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 * .pushsection .rodata
115 * .ascii "mov r0, r7" @ text title for test case
118 * @ start of inline data...
119 * .word 10b @ pointer to title in .rodata section
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...
135 * .code TEST_ISA @ switch to ISA being tested
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
144 * 99: bl __kprobes_test_case_end_##TEST_ISA
147 * When the above is execute the following happens...
149 * __kprobes_test_case_start() is an assembler wrapper which sets up space
150 * for a stack buffer and calls the C function kprobes_test_case_start().
151 * This C function will do some initial processing of the inline data and
152 * setup some global state. It then inserts the test_before and test_after
153 * kprobes and returns a value which causes the assembler wrapper to jump
154 * to the start of the test case code, (local label '0').
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.
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
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().
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.
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.
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().
187 * BUILDING TEST CASES
188 * -------------------
191 * As an aid to building test cases, the stack buffer is initialised with
192 * some special values:
194 * [SP+13*4] Contains SP+120. This can be used to test instructions
195 * which load a value into SP.
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
203 #include <linux/kernel.h>
204 #include <linux/module.h>
205 #include <linux/slab.h>
206 #include <linux/kprobes.h>
207 #include <linux/errno.h>
208 #include <linux/stddef.h>
209 #include <linux/bug.h>
210 #include <asm/opcodes.h>
213 #include "probes-arm.h"
214 #include "probes-thumb.h"
215 #include "kprobes-test.h"
218 #define BENCHMARKING 1
225 static bool test_regs_ok;
226 static int test_func_instance;
227 static int pre_handler_called;
228 static int post_handler_called;
229 static int jprobe_func_called;
230 static int kretprobe_handler_called;
231 static int tests_failed;
233 #define FUNC_ARG1 0x12345678
234 #define FUNC_ARG2 0xabcdef
237 #ifndef CONFIG_THUMB2_KERNEL
239 long arm_func(long r0, long r1);
241 static void __used __naked __arm_kprobes_test_func(void)
243 __asm__ __volatile__ (
245 ".type arm_func, %%function \n\t"
247 "adds r0, r0, r1 \n\t"
249 ".code "NORMAL_ISA /* Back to Thumb if necessary */
250 : : : "r0", "r1", "cc"
254 #else /* CONFIG_THUMB2_KERNEL */
256 long thumb16_func(long r0, long r1);
257 long thumb32even_func(long r0, long r1);
258 long thumb32odd_func(long r0, long r1);
260 static void __used __naked __thumb_kprobes_test_funcs(void)
262 __asm__ __volatile__ (
263 ".type thumb16_func, %%function \n\t"
265 "adds.n r0, r0, r1 \n\t"
269 ".type thumb32even_func, %%function \n\t"
270 "thumb32even_func: \n\t"
271 "adds.w r0, r0, r1 \n\t"
276 ".type thumb32odd_func, %%function \n\t"
277 "thumb32odd_func: \n\t"
278 "adds.w r0, r0, r1 \n\t"
281 : : : "r0", "r1", "cc"
285 #endif /* CONFIG_THUMB2_KERNEL */
288 static int call_test_func(long (*func)(long, long), bool check_test_regs)
292 ++test_func_instance;
293 test_regs_ok = false;
295 ret = (*func)(FUNC_ARG1, FUNC_ARG2);
296 if (ret != FUNC_ARG1 + FUNC_ARG2) {
297 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
301 if (check_test_regs && !test_regs_ok) {
302 pr_err("FAIL: test regs not OK\n");
309 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
311 pre_handler_called = test_func_instance;
312 if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
317 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
320 post_handler_called = test_func_instance;
321 if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
322 test_regs_ok = false;
325 static struct kprobe the_kprobe = {
327 .pre_handler = pre_handler,
328 .post_handler = post_handler
331 static int test_kprobe(long (*func)(long, long))
335 the_kprobe.addr = (kprobe_opcode_t *)func;
336 ret = register_kprobe(&the_kprobe);
338 pr_err("FAIL: register_kprobe failed with %d\n", ret);
342 ret = call_test_func(func, true);
344 unregister_kprobe(&the_kprobe);
