arch/um/kernel/physmem.c

   1 /*
   2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/mm.h"
   7 #include "linux/ghash.h"
   8 #include "linux/slab.h"
   9 #include "linux/vmalloc.h"
  10 #include "linux/bootmem.h"
  11 #include "asm/types.h"
  12 #include "asm/pgtable.h"
  13 #include "kern_util.h"
  14 #include "user_util.h"
  15 #include "mode_kern.h"
  16 #include "mem.h"
  17 #include "mem_user.h"
  18 #include "os.h"
  19 #include "kern.h"
  20 #include "init.h"
  21
  22 #if 0
  23 static pgd_t physmem_pgd[PTRS_PER_PGD];
  24
  25 static struct phys_desc *lookup_mapping(void *addr)
  26 {
  27         pgd = &physmem_pgd[pgd_index(addr)];
  28         if(pgd_none(pgd))
  29                 return(NULL);
  30
  31         pmd = pmd_offset(pgd, addr);
  32         if(pmd_none(pmd))
  33                 return(NULL);
  34
  35         pte = pte_offset_kernel(pmd, addr);
  36         return((struct phys_desc *) pte_val(pte));
  37 }
  38
  39 static struct add_mapping(void *addr, struct phys_desc *new)
  40 {
  41 }
  42 #endif
  43
  44 #define PHYS_HASHSIZE (8192)
  45
  46 struct phys_desc;
  47
  48 DEF_HASH_STRUCTS(virtmem, PHYS_HASHSIZE, struct phys_desc);
  49
  50 struct phys_desc {
  51         struct virtmem_ptrs virt_ptrs;
  52         int fd;
  53         __u64 offset;
  54         void *virt;
  55         unsigned long phys;
  56         struct list_head list;
  57 };
  58
  59 struct virtmem_table virtmem_hash;
  60
  61 static int virt_cmp(void *virt1, void *virt2)
  62 {
  63         return(virt1 != virt2);
  64 }
  65
  66 static int virt_hash(void *virt)
  67 {
  68         unsigned long addr = ((unsigned long) virt) >> PAGE_SHIFT;
  69         return(addr % PHYS_HASHSIZE);
  70 }
  71
  72 DEF_HASH(static, virtmem, struct phys_desc, virt_ptrs, void *, virt, virt_cmp,
  73          virt_hash);
  74
  75 LIST_HEAD(descriptor_mappings);
  76
  77 struct desc_mapping {
  78         int fd;
  79         struct list_head list;
  80         struct list_head pages;
  81 };
  82
  83 static struct desc_mapping *find_mapping(int fd)
  84 {
  85         struct desc_mapping *desc;
  86         struct list_head *ele;
  87
  88         list_for_each(ele, &descriptor_mappings){
  89                 desc = list_entry(ele, struct desc_mapping, list);
  90                 if(desc->fd == fd)
  91                         return(desc);
  92         }
  93
  94         return(NULL);
  95 }
  96
  97 static struct desc_mapping *descriptor_mapping(int fd)
  98 {
  99         struct desc_mapping *desc;
 100
 101         desc = find_mapping(fd);
 102         if(desc != NULL)
 103                 return(desc);
 104
 105         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 106         if(desc == NULL)
 107                 return(NULL);
 108
 109         *desc = ((struct desc_mapping)
 110                 { .fd =         fd,
 111                   .list =       LIST_HEAD_INIT(desc->list),
 112                   .pages =      LIST_HEAD_INIT(desc->pages) });
 113         list_add(&desc->list, &descriptor_mappings);
 114
 115         return(desc);
 116 }
 117
 118 int physmem_subst_mapping(void *virt, int fd, __u64 offset, int w)
 119 {
 120         struct desc_mapping *fd_maps;
 121         struct phys_desc *desc;
 122         unsigned long phys;
 123         int err;
 124
 125         fd_maps = descriptor_mapping(fd);
 126         if(fd_maps == NULL)
 127                 return(-ENOMEM);
 128
 129         phys = __pa(virt);
 130         if(find_virtmem_hash(&virtmem_hash, virt) != NULL)
 131                 panic("Address 0x%p is already substituted\n", virt);
 132
 133         err = -ENOMEM;
 134         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 135         if(desc == NULL)
 136                 goto out;
 137
 138         *desc = ((struct phys_desc)
 139                 { .virt_ptrs =  { NULL, NULL },
 140                   .fd =         fd,
 141                   .offset =             offset,
 142                   .virt =               virt,
 143                   .phys =               __pa(virt),
 144                   .list =               LIST_HEAD_INIT(desc->list) });
 145         insert_virtmem_hash(&virtmem_hash, desc);
 146
 147         list_add(&desc->list, &fd_maps->pages);
 148
 149         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 150         err = os_map_memory(virt, fd, offset, PAGE_SIZE, 1, w, 0);
 151         if(!err)
 152                 goto out;
 153
 154         remove_virtmem_hash(&virtmem_hash, desc);
 155         kfree(desc);
 156  out:
 157         return(err);
 158 }
 159
 160 static int physmem_fd = -1;
 161
 162 static void remove_mapping(struct phys_desc *desc)
 163 {
 164         void *virt = desc->virt;
 165         int err;
 166
 167         remove_virtmem_hash(&virtmem_hash, desc);
 168         list_del(&desc->list);
 169         kfree(desc);
 170
 171         err = os_map_memory(virt, physmem_fd, __pa(virt), PAGE_SIZE, 1, 1, 0);
 172         if(err)
