libbpf: Add LIBBPF_DEPRECATED_SINCE macro for scheduling API deprecations
Introduce a macro LIBBPF_DEPRECATED_SINCE(major, minor, message) to prepare the deprecation of two API functions. This macro marks functions as deprecated when libbpf's version reaches the values passed as an argument. As part of this change libbpf_version.h header is added with recorded major (LIBBPF_MAJOR_VERSION) and minor (LIBBPF_MINOR_VERSION) libbpf version macros. They are now part of libbpf public API and can be relied upon by user code. libbpf_version.h is installed system-wide along other libbpf public headers. Due to this new build-time auto-generated header, in-kernel applications relying on libbpf (resolve_btfids, bpftool, bpf_preload) are updated to include libbpf's output directory as part of a list of include search paths. Better fix would be to use libbpf's make_install target to install public API headers, but that clean up is left out as a future improvement. The build changes were tested by building kernel (with KBUILD_OUTPUT and O= specified explicitly), bpftool, libbpf, selftests/bpf, and resolve_btfids builds. No problems were detected. Note that because of the constraints of the C preprocessor we have to write a few lines of macro magic for each version used to prepare deprecation (0.6 for now). Also, use LIBBPF_DEPRECATED_SINCE() to schedule deprecation of btf__get_from_id() and btf__load(), which are replaced by btf__load_from_kernel_by_id() and btf__load_into_kernel(), respectively, starting from future libbpf v0.6. This is part of libbpf 1.0 effort ([0]). [0] Closes: https://github.com/libbpf/libbpf/issues/278 Co-developed-by: Quentin Monnet <quentin@isovalent.com> Co-developed-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210908213226.1871016-1-andrii@kernel.org
This commit is contained in:
Quentin Monnet
Daniel Borkmann
parent
006a5099fc
commit
0b46b75505
@ -10,12 +10,15 @@ LIBBPF_OUT = $(abspath $(obj))
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$(LIBBPF_A):
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$(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
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userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
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userccflags += -I$(LIBBPF_OUT) -I $(srctree)/tools/include/ \
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-I $(srctree)/tools/include/uapi \
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-I $(srctree)/tools/lib/ -Wno-unused-result
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userprogs := bpf_preload_umd
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clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/
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clean-files := $(userprogs) libbpf_version.h bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/
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$(obj)/iterators/iterators.o: $(LIBBPF_A)
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bpf_preload_umd-objs := iterators/iterators.o
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bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz
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@ -60,6 +60,7 @@ CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers
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CFLAGS += $(filter-out -Wswitch-enum -Wnested-externs,$(EXTRA_WARNINGS))
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CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
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-I$(if $(OUTPUT),$(OUTPUT),.) \
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$(if $(LIBBPF_OUTPUT),-I$(LIBBPF_OUTPUT)) \
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-I$(srctree)/kernel/bpf/ \
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-I$(srctree)/tools/include \
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-I$(srctree)/tools/include/uapi \
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@ -137,7 +138,10 @@ endif
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BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool
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BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o xlated_dumper.o btf_dumper.o disasm.o)
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$(BOOTSTRAP_OBJS): $(LIBBPF_BOOTSTRAP)
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OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
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$(OBJS): $(LIBBPF)
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VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
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$(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \
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@ -26,6 +26,7 @@ LIBBPF_SRC := $(srctree)/tools/lib/bpf/
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SUBCMD_SRC := $(srctree)/tools/lib/subcmd/
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BPFOBJ := $(OUTPUT)/libbpf/libbpf.a
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LIBBPF_OUT := $(abspath $(dir $(BPFOBJ)))/
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SUBCMDOBJ := $(OUTPUT)/libsubcmd/libsubcmd.a
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BINARY := $(OUTPUT)/resolve_btfids
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@ -41,11 +42,12 @@ $(SUBCMDOBJ): fixdep FORCE | $(OUTPUT)/libsubcmd
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$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
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$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)/libbpf
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$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
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$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(LIBBPF_OUT) $(abspath $@)
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CFLAGS := -g \
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-I$(srctree)/tools/include \
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-I$(srctree)/tools/include/uapi \
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-I$(LIBBPF_OUT) \
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-I$(LIBBPF_SRC) \
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-I$(SUBCMD_SRC)
