Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754471AbaJXBlT (ORCPT ); Thu, 23 Oct 2014 21:41:19 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:39854 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751507AbaJXBlR (ORCPT ); Thu, 23 Oct 2014 21:41:17 -0400 From: Alexei Starovoitov To: "David S. Miller" Cc: Geert Uytterhoeven , Josh Triplett , Ingo Molnar , Steven Rostedt , Hannes Frederic Sowa , Eric Dumazet , Daniel Borkmann , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net] bpf: split eBPF out of NET Date: Thu, 23 Oct 2014 18:41:08 -0700 Message-Id: <1414114868-28228-1-git-send-email-ast@plumgrid.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org introduce two configs: - hidden CONFIG_BPF to select eBPF interpreter that classic socket filters depend on - visible CONFIG_BPF_SYSCALL (default off) that tracing and sockets can use that solves several problems: - tracing and others that wish to use eBPF don't need to depend on NET. They can use BPF_SYSCALL to allow loading from userspace or select BPF to use it directly from kernel in NET-less configs. - in 3.18 programs cannot be attached to events yet, so don't force it on - when the rest of eBPF infra is there in 3.19+, it's still useful to switch it off to minimize kernel size Signed-off-by: Alexei Starovoitov --- bloat-o-meter on x64 shows: add/remove: 0/60 grow/shrink: 0/2 up/down: 0/-15601 (-15601) tested with many different config combinations. Hopefully didn't miss anything. init/Kconfig | 14 ++++++++++++++ kernel/Makefile | 2 +- kernel/bpf/Makefile | 6 +++--- kernel/bpf/core.c | 9 +++++++++ net/Kconfig | 2 +- 5 files changed, 28 insertions(+), 5 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 3ee28ae..340fd92 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1341,6 +1341,10 @@ config SYSCTL_ARCH_UNALIGN_ALLOW config HAVE_PCSPKR_PLATFORM bool +# interpreter that classic socket filters depend on +config BPF + boolean + menuconfig EXPERT bool "Configure standard kernel features (expert users)" # Unhide debug options, to make the on-by-default options visible @@ -1521,6 +1525,16 @@ config EVENTFD If unsure, say Y. +# syscall, maps, verifier +config BPF_SYSCALL + bool "Enable bpf() system call" if EXPERT + select ANON_INODES + select BPF + default n + help + Enable the bpf() system call that allows to manipulate eBPF + programs and maps via file descriptors. + config SHMEM bool "Use full shmem filesystem" if EXPERT default y diff --git a/kernel/Makefile b/kernel/Makefile index dc5c775..17ea6d4 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -86,7 +86,7 @@ obj-$(CONFIG_RING_BUFFER) += trace/ obj-$(CONFIG_TRACEPOINTS) += trace/ obj-$(CONFIG_IRQ_WORK) += irq_work.o obj-$(CONFIG_CPU_PM) += cpu_pm.o -obj-$(CONFIG_NET) += bpf/ +obj-$(CONFIG_BPF) += bpf/ obj-$(CONFIG_PERF_EVENTS) += events/ diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 4542723..0daf7f6 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -1,5 +1,5 @@ -obj-y := core.o syscall.o verifier.o - +obj-y := core.o +obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o ifdef CONFIG_TEST_BPF -obj-y += test_stub.o +obj-$(CONFIG_BPF_SYSCALL) += test_stub.o endif diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index f0c30c5..d6594e4 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -655,3 +655,12 @@ void bpf_prog_free(struct bpf_prog *fp) schedule_work(&aux->work); } EXPORT_SYMBOL_GPL(bpf_prog_free); + +/* 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. + */ +int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, + int len) +{ + return -EFAULT; +} diff --git a/net/Kconfig b/net/Kconfig index 6272420..99815b5 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -6,7 +6,7 @@ menuconfig NET bool "Networking support" select NLATTR select GENERIC_NET_UTILS - select ANON_INODES + select BPF ---help--- Unless you really know what you are doing, you should say Y here. The reason is that some programs need kernel networking support even -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/