From 4dfe1bb95235c553e216222cf0c377faf191dacd Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Mon, 23 Apr 2018 12:11:08 -0700 Subject: [PATCH] bpf: sockmap sample use clang flag, -target bpf Per Documentation/bpf/bpf_devel_QA.txt add the -target flag to the sockmap Makefile. Relevant text quoted here, Otherwise, you can use bpf target. Additionally, you _must_ use bpf target when: - Your program uses data structures with pointer or long / unsigned long types that interface with BPF helpers or context data structures. Access into these structures is verified by the BPF verifier and may result in verification failures if the native architecture is not aligned with the BPF architecture, e.g. 64-bit. An example of this is BPF_PROG_TYPE_SK_MSG require '-target bpf' Fixes: 69e8cc134bcb ("bpf: sockmap sample program") Signed-off-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann --- samples/sockmap/Makefile | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/samples/sockmap/Makefile b/samples/sockmap/Makefile index 9bf2881bd11b..fa53f4d77834 100644 --- a/samples/sockmap/Makefile +++ b/samples/sockmap/Makefile @@ -65,11 +65,14 @@ $(src)/*.c: verify_target_bpf # asm/sysreg.h - inline assembly used by it is incompatible with llvm. # But, there is no easy way to fix it, so just exclude it since it is # useless for BPF samples. +# +# -target bpf option required with SK_MSG programs, this is to ensure +# reading 'void *' data types for data and data_end are __u64 reads. $(obj)/%.o: $(src)/%.c $(CLANG) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) $(EXTRA_CFLAGS) -I$(obj) \ -D__KERNEL__ -D__ASM_SYSREG_H -Wno-unused-value -Wno-pointer-sign \ -Wno-compare-distinct-pointer-types \ -Wno-gnu-variable-sized-type-not-at-end \ -Wno-address-of-packed-member -Wno-tautological-compare \ - -Wno-unknown-warning-option \ - -O2 -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@ + -Wno-unknown-warning-option -O2 -target bpf \ + -emit-llvm -c $< -o -| $(LLC) -march=bpf -filetype=obj -o $@