powerpc: Add PACA fields specific to 64-bit Book3E processors

This adds various fields in the PACA that are for use specifically
by Book3E processors, such as exception save areas, current pgd
pointer, special exceptions kernel stacks etc...

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index e9962c7..d16b1ea 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -13,6 +13,7 @@
 #include <asm/lppaca.h>
 #include <asm/paca.h>
 #include <asm/sections.h>
+#include <asm/pgtable.h>
 
 /* This symbol is provided by the linker - let it fill in the paca
  * field correctly */
@@ -87,6 +88,8 @@
 
 #ifdef CONFIG_PPC_BOOK3S
 		new_paca->lppaca_ptr = &lppaca[cpu];
+#else
+		new_paca->kernel_pgd = swapper_pg_dir;
 #endif
 		new_paca->lock_token = 0x8000;
 		new_paca->paca_index = cpu;