Explicitly disable generation of Altivec instructions in the kernel on PowerPC,

and add support to allow users to set their CPUTYPE in make.conf.

share/mk/bsd.cpu.mk

@@ -118,6 +118,8 @@ _CPUCFLAGS = -mcpu=${CPUTYPE}
 .  if ${CPUTYPE} == "e500"
 MACHINE_CPU = booke
 _CPUCFLAGS = -Wa,-me500 -msoft-float
+.  else
+_CPUCFLAGS = -mcpu=${CPUTYPE}
 .  endif
 . elif ${MACHINE_ARCH} == "mips"
 .  if ${CPUTYPE} == "mips32"

sys/conf/kern.mk

@@ -78,9 +78,10 @@ INLINE_LIMIT?=	8000
 #
 # For PowerPC we tell gcc to use floating point emulation.  This avoids using
 # floating point registers for integer operations which it has a tendency to do.
+# Also explicitly disable Altivec instructions inside the kernel.
 #
 .if ${MACHINE_ARCH} == "powerpc"
-CFLAGS+=	-msoft-float
+CFLAGS+=	-msoft-float -mno-altivec
 INLINE_LIMIT?=	15000
 .endif