linux/arch/xtensa/include/asm/page.h
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   1/*
   2 * include/asm-xtensa/page.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 version2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * Copyright (C) 2001 - 2007 Tensilica Inc.
   9 */
  10
  11#ifndef _XTENSA_PAGE_H
  12#define _XTENSA_PAGE_H
  13
  14#include <asm/processor.h>
  15#include <asm/types.h>
  16#include <asm/cache.h>
  17#include <asm/kmem_layout.h>
  18
  19/*
  20 * PAGE_SHIFT determines the page size
  21 */
  22
  23#define PAGE_SHIFT      12
  24#define PAGE_SIZE       (__XTENSA_UL_CONST(1) << PAGE_SHIFT)
  25#define PAGE_MASK       (~(PAGE_SIZE-1))
  26
  27#ifdef CONFIG_MMU
  28#define PAGE_OFFSET     XCHAL_KSEG_CACHED_VADDR
  29#define PHYS_OFFSET     XCHAL_KSEG_PADDR
  30#define MAX_LOW_PFN     (PHYS_PFN(XCHAL_KSEG_PADDR) + \
  31                         PHYS_PFN(XCHAL_KSEG_SIZE))
  32#else
  33#define PAGE_OFFSET     _AC(CONFIG_DEFAULT_MEM_START, UL)
  34#define PHYS_OFFSET     _AC(CONFIG_DEFAULT_MEM_START, UL)
  35#define MAX_LOW_PFN     PHYS_PFN(0xfffffffful)
  36#endif
  37
  38/*
  39 * Cache aliasing:
  40 *
  41 * If the cache size for one way is greater than the page size, we have to
  42 * deal with cache aliasing. The cache index is wider than the page size:
  43 *
  44 * |    |cache| cache index
  45 * | pfn  |off| virtual address
  46 * |xxxx:X|zzz|
  47 * |    : |   |
  48 * | \  / |   |
  49 * |trans.|   |
  50 * | /  \ |   |
  51 * |yyyy:Y|zzz| physical address
  52 *
  53 * When the page number is translated to the physical page address, the lowest
  54 * bit(s) (X) that are part of the cache index are also translated (Y).
  55 * If this translation changes bit(s) (X), the cache index is also afected,
  56 * thus resulting in a different cache line than before.
  57 * The kernel does not provide a mechanism to ensure that the page color
  58 * (represented by this bit) remains the same when allocated or when pages
  59 * are remapped. When user pages are mapped into kernel space, the color of
  60 * the page might also change.
  61 *
  62 * We use the address space VMALLOC_END ... VMALLOC_END + DCACHE_WAY_SIZE * 2
  63 * to temporarily map a patch so we can match the color.
  64 */
  65
  66#if DCACHE_WAY_SIZE > PAGE_SIZE
  67# define DCACHE_ALIAS_ORDER     (DCACHE_WAY_SHIFT - PAGE_SHIFT)
  68# define DCACHE_ALIAS_MASK      (PAGE_MASK & (DCACHE_WAY_SIZE - 1))
  69# define DCACHE_ALIAS(a)        (((a) & DCACHE_ALIAS_MASK) >> PAGE_SHIFT)
  70# define DCACHE_ALIAS_EQ(a,b)   ((((a) ^ (b)) & DCACHE_ALIAS_MASK) == 0)
  71#else
  72# define DCACHE_ALIAS_ORDER     0
  73# define DCACHE_ALIAS(a)        ((void)(a), 0)
  74#endif
  75#define DCACHE_N_COLORS         (1 << DCACHE_ALIAS_ORDER)
  76
  77#if ICACHE_WAY_SIZE > PAGE_SIZE
  78# define ICACHE_ALIAS_ORDER     (ICACHE_WAY_SHIFT - PAGE_SHIFT)
  79# define ICACHE_ALIAS_MASK      (PAGE_MASK & (ICACHE_WAY_SIZE - 1))
  80# define ICACHE_ALIAS(a)        (((a) & ICACHE_ALIAS_MASK) >> PAGE_SHIFT)
  81# define ICACHE_ALIAS_EQ(a,b)   ((((a) ^ (b)) & ICACHE_ALIAS_MASK) == 0)
  82#else
  83# define ICACHE_ALIAS_ORDER     0
  84#endif
  85
  86
  87#ifdef __ASSEMBLY__
  88
  89#define __pgprot(x)     (x)
  90
  91#else
  92
  93/*
  94 * These are used to make use of C type-checking..
