From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752909AbdLFWq4 (ORCPT ); Wed, 6 Dec 2017 17:46:56 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:34216 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752390AbdLFWpY (ORCPT ); Wed, 6 Dec 2017 17:45:24 -0500 Smtp-Origin-Hostprefix: devbig From: Song Liu Smtp-Origin-Hostname: devbig102.frc2.facebook.com To: , , , , , , CC: , Song Liu Smtp-Origin-Cluster: frc2c02 Subject: [PATCH v5 5/6] bpf: add option for bpf_load.c to use perf_kprobe Date: Wed, 6 Dec 2017 14:45:17 -0800 Message-ID: <20171206224518.3598254-8-songliubraving@fb.com> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20171206224518.3598254-1-songliubraving@fb.com> References: <20171206224518.3598254-1-songliubraving@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-12-06_08:,, signatures=0 X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Function load_and_attach() is updated to be able to create kprobes with either old text based API, or the new perf_event_open API. A global flag use_perf_kprobe is added to select between the two APIs. Signed-off-by: Song Liu Reviewed-by: Josef Bacik --- samples/bpf/bpf_load.c | 61 +++++++++++++++++++++++++++++++++++++++++++------- samples/bpf/bpf_load.h | 10 +++++++++ 2 files changed, 63 insertions(+), 8 deletions(-) diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c index 2325d7a..86e3818 100644 --- a/samples/bpf/bpf_load.c +++ b/samples/bpf/bpf_load.c @@ -8,7 +8,6 @@ #include #include #include -#include #include #include #include @@ -29,6 +28,7 @@ #include "perf-sys.h" #define DEBUGFS "/sys/kernel/debug/tracing/" +#define KPROBE_TYPE_FILE "/sys/bus/event_source/devices/kprobe/type" static char license[128]; static int kern_version; @@ -42,6 +42,8 @@ int prog_array_fd = -1; struct bpf_map_data map_data[MAX_MAPS]; int map_data_count = 0; +bool use_perf_kprobe = true; +int perf_kprobe_type = -1; static int populate_prog_array(const char *event, int prog_fd) { @@ -55,6 +57,26 @@ static int populate_prog_array(const char *event, int prog_fd) return 0; } +int get_perf_kprobe_type_id(void) +{ + int tfd; + int err; + char buf[16]; + + tfd = open(KPROBE_TYPE_FILE, O_RDONLY); + if (tfd < 0) + return -1; + + err = read(tfd, buf, sizeof(buf)); + close(tfd); + + if (err < 0 || err >= sizeof(buf)) + return -1; + buf[err] = 0; + perf_kprobe_type = atoi(buf); + return perf_kprobe_type; +} + static int load_and_attach(const char *event, struct bpf_insn *prog, int size) { bool is_socket = strncmp(event, "socket", 6) == 0; @@ -70,7 +92,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) size_t insns_cnt = size / sizeof(struct bpf_insn); enum bpf_prog_type prog_type; char buf[256]; - int fd, efd, err, id; + int fd, efd, err, id = -1; struct perf_event_attr attr = {}; attr.type = PERF_TYPE_TRACEPOINT; @@ -128,7 +150,13 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) return populate_prog_array(event, fd); } - if (is_kprobe || is_kretprobe) { + if (use_perf_kprobe && perf_kprobe_type == -1) { + get_perf_kprobe_type_id(); + if (perf_kprobe_type == -1) + use_perf_kprobe = false; + } + + if (!use_perf_kprobe && (is_kprobe || is_kretprobe)) { if (is_kprobe) event += 7; else @@ -169,27 +197,44 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) strcat(buf, "/id"); } + if (use_perf_kprobe && (is_kprobe || is_kretprobe)) { + attr.type = perf_kprobe_type; + attr.kprobe_func = ptr_to_u64( + event + strlen(is_kprobe ? "kprobe/" : "kretprobe/")); + attr.probe_offset = 0; + + /* PERF_PROBE_CONFIG_IS_RETPROBE in kernel/events/core.c */ + if (is_kretprobe) + attr.config |= 1 << 0; + } else { efd = open(buf, O_RDONLY, 0); if (efd < 0) { printf("failed to open event %s\n", event); return -1; } - err = read(efd, buf, sizeof(buf)); if (err < 0 || err >= sizeof(buf)) { - printf("read from '%s' failed '%s'\n", event, strerror(errno)); + printf("read from '%s' failed '%s'\n", event, + strerror(errno)); return -1; } - close(efd); - buf[err] = 0; id = atoi(buf); attr.config = id; + } efd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0); if (efd < 0) { - printf("event %d fd %d err %s\n", id, efd, strerror(errno)); + if (use_perf_kprobe && (is_kprobe || is_kretprobe)) + printf("k%sprobe %s fd %d err %s\n", + is_kprobe ? "" : "ret", + event + strlen(is_kprobe ? "kprobe/" + : "kretprobe/"), + efd, strerror(errno)); + else + printf("event %d fd %d err %s\n", id, efd, + strerror(errno)); return -1; } event_fd[prog_cnt - 1] = efd; diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h index 7d57a42..95d6be5 100644 --- a/samples/bpf/bpf_load.h +++ b/samples/bpf/bpf_load.h @@ -2,6 +2,7 @@ #ifndef __BPF_LOAD_H #define __BPF_LOAD_H +#include #include "libbpf.h" #define MAX_MAPS 32 @@ -38,6 +39,10 @@ extern int map_fd[MAX_MAPS]; extern struct bpf_map_data map_data[MAX_MAPS]; extern int map_data_count; +extern bool use_perf_kprobe; +extern int perf_kprobe_type; +extern int get_perf_kprobe_type_id(void); + /* parses elf file compiled by llvm .c->.o * . parses 'maps' section and creates maps via BPF syscall * . parses 'license' section and passes it to syscall @@ -59,6 +64,11 @@ struct ksym { char *name; }; +static inline __u64 ptr_to_u64(const void *ptr) +{ + return (__u64) (unsigned long) ptr; +} + int load_kallsyms(void); struct ksym *ksym_search(long key); int set_link_xdp_fd(int ifindex, int fd, __u32 flags); -- 2.9.5