linux/arch/um/kernel/mem.c
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   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/module.h>
   8#include <linux/bootmem.h>
   9#include <linux/highmem.h>
  10#include <linux/mm.h>
  11#include <linux/swap.h>
  12#include <linux/slab.h>
  13#include <asm/fixmap.h>
  14#include <asm/page.h>
  15#include "as-layout.h"
  16#include "init.h"
  17#include "kern.h"
  18#include "kern_util.h"
  19#include "mem_user.h"
  20#include "os.h"
  21
  22/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
  23unsigned long *empty_zero_page = NULL;
  24EXPORT_SYMBOL(empty_zero_page);
  25/* allocated in paging_init and unchanged thereafter */
  26static unsigned long *empty_bad_page = NULL;
  27
  28/*
  29 * Initialized during boot, and readonly for initializing page tables
  30 * afterwards
  31 */
  32pgd_t swapper_pg_dir[PTRS_PER_PGD];
  33
  34/* Initialized at boot time, and readonly after that */
  35unsigned long long highmem;
  36int kmalloc_ok = 0;
  37
  38/* Used during early boot */
  39static unsigned long brk_end;
  40
  41#ifdef CONFIG_HIGHMEM
  42static void setup_highmem(unsigned long highmem_start,
  43                          unsigned long highmem_len)
  44{
  45        struct page *page;
  46        unsigned long highmem_pfn;
  47        int i;
  48
  49        highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  50        for (i = 0; i < highmem_len >> PAGE_SHIFT; i++) {
  51                page = &mem_map[highmem_pfn + i];
  52                ClearPageReserved(page);
  53                init_page_count(page);
  54                __free_page(page);
  55        }
  56}
  57#endif
  58
  59void __init mem_init(void)
  60{
  61        /* clear the zero-page */
  62        memset(empty_zero_page, 0, PAGE_SIZE);
  63
  64        /* Map in the area just after the brk now that kmalloc is about
  65         * to be turned on.
  66         */
  67        brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  68        map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  69        free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  70        uml_reserved = brk_end;
  71
  72        /* this will put all low memory onto the freelists */
  73        totalram_pages = free_all_bootmem();
  74        max_low_pfn = totalram_pages;
  75#ifdef CONFIG_HIGHMEM
  76        totalhigh_pages = highmem >> PAGE_SHIFT;
  77        totalram_pages += totalhigh_pages;
  78#endif
  79        num_physpages = totalram_pages;
  80        max_pfn = totalram_pages;
  81        printk(KERN_INFO "Memory: %luk available\n",
  82               nr_free_pages() << (PAGE_SHIFT-10));
  83        kmalloc_ok = 1;
  84
  85#ifdef CONFIG_HIGHMEM
  86        setup_highmem(end_iomem, highmem);
  87#endif
  88}
  89
  90/*
  91 * Create a page table and place a pointer to it in a middle page
  92 * directory entry.
  93 */
  94static void __init one_page_table_init(pmd_t *pmd)
  95{
  96        if (pmd_none(*pmd)) {
  97                pte_t *pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  98                set_pmd(pmd, __pmd(_KERNPG_TABLE +
  99                                           (unsigned long) __pa(pte)));
 100                if (pte != pte_offset_kernel(pmd, 0))
 101                        BUG();
 102        }
 103}
 104
 105static void __init one_md_table_init(pud_t *pud)
 106{
 107#ifdef CONFIG_3_LEVEL_PGTABLES
 108        pmd_t *pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 109        set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
 110        if (pmd_table != pmd_offset(pud, 0))
 111                BUG();
 112#endif
 113}
 114
 115static void __init fixrange_init(unsigned long start, unsigned long end,
 116                                 pgd_t *pgd_base)
 117{
 118        pgd_t *pgd;
 119        pud_t *pud;
 120        pmd_t *pmd;
 121        int i, j;
 122        unsigned long vaddr;
 123
 124        vaddr = start;
 125        i = pgd_index(vaddr);
 126        j = pmd_index(vaddr);
 127        pgd = pgd_base + i;
 128
 129        for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 130                pud = pud_offset(pgd, vaddr);
 131                if (pud_none(*pud))
 132                        one_md_table_init(pud);
 133                pmd = pmd_offset(pud, vaddr);
 134                for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
 135                        one_page_table_init(pmd);
 136                        vaddr += PMD_SIZE;
 137                }
 138                j = 0;
 139        }
 140}
 141
 142#ifdef CONFIG_HIGHMEM
 143pte_t *kmap_pte;
 144pgprot_t kmap_prot;
 145
 146#define kmap_get_fixmap_pte(vaddr)                                      \
 147        pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\
 148                                     (vaddr)), (vaddr))
 149
 150static void __init kmap_init(void)
 151{
 152        unsigned long kmap_vstart;
 153
 154        /* cache the first kmap pte */
 155        kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 156        kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 157
