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 jprobe_func_called
;
231 static int kretprobe_handler_called
;
232 static int tests_failed
;
234 #define FUNC_ARG1 0x12345678
235 #define FUNC_ARG2 0xabcdef
238 #ifndef CONFIG_THUMB2_KERNEL
240 #define RET(reg) "mov pc, "#reg
242 long arm_func(long r0
, long r1
);
244 static void __used __naked
__arm_kprobes_test_func(void)
246 __asm__
__volatile__ (
248 ".type arm_func, %%function \n\t"
250 "adds r0, r0, r1 \n\t"
252 ".code "NORMAL_ISA
/* Back to Thumb if necessary */
253 : : : "r0", "r1", "cc"
257 #else /* CONFIG_THUMB2_KERNEL */
259 #define RET(reg) "bx "#reg
261 long thumb16_func(long r0
, long r1
);
262 long thumb32even_func(long r0
, long r1
);
263 long thumb32odd_func(long r0
, long r1
);
265 static void __used __naked
__thumb_kprobes_test_funcs(void)
267 __asm__
__volatile__ (
268 ".type thumb16_func, %%function \n\t"
270 "adds.n r0, r0, r1 \n\t"
274 ".type thumb32even_func, %%function \n\t"
275 "thumb32even_func: \n\t"
276 "adds.w r0, r0, r1 \n\t"
281 ".type thumb32odd_func, %%function \n\t"
282 "thumb32odd_func: \n\t"
283 "adds.w r0, r0, r1 \n\t"
286 : : : "r0", "r1", "cc"
290 #endif /* CONFIG_THUMB2_KERNEL */
293 static int call_test_func(long (*func
)(long, long), bool check_test_regs
)
297 ++test_func_instance
;
298 test_regs_ok
= false;
300 ret
= (*func
)(FUNC_ARG1
, FUNC_ARG2
);
301 if (ret
!= FUNC_ARG1
+ FUNC_ARG2
) {
302 pr_err("FAIL: call_test_func: func returned %lx\n", ret
);
306 if (check_test_regs
&& !test_regs_ok
) {
307 pr_err("FAIL: test regs not OK\n");
314 static int __kprobes
pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
316 pre_handler_called
= test_func_instance
;
317 if (regs
->ARM_r0
== FUNC_ARG1
&& regs
->ARM_r1
== FUNC_ARG2
)
322 static void __kprobes
post_handler(struct kprobe
*p
, struct pt_regs
*regs
,
325 post_handler_called
= test_func_instance
;
326 if (regs
->ARM_r0
!= FUNC_ARG1
+ FUNC_ARG2
|| regs
->ARM_r1
!= FUNC_ARG2
)
327 test_regs_ok
= false;
330 static struct kprobe the_kprobe
= {
332 .pre_handler
= pre_handler
,
333 .post_handler
= post_handler
336 static int test_kprobe(long (*func
)(long, long))
340 the_kprobe
.addr
= (kprobe_opcode_t
*)func
;
341 ret
= register_kprobe(&the_kprobe
);
343 pr_err("FAIL: register_kprobe failed with %d\n", ret
);
347 ret
= call_test_func(func
, true);
349 unregister_kprobe(&the_kprobe
);
350 the_kprobe
.flags
= 0; /* Clear disable flag to allow reuse */
354 if (pre_handler_called
!= test_func_instance
) {
355 pr_err("FAIL: kprobe pre_handler not called\n");
358 if (post_handler_called
!= test_func_instance
) {
359 pr_err("FAIL: kprobe post_handler not called\n");
362 if (!call_test_func(func
, false))
364 if (pre_handler_called
== test_func_instance
||
365 post_handler_called
== test_func_instance
) {
366 pr_err("FAIL: probe called after unregistering\n");
373 static void __kprobes
jprobe_func(long r0
, long r1
)
375 jprobe_func_called
= test_func_instance
;
376 if (r0
== FUNC_ARG1
&& r1
== FUNC_ARG2
)
381 static struct jprobe the_jprobe
= {
382 .entry
= jprobe_func
,
385 static int test_jprobe(long (*func
)(long, long))
389 the_jprobe
.kp
.addr
= (kprobe_opcode_t
*)func
;
390 ret
= register_jprobe(&the_jprobe
);
392 pr_err("FAIL: register_jprobe failed with %d\n", ret
);
396 ret
= call_test_func(func
, true);
398 unregister_jprobe(&the_jprobe
);
399 the_jprobe
.kp
.flags
= 0; /* Clear disable flag to allow reuse */
403 if (jprobe_func_called
!= test_func_instance
) {
404 pr_err("FAIL: jprobe handler function not called\n");
407 if (!call_test_func(func
, false))
409 if (jprobe_func_called
== test_func_instance
) {
410 pr_err("FAIL: probe called after unregistering\n");
418 kretprobe_handler(struct kretprobe_instance
*ri
, struct pt_regs
*regs
)
420 kretprobe_handler_called
= test_func_instance
;
421 if (regs_return_value(regs
) == FUNC_ARG1
+ FUNC_ARG2
)
426 static struct kretprobe the_kretprobe
= {
427 .handler
= kretprobe_handler
,
430 static int test_kretprobe(long (*func
)(long, long))
434 the_kretprobe
.kp
.addr
= (kprobe_opcode_t
*)func
;
435 ret
