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Re: Preemption in do_cpu

Subject: Re: Preemption in do_cpu
From: Atsushi Nemoto <>
Date: Tue, 19 Apr 2005 10:24:37 +0900 (JST)
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <>
>>>>> On Mon, 18 Apr 2005 14:20:21 -0700, Jun Sun <> said:
jsun> fpu_emulator maintains global variables and in general is
jsun> dangerous to be preempted in the middle of processing.

jsun> The quick fix for this problem is probably to move preemption
jsun> disabling/ enabling inside fpu_emulator_cop1Handler().

Also, get_user/put_user should not be used with preempt disabled.

Here is Quick and dirty workaround (including some other preemption fixes):

jsun> Better fix is probably to modify fpu emulator so that it is
jsun> preemption safe overall.

Sure.  It will make fpu emulator SMP safe also.

Atsushi Nemoto

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