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-rw-r--r--arch/openrisc/mm/tlb.c193
1 files changed, 193 insertions, 0 deletions
diff --git a/arch/openrisc/mm/tlb.c b/arch/openrisc/mm/tlb.c
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+++ b/arch/openrisc/mm/tlb.c
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+/*
+ * OpenRISC tlb.c
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others. All original copyrights apply as per the original source
+ * declaration.
+ *
+ * Modifications for the OpenRISC architecture:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Julius Baxter <julius.baxter@orsoc.se>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+
+#include <asm/system.h>
+#include <asm/segment.h>
+#include <asm/tlbflush.h>
+#include <asm/pgtable.h>
+#include <asm/mmu_context.h>
+#include <asm/spr_defs.h>
+
+#define NO_CONTEXT -1
+
+#define NUM_DTLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \
+ SPR_DMMUCFGR_NTS_OFF))
+#define NUM_ITLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \
+ SPR_IMMUCFGR_NTS_OFF))
+#define DTLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_DTLB_SETS-1))
+#define ITLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_ITLB_SETS-1))
+/*
+ * Invalidate all TLB entries.
+ *
+ * This comes down to setting the 'valid' bit for all xTLBMR registers to 0.
+ * Easiest way to accomplish this is to just zero out the xTLBMR register
+ * completely.
+ *
+ */
+
+void flush_tlb_all(void)
+{
+ int i;
+ unsigned long num_tlb_sets;
+
+ /* Determine number of sets for IMMU. */
+ /* FIXME: Assumption is I & D nsets equal. */
+ num_tlb_sets = NUM_ITLB_SETS;
+
+ for (i = 0; i < num_tlb_sets; i++) {
+ mtspr_off(SPR_DTLBMR_BASE(0), i, 0);
+ mtspr_off(SPR_ITLBMR_BASE(0), i, 0);
+ }
+}
+
+#define have_dtlbeir (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_TEIRI)
+#define have_itlbeir (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_TEIRI)
+
+/*
+ * Invalidate a single page. This is what the xTLBEIR register is for.
+ *
+ * There's no point in checking the vma for PAGE_EXEC to determine whether it's
+ * the data or instruction TLB that should be flushed... that would take more
+ * than the few instructions that the following compiles down to!
+ *
+ * The case where we don't have the xTLBEIR register really only works for
+ * MMU's with a single way and is hard-coded that way.
+ */
+
+#define flush_dtlb_page_eir(addr) mtspr(SPR_DTLBEIR, addr)
+#define flush_dtlb_page_no_eir(addr) \
+ mtspr_off(SPR_DTLBMR_BASE(0), DTLB_OFFSET(addr), 0);
+
+#define flush_itlb_page_eir(addr) mtspr(SPR_ITLBEIR, addr)
+#define flush_itlb_page_no_eir(addr) \
+ mtspr_off(SPR_ITLBMR_BASE(0), ITLB_OFFSET(addr), 0);
+
+void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
+{
+ if (have_dtlbeir)
+ flush_dtlb_page_eir(addr);
+ else
+ flush_dtlb_page_no_eir(addr);
+
+ if (have_itlbeir)
+ flush_itlb_page_eir(addr);
+ else
+ flush_itlb_page_no_eir(addr);
+}
+
+void flush_tlb_range(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ int addr;
+ bool dtlbeir;
+ bool itlbeir;
+
+ dtlbeir = have_dtlbeir;
+ itlbeir = have_itlbeir;
+
+ for (addr = start; addr < end; addr += PAGE_SIZE) {
+ if (dtlbeir)
+ flush_dtlb_page_eir(addr);
+ else
+ flush_dtlb_page_no_eir(addr);
+
+ if (itlbeir)
+ flush_itlb_page_eir(addr);
+ else
+ flush_itlb_page_no_eir(addr);
+ }
+}
+
+/*
+ * Invalidate the selected mm context only.
+ *
+ * FIXME: Due to some bug here, we're flushing everything for now.
+ * This should be changed to loop over over mm and call flush_tlb_range.
+ */
+
+void flush_tlb_mm(struct mm_struct *mm)
+{
+
+ /* Was seeing bugs with the mm struct passed to us. Scrapped most of
+ this function. */
+ /* Several architctures do this */
+ flush_tlb_all();
+}
+
+/* called in schedule() just before actually doing the switch_to */
+
+void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+ struct task_struct *next_tsk)
+{
+ /* remember the pgd for the fault handlers
+ * this is similar to the pgd register in some other CPU's.
+ * we need our own copy of it because current and active_mm
+ * might be invalid at points where we still need to derefer
+ * the pgd.
+ */
+ current_pgd = next->pgd;
+
+ /* We don't have context support implemented, so flush all
+ * entries belonging to previous map
+ */
+
+ if (prev != next)
+ flush_tlb_mm(prev);
+
+}
+
+/*
+ * Initialize the context related info for a new mm_struct
+ * instance.
+ */
+
+int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+ mm->context = NO_CONTEXT;
+ return 0;
+}
+
+/* called by __exit_mm to destroy the used MMU context if any before
+ * destroying the mm itself. this is only called when the last user of the mm
+ * drops it.
+ */
+
+void destroy_context(struct mm_struct *mm)
+{
+ flush_tlb_mm(mm);
+
+}
+
+/* called once during VM initialization, from init.c */
+
+void __init tlb_init(void)
+{
+ /* Do nothing... */
+ /* invalidate the entire TLB */
+ /* flush_tlb_all(); */
+}