 173                 panic("Failed to unmap block device page from physical memory, "
 174                       "errno = %d", -err);
 175 }
 176
 177 int physmem_remove_mapping(void *virt)
 178 {
 179         struct phys_desc *desc;
 180
 181         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 182         desc = find_virtmem_hash(&virtmem_hash, virt);
 183         if(desc == NULL)
 184                 return(0);
 185
 186         remove_mapping(desc);
 187         return(1);
 188 }
 189
 190 void physmem_forget_descriptor(int fd)
 191 {
 192         struct desc_mapping *desc;
 193         struct phys_desc *page;
 194         struct list_head *ele, *next;
 195         __u64 offset;
 196         void *addr;
 197         int err;
 198
 199         desc = find_mapping(fd);
 200         if(desc == NULL)
 201                 return;
 202
 203         list_for_each_safe(ele, next, &desc->pages){
 204                 page = list_entry(ele, struct phys_desc, list);
 205                 offset = page->offset;
 206                 addr = page->virt;
 207                 remove_mapping(page);
 208                 err = os_seek_file(fd, offset);
 209                 if(err)
 210                         panic("physmem_forget_descriptor - failed to seek "
 211                               "to %lld in fd %d, error = %d\n",
 212                               offset, fd, -err);
 213                 err = os_read_file(fd, addr, PAGE_SIZE);
 214                 if(err < 0)
 215                         panic("physmem_forget_descriptor - failed to read "
 216                               "from fd %d to 0x%p, error = %d\n",
 217                               fd, addr, -err);
 218         }
 219
 220         list_del(&desc->list);
 221         kfree(desc);
 222 }
 223
 224 void arch_free_page(struct page *page, int order)
 225 {
 226         void *virt;
 227         int i;
 228
 229         for(i = 0; i < (1 << order); i++){
 230                 virt = __va(page_to_phys(page + i));
 231                 physmem_remove_mapping(virt);
 232         }
 233 }
 234
 235 int is_remapped(void *virt)
 236 {
 237         return(find_virtmem_hash(&virtmem_hash, virt) != NULL);
 238 }
 239
 240 /* Changed during early boot */
 241 unsigned long high_physmem;
 242
 243 extern unsigned long physmem_size;
 244
 245 void *to_virt(unsigned long phys)
 246 {
 247         return((void *) uml_physmem + phys);
 248 }
 249
 250 unsigned long to_phys(void *virt)
 251 {
 252         return(((unsigned long) virt) - uml_physmem);
 253 }
 254
 255 int init_maps(unsigned long physmem, unsigned long iomem, unsigned long highmem)
 256 {
 257         struct page *p, *map;
 258         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
 259         unsigned long iomem_len, iomem_pages, total_len, total_pages;
 260         int i;
 261
 262         phys_pages = physmem >> PAGE_SHIFT;
 263         phys_len = phys_pages * sizeof(struct page);
 264
 265         iomem_pages = iomem >> PAGE_SHIFT;
 266         iomem_len = iomem_pages * sizeof(struct page);
 267
 268         highmem_pages = highmem >> PAGE_SHIFT;
 269         highmem_len = highmem_pages * sizeof(struct page);
 270
 271         total_pages = phys_pages + iomem_pages + highmem_pages;
 272         total_len = phys_len + iomem_pages + highmem_len;
 273
 274         if(kmalloc_ok){
 275                 map = kmalloc(total_len, GFP_KERNEL);
 276                 if(map == NULL)
 277                         map = vmalloc(total_len);
 278         }
 279         else map = alloc_bootmem_low_pages(total_len);
 280
 281         if(map == NULL)
 282                 return(-ENOMEM);
 283
 284         for(i = 0; i < total_pages; i++){
 285                 p = &map[i];
 286                 set_page_count(p, 0);
 287                 SetPageReserved(p);
 288                 INIT_LIST_HEAD(&p->lru);
 289         }
 290
 291         mem_map = map;
 292         max_mapnr = total_pages;
 293         return(0);
 294 }
 295
 296 struct page *phys_to_page(const unsigned long phys)
 297 {
 298         return(&mem_map[phys >> PAGE_SHIFT]);
 299 }
 300
 301 struct page *__virt_to_page(const unsigned long virt)
 302 {
 303         return(&mem_map[__pa(virt) >> PAGE_SHIFT]);
 304 }
 305
 306 unsigned long page_to_phys(struct page *page)
 307 {
 308         return((page - mem_map) << PAGE_SHIFT);
 309 }
 310
 311 pte_t mk_pte(struct page *page, pgprot_t pgprot)
 312 {
 313         pte_t pte;
 314
 315         pte_val(pte) = page_to_phys(page) + pgprot_val(pgprot);
 316         if(pte_present(pte)) pte_mknewprot(pte_mknewpage(pte));
 317         return(pte);
 318 }
 319
 320 /* Changed during early boot */
 321 static unsigned long kmem_top = 0;
 322
 323 unsigned long get_kmem_end(void)
 324 {
 325         if(kmem_top == 0)
 326                 kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
 327         return(kmem_top);
 328 }
 329
 330 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 331                 int r, int w, int x)
 332 {
 333         __u64 offset;