= register_kretprobe(&the_kretprobe
);
437 pr_err("FAIL: register_kretprobe failed with %d\n", ret
);
441 ret
= call_test_func(func
, true);
443 unregister_kretprobe(&the_kretprobe
);
444 the_kretprobe
.kp
.flags
= 0; /* Clear disable flag to allow reuse */
448 if (kretprobe_handler_called
!= test_func_instance
) {
449 pr_err("FAIL: kretprobe handler not called\n");
452 if (!call_test_func(func
, false))
454 if (jprobe_func_called
== test_func_instance
) {
455 pr_err("FAIL: kretprobe called after unregistering\n");
462 static int run_api_tests(long (*func
)(long, long))
466 pr_info(" kprobe\n");
467 ret
= test_kprobe(func
);
471 pr_info(" jprobe\n");
472 ret
= test_jprobe(func
);
473 #if defined(CONFIG_THUMB2_KERNEL) && !defined(MODULE)
474 if (ret
== -EINVAL
) {
475 pr_err("FAIL: Known longtime bug with jprobe on Thumb kernels\n");
483 pr_info(" kretprobe\n");
484 ret
= test_kretprobe(func
);
498 static void __naked
benchmark_nop(void)
500 __asm__
__volatile__ (
506 #ifdef CONFIG_THUMB2_KERNEL
512 static void __naked
benchmark_pushpop1(void)
514 __asm__
__volatile__ (
515 "stmdb"wide
" sp!, {r3-r11,lr} \n\t"
516 "ldmia"wide
" sp!, {r3-r11,pc}"
520 static void __naked
benchmark_pushpop2(void)
522 __asm__
__volatile__ (
523 "stmdb"wide
" sp!, {r0-r8,lr} \n\t"
524 "ldmia"wide
" sp!, {r0-r8,pc}"
528 static void __naked
benchmark_pushpop3(void)
530 __asm__
__volatile__ (
531 "stmdb"wide
" sp!, {r4,lr} \n\t"
532 "ldmia"wide
" sp!, {r4,pc}"
536 static void __naked
benchmark_pushpop4(void)
538 __asm__
__volatile__ (
539 "stmdb"wide
" sp!, {r0,lr} \n\t"
540 "ldmia"wide
" sp!, {r0,pc}"
545 #ifdef CONFIG_THUMB2_KERNEL
547 static void __naked
benchmark_pushpop_thumb(void)
549 __asm__
__volatile__ (
550 "push.n {r0-r7,lr} \n\t"
558 benchmark_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
563 static int benchmark(void(*fn
)(void))
565 unsigned n
, i
, t
, t0
;
567 for (n
= 1000; ; n
*= 2) {
569 for (i
= n
; i
> 0; --i
)
571 t
= sched_clock() - t0
;
573 break; /* Stop once we took more than 0.25 seconds */
575 return t
/ n
; /* Time for one iteration in nanoseconds */
578 static int kprobe_benchmark(void(*fn
)(void), unsigned offset
)
581 .addr
= (kprobe_opcode_t
*)((uintptr_t)fn
+ offset
),
582 .pre_handler
= benchmark_pre_handler
,
585 int ret
= register_kprobe(&k
);
587 pr_err("FAIL: register_kprobe failed with %d\n", ret
);
593 unregister_kprobe(&k
);
603 static int run_benchmarks(void)
606 struct benchmarks list
[] = {
607 {&benchmark_nop
, 0, "nop"},
609 * benchmark_pushpop{1,3} will have the optimised
610 * instruction emulation, whilst benchmark_pushpop{2,4} will
611 * be the equivalent unoptimised instructions.
613 {&benchmark_pushpop1
, 0, "stmdb sp!, {r3-r11,lr}"},
614 {&benchmark_pushpop1
, 4, "ldmia sp!, {r3-r11,pc}"},
615 {&benchmark_pushpop2
, 0, "stmdb sp!, {r0-r8,lr}"},
616 {&benchmark_pushpop2
, 4, "ldmia sp!, {r0-r8,pc}"},
617 {&benchmark_pushpop3
, 0, "stmdb sp!, {r4,lr}"},
618 {&benchmark_pushpop3
, 4, "ldmia sp!, {r4,pc}"},
619 {&benchmark_pushpop4
, 0, "stmdb sp!, {r0,lr}"},
620 {&benchmark_pushpop4
, 4, "ldmia sp!, {r0,pc}"},
621 #ifdef CONFIG_THUMB2_KERNEL
622 {&benchmark_pushpop_thumb
, 0, "push.n {r0-r7,lr}"},
623 {&benchmark_pushpop_thumb
, 2, "pop.n {r0-r7,pc}"},
628 struct benchmarks
*b
;
629 for (b
= list
; b
->fn
; ++b
) {
630 ret
= kprobe_benchmark(b
->fn
, b
->offset
);
633 pr_info(" %dns for kprobe %s\n", ret
, b
->title
);
640 #endif /* BENCHMARKING */
644 * Decoding table self-consistency tests
647 static const int decode_struct_sizes
[NUM_DECODE_TYPES
] = {
648 [DECODE_TYPE_TABLE
] = sizeof(struct decode_table
),
649 [DECODE_TYPE_CUSTOM
] = sizeof(struct decode_custom
),
650 [DECODE_TYPE_SIMULATE
] = sizeof(struct decode_simulate
),
651 [DECODE_TYPE_EMULATE
] = sizeof(struct decode_emulate
),
652 [DECODE_TYPE_OR
] = sizeof(struct decode_or
),
653 [DECODE_TYPE_REJECT
] = sizeof(struct decode_reject
)
656 static int table_iter(const union decode_item
*table
,
657 int (*fn
)(const struct decode_header
*, void *),
660 const struct decode_header
*h
= (struct decode_header
*)table
;
