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/sched/clock.h>
207 #include <linux/kprobes.h>
208 #include <linux/errno.h>
209 #include <linux/stddef.h>
210 #include <linux/bug.h>
211 #include <asm/opcodes.h>
214 #include "test-core.h"
215 #include "../decode-arm.h"
216 #include "../decode-thumb.h"
219 #define BENCHMARKING 1
226 static bool test_regs_ok;
227 static int test_func_instance;
228 static int pre_handler_called;
229 static int post_handler_called;
230 static int kretprobe_handler_called;
231 static int tests_failed;
233 #define FUNC_ARG1 0x12345678
234 #define FUNC_ARG2 0xabcdef
237 #ifndef CONFIG_THUMB2_KERNEL
239 #define RET(reg) "mov pc, "#reg
241 long arm_func(long r0, long r1);
243 static void __used __naked __arm_kprobes_test_func(void)
245 __asm__ __volatile__ (
247 ".type arm_func, %%function \n\t"
249 "adds r0, r0, r1 \n\t"
251 ".code "NORMAL_ISA /* Back to Thumb if necessary */
252 : : : "r0", "r1", "cc"
256 #else /* CONFIG_THUMB2_KERNEL */
258 #define RET(reg) "bx "#reg
260 long thumb16_func(long r0, long r1);
261 long thumb32even_func(long r0, long r1);
262 long thumb32odd_func(long r0, long r1);
264 static void __used __naked __thumb_kprobes_test_funcs(void)
266 __asm__ __volatile__ (
267 ".type thumb16_func, %%function \n\t"
269 "adds.n r0, r0, r1 \n\t"
273 ".type thumb32even_func, %%function \n\t"
274 "thumb32even_func: \n\t"
275 "adds.w r0, r0, r1 \n\t"
280 ".type thumb32odd_func, %%function \n\t"
281 "thumb32odd_func: \n\t"
282 "adds.w r0, r0, r1 \n\t"
285 : : : "r0", "r1", "cc"
289 #endif /* CONFIG_THUMB2_KERNEL */
292 static int call_test_func(long (*func)(long, long), bool check_test_regs)
296 ++test_func_instance;
297 test_regs_ok = false;
299 ret = (*func)(FUNC_ARG1, FUNC_ARG2);
300 if (ret != FUNC_ARG1 + FUNC_ARG2) {
301 pr_err("FAIL: call_test_func: func returned %lx\n", ret);
305 if (check_test_regs && !test_regs_ok) {
306 pr_err("FAIL: test regs not OK\n");
313 static int __kprobes pre_handler(struct kprobe *p, struct pt_regs *regs)
315 pre_handler_called = test_func_instance;
316 if (regs->ARM_r0 == FUNC_ARG1 && regs->ARM_r1 == FUNC_ARG2)
321 static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
324 post_handler_called = test_func_instance;
325 if (regs->ARM_r0 != FUNC_ARG1 + FUNC_ARG2 || regs->ARM_r1 != FUNC_ARG2)
326 test_regs_ok = false;
329 static struct kprobe the_kprobe = {
331 .pre_handler = pre_handler,
332 .post_handler = post_handler
335 static int test_kprobe(long (*func)(long, long))
339 the_kprobe.addr = (kprobe_opcode_t *)func;
340 ret = register_kprobe(&the_kprobe);
342 pr_err("FAIL: register_kprobe failed with %d\n", ret);
346 ret = call_test_func(func, true);
348 unregister_kprobe(&the_kprobe);
349 the_kprobe.flags = 0; /* Clear disable flag to allow reuse */
353 if (pre_handler_called != test_func_instance) {
354 pr_err("FAIL: kprobe pre_handler not called\n");
357 if (post_handler_called != test_func_instance) {
358 pr_err("FAIL: kprobe post_handler not called\n");
361 if (!call_test_func(func, false))
363 if (pre_handler_called == test_func_instance ||
364 post_handler_called == test_func_instance) {
365 pr_err("FAIL: probe called after unregistering\n");
373 kretprobe_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
375 kretprobe_handler_called = test_func_instance;
376 if (regs_return_value(regs) == FUNC_ARG1 + FUNC_ARG2)
381 static struct kretprobe the_kretprobe = {
382 .handler = kretprobe_handler,
385 static int test_kretprobe(long (*func)(long, long))
389 the_kretprobe.kp.addr = (kprobe_opcode_t *)func;
390 ret = register_kretprobe(&the_kretprobe);
392 pr_err("FAIL: register_kretprobe failed with %d\n", ret);
396 ret = call_test_func(func, true);
398 unregister_kretprobe(&the_kretprobe);
399 the_kretprobe.kp.flags = 0; /* Clear disable flag to allow reuse */
403 if (kretprobe_handler_called != test_func_instance) {