  95 */
  96
  97typedef struct { unsigned long pte; } pte_t;            /* page table entry */
  98typedef struct { unsigned long pgd; } pgd_t;            /* PGD table entry */
  99typedef struct { unsigned long pgprot; } pgprot_t;
 100typedef struct page *pgtable_t;
 101
 102#define pte_val(x)      ((x).pte)
 103#define pgd_val(x)      ((x).pgd)
 104#define pgprot_val(x)   ((x).pgprot)
 105
 106#define __pte(x)        ((pte_t) { (x) } )
 107#define __pgd(x)        ((pgd_t) { (x) } )
 108#define __pgprot(x)     ((pgprot_t) { (x) } )
 109
 110/*
 111 * Pure 2^n version of get_order
 112 * Use 'nsau' instructions if supported by the processor or the generic version.
 113 */
 114
 115#if XCHAL_HAVE_NSA
 116
 117static inline __attribute_const__ int get_order(unsigned long size)
 118{
 119        int lz;
 120        asm ("nsau %0, %1" : "=r" (lz) : "r" ((size - 1) >> PAGE_SHIFT));
 121        return 32 - lz;
 122}
 123
 124#else
 125
 126# include <asm-generic/getorder.h>
 127
 128#endif
 129
 130struct page;
 131struct vm_area_struct;
 132extern void clear_page(void *page);
 133extern void copy_page(void *to, void *from);
 134
 135/*
 136 * If we have cache aliasing and writeback caches, we might have to do
 137 * some extra work
 138 */
 139
 140#if defined(CONFIG_MMU) && DCACHE_WAY_SIZE > PAGE_SIZE
 141extern void clear_page_alias(void *vaddr, unsigned long paddr);
 142extern void copy_page_alias(void *to, void *from,
 143                            unsigned long to_paddr, unsigned long from_paddr);
 144
 145#define clear_user_highpage clear_user_highpage
 146void clear_user_highpage(struct page *page, unsigned long vaddr);
 147#define __HAVE_ARCH_COPY_USER_HIGHPAGE
 148void copy_user_highpage(struct page *to, struct page *from,
 149                        unsigned long vaddr, struct vm_area_struct *vma);
 150#else
 151# define clear_user_page(page, vaddr, pg)       clear_page(page)
 152# define copy_user_page(to, from, vaddr, pg)    copy_page(to, from)
 153#endif
 154
 155/*
 156 * This handles the memory map.  We handle pages at
 157 * XCHAL_KSEG_CACHED_VADDR for kernels with 32 bit address space.
 158 * These macros are for conversion of kernel address, not user
 159 * addresses.
 160 */
 161
 162#define ARCH_PFN_OFFSET         (PHYS_OFFSET >> PAGE_SHIFT)
 163
 164#ifdef CONFIG_MMU
 165static inline unsigned long ___pa(unsigned long va)
 166{
 167        unsigned long off = va - PAGE_OFFSET;
 168
 169        if (off >= XCHAL_KSEG_SIZE)
 170                off -= XCHAL_KSEG_SIZE;
 171
 172#ifndef CONFIG_XIP_KERNEL
 173        return off + PHYS_OFFSET;
 174#else
 175        if (off < XCHAL_KSEG_SIZE)
 176                return off + PHYS_OFFSET;
 177
 178        off -= XCHAL_KSEG_SIZE;
 179        if (off >= XCHAL_KIO_SIZE)
 180                off -= XCHAL_KIO_SIZE;
 181
 182        return off + XCHAL_KIO_PADDR;
 183#endif
 184}
 185#define __pa(x) ___pa((unsigned long)(x))
 186#else
 187#define __pa(x) \
 188        ((unsigned long) (x) - PAGE_OFFSET + PHYS_OFFSET)
 189#endif
 190#define __va(x) \
 191        ((void *)((unsigned long) (x) - PHYS_OFFSET + PAGE_OFFSET))
 192#define pfn_valid(pfn) \
 193        ((pfn) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
 194
 195#define virt_to_page(kaddr)     pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
 196#define page_to_virt(page)      __va(page_to_pfn(page) << PAGE_SHIFT)
 197#define virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 198#define page_to_phys(page)      (page_to_pfn(page) << PAGE_SHIFT)
 199
 200#endif /* __ASSEMBLY__ */
 201
 202#include <asm-generic/memory_model.h>
 203#endif /* _XTENSA_PAGE_H */
 204
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