powerpc/mpic: Remove WHOAMI readback after EOI
authorBogdan Purcareata <bogdan.purcareata@freescale.com>
Tue, 24 Mar 2015 10:43:43 +0000 (10:43 +0000)
committerScott Wood <scottwood@freescale.com>
Wed, 1 Apr 2015 03:23:20 +0000 (22:23 -0500)
commit56302c53d3dc477b8360954fc92c1dfc4fc0ec54
treeefdd635d93e59a6bc82b66515f0640295e56aa56
parent88b7936da39618be04a6e1c2fb052dc528633392
powerpc/mpic: Remove WHOAMI readback after EOI

After previous discussions regarding the subject [1][2], there's no clear
explanation or reason why the call was needed in the first place. The sensible
argument is some sort of synchronization between the CPU and the MPIC, which
hasn't been pointed out precisely and is no longer required (at least on BookE
platforms).

The benefit of this change is saving a MMIO trap per interrupt when running in a
KVM guest.

[1] https://patchwork.ozlabs.org/patch/429098/
[2] https://patchwork.ozlabs.org/patch/433557/

Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
arch/powerpc/sysdev/mpic.c