404 pr_err("FAIL: kretprobe handler not called\n");
407 if (!call_test_func(func, false))
409 if (kretprobe_handler_called == test_func_instance) {
410 pr_err("FAIL: kretprobe called after unregistering\n");
417 static int run_api_tests(long (*func)(long, long))
421 pr_info(" kprobe\n");
422 ret = test_kprobe(func);
426 pr_info(" kretprobe\n");
427 ret = test_kretprobe(func);
441 static void __naked benchmark_nop(void)
443 __asm__ __volatile__ (
449 #ifdef CONFIG_THUMB2_KERNEL
455 static void __naked benchmark_pushpop1(void)
457 __asm__ __volatile__ (
458 "stmdb"wide" sp!, {r3-r11,lr} \n\t"
459 "ldmia"wide" sp!, {r3-r11,pc}"
463 static void __naked benchmark_pushpop2(void)
465 __asm__ __volatile__ (
466 "stmdb"wide" sp!, {r0-r8,lr} \n\t"
467 "ldmia"wide" sp!, {r0-r8,pc}"
471 static void __naked benchmark_pushpop3(void)
473 __asm__ __volatile__ (
474 "stmdb"wide" sp!, {r4,lr} \n\t"
475 "ldmia"wide" sp!, {r4,pc}"
479 static void __naked benchmark_pushpop4(void)
481 __asm__ __volatile__ (
482 "stmdb"wide" sp!, {r0,lr} \n\t"
483 "ldmia"wide" sp!, {r0,pc}"
488 #ifdef CONFIG_THUMB2_KERNEL
490 static void __naked benchmark_pushpop_thumb(void)
492 __asm__ __volatile__ (
493 "push.n {r0-r7,lr} \n\t"
501 benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs)
506 static int benchmark(void(*fn)(void))
508 unsigned n, i, t, t0;
510 for (n = 1000; ; n *= 2) {
512 for (i = n; i > 0; --i)
514 t = sched_clock() - t0;
516 break; /* Stop once we took more than 0.25 seconds */
518 return t / n; /* Time for one iteration in nanoseconds */
521 static int kprobe_benchmark(void(*fn)(void), unsigned offset)
524 .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset),
525 .pre_handler = benchmark_pre_handler,
528 int ret = register_kprobe(&k);
530 pr_err("FAIL: register_kprobe failed with %d\n", ret);
536 unregister_kprobe(&k);
546 static int run_benchmarks(void)
549 struct benchmarks list[] = {
550 {&benchmark_nop, 0, "nop"},
552 * benchmark_pushpop{1,3} will have the optimised
553 * instruction emulation, whilst benchmark_pushpop{2,4} will
554 * be the equivalent unoptimised instructions.
556 {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"},
557 {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"},
558 {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"},
559 {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"},
560 {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"},
561 {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"},
562 {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"},
563 {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"},
564 #ifdef CONFIG_THUMB2_KERNEL
565 {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"},
566 {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"},
571 struct benchmarks *b;
572 for (b = list; b->fn; ++b) {
573 ret = kprobe_benchmark(b->fn, b->offset);
576 pr_info(" %dns for kprobe %s\n", ret, b->title);
583 #endif /* BENCHMARKING */
587 * Decoding table self-consistency tests
590 static const int decode_struct_sizes[NUM_DECODE_TYPES] = {
591 [DECODE_TYPE_TABLE] = sizeof(struct decode_table),
592 [DECODE_TYPE_CUSTOM] = sizeof(struct decode_custom),
593 [DECODE_TYPE_SIMULATE] = sizeof(struct decode_simulate),
594 [DECODE_TYPE_EMULATE] = sizeof(struct decode_emulate),
595 [DECODE_TYPE_OR] = sizeof(struct decode_or),
596 [DECODE_TYPE_REJECT] = sizeof(struct decode_reject)
599 static int table_iter(const union decode_item *table,
600 int (*fn)(const struct decode_header *, void *),
603 const struct decode_header *h = (struct decode_header *)table;
607 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
609 if (type == DECODE_TYPE_END)
612 result = fn(h, args);
616 h = (struct decode_header *)
617 ((uintptr_t)h + decode_struct_sizes[type]);
622 static int table_test_fail(const struct decode_header *h, const char* message)
