[SPARC64]: Sanitize %pstate writes for sun4v.

If we're just switching between different alternate global
sets, nop it out on sun4v.  Also, get rid of all of the
alternate global save/restore in the OBP CIF trampoline code.

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

1 files changed, 10 insertions, 2 deletions

diff --git a/arch/sparc64/kernel/tsb.S b/arch/sparc64/kernel/tsb.S
index 3b45db98005a..96e63168d8b2 100644
--- a/arch/sparc64/kernel/tsb.S
+++ b/arch/sparc64/kernel/tsb.S
@@ -82,9 +82,17 @@ tsb_itlb_load:
         .globl          tsb_do_fault
 tsb_do_fault:
         cmp             %g3, FAULT_CODE_DTLB
-        rdpr            %pstate, %g5
+
+661:    rdpr            %pstate, %g5
+        wrpr            %g5, PSTATE_AG | PSTATE_MG, %pstate
+        .section        .gl_2insn_patch, "ax"
+        .word           661b
+        nop
+        nop
+        .previous
+
         bne,pn          %xcc, tsb_do_itlb_fault
-         wrpr           %g5, PSTATE_AG | PSTATE_MG, %pstate
+         nop
 
 tsb_do_dtlb_fault:
         rdpr    %tl, %g4