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 "as-layout.h"
  17 #include "user_util.h"
  18 #include "mode_kern.h"
  19 #include "mem.h"
  20 #include "mem_user.h"
  21 #include "os.h"
  22 #include "kern.h"
  23 #include "init.h"
  24
  25 struct phys_desc {
  26         struct rb_node rb;
  27         int fd;
  28         __u64 offset;
  29         void *virt;
  30         unsigned long phys;
  31         struct list_head list;
  32 };
  33
  34 static struct rb_root phys_mappings = RB_ROOT;
  35
  36 static struct rb_node **find_rb(void *virt)
  37 {
  38         struct rb_node **n = &phys_mappings.rb_node;
  39         struct phys_desc *d;
  40
  41         while(*n != NULL){
  42                 d = rb_entry(*n, struct phys_desc, rb);
  43                 if(d->virt == virt)
  44                         return n;
  45
  46                 if(d->virt > virt)
  47                         n = &(*n)->rb_left;
  48                 else
  49                         n = &(*n)->rb_right;
  50         }
  51
  52         return n;
  53 }
  54
  55 static struct phys_desc *find_phys_mapping(void *virt)
  56 {
  57         struct rb_node **n = find_rb(virt);
  58
  59         if(*n == NULL)
  60                 return NULL;
  61
  62         return rb_entry(*n, struct phys_desc, rb);
  63 }
  64
  65 static void insert_phys_mapping(struct phys_desc *desc)
  66 {
  67         struct rb_node **n = find_rb(desc->virt);
  68
  69         if(*n != NULL)
  70                 panic("Physical remapping for %p already present",
  71                       desc->virt);
  72
  73         rb_link_node(&desc->rb, rb_parent(*n), n);
  74         rb_insert_color(&desc->rb, &phys_mappings);
  75 }
  76
  77 LIST_HEAD(descriptor_mappings);
  78
  79 struct desc_mapping {
  80         int fd;
  81         struct list_head list;
  82         struct list_head pages;
  83 };
  84
  85 static struct desc_mapping *find_mapping(int fd)
  86 {
  87         struct desc_mapping *desc;
  88         struct list_head *ele;
  89
  90         list_for_each(ele, &descriptor_mappings){
  91                 desc = list_entry(ele, struct desc_mapping, list);
  92                 if(desc->fd == fd)
  93                         return desc;
  94         }
  95
  96         return NULL;
  97 }
  98
  99 static struct desc_mapping *descriptor_mapping(int fd)
 100 {
 101         struct desc_mapping *desc;
 102
 103         desc = find_mapping(fd);
 104         if(desc != NULL)
 105                 return desc;
 106
 107         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 108         if(desc == NULL)
 109                 return NULL;
 110
 111         *desc = ((struct desc_mapping)
 112                 { .fd =         fd,
 113                   .list =       LIST_HEAD_INIT(desc->list),
 114                   .pages =      LIST_HEAD_INIT(desc->pages) });
 115         list_add(&desc->list, &descriptor_mappings);
 116
 117         return desc;
 118 }
 119
 120 int physmem_subst_mapping(void *virt, int fd, __u64 offset, int w)
 121 {
 122         struct desc_mapping *fd_maps;
 123         struct phys_desc *desc;
 124         unsigned long phys;
 125         int err;
 126
 127         fd_maps = descriptor_mapping(fd);
 128         if(fd_maps == NULL)
 129                 return -ENOMEM;
 130
 131         phys = __pa(virt);
 132         desc = find_phys_mapping(virt);
 133         if(desc != NULL)
 134                 panic("Address 0x%p is already substituted\n", virt);
 135
 136         err = -ENOMEM;
 137         desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
 138         if(desc == NULL)
 139                 goto out;
 140
 141         *desc = ((struct phys_desc)
 142                 { .fd =                 fd,
 143                   .offset =             offset,
 144                   .virt =               virt,
 145                   .phys =               __pa(virt),
 146                   .list =               LIST_HEAD_INIT(desc->list) });
 147         insert_phys_mapping(desc);
 148
 149         list_add(&desc->list, &fd_maps->pages);
 150
 151         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 152         err = os_map_memory(virt, fd, offset, PAGE_SIZE, 1, w, 0);
 153         if(!err)
 154                 goto out;
 155
 156         rb_erase(&desc->rb, &phys_mappings);
 157         kfree(desc);
 158  out:
 159         return err;
 160 }
 161
 162 static int physmem_fd = -1;
 163
 164 static void remove_mapping(struct phys_desc *desc)
 165 {
 166         void *virt = desc->virt;
 167         int err;
 168
 169         rb_erase(&desc->rb, &phys_mappings);
 170         list_del(&desc->list);
 171         kfree(desc);
 172
 173         err = os_map_memory(virt, physmem_fd, __pa(virt), PAGE_SIZE, 1, 1, 0);
 174         if(err)
 175                 panic("Failed to unmap block device page from physical memory, "
 176                       "errno = %d", -err);
 177 }
 178
 179 int physmem_remove_mapping(void *virt)
 180 {
 181         struct phys_desc *desc;
 182
 183         virt = (void *) ((unsigned long) virt & PAGE_MASK);
 184         desc = find_phys_mapping(virt);
 185         if(desc == NULL)
 186                 return 0;
 187
 188         remove_mapping(desc);
 189         return 1;
 190 }
 191
 192 void physmem_forget_descriptor(int fd)
 193 {
 194         struct desc_mapping *desc;
 195         struct phys_desc *page;
 196         struct list_head *ele, *next;
 197         __u64 offset;
 198         void *addr;
 199         int err;
 200
 201         desc = find_mapping(fd);
 202         if(desc == NULL)
 203                 return;
 204
 205         list_for_each_safe(ele, next, &desc->pages){
 206                 page = list_entry(ele, struct phys_desc, list);
 207                 offset = page->offset;
 208                 addr = page->virt;
 209                 remove_mapping(page);
 210                 err = os_seek_file(fd, offset);
 211                 if(err)
 212                         panic("physmem_forget_descriptor - failed to seek "
 213                               "to %lld in fd %d, error = %d\n",
 214                               offset, fd, -err);
 215                 err = os_read_file(fd, addr, PAGE_SIZE);
 216                 if(err < 0)
 217                         panic("physmem_forget_descriptor - failed to read "
 218                               "from fd %d to 0x%p, error = %d\n",
 219                               fd, addr, -err);
 220         }
 221
 222         list_del(&desc->list);
 223         kfree(desc);
 224 }
 225
 226 EXPORT_SYMBOL(physmem_forget_descriptor);
 227 EXPORT_SYMBOL(physmem_remove_mapping);
 228 EXPORT_SYMBOL(physmem_subst_mapping);
 229
 230 void arch_free_page(struct page *page, int order)
 231 {
 232         void *virt;
 233         int i;
 234
 235         for(i = 0; i < (1 << order); i++){
 236                 virt = __va(page_to_phys(page + i));
 237                 physmem_remove_mapping(virt);
 238         }
 239 }
 240
 241 int is_remapped(void *virt)
 242 {
 243         struct phys_desc *desc = find_phys_mapping(virt);
 244
 245         return desc != NULL;
 246 }
 247
 248 /* Changed during early boot */
 249 unsigned long high_physmem;
 250
 251 extern unsigned long long physmem_size;
 252
 253 int init_maps(unsigned long physmem, unsigned long iomem, unsigned long highmem)
 254 {
 255         struct page *p, *map;
 256         unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
 257         unsigned long iomem_len, iomem_pages, total_len, total_pages;
 258         int i;
 259
 260         phys_pages = physmem >> PAGE_SHIFT;
 261         phys_len = phys_pages * sizeof(struct page);
 262
 263         iomem_pages = iomem >> PAGE_SHIFT;
 264         iomem_len = iomem_pages * sizeof(struct page);
 265
 266         highmem_pages = highmem >> PAGE_SHIFT;
 267         highmem_len = highmem_pages * sizeof(struct page);
 268
 269         total_pages = phys_pages + iomem_pages + highmem_pages;
 270         total_len = phys_len + iomem_len + highmem_len;
 271
 272         if(kmalloc_ok){
 273                 map = kmalloc(total_len, GFP_KERNEL);
 274                 if(map == NULL)
 275                         map = vmalloc(total_len);
 276         }
 277         else map = alloc_bootmem_low_pages(total_len);
 278
 279         if(map == NULL)
 280                 return -ENOMEM;
 281
 282         for(i = 0; i < total_pages; i++){
 283                 p = &map[i];
 284                 memset(p, 0, sizeof(struct page));
 285                 SetPageReserved(p);
 286                 INIT_LIST_HEAD(&p->lru);
 287         }
 288
 289         max_mapnr = total_pages;
 290         return 0;
 291 }
 292
 293 /* Changed during early boot */
 294 static unsigned long kmem_top = 0;
 295
 296 unsigned long get_kmem_end(void)
 297 {
 298         if(kmem_top == 0)
 299                 kmem_top = CHOOSE_MODE(kmem_end_tt, kmem_end_skas);
 300         return kmem_top;
 301 }
 302
 303 void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 304                 int r, int w, int x)
 305 {
 306         __u64 offset;
 307         int fd, err;
 308
 309         fd = phys_mapping(phys, &offset);
 310         err = os_map_memory((void *) virt, fd, offset, len, r, w, x);
 311         if(err) {
 312                 if(err == -ENOMEM)
 313                         printk("try increasing the host's "
 314                                "/proc/sys/vm/max_map_count to <physical "
 315                                "memory size>/4096\n");
 316                 panic("map_memory(0x%lx, %d, 0x%llx, %ld, %d, %d, %d) failed, "
 317                       "err = %d\n", virt, fd, offset, len, r, w, x, err);
 318         }
 319 }
 320
 321 extern int __syscall_stub_start;
 322
 323 void setup_physmem(unsigned long start, unsigned long reserve_end,
 324                    unsigned long len, unsigned long long highmem)
 325 {
 326         unsigned long reserve = reserve_end - start;
 327         int pfn = PFN_UP(__pa(reserve_end));
 328         int delta = (len - reserve) >> PAGE_SHIFT;
 329         int err, offset, bootmap_size;
 330
 331         physmem_fd = create_mem_file(len + highmem);
 332
 333         offset = uml_reserved - uml_physmem;
 334         err = os_map_memory((void *) uml_reserved, physmem_fd, offset,
 335                             len - offset, 1, 1, 0);
 336         if(err < 0){
 337                 os_print_error(err, "Mapping memory");
 338                 exit(1);
 339         }
 340
 341         /* Special kludge - This page will be mapped in to userspace processes
 342          * from physmem_fd, so it needs to be written out there.
 343          */
 344         os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
 345         os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
 346
 347         bootmap_size = init_bootmem(pfn, pfn + delta);
 348         free_bootmem(__pa(reserve_end) + bootmap_size,
 349                      len - bootmap_size - reserve);
 350 }
 351
 352 int phys_mapping(unsigned long phys, __u64 *offset_out)
 353 {
 354         struct phys_desc *desc = find_phys_mapping(__va(phys & PAGE_MASK));
 355         int fd = -1;
 356
 357         if(desc != NULL){
 358                 fd = desc->fd;
 359                 *offset_out = desc->offset;
 360         }
 361         else if(phys < physmem_size){
 362                 fd = physmem_fd;
 363                 *offset_out = phys;
 364         }
 365         else if(phys < __pa(end_iomem)){
 366                 struct iomem_region *region = iomem_regions;
 367
 368                 while(region != NULL){
 369                         if((phys >= region->phys) &&
 370                            (phys < region->phys + region->size)){
 371                                 fd = region->fd;
 372                                 *offset_out = phys - region->phys;
 373                                 break;
 374                         }
 375                         region = region->next;
 376                 }
 377         }
 378         else if(phys < __pa(end_iomem) + highmem){
 379                 fd = physmem_fd;
 380                 *offset_out = phys - iomem_size;
 381         }
 382
 383         return fd;
 384 }
 385
 386 static int __init uml_mem_setup(char *line, int *add)
 387 {
 388         char *retptr;
 389         physmem_size = memparse(line,&retptr);
 390         return 0;
 391 }
 392 __uml_setup("mem=", uml_mem_setup,
 393 "mem=<Amount of desired ram>\n"
 394 "    This controls how much \"physical\" memory the kernel allocates\n"
 395 "    for the system. The size is specified as a number followed by\n"
 396 "    one of 'k', 'K', 'm', 'M', which have the obvious meanings.\n"
 397 "    This is not related to the amount of memory in the host.  It can\n"
 398 "    be more, and the excess, if it's ever used, will just be swapped out.\n"
 399 "       Example: mem=64M\n\n"
 400 );
 401
 402 extern int __init parse_iomem(char *str, int *add);
 403
 404 __uml_setup("iomem=", parse_iomem,
 405 "iomem=<name>,<file>\n"
 406 "    Configure <file> as an IO memory region named <name>.\n\n"
 407 );
 408
 409 /*
 410  * This list is constructed in parse_iomem and addresses filled in in
 411  * setup_iomem, both of which run during early boot.  Afterwards, it's
 412  * unchanged.
 413  */
 414 struct iomem_region *iomem_regions = NULL;
 415
 416 /* Initialized in parse_iomem */
 417 int iomem_size = 0;
 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                 region = region->next;
 430         }
 431
 432         return 0;
 433 }
 434
 435 int setup_iomem(void)
 436 {
 437         struct iomem_region *region = iomem_regions;
 438         unsigned long iomem_start = high_physmem + PAGE_SIZE;
 439         int err;
 440
 441         while(region != NULL){
 442                 err = os_map_memory((void *) iomem_start, region->fd, 0,
 443                                     region->size, 1, 1, 0);
 444                 if(err)
 445                         printk("Mapping iomem region for driver '%s' failed, "
 446                                "errno = %d\n", region->driver, -err);
 447                 else {
 448                         region->virt = iomem_start;
 449                         region->phys = __pa(region->virt);
 450                 }
 451
 452                 iomem_start += region->size + PAGE_SIZE;
 453                 region = region->next;
 454         }
 455
 456         return 0;
 457 }
 458
 459 __initcall(setup_iomem);