625 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
626 message, h->mask.bits, h->value.bits);
630 struct table_test_args {
631 const union decode_item *root_table;
636 static int table_test_fn(const struct decode_header *h, void *args)
638 struct table_test_args *a = (struct table_test_args *)args;
639 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
641 if (h->value.bits & ~h->mask.bits)
642 return table_test_fail(h, "Match value has bits not in mask");
644 if ((h->mask.bits & a->parent_mask) != a->parent_mask)
645 return table_test_fail(h, "Mask has bits not in parent mask");
647 if ((h->value.bits ^ a->parent_value) & a->parent_mask)
648 return table_test_fail(h, "Value is inconsistent with parent");
650 if (type == DECODE_TYPE_TABLE) {
651 struct decode_table *d = (struct decode_table *)h;
652 struct table_test_args args2 = *a;
653 args2.parent_mask = h->mask.bits;
654 args2.parent_value = h->value.bits;
655 return table_iter(d->table.table, table_test_fn, &args2);
661 static int table_test(const union decode_item *table)
663 struct table_test_args args = {
668 return table_iter(args.root_table, table_test_fn, &args);
673 * Decoding table test coverage analysis
675 * coverage_start() builds a coverage_table which contains a list of
676 * coverage_entry's to match each entry in the specified kprobes instruction
679 * When test cases are run, coverage_add() is called to process each case.
680 * This looks up the corresponding entry in the coverage_table and sets it as
681 * being matched, as well as clearing the regs flag appropriate for the test.
683 * After all test cases have been run, coverage_end() is called to check that
684 * all entries in coverage_table have been matched and that all regs flags are
685 * cleared. I.e. that all possible combinations of instructions described by
686 * the kprobes decoding tables have had a test case executed for them.
691 #define MAX_COVERAGE_ENTRIES 256
693 struct coverage_entry {
694 const struct decode_header *header;
700 struct coverage_table {
701 struct coverage_entry *base;
702 unsigned num_entries;
706 struct coverage_table coverage;
708 #define COVERAGE_ANY_REG (1<<0)
709 #define COVERAGE_SP (1<<1)
710 #define COVERAGE_PC (1<<2)
711 #define COVERAGE_PCWB (1<<3)
713 static const char coverage_register_lookup[16] = {
714 [REG_TYPE_ANY] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
715 [REG_TYPE_SAMEAS16] = COVERAGE_ANY_REG,
716 [REG_TYPE_SP] = COVERAGE_SP,
717 [REG_TYPE_PC] = COVERAGE_PC,
718 [REG_TYPE_NOSP] = COVERAGE_ANY_REG | COVERAGE_SP,
719 [REG_TYPE_NOSPPC] = COVERAGE_ANY_REG | COVERAGE_SP | COVERAGE_PC,
720 [REG_TYPE_NOPC] = COVERAGE_ANY_REG | COVERAGE_PC,
721 [REG_TYPE_NOPCWB] = COVERAGE_ANY_REG | COVERAGE_PC | COVERAGE_PCWB,
722 [REG_TYPE_NOPCX] = COVERAGE_ANY_REG,
723 [REG_TYPE_NOSPPCX] = COVERAGE_ANY_REG | COVERAGE_SP,
726 unsigned coverage_start_registers(const struct decode_header *h)
730 for (i = 0; i < 20; i += 4) {
731 int r = (h->type_regs.bits >> (DECODE_TYPE_BITS + i)) & 0xf;
732 regs |= coverage_register_lookup[r] << i;
737 static int coverage_start_fn(const struct decode_header *h, void *args)
739 struct coverage_table *coverage = (struct coverage_table *)args;
740 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
741 struct coverage_entry *entry = coverage->base + coverage->num_entries;
743 if (coverage->num_entries == MAX_COVERAGE_ENTRIES - 1) {
744 pr_err("FAIL: Out of space for test coverage data");
748 ++coverage->num_entries;
751 entry->regs = coverage_start_registers(h);
752 entry->nesting = coverage->nesting;
753 entry->matched = false;
755 if (type == DECODE_TYPE_TABLE) {
756 struct decode_table *d = (struct decode_table *)h;
759 ret = table_iter(d->table.table, coverage_start_fn, coverage);
767 static int coverage_start(const union decode_item *table)
769 coverage.base = kmalloc_array(MAX_COVERAGE_ENTRIES,
