From: Andrii Nakryiko <andrii.nakryiko@gmail.com> To: Nick Desaulniers <ndesaulniers@google.com> Cc: Pavo Banicevic <pavo.banicevic@sartura.hr>, Arnd Bergmann <arnd@linaro.org>, linux@armlinux.org.uk, Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>, john fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@kernel.org>, Nathan Chancellor <nathan@kernel.org>, Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, open list <linux-kernel@vger.kernel.org>, Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>, clang-built-linux <clang-built-linux@googlegroups.com>, matt.redfearn@mips.com, Ingo Molnar <mingo@kernel.org>, dvlasenk@redhat.com, Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>, robert.marko@sartura.hr, Luka Perkov <luka.perkov@sartura.hr>, Jakov Petrina <jakov.petrina@sartura.hr> Subject: Re: [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang Date: Tue, 27 Jul 2021 14:43:39 -0700 [thread overview] Message-ID: <CAEf4Bza2zZK2m4fmDUXKoURxMmUcfr8gvLR9wxF1vFPBmc2gHA@mail.gmail.com> (raw) In-Reply-To: <CAKwvOdkwwXV9rN6bzRs_+hbq5thHNSbEtqwOZ7340a79=NqjSg@mail.gmail.com> On Tue, Jul 27, 2021 at 10:53 AM Nick Desaulniers <ndesaulniers@google.com> wrote: > > On Tue, Jul 27, 2021 at 7:12 AM Pavo Banicevic > <pavo.banicevic@sartura.hr> wrote: > > > > From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> > > > > The samples/bpf with clang -emit-llvm reuses linux headers to build > > bpf samples, and this w/a only for samples (samples/bpf/Makefile > > CLANG-bpf). > > > > It allows to build samples/bpf for arm bpf using clang. > > In another way clang -emit-llvm generates errors like: > > > > CLANG-bpf samples/bpf/tc_l2_redirect_kern.o > > <inline asm>:1:2: error: invalid register/token name > > rev16 r3, r0 > > > > This decision is arguable, probably there is another way, but > > it doesn't have impact on samples/bpf, so it's easier just ignore > > it for clang, at least for now. > > NACK > > The way to fix these is to sort out the header includes, not turning > off arbitrary things that are used by the actual kernel build for 32b > ARM. Would it be too horrible to just get rid of `clang -emit-llvm` and use vmlinux.h (we don't need to do CO-RE, btw, just generate vmlinux.h from the matching kernel)? Kumar has already started moving in that direction in his recent patch set ([0]). Would that get rid of all these issues? [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=519281&state=* > > > > > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> > > --- > > arch/arm/include/asm/swab.h | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/arm/include/asm/swab.h b/arch/arm/include/asm/swab.h > > index c6051823048b..a9fd9cd33d5e 100644 > > --- a/arch/arm/include/asm/swab.h > > +++ b/arch/arm/include/asm/swab.h > > @@ -25,8 +25,11 @@ static inline __attribute_const__ __u32 __arch_swahb32(__u32 x) > > __asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x)); > > return x; > > } > > + > > +#ifndef __clang__ > > #define __arch_swahb32 __arch_swahb32 > > #define __arch_swab16(x) ((__u16)__arch_swahb32(x)) > > +#endif > > > > static inline __attribute_const__ __u32 __arch_swab32(__u32 x) > > { > > -- > > 2.32.0 > > > > > -- > Thanks, > ~Nick Desaulniers
WARNING: multiple messages have this Message-ID (diff)
