On Tue, Sep 28, 2021 at 10:58:01AM IST, Andrii Nakryiko wrote: > On Mon, Sep 27, 2021 at 9:51 PM Kumar Kartikeya Dwivedi > <memxor@xxxxxxxxx> wrote: > > > > On Tue, Sep 28, 2021 at 10:06:09AM IST, Andrii Nakryiko wrote: > > > On Mon, Sep 27, 2021 at 9:16 PM Kumar Kartikeya Dwivedi > > > <memxor@xxxxxxxxx> wrote: > > > > > > > > Generate vmlinux.h only from the in-tree vmlinux, and remove enum > > > > declarations that would cause a build failure in case of version > > > > mismatches. > > > > > > > > There are now two options when building the samples: > > > > 1. Compile the kernel to use in-tree vmlinux for vmlinux.h > > > > 2. Override VMLINUX_BTF for samples using something like this: > > > > make VMLINUX_BTF=/sys/kernel/btf/vmlinux -C samples/bpf > > > > > > > > This change was tested with relative builds, e.g. cases like: > > > > * make O=build -C samples/bpf > > > > * make KBUILD_OUTPUT=build -C samples/bpf > > > > * make -C samples/bpf > > > > * cd samples/bpf && make > > > > > > > > When a suitable VMLINUX_BTF is not found, the following message is > > > > printed: > > > > /home/kkd/src/linux/samples/bpf/Makefile:333: *** Cannot find a vmlinux > > > > for VMLINUX_BTF at any of " ./vmlinux", build the kernel or set > > > > VMLINUX_BTF variable. Stop. > > > > > > > > Cc: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> > > > > Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support) > > > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> > > > > --- > > > > samples/bpf/Makefile | 13 ++++++------- > > > > samples/bpf/xdp_redirect_map_multi.bpf.c | 5 ----- > > > > 2 files changed, 6 insertions(+), 12 deletions(-) > > > > > > > > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile > > > > index 4dc20be5fb96..a05130e91403 100644 > > > > --- a/samples/bpf/Makefile > > > > +++ b/samples/bpf/Makefile > > > > @@ -324,15 +324,9 @@ $(obj)/hbm_edt_kern.o: $(src)/hbm.h $(src)/hbm_kern.h > > > > > > > > VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ > > > > $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \ > > > > - ../../../../vmlinux \ > > > > - /sys/kernel/btf/vmlinux \ > > > > - /boot/vmlinux-$(shell uname -r) > > > > + ./vmlinux > > > > > > isn't this relative to samples/bpf subdirectory, so shouldn't it be > > > ../../vmlinux? > > > > > > > I was confused about this too; but it executes this when you call make: > > > > # Trick to allow make to be run from this directory > > all: > > $(MAKE) -C ../../ M=$(CURDIR) BPF_SAMPLES_PATH=$(CURDIR) > > > > so it fails if the path isn't relative to kernel source root. > > Hm... what if we do $(abspath ./vmlinux) here (and probably same for > $(O) and $(KBUILD_OUTPUT) just in case those are relative as well, > would that do the right thing here? The way it is right now it's Yeah, that works. I'll send a v2. > extremely confusing (and obviously ../../../../vmlinux never worked > and we never knew that). > Indeed. > > > > > > VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) > > > > > > > > -ifeq ($(VMLINUX_BTF),) > > > > -$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)") > > > > -endif > > > > - > > > > > > [...] > > > > -- > > Kartikeya -- Kartikeya
