powerpc/64s: masked_interrupt() returns to kernel so avoid restoring r13

Places in the kernel where r13 is not the PACA pointer must have
maskable interrupts disabled, so r13 does not have to be restored when
returning from a soft-masked interrupt. We should never have
interrupts soft disabled when we're in user space.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 2cc5e9d4c907e963465d3c6cafb4f048f624d748..6a6d4d9208272733432cf8a9e873770ac8ff76ed 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1379,7 +1379,7 @@ masked_##_H##interrupt:                                   \
        ld      r9,PACA_EXGEN+EX_R9(r13);               \
        ld      r10,PACA_EXGEN+EX_R10(r13);             \
        ld      r11,PACA_EXGEN+EX_R11(r13);             \
-       GET_SCRATCH0(r13);                              \
+       /* returns to kernel where r13 must be set up, so don't restore it */ \
        ##_H##rfid;                                     \
        b       .;                                      \
        MASKED_DEC_HANDLER(_H)