; i += 4) {
831 enum decode_reg_type reg_type = (regs >> i) & 0xf;
832 int reg = (insn >> i) & 0xf;
843 flag = COVERAGE_ANY_REG;
844 entry->regs &= ~(flag << i);
850 case REG_TYPE_SAMEAS16:
868 case REG_TYPE_NOSPPC:
869 case REG_TYPE_NOSPPCX:
870 if (reg == 13 || reg == 15)
874 case REG_TYPE_NOPCWB:
875 if (!is_writeback(insn))
878 entry->regs &= ~(COVERAGE_PCWB << i);
893 static void coverage_add(kprobe_opcode_t insn)
895 struct coverage_entry *entry = coverage.base;
896 struct coverage_entry *end = coverage.base + coverage.num_entries;
897 bool matched = false;
898 unsigned nesting = 0;
900 for (; entry < end; ++entry) {
901 const struct decode_header *h = entry->header;
902 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
904 if (entry->nesting > nesting)
905 continue; /* Skip sub-table we didn't match */
907 if (entry->nesting < nesting)
908 break; /* End of sub-table we were scanning */
911 if ((insn & h->mask.bits) != h->value.bits)
913 entry->matched = true;
918 case DECODE_TYPE_TABLE:
922 case DECODE_TYPE_CUSTOM:
923 case DECODE_TYPE_SIMULATE:
924 case DECODE_TYPE_EMULATE:
925 coverage_add_registers(entry, insn);
932 case DECODE_TYPE_REJECT:
940 static void coverage_end(void)
942 struct coverage_entry *entry = coverage.base;
943 struct coverage_entry *end = coverage.base + coverage.num_entries;
945 for (; entry < end; ++entry) {
946 u32 mask = entry->header->mask.bits;
947 u32 value = entry->header->value.bits;
950 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
951 mask, value, entry->regs);
952 coverage_fail = true;
954 if (!entry->matched) {
955 pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
957 coverage_fail = true;
961 kfree(coverage.base);
966 * Framework for instruction set test cases
969 void __naked __kprobes_test_case_start(void)
971 __asm__ __volatile__ (
972 "stmdb sp!, {r4-r11} \n\t"
973 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
974 "bic r0, lr, #1 @ r0 = inline title string \n\t"
976 "bl kprobes_test_case_start \n\t"
981 #ifndef CONFIG_THUMB2_KERNEL
983 void __naked __kprobes_test_case_end_32(void)
985 __asm__ __volatile__ (
987 "bl kprobes_test_case_end \n\t"
991 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
992 "ldmia sp!, {r4-r11} \n\t"
997 #else /* CONFIG_THUMB2_KERNEL */
999 void __naked __kprobes_test_case_end_16(void)
1001 __asm__ __volatile__ (
1003 "bl kprobes_test_case_end \n\t"
1007 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
1008 "ldmia sp!, {r4-r11} \n\t"
1013 void __naked __kprobes_test_case_end_32(void)
1015 __asm__ __volatile__ (
1017 "orr lr, lr, #1 @ will return to Thumb code \n\t"
1020 ".word __kprobes_test_case_end_16 \n\t"
1027 int kprobe_test_flags;
1028 int kprobe_test_cc_position;
1030 static int test_try_count;
1031 static int test_pass_count;
1032 static int test_fail_count;
1034 static struct pt_regs initial_regs;
1035 static struct pt_regs expected_regs;
1036 static struct pt_regs result_regs;
1038 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1040 static const char *current_title;
1041 static struct test_arg *current_args;
1042 static u32 *current_stack;
1043 static uintptr_t current_branch_target;
1045 static uintptr_t current_code_start;
1046 static kprobe_opcode_t current_instruction;
1049 #define TEST_CASE_PASSED -1
1050 #define TEST_CASE_FAILED -2
1052 static int test_case_run_count;
1053 static bool test_case_is_thumb;
1054 static int test_instance;
1057 * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
1058 * can change randomly as the kernel doesn't take care to preserve or initialise
1059 * this across context switches. Also, with Security Extentions, the flag may
1060 * not be under control of the kernel; for this reason we ignore the state of
1061 * the FIQ disable flag CPSR.F as well.
