[SPARC64]: Do not write garbage into %pstate in tsb_context_switch().

For SUN4V, we were clobbering %o5 to do the hypervisor call.
This clobbers the saved %pstate value and we end up writing
garbage into that register as a result.  Oops.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/sparc64/kernel/tsb.S b/arch/sparc64/kernel/tsb.S
index be8f0892d721..7996c9d66702 100644
--- a/arch/sparc64/kernel/tsb.S
+++ b/arch/sparc64/kernel/tsb.S
@@ -265,13 +265,19 @@ __tsb_context_switch:
         mov     SCRATCHPAD_UTSBREG2, %g1
         stxa    %g2, [%g1] ASI_SCRATCHPAD
 
+        /* Save away %o5's %pstate, we have to use %o5 for
+         * the hypervisor call.
+         */
+        mov     %o5, %g1
+
         mov     HV_FAST_MMU_TSB_CTXNON0, %o5
         mov     1, %o0
         mov     %o4, %o1
         ta      HV_FAST_TRAP
 
+        /* Finish up and restore %o5.  */
         ba,pt   %xcc, 9f
-         nop
+         mov    %g1, %o5
 
         /* SUN4U TSB switch.  */
 1:      mov     TSB_REG, %g1