LXR linux/arch/um/kernel/mem.c

   1/*
   2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3 * Licensed under the GPL
   4 */
   5
   6#include <linux/stddef.h>
   7#include <linux/bootmem.h>
   8#include <linux/gfp.h>
   9#include <linux/highmem.h>
  10#include <linux/mm.h>
  11#include <linux/swap.h>
  12#include <asm/fixmap.h>
  13#include <asm/page.h>
  14#include "as-layout.h"
  15#include "init.h"
  16#include "kern.h"
  17#include "kern_util.h"
  18#include "mem_user.h"
  19#include "os.h"
  20
  21/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  22unsigned long *empty_zero_page = NULL;
  23/* allocated in paging_init and unchanged thereafter */
  24static unsigned long *empty_bad_page = NULL;
  25
  26/*
  27 * Initialized during boot, and readonly for initializing page tables
  28 * afterwards
  29 */
  30pgd_t swapper_pg_dir[PTRS_PER_PGD];
  31
  32/* Initialized at boot time, and readonly after that */
  33unsigned long long highmem;
  34int kmalloc_ok = 0;
  35
  36/* Used during early boot */
  37static unsigned long brk_end;
  38
  39#ifdef CONFIG_HIGHMEM
  40static void setup_highmem(unsigned long highmem_start,
  41                          unsigned long highmem_len)
  42{
  43        struct page *page;
  44        unsigned long highmem_pfn;
  45        int i;
  46
  47        highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  48        for (i = 0; i < highmem_len >> PAGE_SHIFT; i++) {
  49                page = &mem_map[highmem_pfn + i];
  50                ClearPageReserved(page);
  51                init_page_count(page);
  52                __free_page(page);
  53        }
  54}
  55#endif
  56
  57void __init mem_init(void)
  58{
  59        /* clear the zero-page */
  60        memset(empty_zero_page, 0, PAGE_SIZE);
  61
  62        /* Map in the area just after the brk now that kmalloc is about
  63         * to be turned on.
  64         */
  65        brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  66        map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  67        free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  68        uml_reserved = brk_end;
  69
  70        /* this will put all low memory onto the freelists */
  71        totalram_pages = free_all_bootmem();
  72        max_low_pfn = totalram_pages;
  73#ifdef CONFIG_HIGHMEM
  74        totalhigh_pages = highmem >> PAGE_SHIFT;
  75        totalram_pages += totalhigh_pages;
  76#endif
  77        num_physpages = totalram_pages;
  78        max_pfn = totalram_pages;
  79        printk(KERN_INFO "Memory: %luk available\n",
  80               nr_free_pages() << (PAGE_SHIFT-10));
  81        kmalloc_ok = 1;
  82
  83#ifdef CONFIG_HIGHMEM
  84        setup_highmem(end_iomem, highmem);
  85#endif
  86}
  87
  88/*
  89 * Create a page table and place a pointer to it in a middle page
  90 * directory entry.
  91 */
  92static void __init one_page_table_init(pmd_t *pmd)
  93{
  94        if (pmd_none(*pmd)) {
  95                pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  96                set_pmd(pmd, __pmd(_KERNPG_TABLE +
  97                                           (unsigned long) __pa(pte)));
  98                if (pte != pte_offset_kernel(pmd, 0))
  99                        BUG();
 100        }
 101}
 102
 103static void __init one_md_table_init(pud_t *pud)
 104{
 105#ifdef CONFIG_3_LEVEL_PGTABLES
 106        pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 107        set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 108        if (pmd_table != pmd_offset(pud, 0))
 109                BUG();
 110#endif
 111}
 112
 113static void __init fixrange_init(unsigned long start, unsigned long end,
 114                                 pgd_t *pgd_base)
 115{
 116        pgd_t *pgd;
 117        pud_t *pud;
 118        pmd_t *pmd;
 119        int i, j;
 120        unsigned long vaddr;
 121
 122        vaddr = start;
 123        i = pgd_index(vaddr);
 124        j = pmd_index(vaddr);
 125        pgd = pgd_base + i;
 126
 127        for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 128                pud = pud_offset(pgd, vaddr);
 129                if (pud_none(*pud))
 130                        one_md_table_init(pud);
 131                pmd = pmd_offset(pud, vaddr);
 132                for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
 133                        one_page_table_init(pmd);
 134                        vaddr += PMD_SIZE;
 135                }
 136                j = 0;
 137        }
 138}
 139
 140#ifdef CONFIG_HIGHMEM
 141pte_t *kmap_pte;
 142pgprot_t kmap_prot;
 143
 144#define kmap_get_fixmap_pte(vaddr)                                      \
 145        pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 146                                     (vaddr)), (vaddr))
 147
 148static void __init kmap_init(void)
 149{
 150        unsigned long kmap_vstart;
 151
 152        /* cache the first kmap pte */
 153        kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 154        kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 155
