Commit b7a2d774 authored by Ian Rogers's avatar Ian Rogers Committed by Namhyung Kim

perf build: Add ability to build with a generated vmlinux.h

Commit a8874665 ("perf bpf skels: Stop using vmlinux.h generated
from BTF, use subset of used structs + CO-RE") made it so that
vmlinux.h was uncondtionally included from
tools/perf/util/vmlinux.h. This change reverts part of that change (so
that vmlinux.h is once again generated) and makes it so that the
vmlinux.h used at build time is selected from the VMLINUX_H
variable. By default the VMLINUX_H variable is set to the vmlinux.h
added in change a8874665, but if GEN_VMLINUX_H=1 is passed on the
build command line then the previous generation behavior kicks in.

The build with GEN_VMLINUX_H=1 currently fails with:

    util/bpf_skel/lock_contention.bpf.c:419:8: error: redefinition of 'rq'
    struct rq {};
           ^
    /tmp/perf/util/bpf_skel/.tmp/../vmlinux.h:45630:8: note: previous definition is here
    struct rq {
           ^
    1 error generated.
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Acked-by: default avatarJiri Olsa <jolsa@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230623041405.4039475-2-irogers@google.com
[ Format the error message and add a comment for GEN_VMLINUX_H ]
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
parent 4d60e83d
...@@ -680,6 +680,10 @@ ifdef BUILD_BPF_SKEL ...@@ -680,6 +680,10 @@ ifdef BUILD_BPF_SKEL
CFLAGS += -DHAVE_BPF_SKEL CFLAGS += -DHAVE_BPF_SKEL
endif endif
ifndef GEN_VMLINUX_H
VMLINUX_H=$(src-perf)/util/bpf_skel/vmlinux/vmlinux.h
endif
dwarf-post-unwind := 1 dwarf-post-unwind := 1
dwarf-post-unwind-text := BUG dwarf-post-unwind-text := BUG
......
...@@ -132,6 +132,8 @@ include ../scripts/utilities.mak ...@@ -132,6 +132,8 @@ include ../scripts/utilities.mak
# Define EXTRA_TESTS to enable building extra tests useful mainly to perf # Define EXTRA_TESTS to enable building extra tests useful mainly to perf
# developers, such as: # developers, such as:
# x86 instruction decoder - new instructions test # x86 instruction decoder - new instructions test
#
# Define GEN_VMLINUX_H to generate vmlinux.h from the BTF.
# As per kernel Makefile, avoid funny character set dependencies # As per kernel Makefile, avoid funny character set dependencies
unexport LC_ALL unexport LC_ALL
...@@ -1084,7 +1086,21 @@ $(BPFTOOL): | $(SKEL_TMP_OUT) ...@@ -1084,7 +1086,21 @@ $(BPFTOOL): | $(SKEL_TMP_OUT)
$(Q)CFLAGS= $(MAKE) -C ../bpf/bpftool \ $(Q)CFLAGS= $(MAKE) -C ../bpf/bpftool \
OUTPUT=$(SKEL_TMP_OUT)/ bootstrap OUTPUT=$(SKEL_TMP_OUT)/ bootstrap
$(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) | $(SKEL_TMP_OUT) VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
$(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \
../../vmlinux \
/sys/kernel/btf/vmlinux \
/boot/vmlinux-$(shell uname -r)
VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
$(SKEL_OUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
ifeq ($(VMLINUX_H),)
$(QUIET_GEN)$(BPFTOOL) btf dump file $< format c > $@
else
$(Q)cp "$(VMLINUX_H)" $@
endif
$(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) $(SKEL_OUT)/vmlinux.h | $(SKEL_TMP_OUT)
$(QUIET_CLANG)$(CLANG) -g -O2 -target bpf -Wall -Werror $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \ $(QUIET_CLANG)$(CLANG) -g -O2 -target bpf -Wall -Werror $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
-c $(filter util/bpf_skel/%.bpf.c,$^) -o $@ -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@
......
# SPDX-License-Identifier: GPL-2.0-only # SPDX-License-Identifier: GPL-2.0-only
.tmp .tmp
*.skel.h *.skel.h
vmlinux.h
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