770 sizeof(struct coverage_entry),
772 coverage.num_entries = 0;
773 coverage.nesting = 0;
774 return table_iter(table, coverage_start_fn, &coverage);
778 coverage_add_registers(struct coverage_entry *entry, kprobe_opcode_t insn)
780 int regs = entry->header->type_regs.bits >> DECODE_TYPE_BITS;
782 for (i = 0; i < 20; i += 4) {
783 enum decode_reg_type reg_type = (regs >> i) & 0xf;
784 int reg = (insn >> i) & 0xf;
795 flag = COVERAGE_ANY_REG;
796 entry->regs &= ~(flag << i);
802 case REG_TYPE_SAMEAS16:
820 case REG_TYPE_NOSPPC:
821 case REG_TYPE_NOSPPCX:
822 if (reg == 13 || reg == 15)
826 case REG_TYPE_NOPCWB:
827 if (!is_writeback(insn))
830 entry->regs &= ~(COVERAGE_PCWB << i);
845 static void coverage_add(kprobe_opcode_t insn)
847 struct coverage_entry *entry = coverage.base;
848 struct coverage_entry *end = coverage.base + coverage.num_entries;
849 bool matched = false;
850 unsigned nesting = 0;
852 for (; entry < end; ++entry) {
853 const struct decode_header *h = entry->header;
854 enum decode_type type = h->type_regs.bits & DECODE_TYPE_MASK;
856 if (entry->nesting > nesting)
857 continue; /* Skip sub-table we didn't match */
859 if (entry->nesting < nesting)
860 break; /* End of sub-table we were scanning */
863 if ((insn & h->mask.bits) != h->value.bits)
865 entry->matched = true;
870 case DECODE_TYPE_TABLE:
874 case DECODE_TYPE_CUSTOM:
875 case DECODE_TYPE_SIMULATE:
876 case DECODE_TYPE_EMULATE:
877 coverage_add_registers(entry, insn);
884 case DECODE_TYPE_REJECT:
892 static void coverage_end(void)
894 struct coverage_entry *entry = coverage.base;
895 struct coverage_entry *end = coverage.base + coverage.num_entries;
897 for (; entry < end; ++entry) {
898 u32 mask = entry->header->mask.bits;
899 u32 value = entry->header->value.bits;
902 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
903 mask, value, entry->regs);
904 coverage_fail = true;
906 if (!entry->matched) {
907 pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
909 coverage_fail = true;
913 kfree(coverage.base);
918 * Framework for instruction set test cases
921 void __naked __kprobes_test_case_start(void)
923 __asm__ __volatile__ (
925 "bic r3, r2, #7 \n\t"
927 "stmdb sp!, {r2-r11} \n\t"
928 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
929 "bic r0, lr, #1 @ r0 = inline data \n\t"
931 "bl kprobes_test_case_start \n\t"
936 #ifndef CONFIG_THUMB2_KERNEL
938 void __naked __kprobes_test_case_end_32(void)
940 __asm__ __volatile__ (
942 "bl kprobes_test_case_end \n\t"
946 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
947 "ldmia sp!, {r2-r11} \n\t"
953 #else /* CONFIG_THUMB2_KERNEL */
955 void __naked __kprobes_test_case_end_16(void)
957 __asm__ __volatile__ (
959 "bl kprobes_test_case_end \n\t"
963 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
964 "ldmia sp!, {r2-r11} \n\t"
970 void __naked __kprobes_test_case_end_32(void)
972 __asm__ __volatile__ (
974 "orr lr, lr, #1 @ will return to Thumb code \n\t"
977 ".word __kprobes_test_case_end_16 \n\t"
984 int kprobe_test_flags;
985 int kprobe_test_cc_position;
987 static int test_try_count;
988 static int test_pass_count;
989 static int test_fail_count;
991 static struct pt_regs initial_regs;
992 static struct pt_regs expected_regs;
993 static struct pt_regs result_regs;
995 static u32 expected_memory[TEST_MEMORY_SIZE/sizeof(u32)];
997 static const char *current_title;
998 static struct test_arg *current_args;
999 static u32 *current_stack;
1000 static uintptr_t current_branch_target;
1002 static uintptr_t current_code_start;
1003 static kprobe_opcode_t current_instruction;
1006 #define TEST_CASE_PASSED -1
1007 #define TEST_CASE_FAILED -2
1009 static int test_case_run_count;
1010 static bool test_case_is_thumb;
1011 static int test_instance;
1013 static unsigned long test_check_cc(int cc, unsigned long cpsr)
