1 files changed, 55 insertions, 21 deletions

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 335c578b9cc..776f28d02b6 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -41,6 +41,7 @@
 #include <linux/module.h>
 #include <linux/poison.h>
 #include <linux/lmb.h>
+#include <linux/hugetlb.h>
 
 #include <asm/pgalloc.h>
 #include <asm/page.h>
@@ -119,30 +120,63 @@ static void pmd_ctor(void *addr)
         memset(addr, 0, PMD_TABLE_SIZE);
 }
 
-static const unsigned int pgtable_cache_size[2] = {
-        PGD_TABLE_SIZE, PMD_TABLE_SIZE
-};
-static const char *pgtable_cache_name[ARRAY_SIZE(pgtable_cache_size)] = {
-#ifdef CONFIG_PPC_64K_PAGES
-        "pgd_cache", "pmd_cache",
-#else
-        "pgd_cache", "pud_pmd_cache",
-#endif /* CONFIG_PPC_64K_PAGES */
-};
-
-#ifdef CONFIG_HUGETLB_PAGE
-/* Hugepages need an extra cache per hugepagesize, initialized in
- * hugetlbpage.c.  We can't put into the tables above, because HPAGE_SHIFT
- * is not compile time constant. */
-struct kmem_cache *pgtable_cache[ARRAY_SIZE(pgtable_cache_size)+MMU_PAGE_COUNT];
-#else
-struct kmem_cache *pgtable_cache[ARRAY_SIZE(pgtable_cache_size)];
-#endif
+struct kmem_cache *pgtable_cache[MAX_PGTABLE_INDEX_SIZE];
+
+/*
+ * Create a kmem_cache() for pagetables.  This is not used for PTE
+ * pages - they're linked to struct page, come from the normal free
+ * pages pool and have a different entry size (see real_pte_t) to
+ * everything else.  Caches created by this function are used for all
+ * the higher level pagetables, and for hugepage pagetables.
+ */
+void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
+{
+        char *name;
+        unsigned long table_size = sizeof(void *) << shift;
+        unsigned long align = table_size;
+
+        /* When batching pgtable pointers for RCU freeing, we store
+         * the index size in the low bits.  Table alignment must be
+         * big enough to fit it.
+         *
+         * Likewise, hugeapge pagetable pointers contain a (different)
+         * shift value in the low bits.  All tables must be aligned so
+         * as to leave enough 0 bits in the address to contain it. */
+        unsigned long minalign = max(MAX_PGTABLE_INDEX_SIZE + 1,
+                                     HUGEPD_SHIFT_MASK + 1);
+        struct kmem_cache *new;
+
+        /* It would be nice if this was a BUILD_BUG_ON(), but at the
+         * moment, gcc doesn't seem to recognize is_power_of_2 as a
+         * constant expression, so so much for that. */
+        BUG_ON(!is_power_of_2(minalign));
+        BUG_ON((shift < 1) || (shift > MAX_PGTABLE_INDEX_SIZE));
+
+        if (PGT_CACHE(shift))
+                return; /* Already have a cache of this size */
+
+        align = max_t(unsigned long, align, minalign);
+        name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
+        new = kmem_cache_create(name, table_size, align, 0, ctor);
+        PGT_CACHE(shift) = new;
+
+        pr_debug("Allocated pgtable cache for order %d\n", shift);
+}
+
 
 void pgtable_cache_init(void)
 {
-        pgtable_cache[0] = kmem_cache_create(pgtable_cache_name[0], PGD_TABLE_SIZE, PGD_TABLE_SIZE, SLAB_PANIC, pgd_ctor);
-        pgtable_cache[1] = kmem_cache_create(pgtable_cache_name[1], PMD_TABLE_SIZE, PMD_TABLE_SIZE, SLAB_PANIC, pmd_ctor);
+        pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
+        pgtable_cache_add(PMD_INDEX_SIZE, pmd_ctor);
+        if (!PGT_CACHE(PGD_INDEX_SIZE) || !PGT_CACHE(PMD_INDEX_SIZE))
+                panic("Couldn't allocate pgtable caches");
+
+        /* In all current configs, when the PUD index exists it's the
+         * same size as either the pgd or pmd index.  Verify that the
+         * initialization above has also created a PUD cache.  This
+         * will need re-examiniation if we add new possibilities for
+         * the pagetable layout. */
+        BUG_ON(PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE));
 }
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP