powerpc: Add denormalisation exception handling for POWER6/7
On POWER6 and POWER7 if the input operand to an instruction is a
denormalised single precision binary floating point value we can take
a denormalisation exception where it's expected that the hypervisor
(HV=1) will fix up the inputs before the instruction is run.
This adds code to handle this denormalisation exception for POWER6 and
POWER7.
It also add a CONFIG_PPC_DENORMALISATION option and sets it in
pseries/ppc64_defconfig.
This is useful on bare metal systems only. Based on patch from Milton
Miller.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
index db27c82..e263e6a 100644
--- a/arch/powerpc/configs/ppc64_defconfig
+++ b/arch/powerpc/configs/ppc64_defconfig
@@ -51,6 +51,7 @@
CONFIG_IRQ_ALL_CPUS=y
CONFIG_MEMORY_HOTREMOVE=y
CONFIG_SCHED_SMT=y
+CONFIG_PPC_DENORMALISATION=y
CONFIG_PCCARD=y
CONFIG_ELECTRA_CF=y
CONFIG_HOTPLUG_PCI=m