345 the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
349 if (pre_handler_called != test_func_instance) {
350 pr_err("FAIL: kprobe pre_handler not called\n");
353 if (post_handler_called != test_func_instance) {
354 pr_err("FAIL: kprobe post_handler not called\n");
357 if (!call_test_func(func, false))
359 if (pre_handler_called == test_func_instance ||
360 post_handler_called == test_func_instance) {
361 pr_err("FAIL: probe called after unregistering\n");
368 static void __kprobes jprobe_func(long r0, long r1)
370 jprobe_func_called = test_func_instance;
371 if (r0 == FUNC_ARG1 && r1 == FUNC_ARG2)
376 static struct jprobe the_jprobe = {
377 .entry = jprobe_func,
380 static int test_jprobe(long (*func)(long, long))
384 the_jprobe.kp.addr = (kprobe_opcode_t *)func;
385 ret = register_jprobe(&the_jprobe);
387 pr_err("FAIL: register_jprobe failed with %d\n", ret);
391 ret = call_test_func(func, true);
393 unregister_jprobe(&the_jprobe);
394 the_jprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
398 if (jprobe_func_called != test_func_instance) {
399 pr_err("FAIL: jprobe handler function not called\n");
402 if (!call_test_func(func, false))
404 if (jprobe_func_called == test_func_instance) {
405 pr_err("FAIL: probe called after unregistering\n");
413 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
415 kretprobe_handler_called = test_func_instance;
416 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
421 static struct kretprobe the_kretprobe = {
422 .handler = kretprobe_handler,
425 static int test_kretprobe(long (*func)(long, long))
429 the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
430 ret = register_kretprobe(&the_kretprobe);
432 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
436 ret = call_test_func(func, true);
438 unregister_kretprobe(&the_kretprobe);
439 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
443 if (kretprobe_handler_called != test_func_instance) {
444 pr_err("FAIL: kretprobe handler not called\n");
447 if (!call_test_func(func, false))
449 if (jprobe_func_called == test_func_instance) {
450 pr_err("FAIL: kretprobe called after unregistering\n");
457 static int run_api_tests(long (*func)(long, long))
461 pr_info(" kprobe\n");
462 ret = test_kprobe(func);
466 pr_info(" jprobe\n");
467 ret = test_jprobe(func);
468 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE)
469 if (ret == -EINVAL) {
470 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n");
478 pr_info(" kretprobe\n");
479 ret = test_kretprobe(func);
493 static void __naked benchmark_nop(void)
495 __asm__ __volatile__ (
501 #ifdef CONFIG_THUMB2_KERNEL
507 static void __naked benchmark_pushpop1(void)
509 __asm__ __volatile__ (
510 "stmdb"wide" sp!, {r3-r11,lr} \n\t"
511 "ldmia"wide" sp!, {r3-r11,pc}"
515 static void __naked benchmark_pushpop2(void)
517 __asm__ __volatile__ (
518 "stmdb"wide" sp!, {r0-r8,lr} \n\t"
519 "ldmia"wide" sp!, {r0-r8,pc}"
523 static void __naked benchmark_pushpop3(void)
525 __asm__ __volatile__ (
526 "stmdb"wide" sp!, {r4,lr} \n\t"
527 "ldmia"wide" sp!, {r4,pc}"
531 static void __naked benchmark_pushpop4(void)
533 __asm__ __volatile__ (
534 "stmdb"wide" sp!, {r0,lr} \n\t"
535 "ldmia"wide" sp!, {r0,pc}"
540 #ifdef CONFIG_THUMB2_KERNEL
542 static void __naked benchmark_pushpop_thumb(void)
544 __asm__ __volatile__ (
545 "push.n {r0-r7,lr} \n\t"
553 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
558 static int benchmark(void(*fn)(void))
560 unsigned n, i, t, t0;
562 for (n = 1000; ; n *= 2) {
564 for (i = n; i > 0; --i)
566 t = sched_clock() - t0;
568 break; /* Stop once we took more than 0.25 seconds */
570 return t / n; /* Time for one iteration in nanoseconds */
573 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
576 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset),
577 .pre_handler = benchmark_pre_handler,
580 int ret = register_kprobe(&k);
582 pr_err("FAIL: register_kprobe failed with %d\n", ret);
588 unregister_kprobe(&k);
598 static int run_benchmarks(void)
601 struct benchmarks list[] = {
602 {&benchmark_nop, 0, "nop"},
604 * benchmark_pushpop{1,3} will have the optimised
605 * instruction emulation, whilst benchmark_pushpop{2,4} will
606 * be the equivalent unoptimised instructions.
