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/rbtree.h"
   8 #include "linux/slab.h"
   9 #include "linux/vmalloc.h"
  10 #include "linux/bootmem.h"
  11 #include "linux/module.h"
  12 #include "linux/pfn.h"
  13 #include "asm/types.h"
  14 #include "asm/pgtable.h"
  15 #include "kern_util.h"
  16 #include "user_util.h"
  17 #include "mode_kern.h"
  18 #include "mem.h"
  19 #include "mem_user.h"
  20 #include "os.h"
  21 #include "kern.h"
  22 #include "init.h"
  23
  24 struct phys_desc {
  25         struct rb_node rb;
  26         int fd;
  27         __u64 offset;
  28         void *virt;
  29         unsigned long phys;
  30         struct list_head list;
  31 };
  32
  33 static struct rb_root phys_mappings = RB_ROOT;
  34
  35 static struct rb_node **find_rb(void *virt)
  36 {
  37         struct rb_node **n = &phys_mappings.rb_node;
  38         struct phys_desc *d;
  39
  40         while(*n != NULL){
  41                 d = rb_entry(*n, struct phys_desc, rb);
  42                 if(d->virt == virt)
  43                         return(n);
  44
  45                 if(d->virt > virt)
  46                         n = &(*n)->rb_left;
  47                 else
  48                         n = &(*n)->rb_right;
  49         }
  50
  51         return(n);
  52 }
  53
  54 static struct phys_desc *find_phys_mapping(void *virt)
  55 {
  56         struct rb_node **n = find_rb(virt);
  57
  58         if(*n == NULL)
  59                 return(NULL);
  60
  61         return(rb_entry(*n, struct phys_desc, rb));
  62 }
  63
  64 static void insert_phys_mapping(struct phys_desc *desc)
  65 {
  66         struct rb_node **n = find_rb(desc->virt);
  67
  68         if(*n != NULL)
  69                 panic("Physical remapping for %p already present",
  70                       desc->virt);
  71
  72         rb_link_node(&desc->rb, rb_parent(*n), n);
  73         rb_insert_color(&desc->rb, &phys_mappings);
  74 }
  75
  76 LIST_HEAD(descriptor_mappings);
  77
  78 struct desc_mapping {
  79         int fd;
  80         struct list_head list;
  81         struct list_head pages;
  82 };
  83
  84 static struct desc_mapping *find_mapping(int fd)
  85 {
  86         struct desc_mapping *desc;
  87         struct list_head *ele;
  88
  89         list_for_each(ele, &descriptor_mappings){
  90                 desc = list_entry(ele, struct desc_mapping, list);
  91                 if(desc->fd == fd)
  92                         return(desc);
  93         }
  94
  95         return(NULL);
  96 }
  97
  98 static struct desc_mapping *descriptor_mapping(int fd)
  99 {
 100         struct desc_mapping *desc;
 101
 102         desc = find_mapping(fd);
 103         if(desc != NULL)
 104                 return(desc);
 105
 106         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 107         if(desc == NULL)
 108                 return(NULL);
 109
 110         *desc = ((struct desc_mapping)
 111                 { .fd =         fd,
 112                   .list =       LIST_HEAD_INIT(desc->list),
 113                   .pages =      LIST_HEAD_INIT(desc->pages) });
 114         list_add(&desc->list, &descriptor_mappings);
 115
 116         return(desc);
 117 }
 118
 119 int physmem_subst_mapping(void *virt, int fd, __u64 offset, int w)
 120 {
 121         struct desc_mapping *fd_maps;
 122         struct phys_desc *desc;
 123         unsigned long phys;
 124         int err;
 125
 126         fd_maps = descriptor_mapping(fd);
 127         if(fd_maps == NULL)
 128                 return(-ENOMEM);
 129
 130         phys = __pa(virt);
 131         desc = find_phys_mapping(virt);
 132         if(desc != NULL)
 133                 panic("Address 0x%p is already substituted\n", virt);
 134
 135         err = -ENOMEM;
 136         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 137         if(desc == NULL)
 138                 goto out;
 139
 140         *desc = ((struct phys_desc)
 141                 { .fd =                 fd,
 142                   .offset =             offset,
 143                   .virt =               virt,
 144                   .phys =               __pa(virt),
 145                   .list =               LIST_HEAD_INIT(desc->list) });
 146         insert_phys_mapping(desc);
 147
 148         list_add(&desc->list, &fd_maps->pages);
 149
 150         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 151         err = os_map_memory(virt, fd, offset, PAGE_SIZE, 1, w, 0);
 152         if(!err)
 153                 goto out;
 154
 155         rb_erase(&desc->rb, &phys_mappings);
 156         kfree(desc);
 157  out:
 158         return(err);
 159 }
 160
 161 static int physmem_fd = -1;
 162
 163 static void remove_mapping(struct phys_desc *desc)
 164 {
 165         void *virt = desc->virt;
 166         int err;
 167
 168         rb_erase(&desc->rb, &phys_mappings);
 169         list_del(&desc->list);
 170         kfree(desc);
 171
 172         err = os_map_memory(virt, physmem_fd, __pa(virt), PAGE_SIZE, 1, 1, 0);
 173         if(err)
 174                 panic("Failed to unmap block device page from physical memory, "
 175                       "errno = %d", -err);
 176 }
 177
 178 int physmem_remove_mapping(void *virt)
 179 {
 180         struct phys_desc *desc;
 181
 182         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 183         desc = find_phys_mapping(virt);
 184         if(desc == NULL)
 185                 return(0);
