arch/um/kernel/mem.c

   1 /*
   2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/stddef.h"
   7 #include "linux/kernel.h"
   8 #include "linux/mm.h"
   9 #include "linux/bootmem.h"
  10 #include "linux/swap.h"
  11 #include "linux/highmem.h"
  12 #include "linux/gfp.h"
  13 #include "asm/page.h"
  14 #include "asm/fixmap.h"
  15 #include "asm/pgalloc.h"
  16 #include "user_util.h"
  17 #include "kern_util.h"
  18 #include "kern.h"
  19 #include "mem_user.h"
  20 #include "uml_uaccess.h"
  21 #include "os.h"
  22
  23 extern char __binary_start;
  24
  25 /* Changed during early boot */
  26 unsigned long *empty_zero_page = NULL;
  27 unsigned long *empty_bad_page = NULL;
  28 pgd_t swapper_pg_dir[1024];
  29 unsigned long highmem;
  30 int kmalloc_ok = 0;
  31
  32 static unsigned long brk_end;
  33
  34 void unmap_physmem(void)
  35 {
  36         os_unmap_memory((void *) brk_end, uml_reserved - brk_end);
  37 }
  38
  39 static void map_cb(void *unused)
  40 {
  41         map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
  42 }
  43
  44 #ifdef CONFIG_HIGHMEM
  45 static void setup_highmem(unsigned long highmem_start,
  46                           unsigned long highmem_len)
  47 {
  48         struct page *page;
  49         unsigned long highmem_pfn;
  50         int i;
  51
  52         highmem_start_page = virt_to_page(highmem_start);
  53
  54         highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT;
  55         for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){
  56                 page = &mem_map[highmem_pfn + i];
  57                 ClearPageReserved(page);
  58                 set_bit(PG_highmem, &page->flags);
  59                 set_page_count(page, 1);
  60                 __free_page(page);
  61         }
  62 }
  63 #endif
  64
  65 void mem_init(void)
  66 {
  67         unsigned long start;
  68
  69         max_low_pfn = (high_physmem - uml_physmem) >> PAGE_SHIFT;
  70 #ifdef CONFIG_HIGHMEM
  71         highmem_start_page = phys_page(__pa(high_physmem));
  72 #endif
  73
  74         /* clear the zero-page */
  75         memset((void *) empty_zero_page, 0, PAGE_SIZE);
  76
  77         /* Map in the area just after the brk now that kmalloc is about
  78          * to be turned on.
  79          */
  80         brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
  81         map_cb(NULL);
  82         initial_thread_cb(map_cb, NULL);
  83         free_bootmem(__pa(brk_end), uml_reserved - brk_end);
  84         uml_reserved = brk_end;
  85
  86         /* Fill in any hole at the start of the binary */
  87         start = (unsigned long) &__binary_start;
  88         if(uml_physmem != start){
  89                 map_memory(uml_physmem, __pa(uml_physmem), start - uml_physmem,
  90                            1, 1, 0);
  91         }
  92
  93         /* this will put all low memory onto the freelists */
  94         totalram_pages = free_all_bootmem();
  95         totalhigh_pages = highmem >> PAGE_SHIFT;
  96         totalram_pages += totalhigh_pages;
  97         num_physpages = totalram_pages;
  98         max_pfn = totalram_pages;
  99         printk(KERN_INFO "Memory: %luk available\n",
 100                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10));
 101         kmalloc_ok = 1;
 102
 103 #ifdef CONFIG_HIGHMEM
 104         setup_highmem(end_iomem, highmem);
 105 #endif
 106 }
 107
 108 static void __init fixrange_init(unsigned long start, unsigned long end,
 109                                  pgd_t *pgd_base)
 110 {
 111         pgd_t *pgd;
 112         pmd_t *pmd;
 113         pte_t *pte;
 114         int i, j;
 115         unsigned long vaddr;
 116
 117         vaddr = start;
 118         i = pgd_index(vaddr);
 119         j = pmd_index(vaddr);
 120         pgd = pgd_base + i;
 121
 122         for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
 123                 pmd = (pmd_t *)pgd;
 124                 for (; (j < PTRS_PER_PMD) && (vaddr != end); pmd++, j++) {
 125                         if (pmd_none(*pmd)) {
 126                                 pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
 127                                 set_pmd(pmd, __pmd(_KERNPG_TABLE +
 128                                                    (unsigned long) __pa(pte)));
 129                                 if (pte != pte_offset_kernel(pmd, 0))
 130                                         BUG();
 131                         }
 132                         vaddr += PMD_SIZE;
 133                 }
 134                 j = 0;
 135         }
 136 }
 137
 138 #if CONFIG_HIGHMEM
 139 pte_t *kmap_pte;
 140 pgprot_t kmap_prot;
 141
 142 #define kmap_get_fixmap_pte(vaddr)                                      \
 143         pte_offset(pmd_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr))
 144
 145 void __init kmap_init(void)
 146 {
 147         unsigned long kmap_vstart;
 148
 149         /* cache the first kmap pte */
 150         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 151         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 152
 153         kmap_prot = PAGE_KERNEL;
 154 }
 155
 156 static void init_highmem(void)
 157 {
 158         pgd_t *pgd;
 159         pmd_t *pmd;
 160         pte_t *pte;
 161         unsigned long vaddr;
 162
 163         /*
 164          * Permanent kmaps:
 165          */
 166         vaddr = PKMAP_BASE;
 167         fixrange_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, swapper_pg_dir);
 168
 169         pgd = swapper_pg_dir + pgd_index(vaddr);
 170         pmd = pmd_offset(pgd, vaddr);
 171         pte = pte_offset_kernel(pmd, vaddr);
 172         pkmap_page_table = pte;
 173
 174         kmap_init();
 175 }
 176 #endif /* CONFIG_HIGHMEM */
 177
 178 void paging_init(void)
 179 {
 180         unsigned long zones_size[MAX_NR_ZONES], vaddr;
 181         int i;
 182
 183         empty_zero_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 184         empty_bad_page = (unsigned long *) alloc_bootmem_low_pages(PAGE_SIZE);
 185         for(i=0;i<sizeof(zones_size)/sizeof(zones_size[0]);i++)
 186                 zones_size[i] = 0;
 187         zones_size[0] = (end_iomem >> PAGE_SHIFT) - (uml_physmem >> PAGE_SHIFT);
 188         zones_size[2] = highmem >> PAGE_SHIFT;
 189         free_area_init(zones_size);
 190
 191         /*
 192          * Fixed mappings, only the page table structure has to be
 193          * created - mappings will be set by set_fixmap():
 194          */
 195         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 196         fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
 197
 198 #ifdef CONFIG_HIGHMEM
 199         init_highmem();
 200 #endif
 201 }
 202
 203 struct page *arch_validate(struct page *page, int mask, int order)
 204 {
 205         unsigned long addr, zero = 0;
 206         int i;
 207
 208  again:
 209         if(page == NULL) return(page);
 210         if(PageHighMem(page)) return(page);
 211
 212         addr = (unsigned long) page_address(page);
 213         for(i = 0; i < (1 << order); i++){
 214                 current->thread.fault_addr = (void *) addr;
 215                 if(__do_copy_to_user((void *) addr, &zero,
 216                                      sizeof(zero),
 217                                      &current->thread.fault_addr,
 218                                      &current->thread.fault_catcher)){
 219                         if(!(mask & __GFP_WAIT)) return(NULL);
 220                         else break;
 221                 }
 222                 addr += PAGE_SIZE;
 223         }
 224         if(i == (1 << order)) return(page);
 225         page = alloc_pages(mask, order);
 226         goto again;
 227 }
 228
 229 /* This can't do anything because nothing in the kernel image can be freed
 230  * since it's not in kernel physical memory.
 231  */
 232
 233 void free_initmem(void)
 234 {
 235 }
 236
 237 #ifdef CONFIG_BLK_DEV_INITRD
 238
 239 void free_initrd_mem(unsigned long start, unsigned long end)
 240 {
 241         if (start < end)
 242                 printk ("Freeing initrd memory: %ldk freed\n",
 243                         (end - start) >> 10);
 244         for (; start < end; start += PAGE_SIZE) {
 245                 ClearPageReserved(virt_to_page(start));
 246                 set_page_count(virt_to_page(start), 1);
 247                 free_page(start);
 248                 totalram_pages++;
 249         }
 250 }
 251
 252 #endif
 253
 254 void show_mem(void)
 255 {
 256         int pfn, total = 0, reserved = 0;
 257         int shared = 0, cached = 0;
 258         int highmem = 0;
 259         struct page *page;
 260
 261         printk("Mem-info:\n");
 262         show_free_areas();
 263         printk("Free swap:       %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
 264         pfn = max_mapnr;
 265         while(pfn-- > 0) {
 266                 page = pfn_to_page(pfn);
 267                 total++;
 268                 if(PageHighMem(page))
 269                         highmem++;
 270                 if(PageReserved(page))
 271                         reserved++;
 272                 else if(PageSwapCache(page))
 273                         cached++;
 274                 else if(page_count(page))
 275                         shared += page_count(page) - 1;
 276         }
 277         printk("%d pages of RAM\n", total);
 278         printk("%d pages of HIGHMEM\n", highmem);
 279         printk("%d reserved pages\n", reserved);
 280         printk("%d pages shared\n", shared);
 281         printk("%d pages swap cached\n", cached);
 282 }
 283
 284 /*
 285  * Allocate and free page tables.
 286  */
 287
 288 pgd_t *pgd_alloc(struct mm_struct *mm)
 289 {
 290         pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
 291
 292         if (pgd) {
 293                 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
 294                 memcpy(pgd + USER_PTRS_PER_PGD,
 295                        swapper_pg_dir + USER_PTRS_PER_PGD,
 296                        (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
 297         }
 298         return pgd;
 299 }
 300
 301 void pgd_free(pgd_t *pgd)
 302 {
 303         free_page((unsigned long) pgd);
 304 }
 305
 306 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 307 {
 308         pte_t *pte;
 309
 310         pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
 311         if (pte)
 312                 clear_page(pte);
 313         return pte;
 314 }
 315
 316 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
 317 {
 318         struct page *pte;
 319
 320         pte = alloc_pages(GFP_KERNEL|__GFP_REPEAT, 0);
 321         if (pte)
 322                 clear_highpage(pte);
 323         return pte;
 324 }
 325
 326 /*
 327  * Overrides for Emacs so that we follow Linus's tabbing style.
 328  * Emacs will notice this stuff at the end of the file and automatically
 329  * adjust the settings for this buffer only.  This must remain at the end
 330  * of the file.
 331  * ---------------------------------------------------------------------------
 332  * Local variables:
 333  * c-file-style: "linux"
 334  * End:
 335  */