 156        kmap_prot = PAGE_KERNEL;
 157}
 158
 159static void __init init_highmem(void)
 160{
 161        pgd_t *pgd;
 162        pud_t *pud;
 163        pmd_t *pmd;
 164        pte_t *pte;
 165        unsigned long vaddr;
 166
 167        /*
 168         * Permanent kmaps:
 169         */
 170        vaddr = PKMAP_BASE;
 171        fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 172
 173        pgd = swapper_pg_dir + pgd_index(vaddr);
 174        pud = pud_offset(pgd, vaddr);
 175        pmd = pmd_offset(pud, vaddr);
 176        pte = pte_offset_kernel(pmd, vaddr);
 177        pkmap_page_table = pte;
 178
 179        kmap_init();
 180}
 181#endif /* CONFIG_HIGHMEM */
 182
 183static void __init fixaddr_user_init( void)
 184{
 185#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 186        long size = FIXADDR_USER_END - FIXADDR_USER_START;
 187        pgd_t *pgd;
 188        pud_t *pud;
 189        pmd_t *pmd;
 190        pte_t *pte;
 191        phys_t p;
 192        unsigned long v, vaddr = FIXADDR_USER_START;
 193
 194        if (!size)
 195                return;
 196
 197        fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 198        v = (unsigned long) alloc_bootmem_low_pages(size);
 199        memcpy((void *) v , (void *) FIXADDR_USER_START, size);
 200        p = __pa(v);
 201        for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 202                      p += PAGE_SIZE) {
 203                pgd = swapper_pg_dir + pgd_index(vaddr);
 204                pud = pud_offset(pgd, vaddr);
 205                pmd = pmd_offset(pud, vaddr);
 206                pte = pte_offset_kernel(pmd, vaddr);
 207                pte_set_val(*pte, p, PAGE_READONLY);
 208        }
 209#endif
 210}
 211
 212void __init paging_init(void)
 213{
 214        unsigned long zones_size[MAX_NR_ZONES], vaddr;
 215        int i;
 216
 217        empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 218        empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 219        for (i = 0; i < ARRAY_SIZE(zones_size); i++)
 220                zones_size[i] = 0;
 221
 222        zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 223                (uml_physmem >> PAGE_SHIFT);
 224#ifdef CONFIG_HIGHMEM
 225        zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 226#endif
 227        free_area_init(zones_size);
 228
 229        /*
 230         * Fixed mappings, only the page table structure has to be
 231         * created - mappings will be set by set_fixmap():
 232         */
 233        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 234        fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 235
 236        fixaddr_user_init();
 237
 238#ifdef CONFIG_HIGHMEM
 239        init_highmem();
 240#endif
 241}
 242
 243/*
 244 * This can't do anything because nothing in the kernel image can be freed
 245 * since it's not in kernel physical memory.
 246 */
 247
 248void free_initmem(void)
 249{
 250}
 251
 252#ifdef CONFIG_BLK_DEV_INITRD
 253void free_initrd_mem(unsigned long start, unsigned long end)
 254{
 255        if (start < end)
 256                printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
 257                       (end - start) >> 10);
 258        for (; start < end; start += PAGE_SIZE) {
 259                ClearPageReserved(virt_to_page(start));
 260                init_page_count(virt_to_page(start));
 261                free_page(start);
 262                totalram_pages++;
 263        }
 264}
 265#endif
 266
 267/* Allocate and free page tables. */
 268
 269pgd_t *pgd_alloc(struct mm_struct *mm)
 270{
 271        pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 272
 273        if (pgd) {
 274                memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 275                memcpy(pgd + USER_PTRS_PER_PGD,
 276                       swapper_pg_dir + USER_PTRS_PER_PGD,
 277                       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 278        }
 279        return pgd;
 280}
 281
 282void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 283{
 284        free_page((unsigned long) pgd);
 285}
 286
 287pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 288{
 289        pte_t *pte;
 290
 291        pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 292        return pte;
 293}
 294
 295pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 296{
 297        struct page *pte;
 298
 299        pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 300        if (pte)
 301                pgtable_page_ctor(pte);
 302        return pte;
 303}
 304
 305#ifdef CONFIG_3_LEVEL_PGTABLES
 306pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 307{
 308        pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
 309
 310        if (pmd)
 311                memset(pmd, 0, PAGE_SIZE);
 312
 313        return pmd;
 314}
 315#endif
 316
 317void *uml_kmalloc(int size, int flags)
 318{
 319        return kmalloc(size, flags);
 320}
 321