root/include/linux/mm.h

INCLUDED FROM

DEFINITIONS

1. get_free_page
2. expand_stack
3. find_vma
4. find_vma_intersection
5. in_swap_cache
6. find_in_swap_cache
7. delete_from_swap_cache

   1 #ifndef _LINUX_MM_H
   2 #define _LINUX_MM_H
   4 #include <linux/sched.h>
   5 #include <linux/errno.h>
   6 #include <linux/kernel.h>
   7 #include <linux/string.h>
   9 extern unsigned long high_memory;
  11 #include <asm/page.h>
  13 #ifdef __KERNEL__
  15 #define VERIFY_READ 0
  16 #define VERIFY_WRITE 1
  18 extern int verify_area(int, const void *, unsigned long);
  20 /*
  21  * Linux kernel virtual memory manager primitives.
  22  * The idea being to have a "virtual" mm in the same way
  23  * we have a virtual fs - giving a cleaner interface to the
  24  * mm details, and allowing different kinds of memory mappings
  25  * (from shared memory to executable loading to arbitrary
  26  * mmap() functions).
  27  */
  29 /*
  30  * This struct defines a memory VMM memory area. There is one of these
  31  * per VM-area/task.  A VM area is any part of the process virtual memory
  32  * space that has a special rule for the page-fault handlers (ie a shared
  33  * library, the executable area etc).
  34  */
  35 struct vm_area_struct {
  36         struct mm_struct * vm_mm;       /* VM area parameters */
  37         unsigned long vm_start;
  38         unsigned long vm_end;
pgprot_t vm_page_prot;
  40         unsigned short vm_flags;
  41 /* AVL tree of VM areas per task, sorted by address */
  42         short vm_avl_height;
  43         struct vm_area_struct * vm_avl_left;
  44         struct vm_area_struct * vm_avl_right;
  45 /* linked list of VM areas per task, sorted by address */
  46         struct vm_area_struct * vm_next;
  47 /* for areas with inode, the circular list inode->i_mmap */
  48 /* for shm areas, the circular list of attaches */
  49 /* otherwise unused */
  50         struct vm_area_struct * vm_next_share;
  51         struct vm_area_struct * vm_prev_share;
  52 /* more */
  53         struct vm_operations_struct * vm_ops;
  54         unsigned long vm_offset;
  55         struct inode * vm_inode;
  56         unsigned long vm_pte;                   /* shared mem */
  57 };
  59 /*
  60  * vm_flags..
  61  */
  62 #define VM_READ         0x0001  /* currently active flags */
  63 #define VM_WRITE        0x0002
  64 #define VM_EXEC         0x0004
  65 #define VM_SHARED       0x0008
  67 #define VM_MAYREAD      0x0010  /* limits for mprotect() etc */
  68 #define VM_MAYWRITE     0x0020
  69 #define VM_MAYEXEC      0x0040
  70 #define VM_MAYSHARE     0x0080
  72 #define VM_GROWSDOWN    0x0100  /* general info on the segment */
  73 #define VM_GROWSUP      0x0200
  74 #define VM_SHM          0x0400  /* shared memory area, don't swap out */
  75 #define VM_DENYWRITE    0x0800  /* ETXTBSY on write attempts.. */
  77 #define VM_EXECUTABLE   0x1000
  78 #define VM_LOCKED       0x2000
  80 #define VM_STACK_FLAGS  0x0177
  82 /*
  83  * mapping from the currently active vm_flags protection bits (the
  84  * low four bits) to a page protection mask..
  85  */
  86 extern pgprot_t protection_map[16];
  89 /*
  90  * These are the virtual MM functions - opening of an area, closing and
  91  * unmapping it (needed to keep files on disk up-to-date etc), pointer
  92  * to the functions called when a no-page or a wp-page exception occurs. 
  93  */
  94 struct vm_operations_struct {
  95         void (*open)(struct vm_area_struct * area);
  96         void (*close)(struct vm_area_struct * area);
  97         void (*unmap)(struct vm_area_struct *area, unsigned long, size_t);
  98         void (*protect)(struct vm_area_struct *area, unsigned long, size_t, unsigned int newprot);
  99         int (*sync)(struct vm_area_struct *area, unsigned long, size_t, unsigned int flags);
 100         void (*advise)(struct vm_area_struct *area, unsigned long, size_t, unsigned int advise);
 101         unsigned long (*nopage)(struct vm_area_struct * area, unsigned long address,
 102                 unsigned long page, int write_access);
 103         unsigned long (*wppage)(struct vm_area_struct * area, unsigned long address,
 104                 unsigned long page);
