From: David Laight <David.Laight@ACULAB.COM>
To: 'Zhangjin Wu' <falcon@tinylab.org>,
"thomas@t-8ch.de" <thomas@t-8ch.de>, "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 Weißschuh" <linux@weissschuh.net>
Subject: RE: [PATCH v2 1/4] tools/nolibc: sys.h: add __syscall() and __sysret() helpers
Date: Thu, 8 Jun 2023 14:35:49 +0000 [thread overview]
Message-ID: <94dd5170929f454fbc0a10a2eb3b108d@AcuMS.aculab.com> (raw)
In-Reply-To: <a42fb9e1bbe0daf7d8a48ea8f44135ef851030d7.1686036862.git.falcon@tinylab.org>
From: Zhangjin Wu
> Sent: 06 June 2023 09:10
>
> 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.
>
...
> +/* Syscall return helper, set errno as -ret when ret < 0 */
> +static inline __attribute__((always_inline)) long __sysret(long ret)
> +{
> + if (ret < 0) {
> + SET_ERRNO(-ret);
> + ret = -1;
> + }
> + return ret;
> +}
If that right?
I thought that that only the first few (1024?) negative values
got used as errno values.
Do all Linux architectures even use negatives for error?
I thought at least some used the carry flag.
(It is the historic method of indicating a system call failure.)
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
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next prev parent reply other threads:[~2023-06-08 14:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-06 8:08 [PATCH v2 0/4] tools/nolibc: add two new syscall helpers Zhangjin Wu
2023-06-06 8:09 ` [PATCH v2 1/4] tools/nolibc: sys.h: add __syscall() and __sysret() helpers Zhangjin Wu
2023-06-06 10:33 ` Zhangjin Wu
2023-06-08 14:35 ` David Laight [this message]
2023-06-08 16:06 ` Thomas Weißschuh
2023-06-09 4:42 ` Zhangjin Wu
2023-06-09 9:15 ` David Laight
2023-06-06 8:11 ` [PATCH v2 2/4] tools/nolibc: unistd.h: apply __sysret() helper Zhangjin Wu
2023-06-06 8:16 ` [PATCH v2 3/4] tools/nolibc: sys.h: " Zhangjin Wu
2023-06-06 8:17 ` [PATCH v2 4/4] tools/nolibc: sys.h: apply __syscall() helper Zhangjin Wu
2023-06-06 18:36 ` Thomas Weißschuh
2023-06-07 0:34 ` Zhangjin Wu
2023-06-07 4:05 ` Willy Tarreau
2023-06-07 5:39 ` Zhangjin Wu
2023-06-07 6:05 ` Thomas Weißschuh
2023-06-07 6:38 ` Zhangjin Wu
2023-06-10 16:34 ` David Laight
2023-06-10 16:58 ` David Laight
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