664 enum decode_type type
= h
->type_regs
.bits
& DECODE_TYPE_MASK
;
666 if (type
== DECODE_TYPE_END
)
669 result
= fn(h
, args
);
673 h
= (struct decode_header
*)
674 ((uintptr_t)h
+ decode_struct_sizes
[type
]);
679 static int table_test_fail(const struct decode_header
*h
, const char* message
)
682 pr_err("FAIL: kprobes test failure \"%s\" (mask %08x, value %08x)\n",
683 message
, h
->mask
.bits
, h
->value
.bits
);
687 struct table_test_args
{
688 const union decode_item
*root_table
;
693 static int table_test_fn(const struct decode_header
*h
, void *args
)
695 struct table_test_args
*a
= (struct table_test_args
*)args
;
696 enum decode_type type
= h
->type_regs
.bits
& DECODE_TYPE_MASK
;
698 if (h
->value
.bits
& ~h
->mask
.bits
)
699 return table_test_fail(h
, "Match value has bits not in mask");
701 if ((h
->mask
.bits
& a
->parent_mask
) != a
->parent_mask
)
702 return table_test_fail(h
, "Mask has bits not in parent mask");
704 if ((h
->value
.bits
^ a
->parent_value
) & a
->parent_mask
)
705 return table_test_fail(h
, "Value is inconsistent with parent");
707 if (type
== DECODE_TYPE_TABLE
) {
708 struct decode_table
*d
= (struct decode_table
*)h
;
709 struct table_test_args args2
= *a
;
710 args2
.parent_mask
= h
->mask
.bits
;
711 args2
.parent_value
= h
->value
.bits
;
712 return table_iter(d
->table
.table
, table_test_fn
, &args2
);
718 static int table_test(const union decode_item
*table
)
720 struct table_test_args args
= {
725 return table_iter(args
.root_table
, table_test_fn
, &args
);
730 * Decoding table test coverage analysis
732 * coverage_start() builds a coverage_table which contains a list of
733 * coverage_entry's to match each entry in the specified kprobes instruction
736 * When test cases are run, coverage_add() is called to process each case.
737 * This looks up the corresponding entry in the coverage_table and sets it as
738 * being matched, as well as clearing the regs flag appropriate for the test.
740 * After all test cases have been run, coverage_end() is called to check that
741 * all entries in coverage_table have been matched and that all regs flags are
742 * cleared. I.e. that all possible combinations of instructions described by
743 * the kprobes decoding tables have had a test case executed for them.
748 #define MAX_COVERAGE_ENTRIES 256
750 struct coverage_entry
{
751 const struct decode_header
*header
;
757 struct coverage_table
{
758 struct coverage_entry
*base
;
759 unsigned num_entries
;
763 struct coverage_table coverage
;
765 #define COVERAGE_ANY_REG (1<<0)
766 #define COVERAGE_SP (1<<1)
767 #define COVERAGE_PC (1<<2)
768 #define COVERAGE_PCWB (1<<3)
770 static const char coverage_register_lookup
[16] = {
771 [REG_TYPE_ANY
] = COVERAGE_ANY_REG
| COVERAGE_SP
| COVERAGE_PC
,
772 [REG_TYPE_SAMEAS16
] = COVERAGE_ANY_REG
,
773 [REG_TYPE_SP
] = COVERAGE_SP
,
774 [REG_TYPE_PC
] = COVERAGE_PC
,
775 [REG_TYPE_NOSP
] = COVERAGE_ANY_REG
| COVERAGE_SP
,
776 [REG_TYPE_NOSPPC
] = COVERAGE_ANY_REG
| COVERAGE_SP
| COVERAGE_PC
,
777 [REG_TYPE_NOPC
] = COVERAGE_ANY_REG
| COVERAGE_PC
,
778 [REG_TYPE_NOPCWB
] = COVERAGE_ANY_REG
| COVERAGE_PC
| COVERAGE_PCWB
,
779 [REG_TYPE_NOPCX
] = COVERAGE_ANY_REG
,
780 [REG_TYPE_NOSPPCX
] = COVERAGE_ANY_REG
| COVERAGE_SP
,
783 unsigned coverage_start_registers(const struct decode_header
*h
)
787 for (i
= 0; i
< 20; i
+= 4) {
788 int r
= (h
->type_regs
.bits
>> (DECODE_TYPE_BITS
+ i
)) & 0xf;
789 regs
|= coverage_register_lookup
[r
] << i
;
794 static int coverage_start_fn(const struct decode_header
*h
, void *args
)
796 struct coverage_table
*coverage
= (struct coverage_table
*)args
;
797 enum decode_type type
= h
->type_regs
.bits
& DECODE_TYPE_MASK
;
798 struct coverage_entry
*entry
= coverage
->base
+ coverage
->num_entries
;
800 if (coverage
->num_entries
== MAX_COVERAGE_ENTRIES
- 1) {
801 pr_err("FAIL: Out of space for test coverage data");
805 ++coverage
->num_entries
;
808 entry
->regs
= coverage_start_registers(h
);
809 entry
->nesting
= coverage
->nesting
;
810 entry
->matched
= false;
812 if (type
== DECODE_TYPE_TABLE
) {
813 struct decode_table