1063 #define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
1065 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1067 int ret = arm_check_condition(cc << 28, cpsr);
1069 return (ret != ARM_OPCODE_CONDTEST_FAIL);
1072 static int is_last_scenario;
1073 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1074 static int memory_needs_checking;
1076 static unsigned long test_context_cpsr(int scenario)
1080 probe_should_run = 1;
1082 /* Default case is that we cycle through 16 combinations of flags */
1083 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1084 cpsr |= (scenario & 0xf) << 16; /* GE flags */
1085 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1087 if (!test_case_is_thumb) {
1088 /* Testing ARM code */
1089 int cc = current_instruction >> 28;
1091 probe_should_run = test_check_cc(cc, cpsr) != 0;
1093 is_last_scenario = true;
1095 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1096 /* Testing Thumb code without setting ITSTATE */
1097 if (kprobe_test_cc_position) {
1098 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1099 probe_should_run = test_check_cc(cc, cpsr) != 0;
1103 is_last_scenario = true;
1105 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1106 /* Testing Thumb code with all combinations of ITSTATE */
1107 unsigned x = (scenario >> 4);
1108 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1109 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
1112 /* Finish by testing state from instruction 'itt al' */
1115 if ((scenario & 0xf) == 0xf)
1116 is_last_scenario = true;
1119 cpsr |= cond_base << 13; /* ITSTATE<7:5> */
1120 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
1121 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
1122 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
1123 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
1124 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
1126 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1129 /* Testing Thumb code with several combinations of ITSTATE */
1131 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1133 probe_should_run = 0;
1135 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1137 probe_should_run = 0;
1139 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1142 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1144 is_last_scenario = true;
1152 static void setup_test_context(struct pt_regs *regs)
1154 int scenario = test_case_run_count>>1;
1156 struct test_arg *args;
1159 is_last_scenario = false;
1160 memory_needs_checking = false;
1162 /* Initialise test memory on stack */
1163 val = (scenario & 1) ? VALM : ~VALM;
1164 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1165 current_stack[i] = val + (i << 8);
1166 /* Put target of branch on stack for tests which load PC from memory */
1167 if (current_branch_target)
1168 current_stack[15] = current_branch_target;
1169 /* Put a value for SP on stack for tests which load SP from memory */
1170 current_stack[13] = (u32)current_stack + 120;
1172 /* Initialise register values to their default state */
1173 val = (scenario & 2) ? VALR : ~VALR;
1174 for (i = 0; i < 13; ++i)
1175 regs->uregs[i] = val ^ (i << 8);
1176 regs->ARM_lr = val ^ (14 << 8);
1177 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1178 regs->ARM_cpsr |= test_context_cpsr(scenario);
1180 /* Perform testcase specific register setup */
1181 args = current_args;
1182 for (; args[0].type != ARG_TYPE_END; ++args)
1183 switch (args[0].type) {
1184 case ARG_TYPE_REG: {
1185 struct test_arg_regptr *arg =
1186 (struct test_arg_regptr *)args;
1187 regs->uregs[arg->reg] = arg->val;
1190 case ARG_TYPE_PTR: {
1191 struct test_arg_regptr *arg =
1192 (struct test_arg_regptr *)args;
1193 regs->uregs[arg->reg] =
1194 (unsigned long)current_stack + arg->val;
1195 memory_needs_checking = true;
1198 case ARG_TYPE_MEM: {
1199 struct test_arg_mem *arg = (struct test_arg_mem *)args;
1200 current_stack[arg->index] = arg->val;
1209 struct kprobe kprobe;
1214 static void unregister_test_probe(struct test_probe *probe)
1216 if (probe->registered) {
1217 unregister_kprobe(&probe->kprobe);
1218 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1220 probe->registered = false;
1223 static int register_test_probe(struct test_probe *probe)
1227 if (probe->registered)
1230 ret = register_kprobe(&probe->kprobe);
1232 probe->registered = true;
1238 static int __kprobes
1239 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1241 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1245 static void __kprobes
1246 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1247 unsigned long flags)
1249 setup_test_context(regs);
1250 initial_regs = *regs;
1251 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1254 static int __kprobes
1255 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1257 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1261 static int __kprobes
1262 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1264 if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1265 return 0; /* Already run for this test instance */
1267 result_regs = *regs;
1268 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1270 /* Undo any changes done to SP by the test case */
1271 regs->ARM_sp = (unsigned long)current_stack;
1273 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1277 static struct test_probe test_before_probe = {
1278 .kprobe.pre_handler = test_before_pre_handler,
1279 .kprobe.post_handler = test_before_post_handler,
1282 static struct test_probe test_case_probe = {
1283 .kprobe.pre_handler = test_case_pre_handler,
1286 static struct test_probe test_after_probe = {
1287 .kprobe.pre_handler = test_after_pre_handler,
1290 static struct test_probe test_after2_probe = {
1291 .kprobe.pre_handler = test_after_pre_handler,
1294 static void test_case_cleanup(void)
1296 unregister_test_probe(&test_before_probe);
1297 unregister_test_probe(&test_case_probe);
