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From: Ingo Molnar <>
To: Thomas Gleixner <>
Cc: Linus Torvalds <>,
	LKML <>,
	john stultz <>,
	Andrew Morton <>,
	Adrian Bunk <>
Subject: Re: [PATCH] i386: Prevent early access to TSC to avoid crash on TSCless systems
Date: Sat, 24 Mar 2007 23:09:45 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <1174773769.10840.450.camel@localhost.localdomain>

* Thomas Gleixner <> wrote:

> commit f9690982b8c2f9a2c65acdc113e758ec356676a3 removed the check for 
> cpu_khz from sched_clock(), which prevented early access to the TSC by 
> non obvious magic.
> This is harmless as long as the CPU has a TSC. On TSCless systems this 
> results in an illegal instruction trap.
> Replace tsc_disabled and tsc_unstable by tsc_enabled, which is only 
> set when the tsc is available and not unstable.
> Signed-off-by: Thomas Gleixner <>

oops, indeed! I think this should also resolve one of the bugs (TSC-less 
Cyrix?) that were reported against -mm some time ago.

Acked-by: Ingo Molnar <>


  reply	other threads:[~2007-03-24 22:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-24 22:02 Thomas Gleixner
2007-03-24 22:09 ` Ingo Molnar [this message]
2007-03-24 22:30 ` Guillaume Chazarain
2007-03-24 22:32   ` Ingo Molnar

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