unicore32 core architecture: mm related: fault handling
This patch implements fault handling of memory management.
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/unicore32/mm/pgd.c b/arch/unicore32/mm/pgd.c
new file mode 100644
index 0000000..632cef7
--- /dev/null
+++ b/arch/unicore32/mm/pgd.c
@@ -0,0 +1,102 @@
+/*
+ * linux/arch/unicore32/mm/pgd.c
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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/gfp.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 4k 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, 0);
+ if (!new_pgd)
+ goto no_pgd;
+
+ memset(new_pgd, 0, 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 UniCore, first page must always be allocated since it
+ * contains the machine vectors.
+ */
+ new_pmd = pmd_alloc(mm, (pud_t *)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((pud_t *)init_pgd, 0);
+ init_pte = pte_offset_map(init_pmd, 0);
+ set_pte(new_pte, *init_pte);
+ pte_unmap(init_pte);
+ pte_unmap(new_pte);
+ }
+
+ return new_pgd;
+
+no_pte:
+ pmd_free(mm, new_pmd);
+no_pmd:
+ free_pages((unsigned long)new_pgd, 0);
+no_pgd:
+ return NULL;
+}
+
+void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd)
+{
+ pmd_t *pmd;
+ pgtable_t 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_pgtable(*pmd);
+ pmd_clear(pmd);
+ pte_free(mm, pte);
+ pmd_free(mm, pmd);
+free:
+ free_pages((unsigned long) pgd, 0);
+}