| Message ID | 20210928041329.1735524-1-memxor@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf] samples: bpf: Fix vmlinux.h generation for XDP samples | expand |
On Mon, Sep 27, 2021 at 9:16 PM Kumar Kartikeya Dwivedi <memxor@gmail.com> 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@redhat.com> > Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support) > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > --- > 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? > 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 > - [...]
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@gmail.com> 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@redhat.com> > > Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support) > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > > --- > > 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. > > 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
On Mon, Sep 27, 2021 at 9:51 PM Kumar Kartikeya Dwivedi <memxor@gmail.com> 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@gmail.com> 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@redhat.com> > > > Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support) > > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > > > --- > > > 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 extremely confusing (and obviously ../../../../vmlinux never worked and we never knew that). > > > > 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
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@gmail.com> 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@gmail.com> 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@redhat.com> > > > > Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support) > > > > Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > > > > --- > > > > 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
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 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 - $(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) ifeq ($(VMLINUX_H),) $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ @@ -340,6 +334,11 @@ else $(Q)cp "$(VMLINUX_H)" $@ endif +ifeq ($(VMLINUX_BTF),) + $(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)",\ + build the kernel or set VMLINUX_BTF variable) +endif + clean-files += vmlinux.h # Get Clang's default includes on this system, as opposed to those seen by diff --git a/samples/bpf/xdp_redirect_map_multi.bpf.c b/samples/bpf/xdp_redirect_map_multi.bpf.c index 8f59d430cb64..bb0a5a3bfcf0 100644 --- a/samples/bpf/xdp_redirect_map_multi.bpf.c +++ b/samples/bpf/xdp_redirect_map_multi.bpf.c @@ -5,11 +5,6 @@ #include "xdp_sample.bpf.h" #include "xdp_sample_shared.h" -enum { - BPF_F_BROADCAST = (1ULL << 3), - BPF_F_EXCLUDE_INGRESS = (1ULL << 4), -}; - struct { __uint(type, BPF_MAP_TYPE_DEVMAP_HASH); __uint(key_size, sizeof(int));
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@redhat.com> Fixes: 384b6b3bbf0d (samples: bpf: Add vmlinux.h generation support) Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> --- samples/bpf/Makefile | 13 ++++++------- samples/bpf/xdp_redirect_map_multi.bpf.c | 5 ----- 2 files changed, 6 insertions(+), 12 deletions(-) -- 2.33.0