1015 int ret = arm_check_condition(cc << 28, cpsr);
1017 return (ret != ARM_OPCODE_CONDTEST_FAIL);
1020 static int is_last_scenario;
1021 static int probe_should_run; /* 0 = no, 1 = yes, -1 = unknown */
1022 static int memory_needs_checking;
1024 static unsigned long test_context_cpsr(int scenario)
1028 probe_should_run = 1;
1030 /* Default case is that we cycle through 16 combinations of flags */
1031 cpsr = (scenario & 0xf) << 28; /* N,Z,C,V flags */
1032 cpsr |= (scenario & 0xf) << 16; /* GE flags */
1033 cpsr |= (scenario & 0x1) << 27; /* Toggle Q flag */
1035 if (!test_case_is_thumb) {
1036 /* Testing ARM code */
1037 int cc = current_instruction >> 28;
1039 probe_should_run = test_check_cc(cc, cpsr) != 0;
1041 is_last_scenario = true;
1043 } else if (kprobe_test_flags & TEST_FLAG_NO_ITBLOCK) {
1044 /* Testing Thumb code without setting ITSTATE */
1045 if (kprobe_test_cc_position) {
1046 int cc = (current_instruction >> kprobe_test_cc_position) & 0xf;
1047 probe_should_run = test_check_cc(cc, cpsr) != 0;
1051 is_last_scenario = true;
1053 } else if (kprobe_test_flags & TEST_FLAG_FULL_ITBLOCK) {
1054 /* Testing Thumb code with all combinations of ITSTATE */
1055 unsigned x = (scenario >> 4);
1056 unsigned cond_base = x % 7; /* ITSTATE<7:5> */
1057 unsigned mask = x / 7 + 2; /* ITSTATE<4:0>, bits reversed */
1060 /* Finish by testing state from instruction 'itt al' */
1063 if ((scenario & 0xf) == 0xf)
1064 is_last_scenario = true;
1067 cpsr |= cond_base << 13; /* ITSTATE<7:5> */
1068 cpsr |= (mask & 0x1) << 12; /* ITSTATE<4> */
1069 cpsr |= (mask & 0x2) << 10; /* ITSTATE<3> */
1070 cpsr |= (mask & 0x4) << 8; /* ITSTATE<2> */
1071 cpsr |= (mask & 0x8) << 23; /* ITSTATE<1> */
1072 cpsr |= (mask & 0x10) << 21; /* ITSTATE<0> */
1074 probe_should_run = test_check_cc((cpsr >> 12) & 0xf, cpsr) != 0;
1077 /* Testing Thumb code with several combinations of ITSTATE */
1079 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1081 probe_should_run = 0;
1083 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1085 probe_should_run = 0;
1087 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1090 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1092 is_last_scenario = true;
1100 static void setup_test_context(struct pt_regs *regs)
1102 int scenario = test_case_run_count>>1;
1104 struct test_arg *args;
1107 is_last_scenario = false;
1108 memory_needs_checking = false;
1110 /* Initialise test memory on stack */
1111 val = (scenario & 1) ? VALM : ~VALM;
1112 for (i = 0; i < TEST_MEMORY_SIZE / sizeof(current_stack[0]); ++i)
1113 current_stack[i] = val + (i << 8);
1114 /* Put target of branch on stack for tests which load PC from memory */
1115 if (current_branch_target)
1116 current_stack[15] = current_branch_target;
1117 /* Put a value for SP on stack for tests which load SP from memory */
1118 current_stack[13] = (u32)current_stack + 120;
1120 /* Initialise register values to their default state */
1121 val = (scenario & 2) ? VALR : ~VALR;
1122 for (i = 0; i < 13; ++i)
1123 regs->uregs[i] = val ^ (i << 8);
1124 regs->ARM_lr = val ^ (14 << 8);
1125 regs->ARM_cpsr &= ~(APSR_MASK | PSR_IT_MASK);
1126 regs->ARM_cpsr |= test_context_cpsr(scenario);
1128 /* Perform testcase specific register setup */
1129 args = current_args;
1130 for (; args[0].type != ARG_TYPE_END; ++args)
1131 switch (args[0].type) {
1132 case ARG_TYPE_REG: {
1133 struct test_arg_regptr *arg =
1134 (struct test_arg_regptr *)args;
1135 regs->uregs[arg->reg] = arg->val;
1138 case ARG_TYPE_PTR: {
1139 struct test_arg_regptr *arg =
1140 (struct test_arg_regptr *)args;
1141 regs->uregs[arg->reg] =
1142 (unsigned long)current_stack + arg->val;
1143 memory_needs_checking = true;
1145 * Test memory at an address below SP is in danger of
1146 * being altered by an interrupt occurring and pushing
1147 * data onto the stack. Disable interrupts to stop this.
