bpf: Fix the build on BPF_SYSCALL=y && !CONFIG_TRACING kernels, make it more configurable
So bpf_tracing.o depends on CONFIG_BPF_SYSCALL - but that's not its only
dependency, it also depends on the tracing infrastructure and on kprobes,
without which it will fail to build with:
In file included from kernel/trace/bpf_trace.c:14:0:
kernel/trace/trace.h: In function ‘trace_test_and_set_recursion’:
kernel/trace/trace.h:491:28: error: ‘struct task_struct’ has no member named ‘trace_recursion’
unsigned int val = current->trace_recursion;
[...]
It took quite some time to trigger this build failure, because right now
BPF_SYSCALL is very obscure, depends on CONFIG_EXPERT. So also make BPF_SYSCALL
more configurable, not just under CONFIG_EXPERT.
If BPF_SYSCALL, tracing and kprobes are enabled then enable the bpf_tracing
gateway as well.
We might want to make this an interactive option later on, although
I'd not complicate it unnecessarily: enabling BPF_SYSCALL is enough of
an indicator that the user wants BPF support.
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/init/Kconfig b/init/Kconfig
index f5dbc6d..2b4d055 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1513,7 +1513,7 @@
# syscall, maps, verifier
config BPF_SYSCALL
- bool "Enable bpf() system call" if EXPERT
+ bool "Enable bpf() system call"
select ANON_INODES
select BPF
default n
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a5da09c..c8e53c0 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -432,6 +432,14 @@
This option is required if you plan to use perf-probe subcommand
of perf tools on user space applications.
+config BPF_EVENTS
+ depends on BPF_SYSCALL
+ depends on KPROBE_EVENT
+ bool
+ default y
+ help
+ This allows the user to attach BPF programs to kprobe events.
+
config PROBE_EVENTS
def_bool n
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index c575a30..9b1044e 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -53,7 +53,7 @@
endif
obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
-obj-$(CONFIG_BPF_SYSCALL) += bpf_trace.o
+obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o
obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
obj-$(CONFIG_TRACEPOINTS) += power-traces.o
ifeq ($(CONFIG_PM),y)