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From:   Zhangjin Wu <falcon@tinylab.org>
To:     w@1wt.eu
Cc:     falcon@tinylab.org, arnd@arndb.de, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux@weissschuh.net, thomas@t-8ch.de
Subject: [PATCH v2 1/4] tools/nolibc: sys.h: add __syscall() and __sysret() helpers
Date:   Tue,  6 Jun 2023 18:33:24 +0800
Message-Id: <20230606103324.512531-1-falcon@tinylab.org>
In-Reply-To: <a42fb9e1bbe0daf7d8a48ea8f44135ef851030d7.1686036862.git.falcon@tinylab.org>
References: <a42fb9e1bbe0daf7d8a48ea8f44135ef851030d7.1686036862.git.falcon@tinylab.org>
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> most of the library routines share the same code model, let's add two
> helpers to simplify the coding and shrink the code lines too.
> 
> One added for syscall return, one added for syscall call.
> 
> Thomas suggested to use inline function instead of macro for __sysret(),
> and he also helped to simplify the __syscall() a lot.
> 
> Willy suggested to make __sysret() be always inline.
> 
> Suggested-by: Willy Tarreau <w@1wt.eu>
> Link: https://lore.kernel.org/linux-riscv/ZH1+hkhiA2+ItSvX@1wt.eu/
> Suggested-by: Thomas Weißschuh <linux@weissschuh.net>
> Link: https://lore.kernel.org/linux-riscv/ea4e7442-7223-4211-ba29-70821e907888@t-8ch.de/
> Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
> ---
>  tools/include/nolibc/sys.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
> index 5464f93e863e..c12c14db056e 100644
> --- a/tools/include/nolibc/sys.h
> +++ b/tools/include/nolibc/sys.h
> @@ -28,6 +28,18 @@
>  #include "errno.h"
>  #include "types.h"
>  
> +/* Syscall return helper, set errno as -ret when ret < 0 */
> +static inline __attribute__((always_inline)) long __sysret(long ret)

Sorry, the run-user/run targets in tools/testing/selftests/nolibc/Makefile
complains about the above line, seems it doesn't support the 'inline' keyword
and requires '__inline__'.

Just checked my own test script and the run-user / run targets, the only
difference is it forcely uses -std=c89, do we need to align with the kernel
Makefile and use -std=gnu11 instead?

Whatever, I need to change this line to align with the other codes, use
__inline__ as we have used in tools/include/nolibc/stdlib.h:

    diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
    index 0cfc5157845a..48365288a903 100644
    --- a/tools/include/nolibc/sys.h
    +++ b/tools/include/nolibc/sys.h
    @@ -29,7 +29,8 @@
     #include "types.h"
     
     /* Syscall return helper, set errno as -ret when ret < 0 */
    -static inline __attribute__((always_inline)) long __sysret(long ret)
    +static __inline__ __attribute__((unused, always_inline))
    +long __sysret(long ret)
     {
            if (ret < 0) {
                    SET_ERRNO(-ret);

Best regards,
Zhangjin

> +{
> +	if (ret < 0) {
> +		SET_ERRNO(-ret);
> +		ret = -1;
> +	}
> +	return ret;
> +}
> +
> +/* Syscall call helper, use syscall name instead of syscall number */
> +#define __syscall(name, ...) __sysret(sys_##name(__VA_ARGS__))
>  
>  /* Functions in this file only describe syscalls. They're declared static so
>   * that the compiler usually decides to inline them while still being allowed
> -- 
> 2.25.1