linux-kernel - RE: [PATCH v2 4/4] tools/nolibc: sys.h: apply _

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Message-ID: <0295105fe0744200bf2ef99e5bf7bc09@AcuMS.aculab.com>
Date:   Sat, 10 Jun 2023 16:34:16 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Zhangjin Wu' <falcon@...ylab.org>, "w@....eu" <w@....eu>
CC:     "arnd@...db.de" <arnd@...db.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
        "linux-riscv@...ts.infradead.org" <linux-riscv@...ts.infradead.org>,
        "thomas@...ch.de" <thomas@...ch.de>
Subject: RE: [PATCH v2 4/4] tools/nolibc: sys.h: apply __syscall() helper

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

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