POWERPC: Allow 32-bit hashed pgtable code to support 36-bit physical

This rearranges a bit of code, and adds support for
36-bit physical addressing for configs that use a
hashed page table.  The 36b physical support is not
enabled by default on any config - it must be
explicitly enabled via the config system.

This patch *only* expands the page table code to accomodate
large physical addresses on 32-bit systems and enables the
PHYS_64BIT config option for 86xx.  It does *not*
allow you to boot a board with more than about 3.5GB of
RAM - for that, SWIOTLB support is also required (and
coming soon).

Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/kernel/asm-offsets.c

@@ -352,6 +352,7 @@ int main(void)
 #endif
 
 	DEFINE(PGD_TABLE_SIZE, PGD_TABLE_SIZE);
+	DEFINE(PTE_SIZE, sizeof(pte_t));
 
 #ifdef CONFIG_KVM
 	DEFINE(TLBE_BYTES, sizeof(struct tlbe));

arch/powerpc/kernel/head_32.S

@@ -369,13 +369,13 @@ i##n:								\
 DataAccess:
 	EXCEPTION_PROLOG
 	mfspr	r10,SPRN_DSISR
+	stw	r10,_DSISR(r11)
 	andis.	r0,r10,0xa470		/* weird error? */
 	bne	1f			/* if not, try to put a PTE */
 	mfspr	r4,SPRN_DAR		/* into the hash table */
 	rlwinm	r3,r10,32-15,21,21	/* DSISR_STORE -> _PAGE_RW */
 	bl	hash_page
-1:	stw	r10,_DSISR(r11)
-	mr	r5,r10
+1:	lwz	r5,_DSISR(r11)		/* get DSISR value */
 	mfspr	r4,SPRN_DAR
 	EXC_XFER_EE_LITE(0x300, handle_page_fault)
 

arch/powerpc/kernel/head_fsl_booke.S

@@ -422,7 +422,6 @@ skpinv:	addi	r6,r6,1				/* Increment */
  *   r12 is pointer to the pte
  */
 #ifdef CONFIG_PTE_64BIT
-#define PTE_FLAGS_OFFSET	4
 #define FIND_PTE	\
 	rlwinm	r12, r10, 13, 19, 29;	/* Compute pgdir/pmd offset */	\
 	lwzx	r11, r12, r11;		/* Get pgd/pmd entry */		\
@@ -431,7 +430,6 @@ skpinv:	addi	r6,r6,1				/* Increment */
 	rlwimi	r12, r10, 23, 20, 28;	/* Compute pte address */	\
 	lwz	r11, 4(r12);		/* Get pte entry */
 #else
-#define PTE_FLAGS_OFFSET	0
 #define FIND_PTE	\
 	rlwimi	r11, r10, 12, 20, 29;	/* Create L1 (pgdir/pmd) address */	\
 	lwz	r11, 0(r11);		/* Get L1 entry */			\