| Message ID | 20240704143611.2979589-4-arnd@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arch: convert everything to syscall.tbl | expand |
Hi Arnd, On Thu, 4 Jul 2024 16:35:57 +0200 Arnd Bergmann <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > If we start validating the existence of the asm-generic side of > generated headers, this one causes a warning: > > make[3]: *** No rule to make target 'arch/um/include/generated/asm/bpf_perf_event.h', needed by 'all'. Stop. > > The problem is that the asm-generic header only exists for the uapi > variant, but arch/um has no uapi headers and instead uses the x86 > userspace API. > > Add a custom file with an explicit redirect to avoid this. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/um/include/asm/Kbuild | 1 - > arch/um/include/asm/bpf_perf_event.h | 3 +++ > 2 files changed, 3 insertions(+), 1 deletion(-) > create mode 100644 arch/um/include/asm/bpf_perf_event.h > > diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild > index 6fe34779291a..6c583040537c 100644 > --- a/arch/um/include/asm/Kbuild > +++ b/arch/um/include/asm/Kbuild > @@ -1,5 +1,4 @@ > # SPDX-License-Identifier: GPL-2.0 > -generic-y += bpf_perf_event.h > generic-y += bug.h > generic-y += compat.h > generic-y += current.h > diff --git a/arch/um/include/asm/bpf_perf_event.h b/arch/um/include/asm/bpf_perf_event.h > new file mode 100644 > index 000000000000..0a30420c83de > --- /dev/null > +++ b/arch/um/include/asm/bpf_perf_event.h > @@ -0,0 +1,3 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#include <asm-generic/bpf_perf_event.h> Just wondering if that file should have some explanatory comment in it to prevent it being cleaned up in a few years ... or at least to explain why it causes the above error when removed.
On Thu, Jul 4, 2024 at 11:37 PM Arnd Bergmann <arnd@kernel.org> wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > If we start validating the existence of the asm-generic side of > generated headers, this one causes a warning: > > make[3]: *** No rule to make target 'arch/um/include/generated/asm/bpf_perf_event.h', needed by 'all'. Stop. > > The problem is that the asm-generic header only exists for the uapi > variant, but arch/um has no uapi headers and instead uses the x86 > userspace API. > > Add a custom file with an explicit redirect to avoid this. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/um/include/asm/Kbuild | 1 - > arch/um/include/asm/bpf_perf_event.h | 3 +++ > 2 files changed, 3 insertions(+), 1 deletion(-) > create mode 100644 arch/um/include/asm/bpf_perf_event.h > > diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild > index 6fe34779291a..6c583040537c 100644 > --- a/arch/um/include/asm/Kbuild > +++ b/arch/um/include/asm/Kbuild > @@ -1,5 +1,4 @@ > # SPDX-License-Identifier: GPL-2.0 > -generic-y += bpf_perf_event.h > generic-y += bug.h > generic-y += compat.h > generic-y += current.h > diff --git a/arch/um/include/asm/bpf_perf_event.h b/arch/um/include/asm/bpf_perf_event.h > new file mode 100644 > index 000000000000..0a30420c83de > --- /dev/null > +++ b/arch/um/include/asm/bpf_perf_event.h > @@ -0,0 +1,3 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#include <asm-generic/bpf_perf_event.h> > -- > 2.39.2 > I guess this is a step backward. Technically, kernel-space asm/*.h files are allowed to wrap UAPI <asm-generic/*.h>. There is no reason why we ban generic-y for doing this, whereas check-in source is allowed. -- Best Regards Masahiro Yamada
On Fri, Jul 12, 2024, at 10:37, Masahiro Yamada wrote: > On Thu, Jul 4, 2024 at 11:37 PM Arnd Bergmann <arnd@kernel.org> wrote: >> --- a/arch/um/include/asm/Kbuild >> +++ b/arch/um/include/asm/Kbuild >> @@ -1,5 +1,4 @@ >> # SPDX-License-Identifier: GPL-2.0 >> -generic-y += bpf_perf_event.h >> generic-y += bug.h >> generic-y += compat.h >> generic-y += current.h >> diff --git a/arch/um/include/asm/bpf_perf_event.h b/arch/um/include/asm/bpf_perf_event.h >> new file mode 100644 >> index 000000000000..0a30420c83de >> --- /dev/null >> +++ b/arch/um/include/asm/bpf_perf_event.h >> @@ -0,0 +1,3 @@ >> +/* SPDX-License-Identifier: GPL-2.0 */ >> + >> +#include <asm-generic/bpf_perf_event.h> > > I guess this is a step backward. > > Technically, kernel-space asm/*.h files are allowed to > wrap UAPI <asm-generic/*.h>. > There is no reason why we ban generic-y for doing this, > whereas check-in source is allowed. I think in this case, the simplicity is the more important argument: this is the only case we have of wrapping a uapi header from a non-uapi header, and no other architecture would need to do this. The way the syscall-y rule works relies on enforcing some checking for existing asm-generic headers, and I could extend it to allow this special case, but that would make the Makefile rule less readable in exchange for avoiding effectively a one-line file. Arnd
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild index 6fe34779291a..6c583040537c 100644 --- a/arch/um/include/asm/Kbuild +++ b/arch/um/include/asm/Kbuild @@ -1,5 +1,4 @@ # SPDX-License-Identifier: GPL-2.0 -generic-y += bpf_perf_event.h generic-y += bug.h generic-y += compat.h generic-y += current.h diff --git a/arch/um/include/asm/bpf_perf_event.h b/arch/um/include/asm/bpf_perf_event.h new file mode 100644 index 000000000000..0a30420c83de --- /dev/null +++ b/arch/um/include/asm/bpf_perf_event.h @@ -0,0 +1,3 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include <asm-generic/bpf_perf_event.h>