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