1298 unregister_test_probe(&test_after_probe);
1299 unregister_test_probe(&test_after2_probe);
1302 static void print_registers(struct pt_regs *regs)
1304 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1305 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1306 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1307 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1308 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1309 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1310 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1311 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1312 pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1315 static void print_memory(u32 *mem, size_t size)
1318 for (i = 0; i < size / sizeof(u32); i += 4)
1319 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1320 mem[i+2], mem[i+3]);
1323 static size_t expected_memory_size(u32 *sp)
1325 size_t size = sizeof(expected_memory);
1326 int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1332 static void test_case_failed(const char *message)
1334 test_case_cleanup();
1336 pr_err("FAIL: %s\n", message);
1337 pr_err("FAIL: Test %s\n", current_title);
1338 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1341 static unsigned long next_instruction(unsigned long pc)
1343 #ifdef CONFIG_THUMB2_KERNEL
1345 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1352 static uintptr_t __used kprobes_test_case_start(const char *title, void *stack)
1354 struct test_arg *args;
1355 struct test_arg_end *end_arg;
1356 unsigned long test_code;
1358 args = (struct test_arg *)PTR_ALIGN(title + strlen(title) + 1, 4);
1360 current_title = title;
1361 current_args = args;
1362 current_stack = stack;
1366 while (args->type != ARG_TYPE_END)
1368 end_arg = (struct test_arg_end *)args;
1370 test_code = (unsigned long)(args + 1); /* Code starts after args */
1372 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1373 if (test_case_is_thumb)
1376 current_code_start = test_code;
1378 current_branch_target = 0;
1379 if (end_arg->branch_offset != end_arg->end_offset)
1380 current_branch_target = test_code + end_arg->branch_offset;
1382 test_code += end_arg->code_offset;
1383 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1385 test_code = next_instruction(test_code);
1386 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1388 if (test_case_is_thumb) {
1389 u16 *p = (u16 *)(test_code & ~1);
1390 current_instruction = __mem_to_opcode_thumb16(p[0]);
1391 if (is_wide_instruction(current_instruction)) {
1392 u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1393 current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1396 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1399 if (current_title[0] == '.')
1400 verbose("%s\n", current_title);
1402 verbose("%s\t@ %0*x\n", current_title,
1403 test_case_is_thumb ? 4 : 8,
1404 current_instruction);
1406 test_code = next_instruction(test_code);
1407 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1409 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1410 if (!test_case_is_thumb ||
1411 is_wide_instruction(current_instruction)) {
1412 test_case_failed("expected 16-bit instruction");
1416 if (test_case_is_thumb &&
1417 !is_wide_instruction(current_instruction)) {
1418 test_case_failed("expected 32-bit instruction");
1423 coverage_add(current_instruction);
1425 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1426 if (register_test_probe(&test_case_probe) < 0)
1428 test_case_failed("registered probe for unsupported instruction");
1432 if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1433 if (register_test_probe(&test_case_probe) >= 0)
1435 test_case_failed("couldn't register probe for supported instruction");
1439 if (register_test_probe(&test_before_probe) < 0) {
1440 test_case_failed("register test_before_probe failed");
1443 if (register_test_probe(&test_after_probe) < 0) {
1444 test_case_failed("register test_after_probe failed");
1447 if (current_branch_target) {
1448 test_after2_probe.kprobe.addr =
1449 (kprobe_opcode_t *)current_branch_target;
1450 if (register_test_probe(&test_after2_probe) < 0) {
1451 test_case_failed("register test_after2_probe failed");
1456 /* Start first run of test case */
1457 test_case_run_count = 0;
1459 return current_code_start;
1461 test_case_run_count = TEST_CASE_PASSED;
1462 return (uintptr_t)test_after_probe.kprobe.addr;
1464 test_case_run_count = TEST_CASE_FAILED;
1465 return (uintptr_t)test_after_probe.kprobe.addr;
1468 static bool check_test_results(void)
1470 size_t mem_size = 0;
1473 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1474 test_case_failed("registers differ");
1478 if (memory_needs_checking) {
1479 mem = (u32 *)result_regs.ARM_sp;
1480 mem_size = expected_memory_size(mem);
1481 if (memcmp(expected_memory, mem, mem_size)) {
1482 test_case_failed("test memory differs");
1490 pr_err("initial_regs:\n");
1491 print_registers(&initial_regs);
1492 pr_err("expected_regs:\n");
1493 print_registers(&expected_regs);
1494 pr_err("result_regs:\n");
1495 print_registers(&result_regs);
1498 pr_err("current_stack=%p\n", current_stack);
1499 pr_err("expected_memory:\n");
1500 print_memory(expected_memory, mem_size);
1501 pr_err("result_memory:\n");
1502 print_memory(mem, mem_size);
1508 static uintptr_t __used kprobes_test_case_end(void)
1510 if (test_case_run_count < 0) {
1511 if (test_case_run_count == TEST_CASE_PASSED)
1512 /* kprobes_test_case_start did all the needed testing */
1515 /* kprobes_test_case_start failed */
1519 if (test_before_probe.hit != test_instance) {
1520 test_case_failed("test_before_handler not run");
1524 if (test_after_probe.hit != test_instance &&
1525 test_after2_probe.hit != test_instance) {
1526 test_case_failed("test_after_handler not run");
1531 * Even numbered test runs ran without a probe on the test case so
1532 * we can gather reference results. The subsequent odd numbered run
1533 * will have the probe inserted.
