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         phys = __pa(virt);
 126         desc = find_virtmem_hash(&virtmem_hash, (void *) virt);
 127         if(desc != NULL){
 128                 if((virt != desc->virt) || (fd != desc->fd) ||
 129                    (offset != desc->offset))
 130                         panic("Address 0x%p is already substituted\n", virt);
 131                 return(0);
 132         }
 133
 134         fd_maps = descriptor_mapping(fd);
 135         if(fd_maps == NULL)
 136                 return(-ENOMEM);
 137
 138         err = -ENOMEM;
 139         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 140         if(desc == NULL)
 141                 goto out;
 142
 143         *desc = ((struct phys_desc)
 144                 { .virt_ptrs =  { NULL, NULL },
 145                   .fd =         fd,
 146                   .offset =             offset,
 147                   .virt =               virt,
 148                   .phys =               __pa(virt),
 149                   .list =               LIST_HEAD_INIT(desc->list) });
 150         insert_virtmem_hash(&virtmem_hash, desc);
 151
 152         list_add(&desc->list, &fd_maps->pages);
 153
 154         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 155         err = os_map_memory(virt, fd, offset, PAGE_SIZE, 1, w, 0);
 156         if(!err)
 157                 goto out;
 158
 159         remove_virtmem_hash(&virtmem_hash, desc);
 160         kfree(desc);
 161  out:
 162         return(err);
 163 }
 164
 165 static int physmem_fd = -1;
 166
 167 static void remove_mapping(struct phys_desc *desc)
 168 {
 169         void *virt = desc->virt;
 170         int err;
 171
 172         remove_virtmem_hash(&virtmem_hash, desc);
 173         list_del(&desc->list);
 174         kfree(desc);
 175
 176         err = os_map_memory(virt, physmem_fd, __pa(virt), PAGE_SIZE, 1, 1, 0);
 177         if(err)
 178                 panic("Failed to unmap block device page from physical memory, "
 179                       "errno = %d", -err);
 180 }
 181
 182 int physmem_remove_mapping(void *virt)
 183 {
 184         struct phys_desc *desc;
 185
 186         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 187         desc = find_virtmem_hash(&virtmem_hash, virt);
 188         if(desc == NULL)
 189                 return(0);
 190
 191         remove_mapping(desc);
 192         return(1);
 193 }
 194
 195 void physmem_forget_descriptor(int fd)
 196 {
 197         struct desc_mapping *desc;
 198         struct phys_desc *page;
 199         struct list_head *ele, *next;
 200         __u64 offset;
 201         void *addr;
 202         int err;
 203
 204         desc = find_mapping(fd);
 205         if(desc == NULL)
 206                 return;
 207
 208         if(!list_empty(&desc->pages))
 209                 printk("Still have mapped pages on fd %d\n", fd);
 210
 211         list_for_each_safe(ele, next, &desc->pages){
 212                 page = list_entry(ele, struct phys_desc, list);
 213                 offset = page->offset;
 214                 addr = page->virt;
 215                 remove_mapping(page);
 216                 err = os_seek_file(fd, offset);
 217                 if(err)
 218                         panic("physmem_forget_descriptor - failed to seek "
 219                               "to %lld in fd %d, error = %d\n",
 220                               offset, fd, -err);
 221                 err = os_read_file(fd, addr, PAGE_SIZE);
 222                 if(err < 0)
 223                         panic("physmem_forget_descriptor - failed to read "
 224                               "from fd %d to 0x%p, error = %d\n",
 225                               fd, addr, -err);
 226         }
 227
 228         list_del(&desc->list);
 229         kfree(desc);
 230 }
 231
 232 void arch_free_page(struct page *page, int order)
 233 {
 234         void *virt;
 235         int i;
 236
 237         for(i = 0; i < (1 << order); i++){
 238                 virt = __va(page_to_phys(page + i));
 239                 physmem_remove_mapping(virt);
 240         }
 241 }
 242