608 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
609 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
610 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
611 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
612 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
613 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
614 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
615 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
616 #ifdef CONFIG_THUMB2_KERNEL
617 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"},
618 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"},
623 struct benchmarks *b;
624 for (b = list; b->fn; ++b) {
625 ret = kprobe_benchmark(b->fn, b->offset);
628 pr_info(" %dns for kprobe %s\n", ret, b->title);
635 #endif /* BENCHMARKING */
639 * Decoding table self-consistency tests
642 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
643 [DECODE_TYPE_TABLE] = sizeof(struct decode_table),
644 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
645 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
646 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
647 [DECODE_TYPE_OR] = sizeof(struct decode_or),
648 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
651 static int table_iter(const union decode_item *table,
652 int (*fn)(const struct decode_header *, void *),
655 const struct decode_header *h = (struct decode_header *)table;
659 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
661 if (type == DECODE_TYPE_END)
664 result = fn(h, args);
668 h = (struct decode_header *)
669 ((uintptr_t)h + decode_struct_sizes[type]);
674 static int table_test_fail(const struct decode_header *h, const char* message)
677 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
678 message, h->mask.bits, h->value.bits);
682 struct table_test_args {
683 const union decode_item *root_table;
688 static int table_test_fn(const struct decode_header *h, void *args)
690 struct table_test_args *a = (struct table_test_args *)args;
691 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
693 if (h->value.bits & ~h->mask.bits)
694 return table_test_fail(h, "Match value has bits not in mask");
696 if ((h->mask.bits & a->parent_mask) != a->parent_mask)
697 return table_test_fail(h, "Mask has bits not in parent mask");
699 if ((h->value.bits ^ a->parent_value) & a->parent_mask)
700 return table_test_fail(h, "Value is inconsistent with parent");
702 if (type == DECODE_TYPE_TABLE) {
703 struct decode_table *d = (struct decode_table *)h;
704 struct table_test_args args2 = *a;
705 args2.parent_mask = h->mask.bits;
706 args2.parent_value = h->value.bits;
707 return table_iter(d->table.table, table_test_fn, &args2);
713 static int table_test(const union decode_item *table)
715 struct table_test_args args = {
720 return table_iter(args.root_table, table_test_fn, &args);
725 * Decoding table test coverage analysis
727 * coverage_start() builds a coverage_table which contains a list of
728 * coverage_entry's to match each entry in the specified kprobes instruction
731 * When test cases are run, coverage_add() is called to process each case.
732 * This looks up the corresponding entry in the coverage_table and sets it as
733 * being matched, as well as clearing the regs flag appropriate for the test.
735 * After all test cases have been run, coverage_end() is called to check that
736 * all entries in coverage_table have been matched and that all regs flags are
737 * cleared. I.e. that all possible combinations of instructions described by
738 * the kprobes decoding tables have had a test case executed for them.
