Date: Wed, 7 Nov 2007 21:20:05 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Paul Mackerras <paulus@samba.org>
Cc: lkml@davidb.org, linux-kernel@vger.kernel.org, drepper@redhat.com,
       mtk-manpages@gmx.net
Subject: Re: compat_sys_times() bogus until jiffies >= 0.
Message-Id: <20071107212005.f039c279.akpm@linux-foundation.org>
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> On Thu, 8 Nov 2007 15:59:12 +1100 Paul Mackerras <paulus@samba.org> wrote:
> Andrew Morton writes:
> 
> > "the latter" is what my protopatch does isn't it?  It wraps at 0x7fffffff.
> > It appears that glibc treats all of 0x80000000-0xffffffff as an error.
> 
> Not on powerpc.  On powerpc the error indication is carried separately
> in a condition register bit.  So a force_successful_syscall_return()
> call will make glibc automatically do the right thing without any
> glibc changes on powerpc.

OK

> Wrapping at 0x7fffffff will cause programs to see large negative
> deltas between successive calls when the wrap occurs.  I can see that
> giving userspace fits. :)
> 

Yup.  But userspace will already have a fit if either the start or end time
advanced into the glibc-thought-that-was-an-error range.

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