From: Adrian Bunk <bunk@stusta.de>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Arjan van de Ven <arjan@infradead.org>,
Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
Richard Henderson <rth@twiddle.net>
Subject: Re: removing bcopy... because it's half broken
Date: Mon, 10 Jan 2005 01:43:13 +0100 [thread overview]
Message-ID: <20050110004313.GB1483@stusta.de> (raw)
In-Reply-To: <Pine.LNX.4.58.0501091213000.2339@ppc970.osdl.org>
On Sun, Jan 09, 2005 at 12:19:09PM -0800, Linus Torvalds wrote:
>
>
> On Sun, 9 Jan 2005, Arjan van de Ven wrote:
> >
> > Instead of fixing this inconsistency, I decided to remove it entirely,
> > explicit memcpy() and memmove() are prefered anyway (welcome to the 1990's)
> > and nothing in the kernel is using these functions, so this saves code size
> > as well for everyone.
>
> The problem is that at least some gcc versions would historically generate
> calls to "bcopy" on alpha for structure assignments. Maybe it doesn't any
> more, and no such old gcc versions exist any more, but who knows?
>...
include/asm-alpha/string.h says:
/*
* GCC of any recent vintage doesn't do stupid things with bcopy.
* EGCS 1.1 knows all about expanding memcpy inline, others don't.
*
* Similarly for a memset with data = 0.
*/
And Arjan's patch is pretty low-risk:
If it breaks on any architecture with any supported compiler (>= 2.95),
it will break at compile time and there will pretty fast be reports of
this breakage in which case it would be easy to revert his patch.
> Linus
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
next prev parent reply other threads:[~2005-01-10 0:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-09 19:23 removing bcopy... because it's half broken Arjan van de Ven
2005-01-09 19:39 ` Ralf Baechle
2005-01-09 20:03 ` Russell King
2005-01-09 20:19 ` Linus Torvalds
2005-01-09 20:33 ` Arjan van de Ven
2005-01-09 20:34 ` Christoph Hellwig
2005-01-09 20:42 ` Linus Torvalds
2005-01-11 10:10 ` Bastian Blank
2005-01-11 10:32 ` Arjan van de Ven
2005-01-11 16:10 ` Linus Torvalds
2005-01-09 23:38 ` Richard Henderson
2005-01-10 0:43 ` Adrian Bunk [this message]
2005-01-10 16:55 ` Matthias-Christian Ott
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