*d
= (struct decode_table
*)h
;
816 ret
= table_iter(d
->table
.table
, coverage_start_fn
, coverage
);
824 static int coverage_start(const union decode_item
*table
)
826 coverage
.base
= kmalloc(MAX_COVERAGE_ENTRIES
*
827 sizeof(struct coverage_entry
), GFP_KERNEL
);
828 coverage
.num_entries
= 0;
829 coverage
.nesting
= 0;
830 return table_iter(table
, coverage_start_fn
, &coverage
);
834 coverage_add_registers(struct coverage_entry
*entry
, kprobe_opcode_t insn
)
836 int regs
= entry
->header
->type_regs
.bits
>> DECODE_TYPE_BITS
;
838 for (i
= 0; i
< 20; i
+= 4) {
839 enum decode_reg_type reg_type
= (regs
>> i
) & 0xf;
840 int reg
= (insn
>> i
) & 0xf;
851 flag
= COVERAGE_ANY_REG
;
852 entry
->regs
&= ~(flag
<< i
);
858 case REG_TYPE_SAMEAS16
:
876 case REG_TYPE_NOSPPC
:
877 case REG_TYPE_NOSPPCX
:
878 if (reg
== 13 || reg
== 15)
882 case REG_TYPE_NOPCWB
:
883 if (!is_writeback(insn
))
886 entry
->regs
&= ~(COVERAGE_PCWB
<< i
);
901 static void coverage_add(kprobe_opcode_t insn
)
903 struct coverage_entry
*entry
= coverage
.base
;
904 struct coverage_entry
*end
= coverage
.base
+ coverage
.num_entries
;
905 bool matched
= false;
906 unsigned nesting
= 0;
908 for (; entry
< end
; ++entry
) {
909 const struct decode_header
*h
= entry
->header
;
910 enum decode_type type
= h
->type_regs
.bits
& DECODE_TYPE_MASK
;
912 if (entry
->nesting
> nesting
)
913 continue; /* Skip sub-table we didn't match */
915 if (entry
->nesting
< nesting
)
916 break; /* End of sub-table we were scanning */
919 if ((insn
& h
->mask
.bits
) != h
->value
.bits
)
921 entry
->matched
= true;
926 case DECODE_TYPE_TABLE
:
930 case DECODE_TYPE_CUSTOM
:
931 case DECODE_TYPE_SIMULATE
:
932 case DECODE_TYPE_EMULATE
:
933 coverage_add_registers(entry
, insn
);
940 case DECODE_TYPE_REJECT
:
948 static void coverage_end(void)
950 struct coverage_entry
*entry
= coverage
.base
;
951 struct coverage_entry
*end
= coverage
.base
+ coverage
.num_entries
;
953 for (; entry
< end
; ++entry
) {
954 u32 mask
= entry
->header
->mask
.bits
;
955 u32 value
= entry
->header
->value
.bits
;
958 pr_err("FAIL: Register test coverage missing for %08x %08x (%05x)\n",
959 mask
, value
, entry
->regs
);
960 coverage_fail
= true;
962 if (!entry
->matched
) {
963 pr_err("FAIL: Test coverage entry missing for %08x %08x\n",
965 coverage_fail
= true;
969 kfree(coverage
.base
);
974 * Framework for instruction set test cases
977 void __naked
__kprobes_test_case_start(void)
979 __asm__
__volatile__ (
980 "stmdb sp!, {r4-r11} \n\t"
981 "sub sp, sp, #"__stringify(TEST_MEMORY_SIZE
)"\n\t"
982 "bic r0, lr, #1 @ r0 = inline data \n\t"
984 "bl kprobes_test_case_start \n\t"
989 #ifndef CONFIG_THUMB2_KERNEL
991 void __naked
__kprobes_test_case_end_32(void)
993 __asm__
__volatile__ (
995 "bl kprobes_test_case_end \n\t"
999 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE
)"\n\t"
1000 "ldmia sp!, {r4-r11} \n\t"
1005 #else /* CONFIG_THUMB2_KERNEL */
1007 void __naked
__kprobes_test_case_end_16(void)
1009 __asm__
__volatile__ (
1011 "bl kprobes_test_case_end \n\t"
1015 "add sp, sp, #"__stringify(TEST_MEMORY_SIZE
)"\n\t"
1016 "ldmia sp!, {r4-r11} \n\t"
1021 void __naked
__kprobes_test_case_end_32(void)
1023 __asm__
__volatile__ (
1025 "orr lr, lr, #1 @ will return to Thumb code \n\t"
1028 ".word __kprobes_test_case_end_16 \n\t"
1035 int kprobe_test_flags
;
1036 int kprobe_test_cc_position
;
1038 static int test_try_count
;
1039 static int test_pass_count
;
1040 static int test_fail_count
;
1042 static struct pt_regs initial_regs
;
1043 static struct pt_regs expected_regs
;
1044 static struct pt_regs result_regs
;
1046 static u32 expected_memory
[TEST_MEMORY_SIZE
/sizeof(u32
)];
1048 static const char *current_title
;
1049 static struct test_arg
*current_args
;
1050 static u32
*current_stack
;
1051 static uintptr_t current_branch_target
;
1053 static uintptr_t current_code_start
;
1054 static kprobe_opcode_t current_instruction
;
1057 #define TEST_CASE_PASSED -1
1058 #define TEST_CASE_FAILED -2
1060 static int test_case_run_count
;
1061 static bool test_case_is_thumb
;
