From: Daniel Borkmann <daniel@iogearbox•net>
To: Yonghong Song <yhs@fb•com>,
peterz@infradead•org, rostedt@goodmis•org, ast@fb•com,
netdev@vger•kernel.org
Cc: kernel-team@fb•com
Subject: Re: [PATCH net-next v4 3/4] bpf: add helper bpf_perf_prog_read_value
Date: Tue, 19 Sep 2017 22:40:56 +0200 [thread overview]
Message-ID: <59C180D8.1050900@iogearbox.net> (raw)
In-Reply-To: <20170919070413.3838201-4-yhs@fb.com>
On 09/19/2017 09:04 AM, Yonghong Song wrote:
[...]
> #ifdef CONFIG_CGROUP_PERF
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 2c68b9e..ba77022 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -590,6 +590,13 @@ union bpf_attr {
> * @buf: buf to fill
> * @buf_size: size of the buf
> * Return: 0 on success or negative error code
> + *
> + * int bpf_perf_prog_read_value(ctx, buf, buf_size)
> + * read perf prog attached perf event counter and enabled/running time
> + * @ctx: pointer to ctx
> + * @buf: buf to fill
> + * @buf_size: size of the buf
> + * Return : 0 on success or negative error code
> */
> #define __BPF_FUNC_MAPPER(FN) \
> FN(unspec), \
> @@ -647,6 +654,7 @@ union bpf_attr {
> FN(sk_redirect_map), \
> FN(sock_map_update), \
> FN(perf_event_read_value), \
> + FN(perf_prog_read_value), \
(Same here.)
>
> /* integer value in 'imm' field of BPF_CALL instruction selects which helper
> * function eBPF program intends to call
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 2d5bbe5..d039086 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -8081,6 +8081,7 @@ static void bpf_overflow_handler(struct perf_event *event,
> struct bpf_perf_event_data_kern ctx = {
> .data = data,
> .regs = regs,
> + .event = event,
> };
> int ret = 0;
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 39ce5d9..596b5c9 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -603,6 +603,18 @@ BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
> flags, 0, 0);
> }
>
> +BPF_CALL_3(bpf_perf_prog_read_value_tp, void *, ctx, struct bpf_perf_event_value *,
> + buf, u32, size)
Nit: indent
> +{
> + struct bpf_perf_event_data_kern *kctx = (struct bpf_perf_event_data_kern *)ctx;
Why having the arg as void * and have this detour instead of having
struct bpf_perf_event_data_kern * right in the helper signature as
argument?
> + if (size != sizeof(struct bpf_perf_event_value))
unlikely()
> + return -EINVAL;
> +
> + return perf_event_read_local(kctx->event, &buf->counter, &buf->enabled,
> + &buf->running);
> +}
bpf_perf_prog_read_value_proto_tp would go right underneath here,
and bpf_get_stackid_proto_tp below the previous helper above.
> static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
> .func = bpf_get_stackid_tp,
> .gpl_only = true,
> @@ -612,6 +624,15 @@ static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
> .arg3_type = ARG_ANYTHING,
> };
>
> +static const struct bpf_func_proto bpf_perf_prog_read_value_proto_tp = {
> + .func = bpf_perf_prog_read_value_tp,
> + .gpl_only = true,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_CTX,
> + .arg2_type = ARG_PTR_TO_UNINIT_MEM,
Same on error path.
> + .arg3_type = ARG_CONST_SIZE,
> +};
> +
> static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
> {
> switch (func_id) {
> @@ -619,6 +640,8 @@ static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
> return &bpf_perf_event_output_proto_tp;
> case BPF_FUNC_get_stackid:
> return &bpf_get_stackid_proto_tp;
> + case BPF_FUNC_perf_prog_read_value:
> + return &bpf_perf_prog_read_value_proto_tp;
> default:
> return tracing_func_proto(func_id);
> }
>
next prev parent reply other threads:[~2017-09-19 20:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 7:04 [PATCH net-next v4 0/4] bpf: add two helpers to read perf event enabled/running time Yonghong Song
2017-09-19 7:04 ` [PATCH net-next v4 1/4] bpf: add helper bpf_perf_event_read_value for perf event array map Yonghong Song
2017-09-19 20:33 ` Daniel Borkmann
2017-09-19 7:04 ` [PATCH net-next v4 2/4] bpf: add a test case for helper bpf_perf_event_read_value Yonghong Song
2017-09-19 7:04 ` [PATCH net-next v4 3/4] bpf: add helper bpf_perf_prog_read_value Yonghong Song
2017-09-19 20:40 ` Daniel Borkmann [this message]
2017-09-19 7:04 ` [PATCH net-next v4 4/4] bpf: add a test case for " Yonghong Song
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