743 #define MAX_COVERAGE_ENTRIES 256
745 struct coverage_entry {
746 const struct decode_header *header;
752 struct coverage_table {
753 struct coverage_entry *base;
754 unsigned num_entries;
758 struct coverage_table coverage;
760 #define COVERAGE_ANY_REG (1<<0)
761 #define COVERAGE_SP (1<<1)
762 #define COVERAGE_PC (1<<2)
763 #define COVERAGE_PCWB (1<<3)
765 static const char coverage_register_lookup[16] = {
766 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
767 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG,
768 [REG_TYPE_SP] = COVERAGE_SP,
769 [REG_TYPE_PC] = COVERAGE_PC,
770 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP,
771 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
772 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC,
773 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
774 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG,
775 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP,
778 unsigned coverage_start_registers(const struct decode_header *h)
782 for (i = 0; i < 20; i += 4) {
783 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
784 regs |= coverage_register_lookup[r] << i;
789 static int coverage_start_fn(const struct decode_header *h, void *args)
791 struct coverage_table *coverage = (struct coverage_table *)args;
792 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
793 struct coverage_entry *entry = coverage->base + coverage->num_entries;
795 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
796 pr_err("FAIL: Out of space for test coverage data");
800 ++coverage->num_entries;
803 entry->regs = coverage_start_registers(h);
804 entry->nesting = coverage->nesting;
805 entry->matched = false;
807 if (type == DECODE_TYPE_TABLE) {
808 struct decode_table *d = (struct decode_table *)h;
811 ret = table_iter(d->table.table, coverage_start_fn, coverage);
819 static int coverage_start(const union decode_item *table)
821 coverage.base = kmalloc(MAX_COVERAGE_ENTRIES *
822 sizeof(struct coverage_entry), GFP_KERNEL);
823 coverage.num_entries = 0;
824 coverage.nesting = 0;
825 return table_iter(table, coverage_start_fn, &coverage);
829 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
831 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
833 for (i = 0; i < 20; i += 4) {
834 enum decode_reg_type reg_type = (regs >> i) & 0xf;
835 int reg = (insn >> i) & 0xf;
846 flag = COVERAGE_ANY_REG;
847 entry->regs &= ~(flag << i);
853 case REG_TYPE_SAMEAS16:
871 case REG_TYPE_NOSPPC:
872 case REG_TYPE_NOSPPCX:
873 if (reg == 13 || reg == 15)
877 case REG_TYPE_NOPCWB:
878 if (!is_writeback(insn))
881 entry->regs &= ~(COVERAGE_PCWB << i);
896 static void coverage_add(kprobe_opcode_t insn)
898 struct coverage_entry *entry = coverage.base;
899 struct coverage_entry *end = coverage.base + coverage.num_entries;
900 bool matched = false;
901 unsigned nesting = 0;
903 for (; entry < end; ++entry) {
904 const struct decode_header *h = entry->header;
905 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
907 if (entry->nesting > nesting)
908 continue; /* Skip sub-table we didn't match */
910 if (entry->nesting < nesting)
911 break; /* End of sub-table we were scanning */
914 if ((insn & h->mask.bits) != h->value.bits)
916 entry->matched = true;
921 case DECODE_TYPE_TABLE:
925 case DECODE_TYPE_CUSTOM:
926 case DECODE_TYPE_SIMULATE:
927 case DECODE_TYPE_EMULATE:
928 coverage_add_registers(entry, insn);
935 case DECODE_TYPE_REJECT:
943 static void coverage_end(void)
945 struct coverage_entry *entry = coverage.base;
946 struct coverage_entry *end = coverage.base + coverage.num_entries;
948 for (; entry < end; ++entry) {
949 u32 mask = entry->header->mask.bits;
950 u32 value = entry->header->value.bits;
953 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
954 mask, value, entry->regs);
955 coverage_fail = true;
957 if (!entry->matched) {
958 pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
960 coverage_fail = true;
964 kfree(coverage.base);
969 * Framework for instruction set test cases
972 void __naked __kprobes_test_case_start(void)
974 __asm__ __volatile__ (
975 "stmdb sp!, {r4-r11} \n\t"
976 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
977 "bic r0, lr, #1 @ r0 = inline data \n\t"
979 "bl kprobes_test_case_start \n\t"
984 #ifndef CONFIG_THUMB2_KERNEL
986 void __naked __kprobes_test_case_end_32(void)
988 __asm__ __volatile__ (
990 "bl kprobes_test_case_end \n\t"
994 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
