LXR linux/arch/mn10300/mm/cache-flush-icache.c

   1/* Flush dcache and invalidate icache when the dcache is in writeback mode
   2 *
   3 * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public Licence
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the Licence, or (at your option) any later version.
  10 */
  11#include <linux/module.h>
  12#include <linux/mm.h>
  13#include <asm/cacheflush.h>
  14#include <asm/smp.h>
  15#include "cache-smp.h"
  16
  17/**
  18 * flush_icache_page - Flush a page from the dcache and invalidate the icache
  19 * @vma: The VMA the page is part of.
  20 * @page: The page to be flushed.
  21 *
  22 * Write a page back from the dcache and invalidate the icache so that we can
  23 * run code from it that we've just written into it
  24 */
  25void flush_icache_page(struct vm_area_struct *vma, struct page *page)
  26{
  27        unsigned long start = page_to_phys(page);
  28        unsigned long flags;
  29
  30        flags = smp_lock_cache();
  31
  32        mn10300_local_dcache_flush_page(start);
  33        mn10300_local_icache_inv_page(start);
  34
  35        smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start, start + PAGE_SIZE);
  36        smp_unlock_cache(flags);
  37}
  38EXPORT_SYMBOL(flush_icache_page);
  39
  40/**
  41 * flush_icache_page_range - Flush dcache and invalidate icache for part of a
  42 *                              single page
  43 * @start: The starting virtual address of the page part.
  44 * @end: The ending virtual address of the page part.
  45 *
  46 * Flush the dcache and invalidate the icache for part of a single page, as
  47 * determined by the virtual addresses given.  The page must be in the paged
  48 * area.
  49 */
  50static void flush_icache_page_range(unsigned long start, unsigned long end)
  51{
  52        unsigned long addr, size, off;
  53        struct page *page;
  54        pgd_t *pgd;
  55        pud_t *pud;
  56        pmd_t *pmd;
  57        pte_t *ppte, pte;
  58
  59        /* work out how much of the page to flush */
  60        off = start & ~PAGE_MASK;
  61        size = end - start;
  62
  63        /* get the physical address the page is mapped to from the page
  64         * tables */
  65        pgd = pgd_offset(current->mm, start);
  66        if (!pgd || !pgd_val(*pgd))
  67                return;
  68
  69        pud = pud_offset(pgd, start);
  70        if (!pud || !pud_val(*pud))
  71                return;
  72
  73        pmd = pmd_offset(pud, start);
  74        if (!pmd || !pmd_val(*pmd))
  75                return;
  76
  77        ppte = pte_offset_map(pmd, start);
  78        if (!ppte)
  79                return;
  80        pte = *ppte;
  81        pte_unmap(ppte);
  82
  83        if (pte_none(pte))
  84                return;
  85
  86        page = pte_page(pte);
  87        if (!page)
  88                return;
  89
  90        addr = page_to_phys(page);
  91
  92        /* flush the dcache and invalidate the icache coverage on that
  93         * region */
  94        mn10300_local_dcache_flush_range2(addr + off, size);
  95        mn10300_local_icache_inv_range2(addr + off, size);
  96        smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start, end);
  97}
  98
  99/**
 100 * flush_icache_range - Globally flush dcache and invalidate icache for region
 101 * @start: The starting virtual address of the region.
 102 * @end: The ending virtual address of the region.
 103 *
 104 * This is used by the kernel to globally flush some code it has just written
 105 * from the dcache back to RAM and then to globally invalidate the icache over
 106 * that region so that that code can be run on all CPUs in the system.
 107 */
 108void flush_icache_range(unsigned long start, unsigned long end)
 109{
 110        unsigned long start_page, end_page;
 111        unsigned long flags;
 112
 113        flags = smp_lock_cache();
 114
 115        if (end > 0x80000000UL) {
 116                /* addresses above 0xa0000000 do not go through the cache */
 117                if (end > 0xa0000000UL) {
 118                        end = 0xa0000000UL;
 119                        if (start >= end)
 120                                goto done;
 121                }
 122
 123                /* kernel addresses between 0x80000000 and 0x9fffffff do not
 124                 * require page tables, so we just map such addresses
 125                 * directly */
 126                start_page = (start >= 0x80000000UL) ? start : 0x80000000UL;
 127                mn10300_local_dcache_flush_range(start_page, end);
 128                mn10300_local_icache_inv_range(start_page, end);
 129                smp_cache_call(SMP_IDCACHE_INV_FLUSH_RANGE, start_page, end);
 130                if (start_page == start)
 131                        goto done;
 132                end = start_page;
 133        }
 134
 135        start_page = start & PAGE_MASK;
 136        end_page = (end - 1) & PAGE_MASK;
 137
 138        if (start_page == end_page) {
 139                /* the first and last bytes are on the same page */
 140                flush_icache_page_range(start, end);
 141        } else if (start_page + 1 == end_page) {
 142                /* split over two virtually contiguous pages */
 143                flush_icache_page_range(start, end_page);
 144                flush_icache_page_range(end_page, end);
 145        } else {
 146                /* more than 2 pages; just flush the entire cache */
 147                mn10300_dcache_flush();
 148                mn10300_icache_inv();
 149                smp_cache_call(SMP_IDCACHE_INV_FLUSH, 0, 0);
 150        }
 151
 152done:
 153        smp_unlock_cache(flags);
 154}
 155EXPORT_SYMBOL(flush_icache_range);
 156