1062 static int test_instance
;
1064 static unsigned long test_check_cc(int cc
, unsigned long cpsr
)
1066 int ret
= arm_check_condition(cc
<< 28, cpsr
);
1068 return (ret
!= ARM_OPCODE_CONDTEST_FAIL
);
1071 static int is_last_scenario
;
1072 static int probe_should_run
; /* 0 = no, 1 = yes, -1 = unknown */
1073 static int memory_needs_checking
;
1075 static unsigned long test_context_cpsr(int scenario
)
1079 probe_should_run
= 1;
1081 /* Default case is that we cycle through 16 combinations of flags */
1082 cpsr
= (scenario
& 0xf) << 28; /* N,Z,C,V flags */
1083 cpsr
|= (scenario
& 0xf) << 16; /* GE flags */
1084 cpsr
|= (scenario
& 0x1) << 27; /* Toggle Q flag */
1086 if (!test_case_is_thumb
) {
1087 /* Testing ARM code */
1088 int cc
= current_instruction
>> 28;
1090 probe_should_run
= test_check_cc(cc
, cpsr
) != 0;
1092 is_last_scenario
= true;
1094 } else if (kprobe_test_flags
& TEST_FLAG_NO_ITBLOCK
) {
1095 /* Testing Thumb code without setting ITSTATE */
1096 if (kprobe_test_cc_position
) {
1097 int cc
= (current_instruction
>> kprobe_test_cc_position
) & 0xf;
1098 probe_should_run
= test_check_cc(cc
, cpsr
) != 0;
1102 is_last_scenario
= true;
1104 } else if (kprobe_test_flags
& TEST_FLAG_FULL_ITBLOCK
) {
1105 /* Testing Thumb code with all combinations of ITSTATE */
1106 unsigned x
= (scenario
>> 4);
1107 unsigned cond_base
= x
% 7; /* ITSTATE<7:5> */
1108 unsigned mask
= x
/ 7 + 2; /* ITSTATE<4:0>, bits reversed */
1111 /* Finish by testing state from instruction 'itt al' */
1114 if ((scenario
& 0xf) == 0xf)
1115 is_last_scenario
= true;
1118 cpsr
|= cond_base
<< 13; /* ITSTATE<7:5> */
1119 cpsr
|= (mask
& 0x1) << 12; /* ITSTATE<4> */
1120 cpsr
|= (mask
& 0x2) << 10; /* ITSTATE<3> */
1121 cpsr
|= (mask
& 0x4) << 8; /* ITSTATE<2> */
1122 cpsr
|= (mask
& 0x8) << 23; /* ITSTATE<1> */
1123 cpsr
|= (mask
& 0x10) << 21; /* ITSTATE<0> */
1125 probe_should_run
= test_check_cc((cpsr
>> 12) & 0xf, cpsr
) != 0;
1128 /* Testing Thumb code with several combinations of ITSTATE */
1130 case 16: /* Clear NZCV flags and 'it eq' state (false as Z=0) */
1132 probe_should_run
= 0;
1134 case 17: /* Set NZCV flags and 'it vc' state (false as V=1) */
1136 probe_should_run
= 0;
1138 case 18: /* Clear NZCV flags and 'it ls' state (true as C=0) */
1141 case 19: /* Set NZCV flags and 'it cs' state (true as C=1) */
1143 is_last_scenario
= true;
1151 static void setup_test_context(struct pt_regs
*regs
)
1153 int scenario
= test_case_run_count
>>1;
1155 struct test_arg
*args
;
1158 is_last_scenario
= false;
1159 memory_needs_checking
= false;
1161 /* Initialise test memory on stack */
1162 val
= (scenario
& 1) ? VALM
: ~VALM
;
1163 for (i
= 0; i
< TEST_MEMORY_SIZE
/ sizeof(current_stack
[0]); ++i
)
1164 current_stack
[i
] = val
+ (i
<< 8);
1165 /* Put target of branch on stack for tests which load PC from memory */
1166 if (current_branch_target
)
1167 current_stack
[15] = current_branch_target
;
1168 /* Put a value for SP on stack for tests which load SP from memory */
1169 current_stack
[13] = (u32
)current_stack
+ 120;
1171 /* Initialise register values to their default state */
1172 val
= (scenario
& 2) ? VALR
: ~VALR
;
1173 for (i
= 0; i
< 13; ++i
)
1174 regs
->uregs
[i
] = val
^ (i
<< 8);
1175 regs
->ARM_lr
= val
^ (14 << 8);
1176 regs
->ARM_cpsr
&= ~(APSR_MASK
| PSR_IT_MASK
);
1177 regs
->ARM_cpsr
|= test_context_cpsr(scenario
);
1179 /* Perform testcase specific register setup */
1180 args
= current_args
;
1181 for (; args
[0].type
!= ARG_TYPE_END
; ++args
)
1182 switch (args
[0].type
) {
1183 case ARG_TYPE_REG
: {
1184 struct test_arg_regptr
*arg
=
1185 (struct test_arg_regptr
*)args
;
1186 regs
->uregs
[arg
->reg
] = arg
->val
;
1189 case ARG_TYPE_PTR
: {
1190 struct test_arg_regptr
*arg
=
1191 (struct test_arg_regptr
*)args
;
1192 regs
->uregs
[arg
->reg
] =
1193 (unsigned long)current_stack
+ arg
->val
;
1194 memory_needs_checking
= true;
1196 * Test memory at an address below SP is in danger of
1197 * being altered by an interrupt occurring and pushing
1198 * data onto the stack. Disable interrupts to stop this.
