From: Willy Tarreau <w@1wt.eu>
To: Ingo Molnar <mingo@elte.hu>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
torvalds@linux-foundation.org
Subject: Re: Looks broken to me: x86, cyrix: debug
Date: Sun, 12 Oct 2008 00:48:16 +0200 [thread overview]
Message-ID: <20081011224816.GL24654@1wt.eu> (raw)
In-Reply-To: <20081011205858.GA21965@elte.hu>
On Sat, Oct 11, 2008 at 10:58:58PM +0200, Ingo Molnar wrote:
>
> * Maciej W. Rozycki <macro@linux-mips.org> wrote:
>
> > On Sat, 11 Oct 2008, Alan Cox wrote:
> >
> > > > +#define getCx86_old(reg) ({ outb((reg), 0x22); inb(0x23); })
> > >
> > > Doesn't expand to any kind of returned value.
> >
> > Well, actually it returns the value of the inb() expression -- cf the
> > semantics of compound statements. The rest looks suspicious indeed.
>
> indeed it's broken - will sort it out. It's all about breakage that has
> been in this code since v2.6.20, see c6744955d0. Will likely revert the
> whole thing.
In fact the whole commit looks buggy to me as it simply reintroduces the
old bug at several places. The correct way of accessing the registers is
precisely through the inline functions and never through a macro due to
the ordering problem.
Willy
next prev parent reply other threads:[~2008-10-11 22:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200810112003.m9BK3Wwu025556@hera.kernel.org>
2008-10-11 20:40 ` Looks broken to me: x86, cyrix: debug Alan Cox
2008-10-11 20:52 ` Maciej W. Rozycki
2008-10-11 20:58 ` Ingo Molnar
2008-10-11 22:48 ` Willy Tarreau [this message]
2008-10-11 22:55 ` Maciej W. Rozycki
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