On Mon, Jun 05, 2023 at 01:27:09PM -0700, Ian Rogers wrote:
> Commit a887466562b4 ("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 a887466562b4, 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: Ian Rogers <irogers@xxxxxxxxxx>
> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> ---
> tools/perf/Makefile.config | 4 ++++
> tools/perf/Makefile.perf | 16 +++++++++++++++-
> tools/perf/util/bpf_skel/.gitignore | 1 +
> tools/perf/util/bpf_skel/{ => vmlinux}/vmlinux.h | 0
> 4 files changed, 20 insertions(+), 1 deletion(-)
> rename tools/perf/util/bpf_skel/{ => vmlinux}/vmlinux.h (100%)
looks good, but I don't understand why you moved the vmlinux.h
jirka
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index a794d9eca93d..08d4e7eaa721 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -680,6 +680,10 @@ ifdef BUILD_BPF_SKEL
> CFLAGS += -DHAVE_BPF_SKEL
> endif
>
> +ifndef GEN_VMLINUX_H
> + VMLINUX_H=$(src-perf)/util/bpf_skel/vmlinux/vmlinux.h
> +endif
> +
> dwarf-post-unwind := 1
> dwarf-post-unwind-text := BUG
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index f48794816d82..f1840af195c0 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -1080,7 +1080,21 @@ $(BPFTOOL): | $(SKEL_TMP_OUT)
> $(Q)CFLAGS= $(MAKE) -C ../bpf/bpftool \
> OUTPUT=$(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) \
> -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@
>
> diff --git a/tools/perf/util/bpf_skel/.gitignore b/tools/perf/util/bpf_skel/.gitignore
> index 7a1c832825de..cd01455e1b53 100644
> --- a/tools/perf/util/bpf_skel/.gitignore
> +++ b/tools/perf/util/bpf_skel/.gitignore
> @@ -1,3 +1,4 @@
> # SPDX-License-Identifier: GPL-2.0-only
> .tmp
> *.skel.h
> +vmlinux.h
> diff --git a/tools/perf/util/bpf_skel/vmlinux.h b/tools/perf/util/bpf_skel/vmlinux/vmlinux.h
> similarity index 100%
> rename from tools/perf/util/bpf_skel/vmlinux.h
> rename to tools/perf/util/bpf_skel/vmlinux/vmlinux.h
> --
> 2.41.0.rc0.172.g3f132b7071-goog
>
