From patchwork Sat Mar 14 01:27:17 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Borkmann X-Patchwork-Id: 450134 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 892571402AB for ; Sat, 14 Mar 2015 12:27:37 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752625AbbCNB10 (ORCPT ); Fri, 13 Mar 2015 21:27:26 -0400 Received: from www62.your-server.de ([213.133.104.62]:56327 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbbCNB1V (ORCPT ); Fri, 13 Mar 2015 21:27:21 -0400 Received: from [83.76.24.107] (helo=localhost) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES128-GCM-SHA256:128) (Exim 4.80.1) (envelope-from ) id 1YWarI-00018B-No; Sat, 14 Mar 2015 02:27:20 +0100 From: Daniel Borkmann To: davem@davemloft.net Cc: ast@plumgrid.com, netdev@vger.kernel.org, Daniel Borkmann Subject: [PATCH net-next v2 2/2] ebpf: add helper for obtaining current processor id Date: Sat, 14 Mar 2015 02:27:17 +0100 Message-Id: X-Mailer: git-send-email 1.9.3 In-Reply-To: References: In-Reply-To: References: X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.98.5/20194/Fri Mar 13 21:25:09 2015) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch adds the possibility to obtain raw_smp_processor_id() in eBPF. Currently, this is only possible in classic BPF where commit da2033c28226 ("filter: add SKF_AD_RXHASH and SKF_AD_CPU") has added facilities for this. Perhaps most importantly, this would also allow us to track per CPU statistics with eBPF maps, or to implement a poor-man's per CPU data structure through eBPF maps. Example function proto-type looks like: u32 (*smp_processor_id)(void) = (void *)BPF_FUNC_get_smp_processor_id; Signed-off-by: Daniel Borkmann --- v1->v2: - Changed function name include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 1 + kernel/bpf/core.c | 1 + kernel/bpf/helpers.c | 12 ++++++++++++ net/core/filter.c | 2 ++ 5 files changed, 17 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 50bf95e..30bfd33 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -155,5 +155,6 @@ extern const struct bpf_func_proto bpf_map_update_elem_proto; extern const struct bpf_func_proto bpf_map_delete_elem_proto; extern const struct bpf_func_proto bpf_get_prandom_u32_proto; +extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; #endif /* _LINUX_BPF_H */ diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1c2ca2b..de1f636 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -166,6 +166,7 @@ enum bpf_func_id { BPF_FUNC_map_update_elem, /* int map_update_elem(&map, &key, &value, flags) */ BPF_FUNC_map_delete_elem, /* int map_delete_elem(&map, &key) */ BPF_FUNC_get_prandom_u32, /* u32 prandom_u32(void) */ + BPF_FUNC_get_smp_processor_id, /* u32 raw_smp_processor_id(void) */ __BPF_FUNC_MAX_ID, }; diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index c1dbbb5d..4139a0f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -662,6 +662,7 @@ const struct bpf_func_proto bpf_map_update_elem_proto __weak; const struct bpf_func_proto bpf_map_delete_elem_proto __weak; const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; +const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call * skb_copy_bits(), so provide a weak definition of it for NET-less config. diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 95eb59a..bd7f598 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -12,6 +12,7 @@ #include #include #include +#include /* If kernel subsystem is allowing eBPF programs to call this function, * inside its own verifier_ops->get_func_proto() callback it should return @@ -99,3 +100,14 @@ const struct bpf_func_proto bpf_get_prandom_u32_proto = { .gpl_only = false, .ret_type = RET_INTEGER, }; + +static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) +{ + return raw_smp_processor_id(); +} + +const struct bpf_func_proto bpf_get_smp_processor_id_proto = { + .func = bpf_get_smp_processor_id, + .gpl_only = false, + .ret_type = RET_INTEGER, +}; diff --git a/net/core/filter.c b/net/core/filter.c index 4344db3..33310ee 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1141,6 +1141,8 @@ sk_filter_func_proto(enum bpf_func_id func_id) return &bpf_map_delete_elem_proto; case BPF_FUNC_get_prandom_u32: return &bpf_get_prandom_u32_proto; + case BPF_FUNC_get_smp_processor_id: + return &bpf_get_smp_processor_id_proto; default: return NULL; }