From e64fbcaa7a666f16329b1c67af15ea501bc84586 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Fri, 3 Dec 2021 20:50:03 +0100 Subject: [PATCH 1/2] samples: bpf: Fix xdp_sample_user.o linking with Clang Clang (13) doesn't get the jokes about specifying libraries to link in cclags of individual .o objects: clang-13: warning: -lm: 'linker' input unused [-Wunused-command-line-argument] [ ... ] LD samples/bpf/xdp_redirect_cpu LD samples/bpf/xdp_redirect_map_multi LD samples/bpf/xdp_redirect_map LD samples/bpf/xdp_redirect LD samples/bpf/xdp_monitor /usr/bin/ld: samples/bpf/xdp_sample_user.o: in function `sample_summary_print': xdp_sample_user.c:(.text+0x84c): undefined reference to `floor' /usr/bin/ld: xdp_sample_user.c:(.text+0x870): undefined reference to `ceil' /usr/bin/ld: xdp_sample_user.c:(.text+0x8cf): undefined reference to `floor' /usr/bin/ld: xdp_sample_user.c:(.text+0x8f3): undefined reference to `ceil' [ more ] Specify '-lm' as ldflags for all xdp_sample_user.o users in the main Makefile and remove it from ccflags of ^ in Makefile.target -- just like it's done for all other samples. This works with all compilers. Fixes: 6e1051a54e31 ("samples: bpf: Convert xdp_monitor to XDP samples helper") Fixes: b926c55d856c ("samples: bpf: Convert xdp_redirect to XDP samples helper") Fixes: e531a220cc59 ("samples: bpf: Convert xdp_redirect_cpu to XDP samples helper") Fixes: bbe65865aa05 ("samples: bpf: Convert xdp_redirect_map to XDP samples helper") Fixes: 594a116b2aa1 ("samples: bpf: Convert xdp_redirect_map_multi to XDP samples helper") Signed-off-by: Alexander Lobakin Signed-off-by: Andrii Nakryiko Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/bpf/20211203195004.5803-2-alexandr.lobakin@intel.com --- samples/bpf/Makefile | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 6ae62b1dc938..38638845db9d 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -215,6 +215,11 @@ TPROGS_LDFLAGS := -L$(SYSROOT)/usr/lib endif TPROGS_LDLIBS += $(LIBBPF) -lelf -lz +TPROGLDLIBS_xdp_monitor += -lm +TPROGLDLIBS_xdp_redirect += -lm +TPROGLDLIBS_xdp_redirect_cpu += -lm +TPROGLDLIBS_xdp_redirect_map += -lm +TPROGLDLIBS_xdp_redirect_map_multi += -lm TPROGLDLIBS_tracex4 += -lrt TPROGLDLIBS_trace_output += -lrt TPROGLDLIBS_map_perf_test += -lrt @@ -345,7 +350,7 @@ $(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h # Override includes for xdp_sample_user.o because $(srctree)/usr/include in # TPROGS_CFLAGS causes conflicts -XDP_SAMPLE_CFLAGS += -Wall -O2 -lm \ +XDP_SAMPLE_CFLAGS += -Wall -O2 \ -I$(src)/../../tools/include \ -I$(src)/../../tools/include/uapi \ -I$(LIBBPF_INCLUDE) \ From 6f670d06e47c774bc065aaa84a527a4838f34bd8 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Fri, 3 Dec 2021 20:50:04 +0100 Subject: [PATCH 2/2] samples: bpf: Fix 'unknown warning group' build warning on Clang Clang doesn't have 'stringop-truncation' group like GCC does, and complains about it when building samples which use xdp_sample_user infra: samples/bpf/xdp_sample_user.h:48:32: warning: unknown warning group '-Wstringop-truncation', ignored [-Wunknown-warning-option] #pragma GCC diagnostic ignored "-Wstringop-truncation" ^ [ repeat ] Those are harmless, but avoidable when guarding it with ifdef. I could guard push/pop as well, but this would require one more ifdef cruft around a single line which I don't think is reasonable. Fixes: 156f886cf697 ("samples: bpf: Add basic infrastructure for XDP samples") Signed-off-by: Alexander Lobakin Signed-off-by: Andrii Nakryiko Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/bpf/20211203195004.5803-3-alexandr.lobakin@intel.com --- samples/bpf/xdp_sample_user.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/samples/bpf/xdp_sample_user.h b/samples/bpf/xdp_sample_user.h index d97465ff8c62..5f44b877ecf5 100644 --- a/samples/bpf/xdp_sample_user.h +++ b/samples/bpf/xdp_sample_user.h @@ -45,7 +45,9 @@ const char *get_driver_name(int ifindex); int get_mac_addr(int ifindex, void *mac_addr); #pragma GCC diagnostic push +#ifndef __clang__ #pragma GCC diagnostic ignored "-Wstringop-truncation" +#endif __attribute__((unused)) static inline char *safe_strncpy(char *dst, const char *src, size_t size) {