 334         int fd, err;
 335
 336         fd = phys_mapping(phys, &offset);
 337         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
 338         if(err)
 339                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
 340                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
 341 }
 342
 343 #define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
 344
 345 void setup_physmem(unsigned long start, unsigned long reserve_end,
 346                    unsigned long len, unsigned long highmem)
 347 {
 348         unsigned long reserve = reserve_end - start;
 349         int pfn = PFN_UP(__pa(reserve_end));
 350         int delta = (len - reserve) >> PAGE_SHIFT;
 351         int err, offset, bootmap_size;
 352
 353         physmem_fd = create_mem_file(len + highmem);
 354
 355         offset = uml_reserved - uml_physmem;
 356         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 357                             len - offset, 1, 1, 0);
 358         if(err < 0){
 359                 os_print_error(err, "Mapping memory");
 360                 exit(1);
 361         }
 362
 363         bootmap_size = init_bootmem(pfn, pfn + delta);
 364         free_bootmem(__pa(reserve_end) + bootmap_size,
 365                      len - bootmap_size - reserve);
 366 }
 367
 368 int phys_mapping(unsigned long phys, __u64 *offset_out)
 369 {
 370         struct phys_desc *desc = find_virtmem_hash(&virtmem_hash,
 371                                                    __va(phys & PAGE_MASK));
 372         int fd = -1;
 373
 374         if(desc != NULL){
 375                 fd = desc->fd;
 376                 *offset_out = desc->offset;
 377         }
 378         else if(phys < physmem_size){
 379                 fd = physmem_fd;
 380                 *offset_out = phys;
 381         }
 382         else if(phys < __pa(end_iomem)){
 383                 struct iomem_region *region = iomem_regions;
 384
 385                 while(region != NULL){
 386                         if((phys >= region->phys) &&
 387                            (phys < region->phys + region->size)){
 388                                 fd = region->fd;
 389                                 *offset_out = phys - region->phys;
 390                                 break;
 391                         }
 392                         region = region->next;
 393                 }
 394         }
 395         else if(phys < __pa(end_iomem) + highmem){
 396                 fd = physmem_fd;
 397                 *offset_out = phys - iomem_size;
 398         }
 399
 400         return(fd);
 401 }
 402
 403 static int __init uml_mem_setup(char *line, int *add)
 404 {
 405         char *retptr;
 406         physmem_size = memparse(line,&retptr);
 407         return 0;
 408 }
 409 __uml_setup("mem=", uml_mem_setup,
 410 "mem=<Amount of desired ram>\n"
 411 "    This controls how much \"physical\" memory the kernel allocates\n"
 412 "    for the system. The size is specified as a number followed by\n"
 413 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 414 "    This is not related to the amount of memory in the host.  It can\n"
 415 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 416 "       Example: mem=64M\n\n"
 417 );
 418
 419 unsigned long find_iomem(char *driver, unsigned long *len_out)
 420 {
 421         struct iomem_region *region = iomem_regions;
 422
 423         while(region != NULL){
 424                 if(!strcmp(region->driver, driver)){
 425                         *len_out = region->size;
 426                         return(region->virt);
 427                 }
 428         }
 429
 430         return(0);
 431 }
 432
 433 int setup_iomem(void)
 434 {
 435         struct iomem_region *region = iomem_regions;
 436         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 437         int err;
 438
 439         while(region != NULL){
 440                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 441                                     region->size, 1, 1, 0);
 442                 if(err)
 443                         printk("Mapping iomem region for driver '%s' failed, "
 444                                "errno = %d\n", region->driver, -err);
 445                 else {
 446                         region->virt = iomem_start;
 447                         region->phys = __pa(region->virt);
 448                 }
 449
 450                 iomem_start += region->size + PAGE_SIZE;
 451                 region = region->next;
 452         }
 453
 454         return(0);
 455 }
 456
 457 __initcall(setup_iomem);
 458
 459 /*
 460  * Overrides for Emacs so that we follow Linus's tabbing style.
 461  * Emacs will notice this stuff at the end of the file and automatically
 462  * adjust the settings for this buffer only.  This must remain at the end
 463  * of the file.
 464  * ---------------------------------------------------------------------------
 465  * Local variables:
 466  * c-file-style: "linux"
 467  * End:
 468  */