Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   David Laight <David.Laight@ACULAB.COM>
To:     'Zhangjin Wu' <falcon@tinylab.org>, "w@1wt.eu" <w@1wt.eu>
CC:     "arnd@arndb.de" <arnd@arndb.de>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-kselftest@vger.kernel.org" <linux-kselftest@vger.kernel.org>,
        "linux-riscv@lists.infradead.org" <linux-riscv@lists.infradead.org>,
        "thomas@t-8ch.de" <thomas@t-8ch.de>
Subject: RE: [PATCH v2 4/4] tools/nolibc: sys.h: apply __syscall() helper
Thread-Topic: [PATCH v2 4/4] tools/nolibc: sys.h: apply __syscall() helper
Thread-Index: AQHZmQJ1YTdtMnXhOkqSBnIhvL9uWq+EPW+g
Date:   Sat, 10 Jun 2023 16:34:16 +0000
Message-ID: <0295105fe0744200bf2ef99e5bf7bc09@AcuMS.aculab.com>
References: <ZIAB7bFYegCuXT9g@1wt.eu>
 <20230607053920.667272-1-falcon@tinylab.org>
In-Reply-To: <20230607053920.667272-1-falcon@tinylab.org>
Accept-Language: en-GB, en-US
MIME-Version: 1.0
Content-Language: en-US
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8BIT
Precedence: bulk

From: Zhangjin Wu
> Sent: 07 June 2023 06:39
...
> As a summary, will use 'sysret()' and something like:
> 
>    static __attribute__((unused))
>    int chdir(const char *path)
>    {
>    	return sysret(chdir(path));
>    }
> 
> to renew the syscall helper patchset, Thanks you very much.

While I'm all for using 'cpp-magic' to abstract and (hopefully)
simplify things. Token-pasting the sys_ here doesn't seem to gain
anything.
Anyone grepping the code for 'sys_chdir' is also going to
wonder where it is used.

There might be scope for something like:
#define syscall_wrapper(func, type) \
	static __attribute__((unused)) \
	int func(type *arg) \
	{ \
		return sysret(sys_#func(arg)); \
	}
and then:
syscall_wrapper(chdir, const char *)
would expand to the code above.

I think you'd need separate defines for each number of arguments.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)