[PATCH v5 net-next 17/29] bpf: split eBPF out of NET

From: Alexei Starovoitov
Date: Sun Aug 24 2014 - 16:22:38 EST


let eBPF have its own CONFIG_BPF, so that tracing and other subsystems don't
need to depend on all of NET

Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
---
arch/Kconfig | 4 ++++
kernel/Makefile | 2 +-
kernel/bpf/core.c | 12 ++++++++++++
net/Kconfig | 1 +
4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 0eae9df35b88..98cb1838c8ff 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -333,6 +333,10 @@ config SECCOMP_FILTER

See Documentation/prctl/seccomp_filter.txt for details.

+config BPF
+ select NLATTR
+ boolean
+
config HAVE_CC_STACKPROTECTOR
bool
help
diff --git a/kernel/Makefile b/kernel/Makefile
index dc5c77544fd6..17ea6d4a9a24 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/core.c b/kernel/bpf/core.c
index 0434c2170f2b..c17ba0ef3dcf 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -537,3 +537,15 @@ void bpf_prog_free(struct bpf_prog *fp)
bpf_jit_free(fp);
}
EXPORT_SYMBOL_GPL(bpf_prog_free);
+
+/* To emulate LD_ABS/LD_IND instructions __sk_run_filter() may call
+ * skb_copy_bits(), so provide a weak definition for it in NET-less config.
+ * seccomp_check_filter() verifies that seccomp filters are not using
+ * LD_ABS/LD_IND instructions. Other BPF users (like tracing filters)
+ * must not use these instructions unless ctx==skb
+ */
+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 4051fdfa4367..9a99e16d6f28 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -6,6 +6,7 @@ menuconfig NET
bool "Networking support"
select NLATTR
select GENERIC_NET_UTILS
+ 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

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