From: Al Viro <viro@ZenIV.linux.org.uk>
To: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
rth@twiddle.net, linux-kernel@vger.kernel.org
Subject: Re: alpha: potential race around hae_cache in RESTORE_ALL
Date: Mon, 27 Sep 2010 13:12:28 +0100 [thread overview]
Message-ID: <20100927121227.GB19804@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20100927075828.GA15344@jurassic.park.msu.ru>
On Mon, Sep 27, 2010 at 11:58:28AM +0400, Ivan Kokshaysky wrote:
> On Sat, Sep 25, 2010 at 08:25:09PM +0100, Al Viro wrote:
> > BTW, am I right assuming that HAE modifications is UP-only thing? It would
> > be obviously b0rken on any SMP box, since alpha_mv is not per-CPU thing...
>
> The only SMP system that does HAE modifications at runtime is T2, so it has
> a spinlock protection around set_hae() - see core_t2.h. Others are either
> limited to use HAE window 0 only, or do not have HAE hardware at all.
Um? Pardon me, but that makes no sense; how would a spinlock taken in
e.g. readl() stop another process from leaving a syscall, getting to
RESTORE_ALL and overwriting HAE register while we are halfway through
the spinlock-protected area?
next prev parent reply other threads:[~2010-09-27 12:12 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-25 18:13 alpha: potential race around hae_cache in RESTORE_ALL Al Viro
2010-09-25 18:42 ` Linus Torvalds
2010-09-25 19:18 ` Al Viro
2010-09-25 19:25 ` Al Viro
[not found] ` <AANLkTikEVr6wA6D_f2Z6OEFu6SCP_-89u0-k-K-wKgb=@mail.gmail.com>
2010-09-25 21:33 ` Linus Torvalds
2010-09-27 7:58 ` Ivan Kokshaysky
2010-09-27 12:12 ` Al Viro [this message]
2010-09-27 12:46 ` Al Viro
2010-09-27 16:26 ` Ivan Kokshaysky
2010-09-27 17:10 ` Linus Torvalds
2010-09-27 18:05 ` Richard Henderson
2010-09-27 19:01 ` Al Viro
2010-09-27 21:21 ` Ivan Kokshaysky
2010-09-25 20:07 ` [PATCH] alpha: fix hae_cache race " Al Viro
2010-09-25 20:07 ` [PATCH] alpha: fix usp value in multithreaded coredumps Al Viro
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