Commit f1bdebbb authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf bpf: Fix build with libbpf 0.7.0 by checking if bpf_program__set_insns() is available 



During the transition to libbpf 1.0 some functions that perf used were
deprecated and finally removed from libbpf, so bpf_program__set_insns()
was introduced for perf to continue to use its bpf loader.

But when build with LIBBPF_DYNAMIC=1 we now need to check if that
function is available so that perf can build with older libbpf versions,
even if the end result is emitting a warning to the user that the use
of the perf BPF loader requires a newer libbpf, since bpf_program__set_insns()
touches libbpf objects internal state.

This affects only 'perf trace' when using bpf C code or pre-compiled
bytecode as an event.

Noticed on RHEL9, that has libbpf 0.7.0, where bpf_program__set_insns()
isn't available.

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 409fb6bd

tools/build/Makefile.feature

+1 −0
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ FEATURE_TESTS_EXTRA := \ 
         libbpf-bpf_prog_load           \

         libbpf-bpf_object__next_program \

         libbpf-bpf_object__next_map    \

         libbpf-bpf_program__set_insns  \

         libbpf-bpf_create_map		\

         libpfm4                        \

         libdebuginfod			\

tools/build/feature/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ FILES= \ 
         test-libbpf-bpf_map_create.bin		\

         test-libbpf-bpf_object__next_program.bin \

         test-libbpf-bpf_object__next_map.bin   \

         test-libbpf-bpf_program__set_insns.bin	\

         test-libbpf-btf__raw_data.bin          \

         test-get_cpuid.bin                     \

         test-sdt.bin                           \
@@ -316,6 +317,9 @@ $(OUTPUT)test-libbpf-bpf_object__next_program.bin: 
$(OUTPUT)test-libbpf-bpf_object__next_map.bin:

	$(BUILD) -lbpf



$(OUTPUT)test-libbpf-bpf_program__set_insns.bin:

	$(BUILD) -lbpf



$(OUTPUT)test-libbpf-btf__raw_data.bin:

	$(BUILD) -lbpf

tools/build/feature/test-libbpf-bpf_program__set_insns.c

0 → 100644
+8 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <bpf/libbpf.h>



int main(void)

{

	bpf_program__set_insns(NULL /* prog */, NULL /* new_insns */, 0 /* new_insn_cnt */);

	return 0;

}

tools/perf/Makefile.config

+5 −0
Original line number Diff line number Diff line
@@ -588,6 +588,10 @@ ifndef NO_LIBELF 
          ifeq ($(feature-libbpf-bpf_object__next_map), 1)

            CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP

          endif

          $(call feature_check,libbpf-bpf_program__set_insns)

          ifeq ($(feature-libbpf-bpf_program__set_insns), 1)

            CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS

          endif

          $(call feature_check,libbpf-btf__raw_data)

          ifeq ($(feature-libbpf-btf__raw_data), 1)

            CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA
@@ -604,6 +608,7 @@ ifndef NO_LIBELF 
        CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD

        CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM

        CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP

        CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS

        CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA

        CFLAGS += -DHAVE_LIBBPF_BPF_MAP_CREATE

      endif

tools/perf/util/bpf-loader.c

+18 −0
Original line number Diff line number Diff line
@@ -36,6 +36,24 @@ 


#include <internal/xyarray.h>



#ifndef HAVE_LIBBPF_BPF_PROGRAM__SET_INSNS

int bpf_program__set_insns(struct bpf_program *prog __maybe_unused,

			   struct bpf_insn *new_insns __maybe_unused, size_t new_insn_cnt __maybe_unused)

{

	pr_err("%s: not support, update libbpf\n", __func__);

	return -ENOTSUP;

}



int libbpf_register_prog_handler(const char *sec __maybe_unused,

                                 enum bpf_prog_type prog_type __maybe_unused,

                                 enum bpf_attach_type exp_attach_type __maybe_unused,

                                 const struct libbpf_prog_handler_opts *opts __maybe_unused)

{

	pr_err("%s: not support, update libbpf\n", __func__);

	return -ENOTSUP;

}

#endif



/* temporarily disable libbpf deprecation warnings */

#pragma GCC diagnostic ignored "-Wdeprecated-declarations"