On Thu, Aug 18, 2016 at 06:52:47PM +0200, Christophe Leroy wrote:

Le 18/08/2016 à 18:34, Segher Boessenkool a écrit :

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On Thu, Aug 18, 2016 at 05:56:02PM +0200, Christophe Leroy wrote:

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The 8xx has two special registers called EID (External Interrupt
Disable) and EIE (External Interrupt Enable) for clearing/setting
EE in MSR. It avoids the three instructions set mfmsr/ori/mtmsr or
mfmsr/rlwinm/mtmsr.

All 8xx?  What other models?  (5xx for example).

At least 823, 860, 866 and 885 have it.

I haven't been able to find a manual for all 8xx.  But there is AN2055,
which suggests EIE etc. is for all 8xx indeed.

Looks like the 5xx have it too (at least the 565). Does Linux supports 
that one at all ?

All 5xx have it, there is a manual for *that* ("RCPU") :-)

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+/* Special MSR manipulation registers */
+#define SPRN_EIE	80	/* External interrupt enable (EE=1, RI=1) */
+#define SPRN_EID	81	/* External interrupt disable (EE=0, RI=1) */
+#define SPRN_NRI	81	/* Non Recoverable interrupt (EE=0, RI=0) */

Is it correct to set RI in all places you do now?

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This is wrong (NRI is 82).  Don't write code you cannot test / don't submit
code you haven't tested?  :-)

Oops. You're right, copy/paste failure.
Was tested on an 885. Unfortunatly SPRN_NRI is not used (yet) :-(

Well, that was my point!


Segher