 243 int is_remapped(const void *virt, int fd, __u64 offset)
 244 {
 245         struct phys_desc *desc;
 246
 247         desc = find_virtmem_hash(&virtmem_hash, (void *) virt);
 248         if(desc == NULL)
 249                 return(0);
 250         if(offset != desc->offset)
 251                 printk("offset mismatch\n");
 252         return(find_virtmem_hash(&virtmem_hash, (void *) virt) != NULL);
 253 }
 254
 255 /* Changed during early boot */
 256 unsigned long high_physmem;
 257
 258 extern unsigned long physmem_size;
 259
 260 void *to_virt(unsigned long phys)
 261 {
 262         return((void *) uml_physmem + phys);
 263 }
 264
 265 unsigned long to_phys(void *virt)
 266 {
 267         return(((unsigned long) virt) - uml_physmem);
 268 }
 269
 270 int init_maps(unsigned long physmem, unsigned long iomem, unsigned long highmem)
 271 {
 272         struct page *p, *map;
 273         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
 274         unsigned long iomem_len, iomem_pages, total_len, total_pages;
 275         int i;
 276
 277         phys_pages = physmem >> PAGE_SHIFT;
 278         phys_len = phys_pages * sizeof(struct page);
 279
 280         iomem_pages = iomem >> PAGE_SHIFT;
 281         iomem_len = iomem_pages * sizeof(struct page);
 282
 283         highmem_pages = highmem >> PAGE_SHIFT;
 284         highmem_len = highmem_pages * sizeof(struct page);
 285
 286         total_pages = phys_pages + iomem_pages + highmem_pages;
 287         total_len = phys_len + iomem_pages + highmem_len;
 288
 289         if(kmalloc_ok){
 290                 map = kmalloc(total_len, GFP_KERNEL);
 291                 if(map == NULL)
 292                         map = vmalloc(total_len);
 293         }
 294         else map = alloc_bootmem_low_pages(total_len);
 295
 296         if(map == NULL)
 297                 return(-ENOMEM);
 298
 299         for(i = 0; i < total_pages; i++){
 300                 p = &map[i];
 301                 set_page_count(p, 0);
 302                 SetPageReserved(p);
 303                 INIT_LIST_HEAD(&p->lru);
 304         }
 305
 306         mem_map = map;
 307         max_mapnr = total_pages;
 308         return(0);
 309 }
 310
 311 struct page *phys_to_page(const unsigned long phys)
 312 {
 313         return(&mem_map[phys >> PAGE_SHIFT]);
 314 }
 315
 316 struct page *__virt_to_page(const unsigned long virt)
 317 {
 318         return(&mem_map[__pa(virt) >> PAGE_SHIFT]);
 319 }
 320
 321 unsigned long page_to_phys(struct page *page)
 322 {
 323         return((page - mem_map) << PAGE_SHIFT);
 324 }
 325
 326 pte_t mk_pte(struct page *page, pgprot_t pgprot)
 327 {
 328         pte_t pte;
 329
 330         pte_val(pte) = page_to_phys(page) + pgprot_val(pgprot);
 331         if(pte_present(pte)) pte_mknewprot(pte_mknewpage(pte));
 332         return(pte);
 333 }
 334
 335 /* Changed during early boot */
 336 static unsigned long kmem_top = 0;
 337
 338 unsigned long get_kmem_end(void)
 339 {
 340         if(kmem_top == 0)
 341                 kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
 342         return(kmem_top);
 343 }
 344
 345 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 346                 int r, int w, int x)
 347 {
 348         __u64 offset;
 349         int fd, err;
 350
 351         fd = phys_mapping(phys, &offset);
 352         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
 353         if(err)
 354                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
 355                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
 356 }
 357
 358 #define PFN_UP(x) (((x) + PAGE_SIZE-1) >> PAGE_SHIFT)
 359
 360 void setup_physmem(unsigned long start, unsigned long reserve_end,
 361                    unsigned long len, unsigned long highmem)
 362 {
 363         unsigned long reserve = reserve_end - start;
 364         int pfn = PFN_UP(__pa(reserve_end));
 365         int delta = (len - reserve) >> PAGE_SHIFT;
 366         int err, offset, bootmap_size;
 367
 368         physmem_fd = create_mem_file(len + highmem);
 369
 370         offset = uml_reserved - uml_physmem;
 371         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 372                             len - offset, 1, 1, 0);
 373         if(err < 0){
 374                 os_print_error(err, "Mapping memory");
 375                 exit(1);
 376         }
 377
 378         bootmap_size = init_bootmem(pfn, pfn + delta);
 379         free_bootmem(__pa(reserve_end) + bootmap_size,
 380                      len - bootmap_size - reserve);
 381 }
 382
 383 int phys_mapping(unsigned long phys, __u64 *offset_out)
 384 {
 385         struct phys_desc *desc = find_virtmem_hash(&virtmem_hash,
 386                                                    __va(phys & PAGE_MASK));
 387         int fd = -1;
 388
 389         if(desc != NULL){
 390                 fd = desc->fd;
 391                 *offset_out = desc->offset;
 392         }
 393         else if(phys < physmem_size){
 394                 fd = physmem_fd;
 395                 *offset_out = phys;
 396         }
 397         else if(phys < __pa(end_iomem)){
 398                 struct iomem_region *region = iomem_regions;
 399
 400                 while(region != NULL){
 401                         if((phys >= region->phys) &&
 402                            (phys < region->phys + region->size)){
 403                                 fd = region->fd;
 404                                 *offset_out = phys - region->phys;
 405                                 break;
 406                         }
 407                         region = region->next;
 408                 }
 409         }
 410         else if(phys < __pa(end_iomem) + highmem){
 411                 fd = physmem_fd;
 412                 *offset_out = phys - iomem_size;
 413         }
 414
 415         return(fd);
 416 }
 417
 418 static int __init uml_mem_setup(char *line, int *add)
 419 {
 420         char *retptr;
 421         physmem_size = memparse(line,&retptr);
 422         return 0;
 423 }
 424 __uml_setup("mem=", uml_mem_setup,
 425 "mem=<Amount of desired ram>\n"
 426 "    This controls how much \"physical\" memory the kernel allocates\n"
 427 "    for the system. The size is specified as a number followed by\n"
 428 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 429 "    This is not related to the amount of memory in the host.  It can\n"
 430 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 431 "       Example: mem=64M\n\n"
 432 );
 433
 434 unsigned long find_iomem(char *driver, unsigned long *len_out)
 435 {
 436         struct iomem_region *region = iomem_regions;
 437
 438         while(region != NULL){
 439                 if(!strcmp(region->driver, driver)){
 440                         *len_out = region->size;
 441                         return(region->virt);
 442                 }
 443         }
 444
 445         return(0);
 446 }
 447
 448 int setup_iomem(void)
 449 {
 450         struct iomem_region *region = iomem_regions;
 451         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 452         int err;
 453
 454         while(region != NULL){
 455                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 456                                     region->size, 1, 1, 0);
 457                 if(err)
 458                         printk("Mapping iomem region for driver '%s' failed, "
 459                                "errno = %d\n", region->driver, -err);
 460                 else {
 461                         region->virt = iomem_start;
 462                         region->phys = __pa(region->virt);
 463                 }
 464
 465                 iomem_start += region->size + PAGE_SIZE;
 466                 region = region->next;
 467         }
 468
 469         return(0);
 470 }
 471
 472 __initcall(setup_iomem);
 473
 474 /*
 475  * Overrides for Emacs so that we follow Linus's tabbing style.
 476  * Emacs will notice this stuff at the end of the file and automatically
 477  * adjust the settings for this buffer only.  This must remain at the end
 478  * of the file.
 479  * ---------------------------------------------------------------------------
 480  * Local variables:
 481  * c-file-style: "linux"
 482  * End:
 483  */