1201 regs
->ARM_cpsr
|= PSR_I_BIT
;
1204 case ARG_TYPE_MEM
: {
1205 struct test_arg_mem
*arg
= (struct test_arg_mem
*)args
;
1206 current_stack
[arg
->index
] = arg
->val
;
1215 struct kprobe kprobe
;
1220 static void unregister_test_probe(struct test_probe
*probe
)
1222 if (probe
->registered
) {
1223 unregister_kprobe(&probe
->kprobe
);
1224 probe
->kprobe
.flags
= 0; /* Clear disable flag to allow reuse */
1226 probe
->registered
= false;
1229 static int register_test_probe(struct test_probe
*probe
)
1233 if (probe
->registered
)
1236 ret
= register_kprobe(&probe
->kprobe
);
1238 probe
->registered
= true;
1244 static int __kprobes
1245 test_before_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
1247 container_of(p
, struct test_probe
, kprobe
)->hit
= test_instance
;
1251 static void __kprobes
1252 test_before_post_handler(struct kprobe
*p
, struct pt_regs
*regs
,
1253 unsigned long flags
)
1255 setup_test_context(regs
);
1256 initial_regs
= *regs
;
1257 initial_regs
.ARM_cpsr
&= ~PSR_IGNORE_BITS
;
1260 static int __kprobes
1261 test_case_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
1263 container_of(p
, struct test_probe
, kprobe
)->hit
= test_instance
;
1267 static int __kprobes
1268 test_after_pre_handler(struct kprobe
*p
, struct pt_regs
*regs
)
1270 struct test_arg
*args
;
1272 if (container_of(p
, struct test_probe
, kprobe
)->hit
== test_instance
)
1273 return 0; /* Already run for this test instance */
1275 result_regs
= *regs
;
1277 /* Mask out results which are indeterminate */
1278 result_regs
.ARM_cpsr
&= ~PSR_IGNORE_BITS
;
1279 for (args
= current_args
; args
[0].type
!= ARG_TYPE_END
; ++args
)
1280 if (args
[0].type
== ARG_TYPE_REG_MASKED
) {
1281 struct test_arg_regptr
*arg
=
1282 (struct test_arg_regptr
*)args
;
1283 result_regs
.uregs
[arg
->reg
] &= arg
->val
;
1286 /* Undo any changes done to SP by the test case */
1287 regs
->ARM_sp
= (unsigned long)current_stack
;
1288 /* Enable interrupts in case setup_test_context disabled them */
1289 regs
->ARM_cpsr
&= ~PSR_I_BIT
;
1291 container_of(p
, struct test_probe
, kprobe
)->hit
= test_instance
;
1295 static struct test_probe test_before_probe
= {
1296 .kprobe
.pre_handler
= test_before_pre_handler
,
1297 .kprobe
.post_handler
= test_before_post_handler
,
1300 static struct test_probe test_case_probe
= {
1301 .kprobe
.pre_handler
= test_case_pre_handler
,
1304 static struct test_probe test_after_probe
= {
1305 .kprobe
.pre_handler
= test_after_pre_handler
,
1308 static struct test_probe test_after2_probe
= {
1309 .kprobe
.pre_handler
= test_after_pre_handler
,
1312 static void test_case_cleanup(void)
1314 unregister_test_probe(&test_before_probe
);
1315 unregister_test_probe(&test_case_probe
);
1316 unregister_test_probe(&test_after_probe
);
1317 unregister_test_probe(&test_after2_probe
);
1320 static void print_registers(struct pt_regs
*regs
)
1322 pr_err("r0 %08lx | r1 %08lx | r2 %08lx | r3 %08lx\n",
1323 regs
->ARM_r0
, regs
->ARM_r1
, regs
->ARM_r2
, regs
->ARM_r3
);
1324 pr_err("r4 %08lx | r5 %08lx | r6 %08lx | r7 %08lx\n",
1325 regs
->ARM_r4
, regs
->ARM_r5
, regs
->ARM_r6
, regs
->ARM_r7
);
1326 pr_err("r8 %08lx | r9 %08lx | r10 %08lx | r11 %08lx\n",
1327 regs
->ARM_r8
, regs
->ARM_r9
, regs
->ARM_r10
, regs
->ARM_fp
);
1328 pr_err("r12 %08lx | sp %08lx | lr %08lx | pc %08lx\n",
1329 regs
->ARM_ip
, regs
->ARM_sp
, regs
->ARM_lr
, regs
->ARM_pc
);
1330 pr_err("cpsr %08lx\n", regs
->ARM_cpsr
);
1333 static void print_memory(u32
*mem
, size_t size
)
1336 for (i
= 0; i
< size
/ sizeof(u32
); i
+= 4)
1337 pr_err("%08x %08x %08x %08x\n", mem
[i
], mem
[i
+1],
1338 mem
[i
+2], mem
[i
+3]);
1341 static size_t expected_memory_size(u32
*sp
)
1343 size_t size
= sizeof(expected_memory
);
1344 int offset
= (uintptr_t)sp
- (uintptr_t)current_stack
;
1350 static void test_case_failed(const char *message
)
1352 test_case_cleanup();
1354 pr_err("FAIL: %s\n", message