995 "ldmia sp!, {r4-r11} \n\t"
1000 #else /* CONFIG_THUMB2_KERNEL */
1002 void __naked __kprobes_test_case_end_16(void)
1004 __asm__ __volatile__ (
1006 "bl kprobes_test_case_end \n\t"
1010 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
1011 "ldmia sp!, {r4-r11} \n\t"
1016 void __naked __kprobes_test_case_end_32(void)
1018 __asm__ __volatile__ (
1020 "orr lr, lr, #1 @ will return to Thumb code \n\t"
1023 ".word __kprobes_test_case_end_16 \n\t"
1030 int kprobe_test_flags;
1031 int kprobe_test_cc_position;
1033 static int test_try_count;
1034 static int test_pass_count;
1035 static int test_fail_count;
1037 static struct pt_regs initial_regs;
1038 static struct pt_regs expected_regs;
1039 static struct pt_regs result_regs;
1041 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
1043 static const char *current_title;
1044 static struct test_arg *current_args;
1045 static u32 *current_stack;
1046 static uintptr_t current_branch_target;
1048 static uintptr_t current_code_start;
1049 static kprobe_opcode_t current_instruction;
1052 #define TEST_CASE_PASSED -1
1053 #define TEST_CASE_FAILED -2
1055 static int test_case_run_count;
1056 static bool test_case_is_thumb;
1057 static int test_instance;
1060 * We ignore the state of the imprecise abort disable flag (CPSR.A) because this
1061 * can change randomly as the kernel doesn't take care to preserve or initialise
1062 * this across context switches. Also, with Security Extentions, the flag may
1063 * not be under control of the kernel; for this reason we ignore the state of
1064 * the FIQ disable flag CPSR.F as well.
1066 #define PSR_IGNORE_BITS (PSR_A_BIT | PSR_F_BIT)
1068 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1070 int ret = arm_check_condition(cc << 28, cpsr);
1072 return (ret != ARM_OPCODE_CONDTEST_FAIL);
1075 static int is_last_scenario;
1076 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1077 static int memory_needs_checking;
1079 static unsigned long test_context_cpsr(int scenario)
1083 probe_should_run = 1;
1085 /* Default case is that we cycle through 16 combinations of flags */
1086 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1087 cpsr |= (scenario & 0xf) << 16; /* GE flags */
1088 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1090 if (!test_case_is_thumb) {
1091 /* Testing ARM code */
1092 int cc = current_instruction >> 28;
1094 probe_should_run = test_check_cc(cc, cpsr) != 0;
1096 is_last_scenario = true;
1098 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1099 /* Testing Thumb code without setting ITSTATE */
1100 if (kprobe_test_cc_position) {
1101 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1102 probe_should_run = test_check_cc(cc, cpsr) != 0;
1106 is_last_scenario = true;
1108 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1109 /* Testing Thumb code with all combinations of ITSTATE */
1110 unsigned x = (scenario >> 4);
1111 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1112 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
1115 /* Finish by testing state from instruction 'itt al' */
1118 if ((scenario & 0xf) == 0xf)
1119 is_last_scenario = true;
1122 cpsr |= cond_base << 13; /* ITSTATE<7:5> */
1123 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
1124 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
1125 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
1126 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
1127 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
1129 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1132 /* Testing Thumb code with several combinations of ITSTATE */
1134 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1136 probe_should_run = 0;
1138 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1140 probe_should_run = 0;
1142 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1145 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1147 is_last_scenario = true;
1155 static void setup_test_context(struct pt_regs *regs)
1157 int scenario = test_case_run_count>>1;
1159 struct test_arg *args;
1162 is_last_scenario = false;
1163 memory_needs_checking = false;
1165 /* Initialise test memory on stack */
1166 val = (scenario & 1) ? VALM : ~VALM;
1167 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1168 current_stack[i] = val + (i << 8);
1169 /* Put target of branch on stack for tests which load PC from memory */
1170 if (current_branch_target)
1171 current_stack[15] = current_branch_target;
