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Subject: Re: [PATCH 2/2] compiler.h: Include asm/rwonce.h under ARM64 and
 ALPHA to fix build errors
To:     Tiezhu Yang <yangtiezhu@loongson.cn>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai 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 <natechancellor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>
Cc:     linux-sparse@vger.kernel.org, netdev@vger.kernel.org,
        bpf@vger.kernel.org, clang-built-linux@googlegroups.com,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        Xuefeng Li <lixuefeng@loongson.cn>
References: <1610535453-2352-1-git-send-email-yangtiezhu@loongson.cn>
 <1610535453-2352-3-git-send-email-yangtiezhu@loongson.cn>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Organization: Brain-dead Software
Message-ID: <04749e2c-6e80-5316-a575-e4aaf780bb81@gmail.com>
Date:   Thu, 14 Jan 2021 11:40:39 +0300
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Hello!

On 13.01.2021 13:57, Tiezhu Yang wrote:

> When make M=samples/bpf on the Loongson 3A3000 platform which
> belongs to MIPS arch, there exists many similar build errors
> about 'asm/rwonce.h' file not found, so include it only under
> CONFIG_ARM64 and CONFIG_ALPHA due to it exists only in arm64
> and alpha arch.
> 
>    CLANG-bpf  samples/bpf/xdpsock_kern.o
> In file included from samples/bpf/xdpsock_kern.c:2:
> In file included from ./include/linux/bpf.h:9:
> In file included from ./include/linux/workqueue.h:9:
> In file included from ./include/linux/timer.h:5:
> In file included from ./include/linux/list.h:9:
> In file included from ./include/linux/kernel.h:10:
> ./include/linux/compiler.h:246:10: fatal error: 'asm/rwonce.h' file not found
>           ^~~~~~~~~~~~~~
> 1 error generated.
> 
> $ find . -name rwonce.h
> ./include/asm-generic/rwonce.h
> ./arch/arm64/include/asm/rwonce.h
> ./arch/alpha/include/asm/rwonce.h
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>   include/linux/compiler.h | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index b8fe0c2..bdbe759 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -243,6 +243,12 @@ static inline void *offset_to_ptr(const int *off)
>    */
>   #define prevent_tail_call_optimization()	mb()
>   
> +#ifdef CONFIG_ARM64

    Why not #if defined(CONFIG_ALPHA) || defined(CONFIG_ARM64)?

>   #include <asm/rwonce.h>
> +#endif
> +
> +#ifdef CONFIG_ALPHA
> +#include <asm/rwonce.h>
> +#endif
>   
>   #endif /* __LINUX_COMPILER_H */
> 

MBR, Sergei