When we're not compiling for a specific CPU, ie. none of the
CONFIG_POWERx_CPU options are set, and CONFIG_GENERIC_CPU *is* set, we
currently don't pass any -mcpu option to the compiler. This means the
compiler builds for a "generic" Power CPU.
But back in 2014 we dropped support for pre power4 CPUs in commit
468a33028edd ("powerpc: Drop support for pre-POWER4 cpus").
Given that, there's no point in building the kernel to run on pre power4
cpus. So update the flags we pass to the compiler when
CONFIG_GENERIC_CPU is set, to specify -mcpu=power4.
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
---
arch/powerpc/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 617dece67924..041fda1e2a5d 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -121,6 +121,7 @@ CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 $(MULTIPLEWORD)
ifeq ($(CONFIG_PPC_BOOK3S_64),y)
CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4)
+CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=power4
else
CFLAGS-$(CONFIG_GENERIC_CPU) += -mcpu=powerpc64
endif
--
2.7.4
