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-rw-r--r--arch/nios2/mm/pgtable.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/arch/nios2/mm/pgtable.c b/arch/nios2/mm/pgtable.c
new file mode 100644
index 000000000000..61e24a25f71a
--- /dev/null
+++ b/arch/nios2/mm/pgtable.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2009 Wind River Systems Inc
+ * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/mm.h>
+#include <linux/sched.h>
+
+#include <asm/pgtable.h>
+#include <asm/cpuinfo.h>
+
+/* pteaddr:
+ * ptbase | vpn* | zero
+ * 31-22 | 21-2 | 1-0
+ *
+ * *vpn is preserved on double fault
+ *
+ * tlbacc:
+ * IG |*flags| pfn
+ * 31-25|24-20 | 19-0
+ *
+ * *crwxg
+ *
+ * tlbmisc:
+ * resv |way |rd | we|pid |dbl|bad|perm|d
+ * 31-24 |23-20 |19 | 20|17-4|3 |2 |1 |0
+ *
+ */
+
+/*
+ * Initialize a new pgd / pmd table with invalid pointers.
+ */
+static void pgd_init(pgd_t *pgd)
+{
+ unsigned long *p = (unsigned long *) pgd;
+ int i;
+
+ for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
+ p[i + 0] = (unsigned long) invalid_pte_table;
+ p[i + 1] = (unsigned long) invalid_pte_table;
+ p[i + 2] = (unsigned long) invalid_pte_table;
+ p[i + 3] = (unsigned long) invalid_pte_table;
+ p[i + 4] = (unsigned long) invalid_pte_table;
+ p[i + 5] = (unsigned long) invalid_pte_table;
+ p[i + 6] = (unsigned long) invalid_pte_table;
+ p[i + 7] = (unsigned long) invalid_pte_table;
+ }
+}
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *ret, *init;
+
+ ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_ORDER);
+ if (ret) {
+ init = pgd_offset(&init_mm, 0UL);
+ pgd_init(ret);
+ memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
+ (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+ }
+
+ return ret;
+}
+
+void __init pagetable_init(void)
+{
+ /* Initialize the entire pgd. */
+ pgd_init(swapper_pg_dir);
+ pgd_init(swapper_pg_dir + USER_PTRS_PER_PGD);
+}

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