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Message-ID: <4F453086.8030602@zytor.com>
Date: Wed, 22 Feb 2012 10:14:30 -0800
From: "H. Peter Anvin" <hpa@...or.com>
To: Arnd Bergmann <arnd@...db.de>
CC: Linus Torvalds <torvalds@...ux-foundation.org>,
linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
mingo@...nel.org, tglx@...utronix.de, akpm@...ux-foundation.org,
hjl.tools@...il.com
Subject: Re: [PATCH 02/30] x86-64: Use explicit sizes in sigcontext.h, prepare
for x32
On 02/22/2012 04:22 AM, Arnd Bergmann wrote:
> On Monday 20 February 2012, H. Peter Anvin wrote:
>> We are using __u64 as x86-32 compatible since we are sharing most of the
>> really complex path (like ioctl) with i386 much more so than x86-64. So
>> it is defined in userspace as:
>>
>> typedef unsigned long long __u64 __attribute__((aligned(4)));
>>
>> __aligned_u64 obviously is naturally aligned, which matches uint64_t is
>> userspace.
>
> Has someone audited the interfaces to check if there are data structures that
> use a plain signed or unsigned "long long" instead of __s64/__u64 in places
> where i386 differs from the other compat implementations?
>
> I found DRM_IOCTL_UPDATE_DRAW, but there could be more like this one.
>
Has someone audited every single ioctl in the kernel? Definitely not,
which is why x32 is marked EXPERIMENTAL. I think it is still time for
this work to switch to happening in the upstream, however.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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