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@ -54,7 +56,7 @@ LIBS = -lelf -lz
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export srctree OUTPUT CFLAGS Q
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include $(srctree)/tools/build/Makefile.include
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$(BINARY_IN): fixdep FORCE | $(OUTPUT)
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$(BINARY_IN): $(BPFOBJ) fixdep FORCE | $(OUTPUT)
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$(Q)$(MAKE) $(build)=resolve_btfids
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$(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
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@ -8,7 +8,8 @@ VERSION_SCRIPT := libbpf.map
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LIBBPF_VERSION := $(shell \
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grep -oE '^LIBBPF_([0-9.]+)' $(VERSION_SCRIPT) | \
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sort -rV | head -n1 | cut -d'_' -f2)
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LIBBPF_MAJOR_VERSION := $(firstword $(subst ., ,$(LIBBPF_VERSION)))
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LIBBPF_MAJOR_VERSION := $(word 1,$(subst ., ,$(LIBBPF_VERSION)))
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LIBBPF_MINOR_VERSION := $(word 2,$(subst ., ,$(LIBBPF_VERSION)))
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MAKEFLAGS += --no-print-directory
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@ -59,7 +60,8 @@ ifndef VERBOSE
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VERBOSE = 0
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endif
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INCLUDES = -I. -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi
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INCLUDES = -I$(if $(OUTPUT),$(OUTPUT),.) \
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-I$(srctree)/tools/include -I$(srctree)/tools/include/uapi
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export prefix libdir src obj
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@ -111,7 +113,9 @@ SHARED_OBJDIR := $(OUTPUT)sharedobjs/
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STATIC_OBJDIR := $(OUTPUT)staticobjs/
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BPF_IN_SHARED := $(SHARED_OBJDIR)libbpf-in.o
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BPF_IN_STATIC := $(STATIC_OBJDIR)libbpf-in.o
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VERSION_HDR := $(OUTPUT)libbpf_version.h
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BPF_HELPER_DEFS := $(OUTPUT)bpf_helper_defs.h
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BPF_GENERATED := $(BPF_HELPER_DEFS) $(VERSION_HDR)
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LIB_TARGET := $(addprefix $(OUTPUT),$(LIB_TARGET))
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LIB_FILE := $(addprefix $(OUTPUT),$(LIB_FILE))
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@ -136,7 +140,7 @@ all: fixdep
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all_cmd: $(CMD_TARGETS) check
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$(BPF_IN_SHARED): force $(BPF_HELPER_DEFS)
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$(BPF_IN_SHARED): force $(BPF_GENERATED)
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@(test -f ../../include/uapi/linux/bpf.h -a -f ../../../include/uapi/linux/bpf.h && ( \
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(diff -B ../../include/uapi/linux/bpf.h ../../../include/uapi/linux/bpf.h >/dev/null) || \
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echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'" >&2 )) || true
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@ -154,13 +158,19 @@ $(BPF_IN_SHARED): force $(BPF_HELPER_DEFS)
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echo "Warning: Kernel ABI header at 'tools/include/uapi/linux/if_xdp.h' differs from latest version at 'include/uapi/linux/if_xdp.h'" >&2 )) || true
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$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(SHARED_OBJDIR) CFLAGS="$(CFLAGS) $(SHLIB_FLAGS)"
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$(BPF_IN_STATIC): force $(BPF_HELPER_DEFS)
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$(BPF_IN_STATIC): force $(BPF_GENERATED)
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$(Q)$(MAKE) $(build)=libbpf OUTPUT=$(STATIC_OBJDIR)
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$(BPF_HELPER_DEFS): $(srctree)/tools/include/uapi/linux/bpf.h
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$(QUIET_GEN)$(srctree)/scripts/bpf_doc.py --header \
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--file $(srctree)/tools/include/uapi/linux/bpf.h > $(BPF_HELPER_DEFS)
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$(VERSION_HDR): force
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$(QUIET_GEN)echo "/* This file was auto-generated. */" > $@
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@echo "" >> $@
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@echo "#define LIBBPF_MAJOR_VERSION $(LIBBPF_MAJOR_VERSION)" >> $@
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@echo "#define LIBBPF_MINOR_VERSION $(LIBBPF_MINOR_VERSION)" >> $@
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$(OUTPUT)libbpf.so: $(OUTPUT)libbpf.so.$(LIBBPF_VERSION)
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$(OUTPUT)libbpf.so.$(LIBBPF_VERSION): $(BPF_IN_SHARED) $(VERSION_SCRIPT)
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@ -224,10 +234,10 @@ install_lib: all_cmd
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cp -fpR $(LIB_FILE) $(DESTDIR)$(libdir_SQ)
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INSTALL_HEADERS = bpf.h libbpf.h btf.h libbpf_common.h libbpf_legacy.h xsk.h \
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bpf_helpers.h $(BPF_HELPER_DEFS) bpf_tracing.h \
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bpf_helpers.h $(BPF_GENERATED) bpf_tracing.h \
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bpf_endian.h bpf_core_read.h skel_internal.h
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install_headers: $(BPF_HELPER_DEFS)
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install_headers: $(BPF_GENERATED)
