include/asm-xtensa/pgalloc.h

   1 /*
   2  * linux/include/asm-xtensa/pgalloc.h
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Copyright (C) 2001-2005 Tensilica Inc.
   9  */
  10
  11 #ifndef _XTENSA_PGALLOC_H
  12 #define _XTENSA_PGALLOC_H
  13
  14 #ifdef __KERNEL__
  15
  16 #include <linux/config.h>
  17 #include <linux/threads.h>
  18 #include <linux/highmem.h>
  19 #include <asm/processor.h>
  20 #include <asm/cacheflush.h>
  21
  22
  23 /* Cache aliasing:
  24  *
  25  * If the cache size for one way is greater than the page size, we have to
  26  * deal with cache aliasing. The cache index is wider than the page size:
  27  *
  28  *      |cache |
  29  * |pgnum |page|        virtual address
  30  * |xxxxxX|zzzz|
  31  * |      |    |
  32  *   \  / |    |
  33  *  trans.|    |
  34  *   /  \ |    |
  35  * |yyyyyY|zzzz|        physical address
  36  *
  37  * When the page number is translated to the physical page address, the lowest
  38  * bit(s) (X) that are also part of the cache index are also translated (Y).
  39  * If this translation changes this bit (X), the cache index is also afected,
  40  * thus resulting in a different cache line than before.
  41  * The kernel does not provide a mechanism to ensure that the page color
  42  * (represented by this bit) remains the same when allocated or when pages
  43  * are remapped. When user pages are mapped into kernel space, the color of
  44  * the page might also change.
  45  *
  46  * We use the address space VMALLOC_END ... VMALLOC_END + DCACHE_WAY_SIZE * 2
  47  * to temporarily map a patch so we can match the color.
  48  */
  49
  50 #if (DCACHE_WAY_SIZE > PAGE_SIZE)
  51 # define PAGE_COLOR_MASK        (PAGE_MASK & (DCACHE_WAY_SIZE-1))
  52 # define PAGE_COLOR(a)          \
  53         (((unsigned long)(a)&PAGE_COLOR_MASK) >> PAGE_SHIFT)
  54 # define PAGE_COLOR_EQ(a,b)     \
  55         ((((unsigned long)(a) ^ (unsigned long)(b)) & PAGE_COLOR_MASK) == 0)
  56 # define PAGE_COLOR_MAP0(v)     \
  57         (VMALLOC_END + ((unsigned long)(v) & PAGE_COLOR_MASK))
  58 # define PAGE_COLOR_MAP1(v)     \
  59         (VMALLOC_END + ((unsigned long)(v) & PAGE_COLOR_MASK) + DCACHE_WAY_SIZE)
  60 #endif
  61
  62 /*
  63  * Allocating and freeing a pmd is trivial: the 1-entry pmd is
  64  * inside the pgd, so has no extra memory associated with it.
  65  */
  66
  67 #define pgd_free(pgd)   free_page((unsigned long)(pgd))
  68
  69 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
  70
  71 static inline void
  72 pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *pte)
  73 {
  74         pmd_val(*(pmdp)) = (unsigned long)(pte);
  75         __asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp));
  76 }
  77
  78 static inline void
  79 pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *page)
  80 {
  81         pmd_val(*(pmdp)) = (unsigned long)page_to_virt(page);
  82         __asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp));
  83 }
  84
  85
  86
  87 #else
  88
  89 # define pmd_populate_kernel(mm, pmdp, pte)                                  \
  90         (pmd_val(*(pmdp)) = (unsigned long)(pte))
  91 # define pmd_populate(mm, pmdp, page)                                        \
  92         (pmd_val(*(pmdp)) = (unsigned long)page_to_virt(page))
  93
  94 #endif
  95
  96 static inline pgd_t*
  97 pgd_alloc(struct mm_struct *mm)
  98 {
  99         pgd_t *pgd;
 100
 101         pgd = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGD_ORDER);
 102
 103         if (likely(pgd != NULL))
 104                 __flush_dcache_page((unsigned long)pgd);
 105
 106         return pgd;
 107 }
 108
 109 extern pte_t* pte_alloc_one_kernel(struct mm_struct* mm, unsigned long addr);
 110 extern struct page* pte_alloc_one(struct mm_struct* mm, unsigned long addr);
 111
 112 #define pte_free_kernel(pte) free_page((unsigned long)pte)
 113 #define pte_free(pte) __free_page(pte)
 114
 115 #endif /* __KERNEL__ */
 116 #endif /* _XTENSA_PGALLOC_H */