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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/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(); */
}
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