arch/mn10300/mm/cache-inv-icache.c

   1 /* Invalidate icache when dcache doesn't need invalidation as it's in
   2  * write-through mode
   3  *
   4  * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public Licence
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the Licence, or (at your option) any later version.
  11  */
  12 #include <linux/module.h>
  13 #include <linux/mm.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/smp.h>
  16 #include "cache-smp.h"
  17
  18 /**
  19  * flush_icache_page_range - Flush dcache and invalidate icache for part of a
  20  *                              single page
  21  * @start: The starting virtual address of the page part.
  22  * @end: The ending virtual address of the page part.
  23  *
  24  * Invalidate the icache for part of a single page, as determined by the
  25  * virtual addresses given.  The page must be in the paged area.  The dcache is
  26  * not flushed as the cache must be in write-through mode to get here.
  27  */
  28 static void flush_icache_page_range(unsigned long start, unsigned long end)
  29 {
  30         unsigned long addr, size, off;
  31         struct page *page;
  32         pgd_t *pgd;
  33         pud_t *pud;
  34         pmd_t *pmd;
  35         pte_t *ppte, pte;
  36
  37         /* work out how much of the page to flush */
  38         off = start & ~PAGE_MASK;
  39         size = end - start;
  40
  41         /* get the physical address the page is mapped to from the page
  42          * tables */
  43         pgd = pgd_offset(current->mm, start);
  44         if (!pgd || !pgd_val(*pgd))
  45                 return;
  46
  47         pud = pud_offset(pgd, start);
  48         if (!pud || !pud_val(*pud))
  49                 return;
  50
  51         pmd = pmd_offset(pud, start);
  52         if (!pmd || !pmd_val(*pmd))
  53                 return;
  54
  55         ppte = pte_offset_map(pmd, start);
  56         if (!ppte)
  57                 return;
  58         pte = *ppte;
  59         pte_unmap(ppte);
  60
  61         if (pte_none(pte))
  62                 return;
  63
  64         page = pte_page(pte);
  65         if (!page)
  66                 return;
  67
  68         addr = page_to_phys(page);
  69
  70         /* invalidate the icache coverage on that region */
  71         mn10300_local_icache_inv_range2(addr + off, size);
  72         smp_cache_call(SMP_ICACHE_INV_RANGE, start, end);
  73 }
  74
  75 /**
  76  * flush_icache_range - Globally flush dcache and invalidate icache for region
  77  * @start: The starting virtual address of the region.
  78  * @end: The ending virtual address of the region.
  79  *
  80  * This is used by the kernel to globally flush some code it has just written
  81  * from the dcache back to RAM and then to globally invalidate the icache over
  82  * that region so that that code can be run on all CPUs in the system.
  83  */
  84 void flush_icache_range(unsigned long start, unsigned long end)
  85 {
  86         unsigned long start_page, end_page;
  87         unsigned long flags;
  88
  89         flags = smp_lock_cache();
  90
  91         if (end > 0x80000000UL) {
  92                 /* addresses above 0xa0000000 do not go through the cache */
  93                 if (end > 0xa0000000UL) {
  94                         end = 0xa0000000UL;
  95                         if (start >= end)
  96                                 goto done;
  97                 }
  98
  99                 /* kernel addresses between 0x80000000 and 0x9fffffff do not
 100                  * require page tables, so we just map such addresses
 101                  * directly */
 102                 start_page = (start >= 0x80000000UL) ? start : 0x80000000UL;
 103                 mn10300_icache_inv_range(start_page, end);
 104                 smp_cache_call(SMP_ICACHE_INV_RANGE, start, end);
 105                 if (start_page == start)
 106                         goto done;
 107                 end = start_page;
 108         }
 109
 110         start_page = start & PAGE_MASK;
 111         end_page = (end - 1) & PAGE_MASK;
 112
 113         if (start_page == end_page) {
 114                 /* the first and last bytes are on the same page */
 115                 flush_icache_page_range(start, end);
 116         } else if (start_page + 1 == end_page) {
 117                 /* split over two virtually contiguous pages */
 118                 flush_icache_page_range(start, end_page);
 119                 flush_icache_page_range(end_page, end);
 120         } else {
 121                 /* more than 2 pages; just flush the entire cache */
 122                 mn10300_local_icache_inv();
 123                 smp_cache_call(SMP_ICACHE_INV, 0, 0);
 124         }
 125
 126 done:
 127         smp_unlock_cache(flags);
 128 }
 129 EXPORT_SYMBOL(flush_icache_range);