powerpc: Restore VDSO information on critical exception om BookE

Critical exception on 64-bit booke uses user-visible SPRG3 as scratch.
Restore VDSO information in SPRG3 on exception prolog.

Use a common sprg3 field in PACA for all powerpc64 architectures.

Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index daf813fea91f..7796519fd238 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -136,6 +136,7 @@ struct paca_struct {
         u8 io_sync;                     /* writel() needs spin_unlock sync */
         u8 irq_work_pending;            /* IRQ_WORK interrupt while soft-disable */
         u8 nap_state_lost;              /* NV GPR values lost in power7_idle */
+        u64 sprg3;                      /* Saved user-visible sprg */
 
 #ifdef CONFIG_PPC_POWERNV
         /* Pointer to OPAL machine check event structure set by the