Commit fbbb68de authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov

bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object

The resolve_btfids tool scans elf object for .BTF_ids section
and resolves its symbols with BTF ID values.

It will be used to during linking time to resolve arrays of BTF
ID values used in verifier, so these IDs do not need to be
resolved in runtime.

The expected layout of .BTF_ids section is described in main.c
header. Related kernel changes are coming in following changes.

Build issue reported by 0-DAY CI Kernel Test Service.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200711215329.41165-2-jolsa@kernel.org
parent eef8a42d
resolve_btfids-y += main.o
resolve_btfids-y += rbtree.o
resolve_btfids-y += zalloc.o
resolve_btfids-y += string.o
resolve_btfids-y += ctype.o
resolve_btfids-y += str_error_r.o
$(OUTPUT)%.o: ../../lib/%.c FORCE
$(call rule_mkdir)
$(call if_changed_dep,cc_o_c)
# SPDX-License-Identifier: GPL-2.0-only
include ../../scripts/Makefile.include
ifeq ($(srctree),)
srctree := $(patsubst %/,%,$(dir $(CURDIR)))
srctree := $(patsubst %/,%,$(dir $(srctree)))
srctree := $(patsubst %/,%,$(dir $(srctree)))
endif
ifeq ($(V),1)
Q =
msg =
else
Q = @
msg = @printf ' %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))";
MAKEFLAGS=--no-print-directory
endif
OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
LIBBPF_SRC := $(srctree)/tools/lib/bpf/
SUBCMD_SRC := $(srctree)/tools/lib/subcmd/
BPFOBJ := $(OUTPUT)/libbpf.a
SUBCMDOBJ := $(OUTPUT)/libsubcmd.a
BINARY := $(OUTPUT)/resolve_btfids
BINARY_IN := $(BINARY)-in.o
all: $(BINARY)
$(OUTPUT):
$(call msg,MKDIR,,$@)
$(Q)mkdir -p $(OUTPUT)
$(SUBCMDOBJ): fixdep FORCE
$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT)
$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT)
$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
CFLAGS := -g \
-I$(srctree)/tools/include \
-I$(srctree)/tools/include/uapi \
-I$(LIBBPF_SRC) \
-I$(SUBCMD_SRC)
LIBS = -lelf -lz
export srctree OUTPUT CFLAGS Q
include $(srctree)/tools/build/Makefile.include
$(BINARY_IN): fixdep FORCE
$(Q)$(MAKE) $(build)=resolve_btfids
$(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
$(call msg,LINK,$@)
$(Q)$(CC) $(BINARY_IN) $(LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
libsubcmd-clean:
$(Q)$(MAKE) -C $(SUBCMD_SRC) OUTPUT=$(OUTPUT) clean
libbpf-clean:
$(Q)$(MAKE) -C $(LIBBPF_SRC) OUTPUT=$(OUTPUT) clean
clean: libsubcmd-clean libbpf-clean fixdep-clean
$(call msg,CLEAN,$(BINARY))
$(Q)$(RM) -f $(BINARY); \
find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
tags:
$(call msg,GEN,,tags)
$(Q)ctags -R . $(LIBBPF_SRC) $(SUBCMD_SRC)
FORCE:
.PHONY: all FORCE clean tags
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