RISC-V: Paging and MMU
This patch contains code to manage the RISC-V MMU, including definitions
of the page tables and the page walking code.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
diff --git a/arch/riscv/include/asm/mmu_context.h b/arch/riscv/include/asm/mmu_context.h
new file mode 100644
index 0000000..de1fc16
--- /dev/null
+++ b/arch/riscv/include/asm/mmu_context.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _ASM_RISCV_MMU_CONTEXT_H
+#define _ASM_RISCV_MMU_CONTEXT_H
+
+#include <asm-generic/mm_hooks.h>
+
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <asm/tlbflush.h>
+
+static inline void enter_lazy_tlb(struct mm_struct *mm,
+ struct task_struct *task)
+{
+}
+
+/* Initialize context-related info for a new mm_struct */
+static inline int init_new_context(struct task_struct *task,
+ struct mm_struct *mm)
+{
+ return 0;
+}
+
+static inline void destroy_context(struct mm_struct *mm)
+{
+}
+
+static inline pgd_t *current_pgdir(void)
+{
+ return pfn_to_virt(csr_read(sptbr) & SPTBR_PPN);
+}
+
+static inline void set_pgdir(pgd_t *pgd)
+{
+ csr_write(sptbr, virt_to_pfn(pgd) | SPTBR_MODE);
+}
+
+static inline void switch_mm(struct mm_struct *prev,
+ struct mm_struct *next, struct task_struct *task)
+{
+ if (likely(prev != next)) {
+ set_pgdir(next->pgd);
+ local_flush_tlb_all();
+ }
+}
+
+static inline void activate_mm(struct mm_struct *prev,
+ struct mm_struct *next)
+{
+ switch_mm(prev, next, NULL);
+}
+
+static inline void deactivate_mm(struct task_struct *task,
+ struct mm_struct *mm)
+{
+}
+
+#endif /* _ASM_RISCV_MMU_CONTEXT_H */