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From: Pavo Banicevic <pavo.banicevic@sartura.hr>
To: 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, ndesaulniers@google.com,
	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: [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang
Date: Tue, 27 Jul 2021 16:11:17 +0200	[thread overview]
Message-ID: <20210727141119.19812-2-pavo.banicevic@sartura.hr> (raw)
In-Reply-To: <20210727141119.19812-1-pavo.banicevic@sartura.hr>

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.

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


  reply	other threads:[~2021-07-27 14:12 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 ` Pavo Banicevic [this message]
2021-07-27 15:46   ` [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang Yonghong Song
2021-07-27 17:53   ` Nick Desaulniers
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

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