1 files changed, 96 insertions, 0 deletions
diff --git a/arch/nds32/mm/mm-nds32.c b/arch/nds32/mm/mm-nds32.c
new file mode 100644
index 000000000..55bec50cc
--- /dev/null
+++ b/arch/nds32/mm/mm-nds32.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/init_task.h>
+
+#define __HAVE_ARCH_PGD_FREE
+#include <asm/pgalloc.h>
+
+#define FIRST_KERNEL_PGD_NR	(USER_PTRS_PER_PGD)
+
+/*
+ * need to get a page for level 1
+ */
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	pgd_t *new_pgd, *init_pgd;
+	int i;
+
+	new_pgd = (pgd_t *) __get_free_pages(GFP_KERNEL, 0);
+	if (!new_pgd)
+		return NULL;
+	for (i = 0; i < PTRS_PER_PGD; i++) {
+		(*new_pgd) = 1;
+		new_pgd++;
+	}
+	new_pgd -= PTRS_PER_PGD;
+
+	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));
+
+	cpu_dcache_wb_range((unsigned long)new_pgd,
+			    (unsigned long)new_pgd +
+			    PTRS_PER_PGD * sizeof(pgd_t));
+	inc_zone_page_state(virt_to_page((unsigned long *)new_pgd),
+			    NR_PAGETABLE);
+
+	return new_pgd;
+}
+
+void pgd_free(struct mm_struct *mm, pgd_t * pgd)
+{
+	pmd_t *pmd;
+	struct page *pte;
+
+	if (!pgd)
+		return;
+
+	pmd = (pmd_t *) pgd;
+	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_free(mm, pte);
+	mm_dec_nr_ptes(mm);
+	pmd_free(mm, pmd);
+free:
+	free_pages((unsigned long)pgd, 0);
+}
+
+/*
+ * In order to soft-boot, we need to insert a 1:1 mapping in place of
+ * the user-mode pages.  This will then ensure that we have predictable
+ * results when turning the mmu off
+ */
+void setup_mm_for_reboot(char mode)
+{
+	unsigned long pmdval;
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	int i;
+
+	if (current->mm && current->mm->pgd)
+		pgd = current->mm->pgd;
+	else
+		pgd = init_mm.pgd;
+
+	for (i = 0; i < USER_PTRS_PER_PGD; i++) {
+		pmdval = (i << PGDIR_SHIFT);
+		p4d = p4d_offset(pgd, i << PGDIR_SHIFT);
+		pud = pud_offset(p4d, i << PGDIR_SHIFT);
+		pmd = pmd_offset(pud + i, i << PGDIR_SHIFT);
+		set_pmd(pmd, __pmd(pmdval));
+	}
+}