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powerpc: Only disable HAVE_EFFICIENT_UNALIGNED_ACCESS on POWER7 little endian

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POWER8 handles unaligned accesses in little endian mode, but commit
0b5e6661ac ("powerpc: Don't set HAVE_EFFICIENT_UNALIGNED_ACCESS on
little endian builds") disabled it for all.

The issue with unaligned little endian accesses is specific to POWER7,
so update the Kconfig check to match. Using the stat() testcase from
commit a75c380c71 ("powerpc: Enable DCACHE_WORD_ACCESS on ppc64le"),
performance improves 15% on POWER8.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Anton Blanchard 2016-09-25 22:35:40 +10:00 committed by Michael Ellerman
parent 61e98ebff3
commit 8a18cc0c2c
1 changed files with 1 additions and 1 deletions
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arch/powerpc/Kconfig
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@ -96,7 +96,7 @@ config PPC
select VIRT_TO_BUS if !PPC64
select HAVE_IDE
select HAVE_IOREMAP_PROT
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_LITTLE_ENDIAN
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !(CPU_LITTLE_ENDIAN && POWER7_CPU)
select HAVE_KPROBES
select HAVE_ARCH_KGDB
select HAVE_KRETPROBES