Re: [PATCH 1/3] arm: include: asm: swab: mask rev16 instruction for clang
From: Nick Desaulniers <ndesaulniers@google.com>
Date: 2021-07-27 17:53:39
Also in:
bpf, linux-arm-kernel, lkml
On Tue, Jul 27, 2021 at 7:12 AM Pavo Banicevic [off-list ref] wrote:
From: Ivan Khoronzhuk <redacted> 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.
quoted hunk ↗ jump to hunk
Signed-off-by: Ivan Khoronzhuk <redacted> --- 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