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$(call QUIET_INSTALL, headers) \
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$(foreach hdr,$(INSTALL_HEADERS), \
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$(call do_install,$(hdr),$(prefix)/include/bpf,644);)
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@ -240,7 +250,7 @@ install: install_lib install_pkgconfig install_headers
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clean:
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$(call QUIET_CLEAN, libbpf) $(RM) -rf $(CMD_TARGETS) \
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*~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_HELPER_DEFS) \
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*~ .*.d .*.cmd LIBBPF-CFLAGS $(BPF_GENERATED) \
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$(SHARED_OBJDIR) $(STATIC_OBJDIR) \
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$(addprefix $(OUTPUT), \
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*.o *.a *.so *.so.$(LIBBPF_MAJOR_VERSION) *.pc)
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@ -50,9 +50,11 @@ LIBBPF_API struct btf *libbpf_find_kernel_btf(void);
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LIBBPF_API struct btf *btf__load_from_kernel_by_id(__u32 id);
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LIBBPF_API struct btf *btf__load_from_kernel_by_id_split(__u32 id, struct btf *base_btf);
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LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_from_kernel_by_id instead")
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LIBBPF_API int btf__get_from_id(__u32 id, struct btf **btf);
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LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf);
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LIBBPF_DEPRECATED_SINCE(0, 6, "use btf__load_into_kernel instead")
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LIBBPF_API int btf__load(struct btf *btf);
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LIBBPF_API int btf__load_into_kernel(struct btf *btf);
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LIBBPF_API __s32 btf__find_by_name(const struct btf *btf,
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@ -10,6 +10,7 @@
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#define __LIBBPF_LIBBPF_COMMON_H
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#include <string.h>
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#include "libbpf_version.h"
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#ifndef LIBBPF_API
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#define LIBBPF_API __attribute__((visibility("default")))
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@ -17,6 +18,24 @@
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#define LIBBPF_DEPRECATED(msg) __attribute__((deprecated(msg)))
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/* Mark a symbol as deprecated when libbpf version is >= {major}.{minor} */
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#define LIBBPF_DEPRECATED_SINCE(major, minor, msg) \
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__LIBBPF_MARK_DEPRECATED_ ## major ## _ ## minor \
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(LIBBPF_DEPRECATED("libbpf v" # major "." # minor "+: " msg))
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#define __LIBBPF_CURRENT_VERSION_GEQ(major, minor) \
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(LIBBPF_MAJOR_VERSION > (major) || \
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(LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor)))
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/* Add checks for other versions below when planning deprecation of API symbols
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* with the LIBBPF_DEPRECATED_SINCE macro.
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*/
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#if __LIBBPF_CURRENT_VERSION_GEQ(0, 6)
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#define __LIBBPF_MARK_DEPRECATED_0_6(X) X
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#else
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#define __LIBBPF_MARK_DEPRECATED_0_6(X)
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#endif
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/* Helper macro to declare and initialize libbpf options struct
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*
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* This dance with uninitialized declaration, followed by memset to zero,
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@ -512,14 +512,14 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
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$(Q)$(CXX) $(CFLAGS) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@
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# Benchmark runner
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$(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h
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$(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ)
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$(call msg,CC,,$@)
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$(Q)$(CC) $(CFLAGS) -c $(filter %.c,$^) $(LDLIBS) -o $@
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$(OUTPUT)/bench_rename.o: $(OUTPUT)/test_overhead.skel.h
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$(OUTPUT)/bench_trigger.o: $(OUTPUT)/trigger_bench.skel.h
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$(OUTPUT)/bench_ringbufs.o: $(OUTPUT)/ringbuf_bench.skel.h \
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$(OUTPUT)/perfbuf_bench.skel.h
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$(OUTPUT)/bench.o: bench.h testing_helpers.h
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$(OUTPUT)/bench.o: bench.h testing_helpers.h $(BPFOBJ)
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$(OUTPUT)/bench: LDLIBS += -lm
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$(OUTPUT)/bench: $(OUTPUT)/bench.o $(OUTPUT)/testing_helpers.o \
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$(OUTPUT)/bench_count.o \
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