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Commit f89b7755 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

bpf: split eBPF out of NET 



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

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.

Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Acked-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8ae3c911

init/Kconfig

+14 −0
Original line number Original line Diff line number Diff line
@@ -1341,6 +1341,10 @@ config SYSCTL_ARCH_UNALIGN_ALLOW 
config HAVE_PCSPKR_PLATFORM

config HAVE_PCSPKR_PLATFORM

	bool

	bool





# interpreter that classic socket filters depend on

config BPF

	bool



menuconfig EXPERT

menuconfig EXPERT

	bool "Configure standard kernel features (expert users)"

	bool "Configure standard kernel features (expert users)"

	# Unhide debug options, to make the on-by-default options visible

	# Unhide debug options, to make the on-by-default options visible
@@ -1521,6 +1525,16 @@ config EVENTFD 




	  If unsure, say Y.

	  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

config SHMEM

	bool "Use full shmem filesystem" if EXPERT

	bool "Use full shmem filesystem" if EXPERT

	default y

	default y

kernel/Makefile

+1 −1
Original line number Original line Diff line number Diff line
@@ -86,7 +86,7 @@ obj-$(CONFIG_RING_BUFFER) += trace/ 
obj-$(CONFIG_TRACEPOINTS) += trace/

obj-$(CONFIG_TRACEPOINTS) += trace/

obj-$(CONFIG_IRQ_WORK) += irq_work.o

obj-$(CONFIG_IRQ_WORK) += irq_work.o

obj-$(CONFIG_CPU_PM) += cpu_pm.o

obj-$(CONFIG_CPU_PM) += cpu_pm.o

obj-$(CONFIG_NET) += bpf/

obj-$(CONFIG_BPF) += bpf/





obj-$(CONFIG_PERF_EVENTS) += events/

obj-$(CONFIG_PERF_EVENTS) += events/

kernel/bpf/Makefile

+3 −3
Original line number Original line Diff line number Diff line 
obj-y := core.o syscall.o verifier.o

obj-y := core.o



obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o

ifdef CONFIG_TEST_BPF

ifdef CONFIG_TEST_BPF

obj-y += test_stub.o

obj-$(CONFIG_BPF_SYSCALL) += test_stub.o

endif
 
endif

kernel/bpf/core.c

+9 −0
Original line number Original line Diff line number Diff line
@@ -655,3 +655,12 @@ void bpf_prog_free(struct bpf_prog *fp) 
	schedule_work(&aux->work);

	schedule_work(&aux->work);

}

}

EXPORT_SYMBOL_GPL(bpf_prog_free);

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;

}

net/Kconfig

+1 −1
Original line number Original line Diff line number Diff line
@@ -6,7 +6,7 @@ menuconfig NET 
	bool "Networking support"

	bool "Networking support"

	select NLATTR

	select NLATTR

	select GENERIC_NET_UTILS

	select GENERIC_NET_UTILS

	select ANON_INODES

	select BPF

	---help---

	---help---

	  Unless you really know what you are doing, you should say Y here.

	  Unless you really know what you are doing, you should say Y here.

	  The reason is that some programs need kernel networking support even

	  The reason is that some programs need kernel networking support even