);
1355 pr_err("FAIL: Test %s\n", current_title
);
1356 pr_err("FAIL: Scenario %d\n", test_case_run_count
>> 1);
1359 static unsigned long next_instruction(unsigned long pc
)
1361 #ifdef CONFIG_THUMB2_KERNEL
1363 !is_wide_instruction(__mem_to_opcode_thumb16(*(u16
*)(pc
- 1))))
1370 static uintptr_t __used
kprobes_test_case_start(const char **title
, void *stack
)
1372 struct test_arg
*args
;
1373 struct test_arg_end
*end_arg
;
1374 unsigned long test_code
;
1376 current_title
= *title
++;
1377 args
= (struct test_arg
*)title
;
1378 current_args
= args
;
1379 current_stack
= stack
;
1383 while (args
->type
!= ARG_TYPE_END
)
1385 end_arg
= (struct test_arg_end
*)args
;
1387 test_code
= (unsigned long)(args
+ 1); /* Code starts after args */
1389 test_case_is_thumb
= end_arg
->flags
& ARG_FLAG_THUMB
;
1390 if (test_case_is_thumb
)
1393 current_code_start
= test_code
;
1395 current_branch_target
= 0;
1396 if (end_arg
->branch_offset
!= end_arg
->end_offset
)
1397 current_branch_target
= test_code
+ end_arg
->branch_offset
;
1399 test_code
+= end_arg
->code_offset
;
1400 test_before_probe
.kprobe
.addr
= (kprobe_opcode_t
*)test_code
;
1402 test_code
= next_instruction(test_code
);
1403 test_case_probe
.kprobe
.addr
= (kprobe_opcode_t
*)test_code
;
1405 if (test_case_is_thumb
) {
1406 u16
*p
= (u16
*)(test_code
& ~1);
1407 current_instruction
= __mem_to_opcode_thumb16(p
[0]);
1408 if (is_wide_instruction(current_instruction
)) {
1409 u16 instr2
= __mem_to_opcode_thumb16(p
[1]);
1410 current_instruction
= __opcode_thumb32_compose(current_instruction
, instr2
);
1413 current_instruction
= __mem_to_opcode_arm(*(u32
*)test_code
);
1416 if (current_title
[0] == '.')
1417 verbose("%s\n", current_title
);
1419 verbose("%s\t@ %0*x\n", current_title
,
1420 test_case_is_thumb
? 4 : 8,
1421 current_instruction
);
1423 test_code
= next_instruction(test_code
);
1424 test_after_probe
.kprobe
.addr
= (kprobe_opcode_t
*)test_code
;
1426 if (kprobe_test_flags
& TEST_FLAG_NARROW_INSTR
) {
1427 if (!test_case_is_thumb
||
1428 is_wide_instruction(current_instruction
)) {
1429 test_case_failed("expected 16-bit instruction");
1433 if (test_case_is_thumb
&&
1434 !is_wide_instruction(current_instruction
)) {
1435 test_case_failed("expected 32-bit instruction");
1440 coverage_add(current_instruction
);
1442 if (end_arg
->flags
& ARG_FLAG_UNSUPPORTED
) {
1443 if (register_test_probe(&test_case_probe
) < 0)
1445 test_case_failed("registered probe for unsupported instruction");
1449 if (end_arg
->flags
& ARG_FLAG_SUPPORTED
) {
1450 if (register_test_probe(&test_case_probe
) >= 0)
1452 test_case_failed("couldn't register probe for supported instruction");
1456 if (register_test_probe(&test_before_probe
) < 0) {
1457 test_case_failed("register test_before_probe failed");
1460 if (register_test_probe(&test_after_probe
) < 0) {
1461 test_case_failed("register test_after_probe failed");
1464 if (current_branch_target
) {
1465 test_after2_probe
.kprobe
.addr
=
1466 (kprobe_opcode_t
*)current_branch_target
;
1467 if (register_test_probe(&test_after2_probe
) < 0) {
1468 test_case_failed("register test_after2_probe failed");
1473 /* Start first run of test case */
1474 test_case_run_count
= 0;
1476 return current_code_start
;
1478 test_case_run_count
= TEST_CASE_PASSED
;
1479 return (uintptr_t)test_after_probe
.kprobe
.addr
;
1481 test_case_run_count
= TEST_CASE_FAILED
;
1482 return (uintptr_t)test_after_probe
.kprobe
.addr
;
1485 static bool check_test_results(void)
1487 size_t mem_size
= 0;
1490 if (memcmp(&expected_regs
, &result_regs
, sizeof(expected_regs
))) {
1491 test_case_failed("registers differ");
1495 if (memory_needs_checking
) {
1496 mem
= (u32
*)result_regs
.ARM_sp
;
1497 mem_size
= expected_memory_size(mem
);
1498 if (memcmp(expected_memory
, mem
, mem_size
)) {
1499 test_case_failed("test memory differs");
1507 pr_err("initial_regs:\n");
1508 print_registers(&initial_regs