 186
 187         remove_mapping(desc);
 188         return(1);
 189 }
 190
 191 void physmem_forget_descriptor(int fd)
 192 {
 193         struct desc_mapping *desc;
 194         struct phys_desc *page;
 195         struct list_head *ele, *next;
 196         __u64 offset;
 197         void *addr;
 198         int err;
 199
 200         desc = find_mapping(fd);
 201         if(desc == NULL)
 202                 return;
 203
 204         list_for_each_safe(ele, next, &desc->pages){
 205                 page = list_entry(ele, struct phys_desc, list);
 206                 offset = page->offset;
 207                 addr = page->virt;
 208                 remove_mapping(page);
 209                 err = os_seek_file(fd, offset);
 210                 if(err)
 211                         panic("physmem_forget_descriptor - failed to seek "
 212                               "to %lld in fd %d, error = %d\n",
 213                               offset, fd, -err);
 214                 err = os_read_file(fd, addr, PAGE_SIZE);
 215                 if(err < 0)
 216                         panic("physmem_forget_descriptor - failed to read "
 217                               "from fd %d to 0x%p, error = %d\n",
 218                               fd, addr, -err);
 219         }
 220
 221         list_del(&desc->list);
 222         kfree(desc);
 223 }
 224
 225 EXPORT_SYMBOL(physmem_forget_descriptor);
 226 EXPORT_SYMBOL(physmem_remove_mapping);
 227 EXPORT_SYMBOL(physmem_subst_mapping);
 228
 229 int arch_free_page(struct page *page, int order)
 230 {
 231         void *virt;
 232         int i;
 233
 234         for(i = 0; i < (1 << order); i++){
 235                 virt = __va(page_to_phys(page + i));
 236                 physmem_remove_mapping(virt);
 237         }
 238
 239         return 0;
 240 }
 241
 242 int is_remapped(void *virt)
 243 {
 244         struct phys_desc *desc = find_phys_mapping(virt);
 245
 246         return(desc != NULL);
 247 }
 248
 249 /* Changed during early boot */
 250 unsigned long high_physmem;
 251
 252 extern unsigned long long physmem_size;
 253
 254 int init_maps(unsigned long physmem, unsigned long iomem, unsigned long highmem)
 255 {
 256         struct page *p, *map;
 257         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
 258         unsigned long iomem_len, iomem_pages, total_len, total_pages;
 259         int i;
 260
 261         phys_pages = physmem >> PAGE_SHIFT;
 262         phys_len = phys_pages * sizeof(struct page);
 263
 264         iomem_pages = iomem >> PAGE_SHIFT;
 265         iomem_len = iomem_pages * sizeof(struct page);
 266
 267         highmem_pages = highmem >> PAGE_SHIFT;
 268         highmem_len = highmem_pages * sizeof(struct page);
 269
 270         total_pages = phys_pages + iomem_pages + highmem_pages;
 271         total_len = phys_len + iomem_len + highmem_len;
 272
 273         if(kmalloc_ok){
 274                 map = kmalloc(total_len, GFP_KERNEL);
 275                 if(map == NULL)
 276                         map = vmalloc(total_len);
 277         }
 278         else map = alloc_bootmem_low_pages(total_len);
 279
 280         if(map == NULL)
 281                 return(-ENOMEM);
 282
 283         for(i = 0; i < total_pages; i++){
 284                 p = &map[i];
 285                 memset(p, 0, sizeof(struct page));
 286                 SetPageReserved(p);
 287                 INIT_LIST_HEAD(&p->lru);
 288         }
 289
 290         max_mapnr = total_pages;
 291         return(0);
 292 }
 293
 294 /* Changed during early boot */
 295 static unsigned long kmem_top = 0;
 296
 297 unsigned long get_kmem_end(void)
 298 {
 299         if(kmem_top == 0)
 300                 kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
 301         return(kmem_top);
 302 }
 303
 304 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 305                 int r, int w, int x)
 306 {
 307         __u64 offset;
 308         int fd, err;
 309
 310         fd = phys_mapping(phys, &offset);
 311         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
 312         if(err) {
 313                 if(err == -ENOMEM)
 314                         printk("try increasing the host's "
 315                                "/proc/sys/vm/max_map_count to <physical "
 316                                "memory size>/4096\n");
 317                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
 318                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
 319         }
 320 }
 321
 322 extern int __syscall_stub_start;
 323
 324 void setup_physmem(unsigned long start, unsigned long reserve_end,
 325                    unsigned long len, unsigned long long highmem)
 326 {
 327         unsigned long reserve = reserve_end - start;
 328         int pfn = PFN_UP(__pa(reserve_end));
 329         int delta = (len - reserve) >> PAGE_SHIFT;
 330         int err, offset, bootmap_size;
 331
 332         physmem_fd = create_mem_file(len + highmem);
 333
 334         offset = uml_reserved - uml_physmem;
 335         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 336                             len - offset, 1, 1, 0);
 337         if(err < 0){
 338                 os_print_error(err, "Mapping memory");
 339                 exit(1);
 340         }
 341
 342         /* Special kludge - This page will be mapped in to userspace processes
 343          * from physmem_fd, so it needs to be written out there.
 344          */
 345         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 346         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
 347
 348         bootmap_size = init_bootmem(pfn, pfn + delta);
 349         free_bootmem(__pa(reserve_end) + bootmap_size,
 350                      len - bootmap_size - reserve);
 351 }
 352
 353 int phys_mapping(unsigned long phys, __u64 *offset_out)
 354 {
 355         struct phys_desc *desc = find_phys_mapping(__va(phys & PAGE_MASK));
 356         int fd = -1;
 357
 358         if(desc != NULL){
 359                 fd = desc->fd;
 360                 *offset_out = desc->offset;
 361         }
 362         else if(phys < physmem_size){
 363                 fd = physmem_fd;
 364                 *offset_out = phys;
 365         }
 366         else if(phys < __pa(end_iomem)){
 367                 struct iomem_region *region = iomem_regions;
 368
 369                 while(region != NULL){
 370                         if((phys >= region->phys) &&
 371                            (phys < region->phys + region->size)){
 372                                 fd = region->fd;
 373                                 *offset_out = phys - region->phys;
 374                                 break;
 375                         }
 376                         region = region->next;
 377                 }
 378         }
 379         else if(phys < __pa(end_iomem) + highmem){
 380                 fd = physmem_fd;
 381                 *offset_out = phys - iomem_size;
 382         }
 383
 384         return(fd);
 385 }
 386
 387 static int __init uml_mem_setup(char *line, int *add)
 388 {
 389         char *retptr;
 390         physmem_size = memparse(line,&retptr);
 391         return 0;
 392 }
 393 __uml_setup("mem=", uml_mem_setup,
 394 "mem=<Amount of desired ram>\n"
 395 "    This controls how much \"physical\" memory the kernel allocates\n"
 396 "    for the system. The size is specified as a number followed by\n"
 397 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 398 "    This is not related to the amount of memory in the host.  It can\n"
 399 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 400 "       Example: mem=64M\n\n"
 401 );
 402
 403 unsigned long find_iomem(char *driver, unsigned long *len_out)
 404 {
 405         struct iomem_region *region = iomem_regions;
 406
 407         while(region != NULL){
 408                 if(!strcmp(region->driver, driver)){
 409                         *len_out = region->size;
 410                         return(region->virt);
 411                 }
 412
 413                 region = region->next;
 414         }
 415
 416         return(0);
 417 }
 418
 419 int setup_iomem(void)
 420 {
 421         struct iomem_region *region = iomem_regions;
 422         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 423         int err;
 424
 425         while(region != NULL){
 426                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 427                                     region->size, 1, 1, 0);
 428                 if(err)
 429                         printk("Mapping iomem region for driver '%s' failed, "
 430                                "errno = %d\n", region->driver, -err);
 431                 else {
 432                         region->virt = iomem_start;
 433                         region->phys = __pa(region->virt);
 434                 }
 435
 436                 iomem_start += region->size + PAGE_SIZE;
 437                 region = region->next;
 438         }
 439
 440         return(0);
 441 }
 442
 443 __initcall(setup_iomem);
 444
 445 /*
 446  * Overrides for Emacs so that we follow Linus's tabbing style.
 447  * Emacs will notice this stuff at the end of the file and automatically
 448  * adjust the settings for this buffer only.  This must remain at the end
 449  * of the file.
 450  * ---------------------------------------------------------------------------
 451  * Local variables:
 452  * c-file-style: "linux"
 453  * End:
 454  */