This patch introduces a new BPF script to test BPF prologue. The new script probes at null_lseek, which is the function pointer when we try to lseek on '/dev/null'.
null_lseek is chosen because it is a function pointer, so we don't need to consider inlining and LTP. By extracting file->f_mode, bpf-script-test-prologue.c should know whether the file is writable or readonly. According to llseek_loop() and bpf-script-test-prologue.c, one forth of total lseeks should be collected. This patch improve test__bpf so it can run multiple BPF programs on different test functions. Signed-off-by: Wang Nan <wangn...@huawei.com> Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Cc: Alexei Starovoitov <a...@plumgrid.com> Cc: Brendan Gregg <brendan.d.gr...@gmail.com> Cc: Daniel Borkmann <dan...@iogearbox.net> Cc: David Ahern <dsah...@gmail.com> Cc: He Kuang <heku...@huawei.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Kaixu Xia <xiaka...@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Peter Zijlstra <a.p.zijls...@chello.nl> Cc: Zefan Li <lize...@huawei.com> Cc: pi3or...@163.com Link: http://lkml.kernel.org/n/ebpf-6yw9eg0ej3l4jnqhinngk...@git.kernel.org --- tools/perf/tests/Build | 9 ++- tools/perf/tests/bpf-script-test-prologue.c | 35 ++++++++++++ tools/perf/tests/bpf.c | 89 +++++++++++++++++++++++------ tools/perf/tests/llvm.c | 5 ++ tools/perf/tests/llvm.h | 8 +++ 5 files changed, 128 insertions(+), 18 deletions(-) create mode 100644 tools/perf/tests/bpf-script-test-prologue.c diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build index 23e2201..1d69493 100644 --- a/tools/perf/tests/Build +++ b/tools/perf/tests/Build @@ -31,7 +31,7 @@ perf-y += sample-parsing.o perf-y += parse-no-sample-id-all.o perf-y += kmod-path.o perf-y += thread-map.o -perf-y += llvm.o llvm-src-base.o llvm-src-kbuild.o +perf-y += llvm.o llvm-src-base.o llvm-src-kbuild.o llvm-src-prologue.o perf-y += bpf.o perf-y += topology.o @@ -49,6 +49,13 @@ $(OUTPUT)tests/llvm-src-kbuild.c: tests/bpf-script-test-kbuild.c $(Q)sed -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@ $(Q)echo ';' >> $@ +$(OUTPUT)tests/llvm-src-prologue.c: tests/bpf-script-test-prologue.c + $(call rule_mkdir) + $(Q)echo '#include <tests/llvm.h>' > $@ + $(Q)echo 'const char test_llvm__bpf_test_prologue_prog[] =' >> $@ + $(Q)sed -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@ + $(Q)echo ';' >> $@ + ifeq ($(ARCH),$(filter $(ARCH),x86 arm arm64)) perf-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o endif diff --git a/tools/perf/tests/bpf-script-test-prologue.c b/tools/perf/tests/bpf-script-test-prologue.c new file mode 100644 index 0000000..7230e62 --- /dev/null +++ b/tools/perf/tests/bpf-script-test-prologue.c @@ -0,0 +1,35 @@ +/* + * bpf-script-test-prologue.c + * Test BPF prologue + */ +#ifndef LINUX_VERSION_CODE +# error Need LINUX_VERSION_CODE +# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig' +#endif +#define SEC(NAME) __attribute__((section(NAME), used)) + +#include <uapi/linux/fs.h> + +#define FMODE_READ 0x1 +#define FMODE_WRITE 0x2 + +static void (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = + (void *) 6; + +SEC("func=null_lseek file->f_mode offset orig") +int bpf_func__null_lseek(void *ctx, int err, unsigned long f_mode, + unsigned long offset, unsigned long orig) +{ + if (err) + return 0; + if (f_mode & FMODE_WRITE) + return 0; + if (offset & 1) + return 0; + if (orig == SEEK_CUR) + return 0; + return 1; +} + +char _license[] SEC("license") = "GPL"; +int _version SEC("version") = LINUX_VERSION_CODE; diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c index 4dd701b..5a6290a 100644 --- a/tools/perf/tests/bpf.c +++ b/tools/perf/tests/bpf.c @@ -19,11 +19,35 @@ static int epoll_pwait_loop(void) return 0; } -static struct bpf_object *prepare_bpf(void *obj_buf, size_t obj_buf_sz) +#ifdef HAVE_BPF_PROLOGUE + +static int llseek_loop(void) +{ + int fds[2], i; + + fds[0] = open("/dev/null", O_RDONLY); + fds[1] = open("/dev/null", O_RDWR); + + if (fds[0] < 0 || fds[1] < 0) + return -1; + + for (i = 0; i < NR_ITERS; i++) { + lseek(fds[i % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET); + lseek(fds[(i + 1) % 2], i, (i / 2) % 2 ? SEEK_CUR : SEEK_SET); + } + close(fds[0]); + close(fds[1]); + return 0; +} + +#endif + +static struct bpf_object *prepare_bpf(const char *name, void *obj_buf, + size_t obj_buf_sz) { struct bpf_object *obj; - obj = bpf__prepare_load_buffer(obj_buf, obj_buf_sz, "[buffer]"); + obj = bpf__prepare_load_buffer(obj_buf, obj_buf_sz, name); if (IS_ERR(obj)) { fprintf(stderr, " (compile failed)"); return NULL; @@ -31,7 +55,7 @@ static struct bpf_object *prepare_bpf(void *obj_buf, size_t obj_buf_sz) return obj; } -static int do_test(struct bpf_object *obj) +static int do_test(struct bpf_object *obj, int (*func)(void), int expect) { struct record_opts opts = { .target = { @@ -101,7 +125,7 @@ static int do_test(struct bpf_object *obj) } perf_evlist__enable(evlist); - epoll_pwait_loop(); + (*func)(); perf_evlist__disable(evlist); for (i = 0; i < evlist->nr_mmaps; i++) { @@ -115,8 +139,8 @@ static int do_test(struct bpf_object *obj) } } - if (count != (NR_ITERS + 1) / 2) { - fprintf(stderr, " (filter result incorrect)"); + if (count != expect) { + fprintf(stderr, " (filter result incorrect: %d != %d)", count, expect); err = -EBADF; } @@ -128,33 +152,32 @@ out: return 0; } -int test__bpf(void) +static int __test__bpf(int index, const char *name, + const char *message_compile, + const char *message_load, + int (*func)(void), int expect) { int err; void *obj_buf; size_t obj_buf_sz; struct bpf_object *obj; - if (geteuid() != 0) { - fprintf(stderr, " (try run as root)"); - return TEST_SKIP; - } - - test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz, LLVM_TESTCASE_BASE); - + test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz, index); if (!obj_buf || !obj_buf_sz) { if (verbose == 0) - fprintf(stderr, " (fix 'perf test LLVM' first)"); + fprintf(stderr, " (%s)", message_compile); return TEST_SKIP; } - obj = prepare_bpf(obj_buf, obj_buf_sz); + obj = prepare_bpf(name, obj_buf, obj_buf_sz); if (!obj) { err = -EINVAL; + if ((verbose == 0) && (message_load[0] != '\0')) + fprintf(stderr, " (%s)", message_load); goto out; } - err = do_test(obj); + err = do_test(obj, func, expect); if (err) goto out; out: @@ -164,6 +187,38 @@ out: return 0; } +int test__bpf(void) +{ + int err; + + if (geteuid() != 0) { + fprintf(stderr, " (try run as root)"); + return TEST_SKIP; + } + + err = __test__bpf(LLVM_TESTCASE_BASE, + "[basic_bpf_test]", + "fix 'perf test LLVM' first", + "load bpf object failed", + &epoll_pwait_loop, + (NR_ITERS + 1) / 2); + if (err) + return err; + +#ifdef HAVE_BPF_PROLOGUE + err = __test__bpf(LLVM_TESTCASE_BPF_PROLOGUE, + "[bpf_prologue_test]", + "fix kbuild first", + "check your vmlinux setting?", + &llseek_loop, + (NR_ITERS + 1) / 4); + return err; +#else + fprintf(stderr, " (skip BPF prologue test)"); + return TEST_OK; +#endif +} + #else int test__bpf(void) { diff --git a/tools/perf/tests/llvm.c b/tools/perf/tests/llvm.c index 75cd99f..e722e8a 100644 --- a/tools/perf/tests/llvm.c +++ b/tools/perf/tests/llvm.c @@ -22,6 +22,11 @@ struct llvm_testcase { [LLVM_TESTCASE_KBUILD] = {.source = test_llvm__bpf_test_kbuild_prog, .errmsg = "llvm.kbuild-dir can be fixed", .tried = false}, + /* Don't output if this one fail. */ + [LLVM_TESTCASE_BPF_PROLOGUE] = { + .source = test_llvm__bpf_test_prologue_prog, + .errmsg = "failed for unknown reason", + .tried = false}, {.source = NULL} }; diff --git a/tools/perf/tests/llvm.h b/tools/perf/tests/llvm.h index 78ec01d..c00c1be 100644 --- a/tools/perf/tests/llvm.h +++ b/tools/perf/tests/llvm.h @@ -10,10 +10,18 @@ struct test_llvm__bpf_result { extern const char test_llvm__bpf_prog[]; extern const char test_llvm__bpf_test_kbuild_prog[]; +extern const char test_llvm__bpf_test_prologue_prog[]; enum test_llvm__testcase { LLVM_TESTCASE_BASE, LLVM_TESTCASE_KBUILD, + /* + * We must put LLVM_TESTCASE_BPF_PROLOGUE after + * LLVM_TESTCASE_KBUILD, so if kbuild test failed, + * don't need to try this one, because it depend on + * kernel header. + */ + LLVM_TESTCASE_BPF_PROLOGUE, NR_LLVM_TESTCASES, }; void test_llvm__fetch_bpf_obj(void **p_obj_buf, size_t *p_obj_buf_sz, int index); -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/