arch/sh/mm/pg-sh4.c

   1 /*
   2  * arch/sh/mm/pg-sh4.c
   3  *
   4  * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
   5  * Copyright (C) 2002 - 2007  Paul Mundt
   6  *
   7  * Released under the terms of the GNU GPL v2.0.
   8  */
   9 #include <linux/mm.h>
  10 #include <linux/mutex.h>
  11 #include <linux/fs.h>
  12 #include <asm/mmu_context.h>
  13 #include <asm/cacheflush.h>
  14
  15 #define CACHE_ALIAS (current_cpu_data.dcache.alias_mask)
  16
  17 static inline void *kmap_coherent(struct page *page, unsigned long addr)
  18 {
  19         enum fixed_addresses idx;
  20         unsigned long vaddr, flags;
  21         pte_t pte;
  22
  23         inc_preempt_count();
  24
  25         idx = (addr & current_cpu_data.dcache.alias_mask) >> PAGE_SHIFT;
  26         vaddr = __fix_to_virt(FIX_CMAP_END - idx);
  27         pte = mk_pte(page, PAGE_KERNEL);
  28
  29         local_irq_save(flags);
  30         flush_tlb_one(get_asid(), vaddr);
  31         local_irq_restore(flags);
  32
  33         update_mmu_cache(NULL, vaddr, pte);
  34
  35         return (void *)vaddr;
  36 }
  37
  38 static inline void kunmap_coherent(struct page *page)
  39 {
  40         dec_preempt_count();
  41         preempt_check_resched();
  42 }
  43
  44 /*
  45  * clear_user_page
  46  * @to: P1 address
  47  * @address: U0 address to be mapped
  48  * @page: page (virt_to_page(to))
  49  */
  50 void clear_user_page(void *to, unsigned long address, struct page *page)
  51 {
  52         __set_bit(PG_mapped, &page->flags);
  53         if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
  54                 clear_page(to);
  55         else {
  56                 void *vto = kmap_coherent(page, address);
  57                 __clear_user_page(vto, to);
  58                 kunmap_coherent(vto);
  59         }
  60 }
  61
  62 /*
  63  * copy_user_page
  64  * @to: P1 address
  65  * @from: P1 address
  66  * @address: U0 address to be mapped
  67  * @page: page (virt_to_page(to))
  68  */
  69 void copy_user_page(void *to, void *from, unsigned long address,
  70                     struct page *page)
  71 {
  72         __set_bit(PG_mapped, &page->flags);
  73         if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
  74                 copy_page(to, from);
  75         else {
  76                 void *vfrom = kmap_coherent(page, address);
  77                 __copy_user_page(vfrom, from, to);
  78                 kunmap_coherent(vfrom);
  79         }
  80 }
  81
  82 /*
  83  * For SH-4, we have our own implementation for ptep_get_and_clear
  84  */
  85 inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
  86 {
  87         pte_t pte = *ptep;
  88
  89         pte_clear(mm, addr, ptep);
  90         if (!pte_not_present(pte)) {
  91                 unsigned long pfn = pte_pfn(pte);
  92                 if (pfn_valid(pfn)) {
  93                         struct page *page = pfn_to_page(pfn);
  94                         struct address_space *mapping = page_mapping(page);
  95                         if (!mapping || !mapping_writably_mapped(mapping))
  96                                 __clear_bit(PG_mapped, &page->flags);
  97                 }
  98         }
  99         return pte;
 100 }