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