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 <linux/highmem.h>
  13 #include <linux/module.h>
  14 #include <asm/mmu_context.h>
  15 #include <asm/cacheflush.h>
  16
  17 #define CACHE_ALIAS (current_cpu_data.dcache.alias_mask)
  18
  19 static inline void *kmap_coherent(struct page *page, unsigned long addr)
  20 {
  21         enum fixed_addresses idx;
  22         unsigned long vaddr, flags;
  23         pte_t pte;
  24
  25         inc_preempt_count();
  26
  27         idx = (addr & current_cpu_data.dcache.alias_mask) >> PAGE_SHIFT;
  28         vaddr = __fix_to_virt(FIX_CMAP_END - idx);
  29         pte = mk_pte(page, PAGE_KERNEL);
  30
  31         local_irq_save(flags);
  32         flush_tlb_one(get_asid(), vaddr);
  33         local_irq_restore(flags);
  34
  35         update_mmu_cache(NULL, vaddr, pte);
  36
  37         return (void *)vaddr;
  38 }
  39
  40 static inline void kunmap_coherent(struct page *page)
  41 {
  42         dec_preempt_count();
  43         preempt_check_resched();
  44 }
  45
  46 /*
  47  * clear_user_page
  48  * @to: P1 address
  49  * @address: U0 address to be mapped
  50  * @page: page (virt_to_page(to))
  51  */
  52 void clear_user_page(void *to, unsigned long address, struct page *page)
  53 {
  54         __set_bit(PG_mapped, &page->flags);
  55
  56         clear_page(to);
  57         if ((((address & PAGE_MASK) ^ (unsigned long)to) & CACHE_ALIAS))
  58                 __flush_wback_region(to, PAGE_SIZE);
  59 }
  60
  61 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
  62                        unsigned long vaddr, void *dst, const void *src,
  63                        unsigned long len)
  64 {
  65         void *vto;
  66
  67         __set_bit(PG_mapped, &page->flags);
  68
  69         vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
  70         memcpy(vto, src, len);
  71         kunmap_coherent(vto);
  72
  73         if (vma->vm_flags & VM_EXEC)
  74                 flush_cache_page(vma, vaddr, page_to_pfn(page));
  75 }
  76
  77 void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
  78                          unsigned long vaddr, void *dst, const void *src,
  79                          unsigned long len)
  80 {
  81         void *vfrom;
  82
  83         __set_bit(PG_mapped, &page->flags);
  84
  85         vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
  86         memcpy(dst, vfrom, len);
  87         kunmap_coherent(vfrom);
  88 }
  89
  90 void copy_user_highpage(struct page *to, struct page *from,
  91                         unsigned long vaddr, struct vm_area_struct *vma)
  92 {
  93         void *vfrom, *vto;
  94
  95         __set_bit(PG_mapped, &to->flags);
  96
  97         vto = kmap_atomic(to, KM_USER1);
  98         vfrom = kmap_coherent(from, vaddr);
  99         copy_page(vto, vfrom);
 100         kunmap_coherent(vfrom);
 101
 102         if (((vaddr ^ (unsigned long)vto) & CACHE_ALIAS))
 103                 __flush_wback_region(vto, PAGE_SIZE);
 104
 105         kunmap_atomic(vto, KM_USER1);
 106         /* Make sure this page is cleared on other CPU's too before using it */
 107         smp_wmb();
 108 }
 109 EXPORT_SYMBOL(copy_user_highpage);
 110
 111 /*
 112  * For SH-4, we have our own implementation for ptep_get_and_clear
 113  */
 114 pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 115 {
 116         pte_t pte = *ptep;
 117
 118         pte_clear(mm, addr, ptep);
 119         if (!pte_not_present(pte)) {
 120                 unsigned long pfn = pte_pfn(pte);
 121                 if (pfn_valid(pfn)) {
 122                         struct page *page = pfn_to_page(pfn);
 123                         struct address_space *mapping = page_mapping(page);
 124                         if (!mapping || !mapping_writably_mapped(mapping))
 125                                 __clear_bit(PG_mapped, &page->flags);
 126                 }
 127         }
 128         return pte;
 129 }