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 0000000..20c1b0d
--- /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);
+}