powerpc/64: Optimise set/clear of CTRL[RUN] (runlatch)

Browse source

On modern CPUs the CTRL register is read-only except bit 63 which is
the run latch control. This means it can be updated with a mtspr
rather than mfspr/mtspr.

To accomodate older CPUs (Cell at least), where there are other bits
in the register, we still do a read/modify/write on pre 2.06 CPUs.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Update change log to mention 2.06 workaround]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

...

This commit is contained in:

Nicholas Piggin 2017-08-12 02:39:07 +10:00 • committed by Michael Ellerman

parent 7b76a1f5ed

commit d1d0d5ffb3

1 changed files with 27 additions and 8 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

35

arch/powerpc/kernel/process.c

View file