1172 /* Put a value for SP on stack for tests which load SP from memory */
1173 current_stack[13] = (u32)current_stack + 120;
1175 /* Initialise register values to their default state */
1176 val = (scenario & 2) ? VALR : ~VALR;
1177 for (i = 0; i < 13; ++i)
1178 regs->uregs[i] = val ^ (i << 8);
1179 regs->ARM_lr = val ^ (14 << 8);
1180 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1181 regs->ARM_cpsr |= test_context_cpsr(scenario);
1183 /* Perform testcase specific register setup */
1184 args = current_args;
1185 for (; args[0].type != ARG_TYPE_END; ++args)
1186 switch (args[0].type) {
1187 case ARG_TYPE_REG: {
1188 struct test_arg_regptr *arg =
1189 (struct test_arg_regptr *)args;
1190 regs->uregs[arg->reg] = arg->val;
1193 case ARG_TYPE_PTR: {
1194 struct test_arg_regptr *arg =
1195 (struct test_arg_regptr *)args;
1196 regs->uregs[arg->reg] =
1197 (unsigned long)current_stack + arg->val;
1198 memory_needs_checking = true;
1201 case ARG_TYPE_MEM: {
1202 struct test_arg_mem *arg = (struct test_arg_mem *)args;
1203 current_stack[arg->index] = arg->val;
1212 struct kprobe kprobe;
1217 static void unregister_test_probe(struct test_probe *probe)
1219 if (probe->registered) {
1220 unregister_kprobe(&probe->kprobe);
1221 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1223 probe->registered = false;
1226 static int register_test_probe(struct test_probe *probe)
1230 if (probe->registered)
1233 ret = register_kprobe(&probe->kprobe);
1235 probe->registered = true;
1241 static int __kprobes
1242 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1244 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1248 static void __kprobes
1249 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1250 unsigned long flags)
1252 setup_test_context(regs);
1253 initial_regs = *regs;
1254 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1257 static int __kprobes
1258 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1260 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1264 static int __kprobes
1265 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1267 if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1268 return 0; /* Already run for this test instance */
1270 result_regs = *regs;
1271 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1273 /* Undo any changes done to SP by the test case */
1274 regs->ARM_sp = (unsigned long)current_stack;
1276 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1280 static struct test_probe test_before_probe = {
1281 .kprobe.pre_handler = test_before_pre_handler,
1282 .kprobe.post_handler = test_before_post_handler,
1285 static struct test_probe test_case_probe = {
1286 .kprobe.pre_handler = test_case_pre_handler,
1289 static struct test_probe test_after_probe = {
1290 .kprobe.pre_handler = test_after_pre_handler,
1293 static struct test_probe test_after2_probe = {
1294 .kprobe.pre_handler = test_after_pre_handler,
1297 static void test_case_cleanup(void)
1299 unregister_test_probe(&test_before_probe);
1300 unregister_test_probe(&test_case_probe);
1301 unregister_test_probe(&test_after_probe);
1302 unregister_test_probe(&test_after2_probe);
1305 static void print_registers(struct pt_regs *regs)
1307 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1308 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1309 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1310 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1311 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1312 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1313 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1314 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1315 pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1318 static void print_memory(u32 *mem, size_t size)
1321 for (i = 0; i < size / sizeof(u32); i += 4)
1322 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1323 mem[i+2], mem[i+3]);
1326 static size_t expected_memory_size(u32 *sp)
1328 size_t size = sizeof(expected_memory);
1329 int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1335 static void test_case_failed(const char *message)
1337 test_case_cleanup();
1339 pr_err("FAIL: %s\n", message);
1340 pr_err("FAIL: Test %s\n", current_title);
1341 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1344 static unsigned long next_instruction(unsigned long pc)
1346 #ifdef CONFIG_THUMB2_KERNEL
1348 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1355 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1357 struct test_arg *args;