);
1509 pr_err("expected_regs:\n");
1510 print_registers(&expected_regs
);
1511 pr_err("result_regs:\n");
1512 print_registers(&result_regs
);
1515 pr_err("current_stack=%p\n", current_stack
);
1516 pr_err("expected_memory:\n");
1517 print_memory(expected_memory
, mem_size
);
1518 pr_err("result_memory:\n");
1519 print_memory(mem
, mem_size
);
1525 static uintptr_t __used
kprobes_test_case_end(void)
1527 if (test_case_run_count
< 0) {
1528 if (test_case_run_count
== TEST_CASE_PASSED
)
1529 /* kprobes_test_case_start did all the needed testing */
1532 /* kprobes_test_case_start failed */
1536 if (test_before_probe
.hit
!= test_instance
) {
1537 test_case_failed("test_before_handler not run");
1541 if (test_after_probe
.hit
!= test_instance
&&
1542 test_after2_probe
.hit
!= test_instance
) {
1543 test_case_failed("test_after_handler not run");
1548 * Even numbered test runs ran without a probe on the test case so
1549 * we can gather reference results. The subsequent odd numbered run
1550 * will have the probe inserted.
1552 if ((test_case_run_count
& 1) == 0) {
1553 /* Save results from run without probe */
1554 u32
*mem
= (u32
*)result_regs
.ARM_sp
;
1555 expected_regs
= result_regs
;
1556 memcpy(expected_memory
, mem
, expected_memory_size(mem
));
1558 /* Insert probe onto test case instruction */
1559 if (register_test_probe(&test_case_probe
) < 0) {
1560 test_case_failed("register test_case_probe failed");
1564 /* Check probe ran as expected */
1565 if (probe_should_run
== 1) {
1566 if (test_case_probe
.hit
!= test_instance
) {
1567 test_case_failed("test_case_handler not run");
1570 } else if (probe_should_run
== 0) {
1571 if (test_case_probe
.hit
== test_instance
) {
1572 test_case_failed("test_case_handler ran");
1577 /* Remove probe for any subsequent reference run */
1578 unregister_test_probe(&test_case_probe
);
1580 if (!check_test_results())
1583 if (is_last_scenario
)
1587 /* Do next test run */
1588 ++test_case_run_count
;
1590 return current_code_start
;
1597 test_case_cleanup();
1603 * Top level test functions
1606 static int run_test_cases(void (*tests
)(void), const union decode_item
*table
)
1610 pr_info(" Check decoding tables\n");
1611 ret
= table_test(table
);
1615 pr_info(" Run test cases\n");
1616 ret
= coverage_start(table
);
1627 static int __init
run_all_tests(void)
1631 pr_info("Beginning kprobe tests...\n");
1633 #ifndef CONFIG_THUMB2_KERNEL
1635 pr_info("Probe ARM code\n");
1636 ret
= run_api_tests(arm_func
);
1640 pr_info("ARM instruction simulation\n");
1641 ret
= run_test_cases(kprobe_arm_test_cases
, probes_decode_arm_table
);
1645 #else /* CONFIG_THUMB2_KERNEL */
1647 pr_info("Probe 16-bit Thumb code\n");
1648 ret
= run_api_tests(thumb16_func
);
1652 pr_info("Probe 32-bit Thumb code, even halfword\n");
1653 ret
= run_api_tests(thumb32even_func
);
1657 pr_info("Probe 32-bit Thumb code, odd halfword\n");
1658 ret
= run_api_tests(thumb32odd_func
);
1662 pr_info("16-bit Thumb instruction simulation\n");
1663 ret
= run_test_cases(kprobe_thumb16_test_cases
,
1664 probes_decode_thumb16_table
);
1668 pr_info("32-bit Thumb instruction simulation\n");
1669 ret
= run_test_cases(kprobe_thumb32_test_cases
,
1670 probes_decode_thumb32_table
);
1675 pr_info("Total instruction simulation tests=%d, pass=%d fail=%d\n",
1676 test_try_count
, test_pass_count
, test_fail_count
);
1677 if (test_fail_count
) {
1683 pr_info("Benchmarks\n");
1684 ret
= run_benchmarks();
1689 #if __LINUX_ARM_ARCH__ >= 7
1690 /* We are able to run all test cases so coverage should be complete */
1691 if (coverage_fail
) {
1692 pr_err("FAIL: Test coverage checks failed\n");
1702 pr_info("Finished kprobe tests OK\n");
1704 pr_err("kprobe tests failed\n");
1716 static void __exit
kprobe_test_exit(void)
1720 module_init(run_all_tests
)
1721 module_exit(kprobe_test_exit
)
1722 MODULE_LICENSE("GPL");
1726 late_initcall(run_all_tests
);