1150 regs->ARM_cpsr |= PSR_I_BIT;
1153 case ARG_TYPE_MEM: {
1154 struct test_arg_mem *arg = (struct test_arg_mem *)args;
1155 current_stack[arg->index] = arg->val;
1164 struct kprobe kprobe;
1169 static void unregister_test_probe(struct test_probe *probe)
1171 if (probe->registered) {
1172 unregister_kprobe(&probe->kprobe);
1173 probe->kprobe.flags = 0; /* Clear disable flag to allow reuse */
1175 probe->registered = false;
1178 static int register_test_probe(struct test_probe *probe)
1182 if (probe->registered)
1185 ret = register_kprobe(&probe->kprobe);
1187 probe->registered = true;
1193 static int __kprobes
1194 test_before_pre_handler(struct kprobe *p, struct pt_regs *regs)
1196 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1200 static void __kprobes
1201 test_before_post_handler(struct kprobe *p, struct pt_regs *regs,
1202 unsigned long flags)
1204 setup_test_context(regs);
1205 initial_regs = *regs;
1206 initial_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1209 static int __kprobes
1210 test_case_pre_handler(struct kprobe *p, struct pt_regs *regs)
1212 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1216 static int __kprobes
1217 test_after_pre_handler(struct kprobe *p, struct pt_regs *regs)
1219 struct test_arg *args;
1221 if (container_of(p, struct test_probe, kprobe)->hit == test_instance)
1222 return 0; /* Already run for this test instance */
1224 result_regs = *regs;
1226 /* Mask out results which are indeterminate */
1227 result_regs.ARM_cpsr &= ~PSR_IGNORE_BITS;
1228 for (args = current_args; args[0].type != ARG_TYPE_END; ++args)
1229 if (args[0].type == ARG_TYPE_REG_MASKED) {
1230 struct test_arg_regptr *arg =
1231 (struct test_arg_regptr *)args;
1232 result_regs.uregs[arg->reg] &= arg->val;
1235 /* Undo any changes done to SP by the test case */
1236 regs->ARM_sp = (unsigned long)current_stack;
1237 /* Enable interrupts in case setup_test_context disabled them */
1238 regs->ARM_cpsr &= ~PSR_I_BIT;
1240 container_of(p, struct test_probe, kprobe)->hit = test_instance;
1244 static struct test_probe test_before_probe = {
1245 .kprobe.pre_handler = test_before_pre_handler,
1246 .kprobe.post_handler = test_before_post_handler,
1249 static struct test_probe test_case_probe = {
1250 .kprobe.pre_handler = test_case_pre_handler,
1253 static struct test_probe test_after_probe = {
1254 .kprobe.pre_handler = test_after_pre_handler,
1257 static struct test_probe test_after2_probe = {
1258 .kprobe.pre_handler = test_after_pre_handler,
1261 static void test_case_cleanup(void)
1263 unregister_test_probe(&test_before_probe);
1264 unregister_test_probe(&test_case_probe);
1265 unregister_test_probe(&test_after_probe);
1266 unregister_test_probe(&test_after2_probe);
1269 static void print_registers(struct pt_regs *regs)
1271 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1272 regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
1273 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1274 regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
1275 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1276 regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp);
1277 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1278 regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc);
1279 pr_err("cpsr %08lx\n", regs->ARM_cpsr);
1282 static void print_memory(u32 *mem, size_t size)
1285 for (i = 0; i < size / sizeof(u32); i += 4)
1286 pr_err("%08x %08x %08x %08x\n", mem[i], mem[i+1],
1287 mem[i+2], mem[i+3]);
1290 static size_t expected_memory_size(u32 *sp)
1292 size_t size = sizeof(expected_memory);
1293 int offset = (uintptr_t)sp - (uintptr_t)current_stack;
1299 static void test_case_failed(const char *message)
1301 test_case_cleanup();
1303 pr_err("FAIL: %s\n", message);
1304 pr_err("FAIL: Test %s\n", current_title);
1305 pr_err("FAIL: Scenario %d\n", test_case_run_count >> 1);
1308 static unsigned long next_instruction(unsigned long pc)
1310 #ifdef CONFIG_THUMB2_KERNEL
1312 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16 *)(pc - 1))))
1319 static uintptr_t __used kprobes_test_case_start(const char **title, void *stack)
1321 struct test_arg *args;
1322 struct test_arg_end *end_arg;
1323 unsigned long test_code;
1325 current_title = *title++;
1326 args = (struct test_arg *)title;