1358 struct test_arg_end *end_arg;
1359 unsigned long test_code;
1361 current_title = *title++;
1362 args = (struct test_arg *)title;
1363 current_args = args;
1364 current_stack = stack;
1368 while (args->type != ARG_TYPE_END)
1370 end_arg = (struct test_arg_end *)args;
1372 test_code = (unsigned long)(args + 1); /* Code starts after args */
1374 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1375 if (test_case_is_thumb)
1378 current_code_start = test_code;
1380 current_branch_target = 0;
1381 if (end_arg->branch_offset != end_arg->end_offset)
1382 current_branch_target = test_code + end_arg->branch_offset;
1384 test_code += end_arg->code_offset;
1385 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1387 test_code = next_instruction(test_code);
1388 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1390 if (test_case_is_thumb) {
1391 u16 *p = (u16 *)(test_code & ~1);
1392 current_instruction = __mem_to_opcode_thumb16(p[0]);
1393 if (is_wide_instruction(current_instruction)) {
1394 u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1395 current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1398 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1401 if (current_title[0] == '.')
1402 verbose("%s\n", current_title);
1404 verbose("%s\t@ %0*x\n", current_title,
1405 test_case_is_thumb ? 4 : 8,
1406 current_instruction);
1408 test_code = next_instruction(test_code);
1409 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1411 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1412 if (!test_case_is_thumb ||
1413 is_wide_instruction(current_instruction)) {
1414 test_case_failed("expected 16-bit instruction");
1418 if (test_case_is_thumb &&
1419 !is_wide_instruction(current_instruction)) {
1420 test_case_failed("expected 32-bit instruction");
1425 coverage_add(current_instruction);
1427 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1428 if (register_test_probe(&test_case_probe) < 0)
1430 test_case_failed("registered probe for unsupported instruction");
1434 if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1435 if (register_test_probe(&test_case_probe) >= 0)
1437 test_case_failed("couldn't register probe for supported instruction");
1441 if (register_test_probe(&test_before_probe) < 0) {
1442 test_case_failed("register test_before_probe failed");
1445 if (register_test_probe(&test_after_probe) < 0) {
1446 test_case_failed("register test_after_probe failed");
1449 if (current_branch_target) {
1450 test_after2_probe.kprobe.addr =
1451 (kprobe_opcode_t *)current_branch_target;
1452 if (register_test_probe(&test_after2_probe) < 0) {
1453 test_case_failed("register test_after2_probe failed");
1458 /* Start first run of test case */
1459 test_case_run_count = 0;
1461 return current_code_start;
1463 test_case_run_count = TEST_CASE_PASSED;
1464 return (uintptr_t)test_after_probe.kprobe.addr;
1466 test_case_run_count = TEST_CASE_FAILED;
1467 return (uintptr_t)test_after_probe.kprobe.addr;
1470 static bool check_test_results(void)
1472 size_t mem_size = 0;
1475 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1476 test_case_failed("registers differ");
1480 if (memory_needs_checking) {
1481 mem = (u32 *)result_regs.ARM_sp;
1482 mem_size = expected_memory_size(mem);
1483 if (memcmp(expected_memory, mem, mem_size)) {
1484 test_case_failed("test memory differs");
1492 pr_err("initial_regs:\n");
1493 print_registers(&initial_regs);
1494 pr_err("expected_regs:\n");
1495 print_registers(&expected_regs);
1496 pr_err("result_regs:\n");
1497 print_registers(&result_regs);
1500 pr_err("current_stack=%p\n", current_stack);
1501 pr_err("expected_memory:\n");
1502 print_memory(expected_memory, mem_size);
1503 pr_err("result_memory:\n");
1504 print_memory(mem, mem_size);
1510 static uintptr_t __used kprobes_test_case_end(void)
1512 if (test_case_run_count < 0) {
1513 if (test_case_run_count == TEST_CASE_PASSED)
1514 /* kprobes_test_case_start did all the needed testing */
1517 /* kprobes_test_case_start failed */
1521 if (test_before_probe.hit != test_instance) {
1522 test_case_failed("test_before_handler not run");
1526 if (test_after_probe.hit != test_instance &&
1527 test_after2_probe.hit != test_instance) {
1528 test_case_failed("test_after_handler not run");
1533 * Even numbered test runs ran without a probe on the test case so
1534 * we can gather reference results. The subsequent odd numbered run
1535 * will have the probe inserted.
