Re: Fix small race in 44x tlbie function
From: David Gibson <hidden>
Date: 2007-08-09 05:39:30
On Thu, Aug 09, 2007 at 12:28:20AM -0500, Kumar Gala wrote:
On Aug 8, 2007, at 11:00 AM, Josh Boyer wrote:quoted
On Wed, 8 Aug 2007 10:20:45 -0500 Kumar Gala [off-list ref] wrote:quoted
On Aug 6, 2007, at 11:20 PM, David Gibson wrote:quoted
The 440 family of processors don't have a tlbie instruction. So, we implement TLB invalidates by explicitly searching the TLB with tlbsx., then clobbering the relevant entry, if any. Unfortunately the PID for the search needs to be stored in the MMUCR register, which is also used by the TLB miss handler. Interrupts were enabled in _tlbie (), so an interrupt between loading the MMUCR and the tlbsx could cause incorrect search results, and thus a failure to invalide TLB entries which needed to be invalidated. This patch fixes the problem in both arch/ppc and arch/powerpc by inhibiting interrupts (even critical and debug interrupts) across the relevant instructions. Signed-off-by: David Gibson <redacted> --- Paul, this one's a bugfix, which I think should go into 2.6.23.Did you actually see this happen?Yes.When? We don't have critical wired to anything, I don't expect watchdog to cause another fault.. so just wondering.
On debug (trace) interrupts on blue gene. -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson