2018-07-26 10:15:37

by Taeung Song

Subject: [PATCH bpf-next v2] samples/bpf: Add BTF build flags to Makefile

To smoothly test BTF supported binary on samples/bpf,
let samples/bpf/Makefile probe llc, pahole and
llvm-objcopy for BPF support and use them
like tools/testing/selftests/bpf/Makefile
changed from the commit c0fa1b6c3efc ("bpf: btf:
Add BTF tests")

Acked-by: Martin KaFai Lau <[email protected]>
Reviewed-by: Jakub Kicinski <[email protected]>
Signed-off-by: Taeung Song <[email protected]>
---
samples/bpf/Makefile | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 9ea2f7b64869..77f512625b8c 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -195,6 +195,8 @@ HOSTLOADLIBES_xdpsock += -pthread
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
LLC ?= llc
CLANG ?= clang
+LLVM_OBJCOPY ?= llvm-objcopy
+BTF_PAHOLE ?= pahole

# Detect that we're cross compiling and use the cross compiler
ifdef CROSS_COMPILE
@@ -202,6 +204,16 @@ HOSTCC = $(CROSS_COMPILE)gcc
CLANG_ARCH_ARGS = -target $(ARCH)
endif

+BTF_LLC_PROBE := $(shell $(LLC) -march=bpf -mattr=help 2>&1 | grep dwarfris)
+BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF)
+BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')
+
+ifneq ($(and $(BTF_LLC_PROBE),$(BTF_PAHOLE_PROBE),$(BTF_OBJCOPY_PROBE)),)
+ EXTRA_CFLAGS += -g
+ LLC_FLAGS += -mattr=dwarfris
+ DWARF2BTF = y
+endif
+
# Trick to allow make to be run from this directory
all:
$(MAKE) -C ../../ $(CURDIR)/ BPF_SAMPLES_PATH=$(CURDIR)
@@ -260,4 +272,7 @@ $(obj)/%.o: $(src)/%.c
-Wno-gnu-variable-sized-type-not-at-end \
-Wno-address-of-packed-member -Wno-tautological-compare \
-Wno-unknown-warning-option $(CLANG_ARCH_ARGS) \
- -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@
+ -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf $(LLC_FLAGS) -filetype=obj -o $@
+ifeq ($(DWARF2BTF),y)
+ $(BTF_PAHOLE) -J $@
+endif
--
2.17.1

2018-07-27 01:53:09

by Daniel Borkmann

Subject: Re: [PATCH bpf-next v2] samples/bpf: Add BTF build flags to Makefile

On 07/26/2018 12:13 PM, Taeung Song wrote:
> To smoothly test BTF supported binary on samples/bpf,
> let samples/bpf/Makefile probe llc, pahole and
> llvm-objcopy for BPF support and use them
> like tools/testing/selftests/bpf/Makefile
> changed from the commit c0fa1b6c3efc ("bpf: btf:
> Add BTF tests")
>
> Acked-by: Martin KaFai Lau <[email protected]>
> Reviewed-by: Jakub Kicinski <[email protected]>
> Signed-off-by: Taeung Song <[email protected]>

Applied to bpf-next, thanks Taeung!