]> git.baikalelectronics.ru Git - kernel.git/commit
powerpc: Better scheduling of CR save code in system call path
authorAnton Blanchard <anton@samba.org>
Thu, 5 Apr 2012 03:44:48 +0000 (03:44 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Mon, 30 Apr 2012 05:37:14 +0000 (15:37 +1000)
commitba146e727ee87ec68e53fb1603befbbf1d967b51
treed642ee27a10ca9914a56e10b8990c45087a515b7
parent94fa09fa9dfcf7db7d21fa387a5a47b8e78a8cab
powerpc: Better scheduling of CR save code in system call path

At the moment system call entry looks like:

crclr so
...
mfcr r9
...
std r9,_CCR(r1)

commit b618e143e53f ([POWERPC] system call micro optimisation) put
some space between the crclr and mfcr in order to avoid a stall.

There is still a stall seen between the mfcr and std. We can avoid
the crclr by doing it in a GPR with rlwinm which gives us more room
to better schedule the sequence.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/kernel/entry_64.S