diff --git a/arch/arm/kernel/kprobes-test.c b/arch/arm/kernel/kprobes-test.c index fe169e934d42..e5740c7c64e5 100644 --- a/arch/arm/kernel/kprobes-test.c +++ b/arch/arm/kernel/kprobes-test.c @@ -185,6 +185,9 @@ #include "kprobes-test.h" +#define BENCHMARKING 1 + + /* * Test basic API */ @@ -443,6 +446,157 @@ static int run_api_tests(long (*func)(long, long)) } +/* + * Benchmarking + */ + +#if BENCHMARKING + +static void __naked benchmark_nop(void) +{ + __asm__ __volatile__ ( + "nop \n\t" + "bx lr" + ); +} + +#ifdef CONFIG_THUMB2_KERNEL +#define wide ".w" +#else +#define wide +#endif + +static void __naked benchmark_pushpop1(void) +{ + __asm__ __volatile__ ( + "stmdb"wide" sp!, {r3-r11,lr} \n\t" + "ldmia"wide" sp!, {r3-r11,pc}" + ); +} + +static void __naked benchmark_pushpop2(void) +{ + __asm__ __volatile__ ( + "stmdb"wide" sp!, {r0-r8,lr} \n\t" + "ldmia"wide" sp!, {r0-r8,pc}" + ); +} + +static void __naked benchmark_pushpop3(void) +{ + __asm__ __volatile__ ( + "stmdb"wide" sp!, {r4,lr} \n\t" + "ldmia"wide" sp!, {r4,pc}" + ); +} + +static void __naked benchmark_pushpop4(void) +{ + __asm__ __volatile__ ( + "stmdb"wide" sp!, {r0,lr} \n\t" + "ldmia"wide" sp!, {r0,pc}" + ); +} + + +#ifdef CONFIG_THUMB2_KERNEL + +static void __naked benchmark_pushpop_thumb(void) +{ + __asm__ __volatile__ ( + "push.n {r0-r7,lr} \n\t" + "pop.n {r0-r7,pc}" + ); +} + +#endif + +static int __kprobes +benchmark_pre_handler(struct kprobe *p, struct pt_regs *regs) +{ + return 0; +} + +static int benchmark(void(*fn)(void)) +{ + unsigned n, i, t, t0; + + for (n = 1000; ; n *= 2) { + t0 = sched_clock(); + for (i = n; i > 0; --i) + fn(); + t = sched_clock() - t0; + if (t >= 250000000) + break; /* Stop once we took more than 0.25 seconds */ + } + return t / n; /* Time for one iteration in nanoseconds */ +}; + +static int kprobe_benchmark(void(*fn)(void), unsigned offset) +{ + struct kprobe k = { + .addr = (kprobe_opcode_t *)((uintptr_t)fn + offset), + .pre_handler = benchmark_pre_handler, + }; + + int ret = register_kprobe(&k); + if (ret < 0) { + pr_err("FAIL: register_kprobe failed with %d\n", ret); + return ret; + } + + ret = benchmark(fn); + + unregister_kprobe(&k); + return ret; +}; + +struct benchmarks { + void (*fn)(void); + unsigned offset; + const char *title; +}; + +static int run_benchmarks(void) +{ + int ret; + struct benchmarks list[] = { + {&benchmark_nop, 0, "nop"}, + /* + * benchmark_pushpop{1,3} will have the optimised + * instruction emulation, whilst benchmark_pushpop{2,4} will + * be the equivalent unoptimised instructions. + */ + {&benchmark_pushpop1, 0, "stmdb sp!, {r3-r11,lr}"}, + {&benchmark_pushpop1, 4, "ldmia sp!, {r3-r11,pc}"}, + {&benchmark_pushpop2, 0, "stmdb sp!, {r0-r8,lr}"}, + {&benchmark_pushpop2, 4, "ldmia sp!, {r0-r8,pc}"}, + {&benchmark_pushpop3, 0, "stmdb sp!, {r4,lr}"}, + {&benchmark_pushpop3, 4, "ldmia sp!, {r4,pc}"}, + {&benchmark_pushpop4, 0, "stmdb sp!, {r0,lr}"}, + {&benchmark_pushpop4, 4, "ldmia sp!, {r0,pc}"}, +#ifdef CONFIG_THUMB2_KERNEL + {&benchmark_pushpop_thumb, 0, "push.n {r0-r7,lr}"}, + {&benchmark_pushpop_thumb, 2, "pop.n {r0-r7,pc}"}, +#endif + {0} + }; + + struct benchmarks *b; + for (b = list; b->fn; ++b) { + ret = kprobe_benchmark(b->fn, b->offset); + if (ret < 0) + return ret; + pr_info(" %dns for kprobe %s\n", ret, b->title); + } + + pr_info("\n"); + return 0; +} + +#endif /* BENCHMARKING */ + + /* * Decoding table self-consistency tests */ @@ -1526,6 +1680,13 @@ static int __init run_all_tests(void) goto out; } +#if BENCHMARKING + pr_info("Benchmarks\n"); + ret = run_benchmarks(); + if (ret) + goto out; +#endif + #if __LINUX_ARM_ARCH__ >= 7 /* We are able to run all test cases so coverage should be complete */ if (coverage_fail) {