1327 current_args = args;
1328 current_stack = stack;
1332 while (args->type != ARG_TYPE_END)
1334 end_arg = (struct test_arg_end *)args;
1336 test_code = (unsigned long)(args + 1); /* Code starts after args */
1338 test_case_is_thumb = end_arg->flags & ARG_FLAG_THUMB;
1339 if (test_case_is_thumb)
1342 current_code_start = test_code;
1344 current_branch_target = 0;
1345 if (end_arg->branch_offset != end_arg->end_offset)
1346 current_branch_target = test_code + end_arg->branch_offset;
1348 test_code += end_arg->code_offset;
1349 test_before_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1351 test_code = next_instruction(test_code);
1352 test_case_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1354 if (test_case_is_thumb) {
1355 u16 *p = (u16 *)(test_code & ~1);
1356 current_instruction = __mem_to_opcode_thumb16(p[0]);
1357 if (is_wide_instruction(current_instruction)) {
1358 u16 instr2 = __mem_to_opcode_thumb16(p[1]);
1359 current_instruction = __opcode_thumb32_compose(current_instruction, instr2);
1362 current_instruction = __mem_to_opcode_arm(*(u32 *)test_code);
1365 if (current_title[0] == '.')
1366 verbose("%s\n", current_title);
1368 verbose("%s\t@ %0*x\n", current_title,
1369 test_case_is_thumb ? 4 : 8,
1370 current_instruction);
1372 test_code = next_instruction(test_code);
1373 test_after_probe.kprobe.addr = (kprobe_opcode_t *)test_code;
1375 if (kprobe_test_flags & TEST_FLAG_NARROW_INSTR) {
1376 if (!test_case_is_thumb ||
1377 is_wide_instruction(current_instruction)) {
1378 test_case_failed("expected 16-bit instruction");
1382 if (test_case_is_thumb &&
1383 !is_wide_instruction(current_instruction)) {
1384 test_case_failed("expected 32-bit instruction");
1389 coverage_add(current_instruction);
1391 if (end_arg->flags & ARG_FLAG_UNSUPPORTED) {
1392 if (register_test_probe(&test_case_probe) < 0)
1394 test_case_failed("registered probe for unsupported instruction");
1398 if (end_arg->flags & ARG_FLAG_SUPPORTED) {
1399 if (register_test_probe(&test_case_probe) >= 0)
1401 test_case_failed("couldn't register probe for supported instruction");
1405 if (register_test_probe(&test_before_probe) < 0) {
1406 test_case_failed("register test_before_probe failed");
1409 if (register_test_probe(&test_after_probe) < 0) {
1410 test_case_failed("register test_after_probe failed");
1413 if (current_branch_target) {
1414 test_after2_probe.kprobe.addr =
1415 (kprobe_opcode_t *)current_branch_target;
1416 if (register_test_probe(&test_after2_probe) < 0) {
1417 test_case_failed("register test_after2_probe failed");
1422 /* Start first run of test case */
1423 test_case_run_count = 0;
1425 return current_code_start;
1427 test_case_run_count = TEST_CASE_PASSED;
1428 return (uintptr_t)test_after_probe.kprobe.addr;
1430 test_case_run_count = TEST_CASE_FAILED;
1431 return (uintptr_t)test_after_probe.kprobe.addr;
1434 static bool check_test_results(void)
1436 size_t mem_size = 0;
1439 if (memcmp(&expected_regs, &result_regs, sizeof(expected_regs))) {
1440 test_case_failed("registers differ");
1444 if (memory_needs_checking) {
1445 mem = (u32 *)result_regs.ARM_sp;
1446 mem_size = expected_memory_size(mem);
1447 if (memcmp(expected_memory, mem, mem_size)) {
1448 test_case_failed("test memory differs");
1456 pr_err("initial_regs:\n");
1457 print_registers(&initial_regs);
1458 pr_err("expected_regs:\n");
1459 print_registers(&expected_regs);
1460 pr_err("result_regs:\n");
1461 print_registers(&result_regs);
1464 pr_err("expected_memory:\n");
1465 print_memory(expected_memory, mem_size);
1466 pr_err("result_memory:\n");
1467 print_memory(mem, mem_size);
1473 static uintptr_t __used kprobes_test_case_end(void)
1475 if (test_case_run_count < 0) {
1476 if (test_case_run_count == TEST_CASE_PASSED)
1477 /* kprobes_test_case_start did all the needed testing */
1480 /* kprobes_test_case_start failed */
1484 if (test_before_probe.hit != test_instance) {
1485 test_case_failed("test_before_handler not run");
1489 if (test_after_probe.hit != test_instance &&
1490 test_after2_probe.hit != test_instance) {
1491 test_case_failed("test_after_handler not run");
1496 * Even numbered test runs ran without a probe on the test case so
1497 * we can gather reference results. The subsequent odd numbered run
1498 * will have the probe inserted.
