[POWERPC] add Kconfig option for optimizing for cell

Since the PPE on cell is an in-order core, it suffers significantly
from wrong instruction scheduling.  This adds a Kconfig option that
enables passing -mtune=cell to gcc in order to generate object
code that runs well on cell.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 6015a92bc2a0..87aff5372d6e 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -92,6 +92,10 @@ else
 endif
 endif
 
+ifeq ($(CONFIG_TUNE_CELL),y)
+        CFLAGS += $(call cc-option,-mtune=cell)
+endif
+
 # No AltiVec instruction when building kernel
 CFLAGS += $(call cc-option,-mno-altivec)