powerpc: Create disable_kernel_{fp,altivec,vsx,spe}()

The enable_kernel_*() functions leave the relevant MSR bits enabled
until we exit the kernel sometime later. Create disable versions
that wrap the kernel use of FP, Altivec VSX or SPE.

While we don't want to disable it normally for performance reasons
(MSR writes are slow), it will be used for a debug boot option that
does this and catches bad uses in other areas of the kernel.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/powerpc/lib/vmx-helper.c b/arch/powerpc/lib/vmx-helper.c
index ac93a3bd2730..b27e030fc9f8 100644
--- a/arch/powerpc/lib/vmx-helper.c
+++ b/arch/powerpc/lib/vmx-helper.c
@@ -46,6 +46,7 @@ int enter_vmx_usercopy(void)
  */
 int exit_vmx_usercopy(void)
 {
+	disable_kernel_altivec();
 	pagefault_enable();
 	preempt_enable();
 	return 0;
@@ -70,6 +71,7 @@ int enter_vmx_copy(void)
  */
 void *exit_vmx_copy(void *dest)
 {
+	disable_kernel_altivec();
 	preempt_enable();
 	return dest;
 }