ppc64: Make hash_preload() and update_mmu_cache() cope with hugepages

[David Gibson]

Paulus, please apply.

At present, hash_preload() (and hence update_mmu_cache()) will not
work correctly if called on a hugepage address, thus relying on the
fact that the hugepage fault paths never call update_mmu_cache().  I'm
not 100% sure that's safe now (although I think it is), and it
certainly won't be safe for some of the places we want to go with
hugepage.

Thus, this patch extends hash_preload() to work correctly on hugepage
addresses.

Signed-off-by: David Gibson <dwg at au1.ibm.com>

Index: working-2.6/arch/powerpc/mm/hash_utils_64.c
===================================================================
--- working-2.6.orig/arch/powerpc/mm/hash_utils_64.c	2005-11-08 11:11:29.000000000 +1100
+++ working-2.6/arch/powerpc/mm/hash_utils_64.c	2005-11-08 12:14:09.000000000 +1100
@@ -638,6 +638,7 @@
 	cpumask_t mask;
 	unsigned long flags;
 	int local = 0;
+	int huge = in_hugepage_area(mm->context, ea);
 
 	/* We don't want huge pages prefaulted for now
 	 */
@@ -651,9 +652,11 @@
 	pgdir = mm->pgd;
 	if (pgdir == NULL)
 		return;
-	ptep = find_linux_pte(pgdir, ea);
-	if (!ptep)
-		return;
+	if (likely(!huge)) {
+		ptep = find_linux_pte(pgdir, ea);
+		if (!ptep)
+			return;
+	}
 	vsid = get_vsid(mm->context.id, ea);
 
 	/* Hash it in */
@@ -661,6 +664,9 @@
 	mask = cpumask_of_cpu(smp_processor_id());
 	if (cpus_equal(mm->cpu_vm_mask, mask))
 		local = 1;
+	if (unlikely(huge))
+		hash_huge_page(mm, access, ea, vsid, local);
+	else
 #ifndef CONFIG_PPC_64K_PAGES
 	__hash_page_4K(ea, access, vsid, ptep, trap, local);
 #else


-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson