linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Nick Desaulniers <ndesaulniers@google.com>
To: Pavo Banicevic <pavo.banicevic@sartura.hr>,
	Arnd Bergmann <arnd@linaro.org>
Cc: linux@armlinux.org.uk, ast@kernel.org, daniel@iogearbox.net,
	andrii@kernel.org, kafai@fb.com, songliubraving@fb.com,
	yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org,
	nathan@kernel.org, ivan.khoronzhuk@linaro.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org, clang-built-linux@googlegroups.com,
	matt.redfearn@mips.com, mingo@kernel.org, dvlasenk@redhat.com,
	juraj.vijtiuk@sartura.hr, robert.marko@sartura.hr,
	luka.perkov@sartura.hr, jakov.petrina@sartura.hr
Subject: Re: [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang
Date: Tue, 27 Jul 2021 10:53:20 -0700	[thread overview]
Message-ID: <CAKwvOdkwwXV9rN6bzRs_+hbq5thHNSbEtqwOZ7340a79=NqjSg@mail.gmail.com> (raw)
In-Reply-To: <20210727141119.19812-2-pavo.banicevic@sartura.hr>

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.

>
> 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

  parent reply	other threads:[~2021-07-27 17:53 UTC|newest]

Thread overview: 9+ 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 ` [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang Pavo Banicevic
2021-07-27 15:46   ` Yonghong Song
2021-07-27 17:53   ` Nick Desaulniers [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 17:55   ` Nick Desaulniers
2021-07-27 14:11 ` [PATCH 3/3] include/uapi/linux/swab: Fix potentially missing __always_inline Pavo Banicevic
2021-07-28 13:49   ` Petr Vaněk

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAKwvOdkwwXV9rN6bzRs_+hbq5thHNSbEtqwOZ7340a79=NqjSg@mail.gmail.com' \
    --to=ndesaulniers@google.com \
    --cc=andrii@kernel.org \
    --cc=arnd@linaro.org \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=clang-built-linux@googlegroups.com \
    --cc=daniel@iogearbox.net \
    --cc=dvlasenk@redhat.com \
    --cc=ivan.khoronzhuk@linaro.org \
    --cc=jakov.petrina@sartura.hr \
    --cc=john.fastabend@gmail.com \
    --cc=juraj.vijtiuk@sartura.hr \
    --cc=kafai@fb.com \
    --cc=kpsingh@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=luka.perkov@sartura.hr \
    --cc=matt.redfearn@mips.com \
    --cc=mingo@kernel.org \
    --cc=nathan@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=pavo.banicevic@sartura.hr \
    --cc=robert.marko@sartura.hr \
    --cc=songliubraving@fb.com \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).