| Message ID | 20180423191107.21348.15124.stgit@john-Precision-Tower-5810 |
|---|---|
| State | Accepted, archived |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf,1/2] bpf: Document sockmap '-target bpf' requirement for PROG_TYPE_SK_MSG | expand |
On Mon, Apr 23, 2018 at 12:11:08PM -0700, John Fastabend wrote: > 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 <john.fastabend@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/samples/sockmap/Makefile b/samples/sockmap/Makefile index 9bf2881..fa53f4d 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 $@
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 <john.fastabend@gmail.com> --- samples/sockmap/Makefile | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)