Commit 44ce0ac1 authored by Pu Lehui's avatar Pu Lehui Committed by Alexei Starovoitov
Browse files

samples: bpf: Suppress readelf stderr when probing for BTF support 



When compiling bpf samples, the following warning appears:

readelf: Error: Missing knowledge of 32-bit reloc types used in DWARF
sections of machine number 247
readelf: Warning: unable to apply unsupported reloc type 10 to section
.debug_info
readelf: Warning: unable to apply unsupported reloc type 1 to section
.debug_info
readelf: Warning: unable to apply unsupported reloc type 10 to section
.debug_info

Same problem was mentioned in commit 2f092126 ("selftests/bpf:
suppress readelf stderr when probing for BTF support"), let's use
readelf that supports btf.

Signed-off-by: default avatarPu Lehui <pulehui@huawei.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20211021123913.48833-1-pulehui@huawei.com
parent db5b6a46

samples/bpf/Makefile

+2 −1
Original line number Original line Diff line number Diff line
@@ -229,6 +229,7 @@ CLANG ?= clang 
OPT ?= opt

OPT ?= opt

LLVM_DIS ?= llvm-dis

LLVM_DIS ?= llvm-dis

LLVM_OBJCOPY ?= llvm-objcopy

LLVM_OBJCOPY ?= llvm-objcopy

LLVM_READELF ?= llvm-readelf

BTF_PAHOLE ?= pahole

BTF_PAHOLE ?= pahole





# Detect that we're cross compiling and use the cross compiler

# Detect that we're cross compiling and use the cross compiler
@@ -252,7 +253,7 @@ BTF_PAHOLE_PROBE := $(shell $(BTF_PAHOLE) --help 2>&1 | grep BTF) 
BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')

BTF_OBJCOPY_PROBE := $(shell $(LLVM_OBJCOPY) --help 2>&1 | grep -i 'usage.*llvm')

BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \

BTF_LLVM_PROBE := $(shell echo "int main() { return 0; }" | \

			  $(CLANG) -target bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o; \

			  $(CLANG) -target bpf -O2 -g -c -x c - -o ./llvm_btf_verify.o; \

			  readelf -S ./llvm_btf_verify.o | grep BTF; \

			  $(LLVM_READELF) -S ./llvm_btf_verify.o | grep BTF; \

			  /bin/rm -f ./llvm_btf_verify.o)

			  /bin/rm -f ./llvm_btf_verify.o)





BPF_EXTRA_CFLAGS += -fno-stack-protector

BPF_EXTRA_CFLAGS += -fno-stack-protector