1537 if ((test_case_run_count & 1) == 0) {
1538 /* Save results from run without probe */
1539 u32 *mem = (u32 *)result_regs.ARM_sp;
1540 expected_regs = result_regs;
1541 memcpy(expected_memory, mem, expected_memory_size(mem));
1543 /* Insert probe onto test case instruction */
1544 if (register_test_probe(&test_case_probe) < 0) {
1545 test_case_failed("register test_case_probe failed");
1549 /* Check probe ran as expected */
1550 if (probe_should_run == 1) {
1551 if (test_case_probe.hit != test_instance) {
1552 test_case_failed("test_case_handler not run");
1555 } else if (probe_should_run == 0) {
1556 if (test_case_probe.hit == test_instance) {
1557 test_case_failed("test_case_handler ran");
1562 /* Remove probe for any subsequent reference run */
1563 unregister_test_probe(&test_case_probe);
1565 if (!check_test_results())
1568 if (is_last_scenario)
1572 /* Do next test run */
1573 ++test_case_run_count;
1575 return current_code_start;
1582 test_case_cleanup();
1588 * Top level test functions
1591 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1595 pr_info(" Check decoding tables\n");
1596 ret = table_test(table);
1600 pr_info(" Run test cases\n");
1601 ret = coverage_start(table);
1612 static int __init run_all_tests(void)
1616 pr_info("Beginning kprobe tests...\n");
1618 #ifndef CONFIG_THUMB2_KERNEL
1620 pr_info("Probe ARM code\n");
1621 ret = run_api_tests(arm_func);
1625 pr_info("ARM instruction simulation\n");
1626 ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1630 #else /* CONFIG_THUMB2_KERNEL */
1632 pr_info("Probe 16-bit Thumb code\n");
1633 ret = run_api_tests(thumb16_func);
1637 pr_info("Probe 32-bit Thumb code, even halfword\n");
1638 ret = run_api_tests(thumb32even_func);
1642 pr_info("Probe 32-bit Thumb code, odd halfword\n");
1643 ret = run_api_tests(thumb32odd_func);
1647 pr_info("16-bit Thumb instruction simulation\n");
1648 ret = run_test_cases(kprobe_thumb16_test_cases,
1649 probes_decode_thumb16_table);
1653 pr_info("32-bit Thumb instruction simulation\n");
1654 ret = run_test_cases(kprobe_thumb32_test_cases,
1655 probes_decode_thumb32_table);
1660 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1661 test_try_count, test_pass_count, test_fail_count);
1662 if (test_fail_count) {
1668 pr_info("Benchmarks\n");
1669 ret = run_benchmarks();
1674 #if __LINUX_ARM_ARCH__ >= 7
1675 /* We are able to run all test cases so coverage should be complete */
1676 if (coverage_fail) {
1677 pr_err("FAIL: Test coverage checks failed\n");
1687 pr_info("Finished kprobe tests OK\n");
1689 pr_err("kprobe tests failed\n");
1701 static void __exit kprobe_test_exit(void)
1705 module_init(run_all_tests)
1706 module_exit(kprobe_test_exit)
1707 MODULE_LICENSE("GPL");
1711 late_initcall(run_all_tests);