Re: [PATCH v6 perf,bpf 07/15] perf, bpf: save bpf_prog_info information as headers to perf.data

Jiri Olsa
2019-03-07T14:06:01Z

On Tue, Mar 05, 2019 at 11:13:51PM -0800, Song Liu wrote:

SNIP

> +static int process_bpf_prog_info(struct feat_fd *ff,
> + void *data __maybe_unused)
> +{
> + struct bpf_prog_info_linear *info_linear;
> + struct bpf_prog_info_node *info_node;
> + struct perf_env *env = &ff->ph->env;
> + u32 count, i;
> + int err = -1;
> +
> + if (do_read_u32(ff, &count))
> + return -1;
> +
> + if (ff->ph->needs_swap)
> + pr_warning("interpreting bpf_prog_info from systems with endianity is not yet supported\n");

return 0; ?

what's here to process?

jirka

> +
> + down_write(&env->bpf_progs.lock);
> +
> + for (i = 0; i < count; ++i) {
> + u32 info_len, data_len;
> +
> + info_linear = NULL;
> + info_node = NULL;
> + if (do_read_u32(ff, &info_len))
> + goto out;
> + if (do_read_u32(ff, &data_len))
> + goto out;
> +
> + if (info_len > sizeof(struct bpf_prog_info)) {
> + pr_warning("detected invalid bpf_prog_info\n");
> + goto out;
> + }
> +
> + info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
> + data_len);
> + if (!info_linear)
> + goto out;
> + info_linear->info_len = sizeof(struct bpf_prog_info);
> + info_linear->data_len = data_len;
> + if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
> + goto out;
> + if (__do_read(ff, &info_linear->info, info_len))
> + goto out;
> + if (info_len < sizeof(struct bpf_prog_info))
> + memset(((void *)(&info_linear->info)) + info_len, 0,
> + sizeof(struct bpf_prog_info) - info_len);
> +
> + if (__do_read(ff, info_linear->data, data_len))
> + goto out;
> +
> + /* endian mismatch, drop the info, continue */
> + if (ff->ph->needs_swap) {
> + free(info_linear);
> + continue;
> + }
> +
> + info_node = malloc(sizeof(struct bpf_prog_info_node));
> + if (!info_node)
> + goto out;
> +
> + /* after reading from file, translate offset to address */
> + bpf_program__bpil_offs_to_addr(info_linear);
> + info_node->info_linear = info_linear;
> + perf_env__insert_bpf_prog_info(env, info_node);
> + }
> +
> + return 0;
> +out:
> + free(info_linear);
> + free(info_node);
> + up_write(&env->bpf_progs.lock);
> + return err;
> +}

SNIP