From: Arjan van de Ven <arjan@infradead.org>
To: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@osdl.org>,
akpm@osdl.org, Andi Kleen <ak@suse.de>,
linux-kernel@vger.kernel.org, discuss@x86-64.org
Subject: Re: [discuss] Re: [PATCH] [3/4] i386: Fix overflow in e820_all_mapped
Date: Fri, 28 Apr 2006 09:34:02 +0200 [thread overview]
Message-ID: <1146209643.3126.7.camel@laptopd505.fenrus.org> (raw)
In-Reply-To: <4451DB47.76E4.0078.0@novell.com>
On Fri, 2006-04-28 at 09:07 +0200, Jan Beulich wrote:
> >>> Linus Torvalds <torvalds@osdl.org> 28.04.06 07:39 >>>
> >
> >
> >On Fri, 28 Apr 2006, Andi Kleen wrote:
> >>
> >> The 32bit version of e820_all_mapped() needs to use u64 to avoid
> >> overflows on PAE systems. Pointed out by Jan Beulich
> >
> >I don't think that's true.
> >
> >It can't be called with 64-bit arguments anyway. If the base address
> >doesn't fit in 32-bit, we'd be screwed in other places, afaik.
>
> The arguments don't necessarily need to be u64, but (at least some of)
> the calculations inside the function do. Otherwise, a region starting
> below 4G and extending to or beyond 4G would not be considered
> correctly.
since this is use-once __init code I rather keep it simple and safe (eg
use u64) than do complex tricks to make it safe in another way.. and the
4G thing is a real potential problem that's easily fixed with the u64
thing.
prev parent reply other threads:[~2006-04-28 7:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-28 5:28 Andi Kleen
2006-04-28 5:39 ` Linus Torvalds
2006-04-28 6:08 ` Andi Kleen
2006-04-28 14:52 ` Linus Torvalds
2006-04-28 7:07 ` [discuss] " Jan Beulich
2006-04-28 7:34 ` Arjan van de Ven [this message]
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