1 files changed, 101 insertions, 0 deletions

diff --git a/arch/arm/mm/pgd.c b/arch/arm/mm/pgd.c
new file mode 100644
index 000000000000..20c1b0df75f2
--- /dev/null
+++ b/arch/arm/mm/pgd.c
@@ -0,0 +1,101 @@
+/*
+ *  linux/arch/arm/mm/pgd.c
+ *
+ *  Copyright (C) 1998-2005 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/mm.h>
+#include <linux/highmem.h>
+
+#include <asm/pgalloc.h>
+#include <asm/page.h>
+#include <asm/tlbflush.h>
+
+#include "mm.h"
+
+#define FIRST_KERNEL_PGD_NR     (FIRST_USER_PGD_NR + USER_PTRS_PER_PGD)
+
+/*
+ * need to get a 16k page for level 1
+ */
+pgd_t *get_pgd_slow(struct mm_struct *mm)
+{
+        pgd_t *new_pgd, *init_pgd;
+        pmd_t *new_pmd, *init_pmd;
+        pte_t *new_pte, *init_pte;
+
+        new_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, 2);
+        if (!new_pgd)
+                goto no_pgd;
+
+        memzero(new_pgd, FIRST_KERNEL_PGD_NR * sizeof(pgd_t));
+
+        /*
+         * Copy over the kernel and IO PGD entries
+         */
+        init_pgd = pgd_offset_k(0);
+        memcpy(new_pgd + FIRST_KERNEL_PGD_NR, init_pgd + FIRST_KERNEL_PGD_NR,
+                       (PTRS_PER_PGD - FIRST_KERNEL_PGD_NR) * sizeof(pgd_t));
+
+        clean_dcache_area(new_pgd, PTRS_PER_PGD * sizeof(pgd_t));
+
+        if (!vectors_high()) {
+                /*
+                 * On ARM, first page must always be allocated since it
+                 * contains the machine vectors.
+                 */
+                new_pmd = pmd_alloc(mm, new_pgd, 0);
+                if (!new_pmd)
+                        goto no_pmd;
+
+                new_pte = pte_alloc_map(mm, new_pmd, 0);
+                if (!new_pte)
+                        goto no_pte;
+
+                init_pmd = pmd_offset(init_pgd, 0);
+                init_pte = pte_offset_map_nested(init_pmd, 0);
+                set_pte(new_pte, *init_pte);
+                pte_unmap_nested(init_pte);
+                pte_unmap(new_pte);
+        }
+
+        return new_pgd;
+
+no_pte:
+        pmd_free(new_pmd);
+no_pmd:
+        free_pages((unsigned long)new_pgd, 2);
+no_pgd:
+        return NULL;
+}
+
+void free_pgd_slow(pgd_t *pgd)
+{
+        pmd_t *pmd;
+        struct page *pte;
+
+        if (!pgd)
+                return;
+
+        /* pgd is always present and good */
+        pmd = pmd_off(pgd, 0);
+        if (pmd_none(*pmd))
+                goto free;
+        if (pmd_bad(*pmd)) {
+                pmd_ERROR(*pmd);
+                pmd_clear(pmd);
+                goto free;
+        }
+
+        pte = pmd_page(*pmd);
+        pmd_clear(pmd);
+        dec_zone_page_state(virt_to_page((unsigned long *)pgd), NR_PAGETABLE);
+        pte_lock_deinit(pte);
+        pte_free(pte);
+        pmd_free(pmd);
+free:
+        free_pages((unsigned long) pgd, 2);
+}