lkml.org 
[lkml]   [2019]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 29/44] perf bpf: Synthesize bpf events with bpf_program__get_prog_info_linear()
    Date
    From: Song Liu <songliubraving@fb.com>

    With bpf_program__get_prog_info_linear, we can simplify the logic that
    synthesizes bpf events.

    This patch doesn't change the behavior of the code.

    Commiter notes:

    Needed this (for all four variables), suggested by Song, to overcome
    build failure on debian experimental cross building to MIPS 32-bit:

    - u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(info->prog_tags);
    + u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);

    util/bpf-event.c: In function 'perf_event__synthesize_one_bpf_prog':
    util/bpf-event.c:143:35: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
    u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(info->prog_tags);
    ^
    util/bpf-event.c:144:22: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
    __u32 *prog_lens = (__u32 *)(info->jited_func_lens);
    ^
    util/bpf-event.c:145:23: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
    __u64 *prog_addrs = (__u64 *)(info->jited_ksyms);
    ^
    util/bpf-event.c:146:22: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
    void *func_infos = (void *)(info->func_info);
    ^
    cc1: all warnings being treated as errors

    Signed-off-by: Song Liu <songliubraving@fb.com>
    Reviewed-by: Jiri Olsa <jolsa@kernel.org>
    Cc: Alexei Starovoitov <ast@kernel.org>
    Cc: Daniel Borkmann <daniel@iogearbox.net>
    Cc: kernel-team@fb.com
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Stanislav Fomichev <sdf@google.com>
    Link: http://lkml.kernel.org/r/20190312053051.2690567-5-songliubraving@fb.com
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    ---
    tools/perf/util/bpf-event.c | 118 ++++++++++++------------------------
    1 file changed, 40 insertions(+), 78 deletions(-)

    diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
    index ea012b735a37..e0cbe7f87170 100644
    --- a/tools/perf/util/bpf-event.c
    +++ b/tools/perf/util/bpf-event.c
    @@ -3,7 +3,9 @@
    #include <stdlib.h>
    #include <bpf/bpf.h>
    #include <bpf/btf.h>
    +#include <bpf/libbpf.h>
    #include <linux/btf.h>
    +#include <linux/err.h>
    #include "bpf-event.h"
    #include "debug.h"
    #include "symbol.h"
    @@ -49,99 +51,62 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
    {
    struct ksymbol_event *ksymbol_event = &event->ksymbol_event;
    struct bpf_event *bpf_event = &event->bpf_event;
    - u32 sub_prog_cnt, i, func_info_rec_size = 0;
    - u8 (*prog_tags)[BPF_TAG_SIZE] = NULL;
    - struct bpf_prog_info info = { .type = 0, };
    - u32 info_len = sizeof(info);
    - void *func_infos = NULL;
    - u64 *prog_addrs = NULL;
    + struct bpf_prog_info_linear *info_linear;
    + struct bpf_prog_info *info;
    struct btf *btf = NULL;
    - u32 *prog_lens = NULL;
    bool has_btf = false;
    - char errbuf[512];
    + u32 sub_prog_cnt, i;
    int err = 0;
    + u64 arrays;

    - /* Call bpf_obj_get_info_by_fd() to get sizes of arrays */
    - err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
    + arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
    + arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
    + arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
    + arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;

    - if (err) {
    - pr_debug("%s: failed to get BPF program info: %s, aborting\n",
    - __func__, str_error_r(errno, errbuf, sizeof(errbuf)));
    + info_linear = bpf_program__get_prog_info_linear(fd, arrays);
    + if (IS_ERR_OR_NULL(info_linear)) {
    + info_linear = NULL;
    + pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
    return -1;
    }
    - if (info_len < offsetof(struct bpf_prog_info, prog_tags)) {
    +
    + if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
    pr_debug("%s: the kernel is too old, aborting\n", __func__);
    return -2;
    }

    + info = &info_linear->info;
    +
    /* number of ksyms, func_lengths, and tags should match */
    - sub_prog_cnt = info.nr_jited_ksyms;
    - if (sub_prog_cnt != info.nr_prog_tags ||
    - sub_prog_cnt != info.nr_jited_func_lens)
    + sub_prog_cnt = info->nr_jited_ksyms;
    + if (sub_prog_cnt != info->nr_prog_tags ||
    + sub_prog_cnt != info->nr_jited_func_lens)
    return -1;

    /* check BTF func info support */
    - if (info.btf_id && info.nr_func_info && info.func_info_rec_size) {
    + if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
    /* btf func info number should be same as sub_prog_cnt */
    - if (sub_prog_cnt != info.nr_func_info) {
    + if (sub_prog_cnt != info->nr_func_info) {
    pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
    - return -1;
    - }
    - if (btf__get_from_id(info.btf_id, &btf)) {
    - pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info.btf_id);
    - return -1;
    + err = -1;
    + goto out;
    }
    - func_info_rec_size = info.func_info_rec_size;
    - func_infos = calloc(sub_prog_cnt, func_info_rec_size);
    - if (!func_infos) {
    - pr_debug("%s: failed to allocate memory for func_infos, aborting\n", __func__);
    - return -1;
    + if (btf__get_from_id(info->btf_id, &btf)) {
    + pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
    + err = -1;
    + btf = NULL;
    + goto out;
    }
    has_btf = true;
    }

    - /*
    - * We need address, length, and tag for each sub program.
    - * Allocate memory and call bpf_obj_get_info_by_fd() again
    - */
    - prog_addrs = calloc(sub_prog_cnt, sizeof(u64));
    - if (!prog_addrs) {
    - pr_debug("%s: failed to allocate memory for prog_addrs, aborting\n", __func__);
    - goto out;
    - }
    - prog_lens = calloc(sub_prog_cnt, sizeof(u32));
    - if (!prog_lens) {
    - pr_debug("%s: failed to allocate memory for prog_lens, aborting\n", __func__);
    - goto out;
    - }
    - prog_tags = calloc(sub_prog_cnt, BPF_TAG_SIZE);
    - if (!prog_tags) {
    - pr_debug("%s: failed to allocate memory for prog_tags, aborting\n", __func__);
    - goto out;
    - }
    -
    - memset(&info, 0, sizeof(info));
    - info.nr_jited_ksyms = sub_prog_cnt;
    - info.nr_jited_func_lens = sub_prog_cnt;
    - info.nr_prog_tags = sub_prog_cnt;
    - info.jited_ksyms = ptr_to_u64(prog_addrs);
    - info.jited_func_lens = ptr_to_u64(prog_lens);
    - info.prog_tags = ptr_to_u64(prog_tags);
    - info_len = sizeof(info);
    - if (has_btf) {
    - info.nr_func_info = sub_prog_cnt;
    - info.func_info_rec_size = func_info_rec_size;
    - info.func_info = ptr_to_u64(func_infos);
    - }
    -
    - err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
    - if (err) {
    - pr_debug("%s: failed to get BPF program info, aborting\n", __func__);
    - goto out;
    - }
    -
    /* Synthesize PERF_RECORD_KSYMBOL */
    for (i = 0; i < sub_prog_cnt; i++) {
    + u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
    + __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
    + __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
    + void *func_infos = (void *)(uintptr_t)(info->func_info);
    const struct bpf_func_info *finfo;
    const char *short_name = NULL;
    const struct btf_type *t;
    @@ -163,13 +128,13 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
    KSYM_NAME_LEN - name_len,
    prog_tags[i], BPF_TAG_SIZE);
    if (has_btf) {
    - finfo = func_infos + i * info.func_info_rec_size;
    + finfo = func_infos + i * info->func_info_rec_size;
    t = btf__type_by_id(btf, finfo->type_id);
    short_name = btf__name_by_offset(btf, t->name_off);
    } else if (i == 0 && sub_prog_cnt == 1) {
    /* no subprog */
    - if (info.name[0])
    - short_name = info.name;
    + if (info->name[0])
    + short_name = info->name;
    } else
    short_name = "F";
    if (short_name)
    @@ -195,9 +160,9 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
    },
    .type = PERF_BPF_EVENT_PROG_LOAD,
    .flags = 0,
    - .id = info.id,
    + .id = info->id,
    };
    - memcpy(bpf_event->tag, prog_tags[i], BPF_TAG_SIZE);
    + memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
    memset((void *)event + event->header.size, 0, machine->id_hdr_size);
    event->header.size += machine->id_hdr_size;
    err = perf_tool__process_synth_event(tool, event,
    @@ -205,10 +170,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_tool *tool,
    }

    out:
    - free(prog_tags);
    - free(prog_lens);
    - free(prog_addrs);
    - free(func_infos);
    + free(info_linear);
    free(btf);
    return err ? -1 : 0;
    }
    --
    2.20.1
    \
     
     \ /
      Last update: 2019-03-21 19:55    [W:4.437 / U:0.352 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site