From: Andrii Nakryiko <andrii.nakryiko@gmail.com> To: Nick Desaulniers <ndesaulniers@google.com> Cc: Pavo Banicevic <pavo.banicevic@sartura.hr>, Arnd Bergmann <arnd@linaro.org>, linux@armlinux.org.uk, Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>, john fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@kernel.org>, Nathan Chancellor <nathan@kernel.org>, Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org>, open list <linux-kernel@vger.kernel.org>, Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>, clang-built-linux <clang-built-linux@googlegroups.com>, matt.redfearn@mips.com, Ingo Molnar <mingo@kernel.org>, dvlasenk@redhat.com, Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>, robert.marko@sartura.hr, Luka Perkov <luka.perkov@sartura.hr>, Jakov Petrina <jakov.petrina@sartura.hr> Subject: Re: [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang Date: Tue, 27 Jul 2021 14:43:39 -0700 [thread overview] Message-ID: <CAEf4Bza2zZK2m4fmDUXKoURxMmUcfr8gvLR9wxF1vFPBmc2gHA@mail.gmail.com> (raw) In-Reply-To: <CAKwvOdkwwXV9rN6bzRs_+hbq5thHNSbEtqwOZ7340a79=NqjSg@mail.gmail.com> On Tue, Jul 27, 2021 at 10:53 AM Nick Desaulniers <ndesaulniers@google.com> wrote: > > On Tue, Jul 27, 2021 at 7:12 AM Pavo Banicevic > <pavo.banicevic@sartura.hr> wrote: > > > > From: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> > > > > The samples/bpf with clang -emit-llvm reuses linux headers to build > > bpf samples, and this w/a only for samples (samples/bpf/Makefile > > CLANG-bpf). > > > > It allows to build samples/bpf for arm bpf using clang. > > In another way clang -emit-llvm generates errors like: > > > > CLANG-bpf samples/bpf/tc_l2_redirect_kern.o > > <inline asm>:1:2: error: invalid register/token name > > rev16 r3, r0 > > > > This decision is arguable, probably there is another way, but > > it doesn't have impact on samples/bpf, so it's easier just ignore > > it for clang, at least for now. > > NACK > > The way to fix these is to sort out the header includes, not turning > off arbitrary things that are used by the actual kernel build for 32b > ARM. Would it be too horrible to just get rid of `clang -emit-llvm` and use vmlinux.h (we don't need to do CO-RE, btw, just generate vmlinux.h from the matching kernel)? Kumar has already started moving in that direction in his recent patch set ([0]). Would that get rid of all these issues? [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=519281&state=* > > > > > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> > > --- > > arch/arm/include/asm/swab.h | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/arm/include/asm/swab.h b/arch/arm/include/asm/swab.h > > index c6051823048b..a9fd9cd33d5e 100644 > > --- a/arch/arm/include/asm/swab.h > > +++ b/arch/arm/include/asm/swab.h > > @@ -25,8 +25,11 @@ static inline __attribute_const__ __u32 __arch_swahb32(__u32 x) > > __asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x)); > > return x; > > } > > + > > +#ifndef __clang__ > > #define __arch_swahb32 __arch_swahb32 > > #define __arch_swab16(x) ((__u16)__arch_swahb32(x)) > > +#endif > > > > static inline __attribute_const__ __u32 __arch_swab32(__u32 x) > > { > > -- > > 2.32.0 > > > > > -- > Thanks, > ~Nick Desaulniers _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-07-27 21:43 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-27 14:11 [PATCH 0/3] Address compilation of eBPF related software with clang compiler on arm architecture Pavo Banicevic 2021-07-27 14:11 ` Pavo Banicevic 2021-07-27 14:11 ` [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang Pavo Banicevic 2021-07-27 14:11 ` Pavo Banicevic 2021-07-27 15:46 ` Yonghong Song 2021-07-27 15:46 ` Yonghong Song 2021-07-27 17:53 ` Nick Desaulniers 2021-07-27 17:53 ` Nick Desaulniers 2021-07-27 21:43 ` Andrii Nakryiko [this message] 2021-07-27 21:43 ` Andrii Nakryiko 2021-07-27 14:11 ` [PATCH 2/3] arm: include: asm: unified: mask .syntax unified " Pavo Banicevic 2021-07-27 14:11 ` Pavo Banicevic 2021-07-27 16:41 ` kernel test robot 2021-07-27 17:55 ` Nick Desaulniers 2021-07-27 17:55 ` Nick Desaulniers 2021-07-27 18:00 ` kernel test robot 2021-07-27 14:11 ` [PATCH 3/3] include/uapi/linux/swab: Fix potentially missing __always_inline Pavo Banicevic 2021-07-27 14:11 ` Pavo Banicevic 2021-07-28 13:49 ` Petr Vaněk 2021-07-28 13:49 ` Petr Vaněk
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