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
);