 158        kmap_prot = PAGE_KERNEL;
 159}
 160
 161static void __init init_highmem(void)
 162{
 163        pgd_t *pgd;
 164        pud_t *pud;
 165        pmd_t *pmd;
 166        pte_t *pte;
 167        unsigned long vaddr;
 168
 169        /*
 170         * Permanent kmaps:
 171         */
 172        vaddr = PKMAP_BASE;
 173        fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 174
 175        pgd = swapper_pg_dir + pgd_index(vaddr);
 176        pud = pud_offset(pgd, vaddr);
 177        pmd = pmd_offset(pud, vaddr);
 178        pte = pte_offset_kernel(pmd, vaddr);
 179        pkmap_page_table = pte;
 180
 181        kmap_init();
 182}
 183#endif /* CONFIG_HIGHMEM */
 184
 185static void __init fixaddr_user_init( void)
 186{
 187#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 188        long size = FIXADDR_USER_END - FIXADDR_USER_START;
 189        pgd_t *pgd;
 190        pud_t *pud;
 191        pmd_t *pmd;
 192        pte_t *pte;
 193        phys_t p;
 194        unsigned long v, vaddr = FIXADDR_USER_START;
 195
 196        if (!size)
 197                return;
 198
 199        fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
 200        v = (unsigned long) alloc_bootmem_low_pages(size);
 201        memcpy((void *) v , (void *) FIXADDR_USER_START, size);
 202        p = __pa(v);
 203        for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 204                      p += PAGE_SIZE) {
 205                pgd = swapper_pg_dir + pgd_index(vaddr);
 206                pud = pud_offset(pgd, vaddr);
 207                pmd = pmd_offset(pud, vaddr);
 208                pte = pte_offset_kernel(pmd, vaddr);
 209                pte_set_val(*pte, p, PAGE_READONLY);
 210        }
 211#endif
 212}
 213
 214void __init paging_init(void)
 215{
 216        unsigned long zones_size[MAX_NR_ZONES], vaddr;
 217        int i;
 218
 219        empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 220        empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 221        for (i = 0; i < ARRAY_SIZE(zones_size); i++)
 222                zones_size[i] = 0;
 223
 224        zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) -
 225                (uml_physmem >> PAGE_SHIFT);
 226#ifdef CONFIG_HIGHMEM
 227        zones_size[ZONE_HIGHMEM] = highmem >> PAGE_SHIFT;
 228#endif
 229        free_area_init(zones_size);
 230
 231        /*
 232         * Fixed mappings, only the page table structure has to be
 233         * created - mappings will be set by set_fixmap():
 234         */
 235        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 236        fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 237
 238        fixaddr_user_init();
 239
 240#ifdef CONFIG_HIGHMEM
 241        init_highmem();
 242#endif
 243}
 244
 245/*
 246 * This can't do anything because nothing in the kernel image can be freed
 247 * since it's not in kernel physical memory.
 248 */
 249
 250void free_initmem(void)
 251{
 252}
 253
 254#ifdef CONFIG_BLK_DEV_INITRD
 255void free_initrd_mem(unsigned long start, unsigned long end)
 256{
 257        if (start < end)
 258                printk(KERN_INFO "Freeing initrd memory: %ldk freed\n",
 259                       (end - start) >> 10);
 260        for (; start < end; start += PAGE_SIZE) {
 261                ClearPageReserved(virt_to_page(start));
 262                init_page_count(virt_to_page(start));
 263                free_page(start);
 264                totalram_pages++;
 265        }
 266}
 267#endif
 268
 269/* Allocate and free page tables. */
 270
 271pgd_t *pgd_alloc(struct mm_struct *mm)
 272{
 273        pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 274
 275        if (pgd) {
 276                memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 277                memcpy(pgd + USER_PTRS_PER_PGD,
 278                       swapper_pg_dir + USER_PTRS_PER_PGD,
 279                       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 280        }
 281        return pgd;
 282}
 283
 284void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 285{
 286        free_page((unsigned long) pgd);
 287}
 288
 289pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 290{
 291        pte_t *pte;
 292
 293        pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 294        return pte;
 295}
 296
 297pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
 298{
 299        struct page *pte;
 300
 301        pte = alloc_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
 302        if (pte)
 303                pgtable_page_ctor(pte);
 304        return pte;
 305}
 306
 307#ifdef CONFIG_3_LEVEL_PGTABLES
 308pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 309{
 310        pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
 311
 312        if (pmd)
 313                memset(pmd, 0, PAGE_SIZE);
 314
 315        return pmd;
 316}
 317#endif
 318
 319void *uml_kmalloc(int size, int flags)
 320{
 321        return kmalloc(size, flags);
 322}
 323
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