1535 if ((test_case_run_count & 1) == 0) {
1536 /* Save results from run without probe */
1537 u32 *mem = (u32 *)result_regs.ARM_sp;
1538 expected_regs = result_regs;
1539 memcpy(expected_memory, mem, expected_memory_size(mem));
1541 /* Insert probe onto test case instruction */
1542 if (register_test_probe(&test_case_probe) < 0) {
1543 test_case_failed("register test_case_probe failed");
1547 /* Check probe ran as expected */
1548 if (probe_should_run == 1) {
1549 if (test_case_probe.hit != test_instance) {
1550 test_case_failed("test_case_handler not run");
1553 } else if (probe_should_run == 0) {
1554 if (test_case_probe.hit == test_instance) {
1555 test_case_failed("test_case_handler ran");
1560 /* Remove probe for any subsequent reference run */
1561 unregister_test_probe(&test_case_probe);
1563 if (!check_test_results())
1566 if (is_last_scenario)
1570 /* Do next test run */
1571 ++test_case_run_count;
1573 return current_code_start;
1580 test_case_cleanup();
1586 * Top level test functions
1589 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1593 pr_info(" Check decoding tables\n");
1594 ret = table_test(table);
1598 pr_info(" Run test cases\n");
1599 ret = coverage_start(table);
1610 static int __init run_all_tests(void)
1614 pr_info("Beginning kprobe tests...\n");
1616 #ifndef CONFIG_THUMB2_KERNEL
1618 pr_info("Probe ARM code\n");
1619 ret = run_api_tests(arm_func);
1623 pr_info("ARM instruction simulation\n");
1624 ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1628 #else /* CONFIG_THUMB2_KERNEL */
1630 pr_info("Probe 16-bit Thumb code\n");
1631 ret = run_api_tests(thumb16_func);
1635 pr_info("Probe 32-bit Thumb code, even halfword\n");
1636 ret = run_api_tests(thumb32even_func);
1640 pr_info("Probe 32-bit Thumb code, odd halfword\n");
1641 ret = run_api_tests(thumb32odd_func);
1645 pr_info("16-bit Thumb instruction simulation\n");
1646 ret = run_test_cases(kprobe_thumb16_test_cases,
1647 probes_decode_thumb16_table);
1651 pr_info("32-bit Thumb instruction simulation\n");
1652 ret = run_test_cases(kprobe_thumb32_test_cases,
1653 probes_decode_thumb32_table);
1658 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1659 test_try_count, test_pass_count, test_fail_count);
1660 if (test_fail_count) {
1666 pr_info("Benchmarks\n");
1667 ret = run_benchmarks();
1672 #if __LINUX_ARM_ARCH__ >= 7
1673 /* We are able to run all test cases so coverage should be complete */
1674 if (coverage_fail) {
1675 pr_err("FAIL: Test coverage checks failed\n");
1685 pr_info("Finished kprobe tests OK\n");
1687 pr_err("kprobe tests failed\n");
1699 static void __exit kprobe_test_exit(void)
1703 module_init(run_all_tests)
1704 module_exit(kprobe_test_exit)
1705 MODULE_LICENSE("GPL");
1709 late_initcall(run_all_tests);