1500 if ((test_case_run_count & 1) == 0) {
1501 /* Save results from run without probe */
1502 u32 *mem = (u32 *)result_regs.ARM_sp;
1503 expected_regs = result_regs;
1504 memcpy(expected_memory, mem, expected_memory_size(mem));
1506 /* Insert probe onto test case instruction */
1507 if (register_test_probe(&test_case_probe) < 0) {
1508 test_case_failed("register test_case_probe failed");
1512 /* Check probe ran as expected */
1513 if (probe_should_run == 1) {
1514 if (test_case_probe.hit != test_instance) {
1515 test_case_failed("test_case_handler not run");
1518 } else if (probe_should_run == 0) {
1519 if (test_case_probe.hit == test_instance) {
1520 test_case_failed("test_case_handler ran");
1525 /* Remove probe for any subsequent reference run */
1526 unregister_test_probe(&test_case_probe);
1528 if (!check_test_results())
1531 if (is_last_scenario)
1535 /* Do next test run */
1536 ++test_case_run_count;
1538 return current_code_start;
1545 test_case_cleanup();
1551 * Top level test functions
1554 static int run_test_cases(void (*tests)(void), const union decode_item *table)
1558 pr_info(" Check decoding tables\n");
1559 ret = table_test(table);
1563 pr_info(" Run test cases\n");
1564 ret = coverage_start(table);
1575 static int __init run_all_tests(void)
1579 pr_info("Beginning kprobe tests...\n");
1581 #ifndef CONFIG_THUMB2_KERNEL
1583 pr_info("Probe ARM code\n");
1584 ret = run_api_tests(arm_func);
1588 pr_info("ARM instruction simulation\n");
1589 ret = run_test_cases(kprobe_arm_test_cases, probes_decode_arm_table);
1593 #else /* CONFIG_THUMB2_KERNEL */
1595 pr_info("Probe 16-bit Thumb code\n");
1596 ret = run_api_tests(thumb16_func);
1600 pr_info("Probe 32-bit Thumb code, even halfword\n");
1601 ret = run_api_tests(thumb32even_func);
1605 pr_info("Probe 32-bit Thumb code, odd halfword\n");
1606 ret = run_api_tests(thumb32odd_func);
1610 pr_info("16-bit Thumb instruction simulation\n");
1611 ret = run_test_cases(kprobe_thumb16_test_cases,
1612 probes_decode_thumb16_table);
1616 pr_info("32-bit Thumb instruction simulation\n");
1617 ret = run_test_cases(kprobe_thumb32_test_cases,
1618 probes_decode_thumb32_table);
1623 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1624 test_try_count, test_pass_count, test_fail_count);
1625 if (test_fail_count) {
1631 pr_info("Benchmarks\n");
1632 ret = run_benchmarks();
1637 #if __LINUX_ARM_ARCH__ >= 7
1638 /* We are able to run all test cases so coverage should be complete */
1639 if (coverage_fail) {
1640 pr_err("FAIL: Test coverage checks failed\n");
1650 pr_info("Finished kprobe tests OK\n");
1652 pr_err("kprobe tests failed\n");
1664 static void __exit kprobe_test_exit(void)
1668 module_init(run_all_tests)
1669 module_exit(kprobe_test_exit)
1670 MODULE_LICENSE("GPL");
1674 late_initcall(run_all_tests);