 105         int (*swapout)(struct vm_area_struct *,  unsigned long, pte_t *);
pte_t (*swapin)(struct vm_area_struct *, unsigned long, unsigned long);
 107 };
 109 typedef struct page {
 110         unsigned int count;
 111         unsigned dirty:16,
age:8,
uptodate:1,
error:1,
unused:5,
reserved:1;
 117         unsigned long offset;
 118         struct inode *inode;
 119         struct wait_queue *wait;
 120         struct page *write_list;
 121         struct page *next, *prev;
 122         struct page *next_hash, *prev_hash;
 123 } mem_map_t;
 125 extern mem_map_t * mem_map;
 127 /*
 128  * Free area management
 129  */
 131 extern int nr_swap_pages;
 132 extern int nr_free_pages;
 133 extern int min_free_pages;
 135 #define NR_MEM_LISTS 6
 137 struct mem_list {
 138         struct mem_list * next;
 139         struct mem_list * prev;
 140 };
 142 extern struct mem_list free_area_list[NR_MEM_LISTS];
 143 extern unsigned int * free_area_map[NR_MEM_LISTS];
 145 /*
 146  * This is timing-critical - most of the time in getting a new page
 147  * goes to clearing the page. If you want a page without the clearing
 148  * overhead, just use __get_free_page() directly..
 149  */
 150 #define __get_free_page(priority) __get_free_pages((priority),0,~0UL)
 151 #define __get_dma_pages(priority, order) __get_free_pages((priority),(order),MAX_DMA_ADDRESS)
 152 extern unsigned long __get_free_pages(int priority, unsigned long gfporder, unsigned long max_addr);
 154 extern inline unsigned long get_free_page(int priority)
     /* [<][>][^][v][top][bottom][index][help] */
 155 {
 156         unsigned long page;
page = __get_free_page(priority);
 159         if (page)
memset((void *) page, 0, PAGE_SIZE);
 161         return page;
 162 }
 164 /* memory.c & swap.c*/
 166 #define free_page(addr) free_pages((addr),0)
 167 extern void free_pages(unsigned long addr, unsigned long order);
 169 extern void show_free_areas(void);
 170 extern unsigned long put_dirty_page(struct task_struct * tsk,unsigned long page,
 171         unsigned long address);
 173 extern void free_page_tables(struct task_struct * tsk);
 174 extern void clear_page_tables(struct task_struct * tsk);
 175 extern int new_page_tables(struct task_struct * tsk);
 176 extern int copy_page_tables(struct task_struct * to);
 178 extern int zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
 179 extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma);
 180 extern int remap_page_range(unsigned long from, unsigned long to, unsigned long size, pgprot_t prot);
 181 extern int zeromap_page_range(unsigned long from, unsigned long size, pgprot_t prot);
 183 extern void vmtruncate(struct inode * inode, unsigned long offset);
 184 extern void handle_mm_fault(struct vm_area_struct *vma, unsigned long address, int write_access);
 185 extern void do_wp_page(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long address, int write_access);
 186 extern void do_no_page(struct task_struct * tsk, struct vm_area_struct * vma, unsigned long address, int write_access);
 188 extern unsigned long paging_init(unsigned long start_mem, unsigned long end_mem);
 189 extern void mem_init(unsigned long start_mem, unsigned long end_mem);
 190 extern void show_mem(void);
 191 extern void oom(struct task_struct * tsk);
 192 extern void si_meminfo(struct sysinfo * val);
 194 /* vmalloc.c */
 196 extern void * vmalloc(unsigned long size);
 197 extern void * vremap(unsigned long offset, unsigned long size);
 198 extern void vfree(void * addr);
 199 extern int vread(char *buf, char *addr, int count);
 201 /* swap.c */
 203 extern void swap_free(unsigned long);
 204 extern void swap_duplicate(unsigned long);
 205 extern void swap_in(struct task_struct *, struct vm_area_struct *, pte_t *, unsigned long id, int write_access);
 207 extern void si_swapinfo(struct sysinfo * val);
 208 extern void rw_swap_page(int rw, unsigned long nr, char * buf);
 210 /* mmap.c */
 211 extern unsigned long do_mmap(struct file * file, unsigned long addr, unsigned long len,
 212         unsigned long prot, unsigned long flags, unsigned long off);
 213 extern void merge_segments(struct task_struct *, unsigned long, unsigned long);
 214 extern void insert_vm_struct(struct task_struct *, struct vm_area_struct *);
 215 extern void remove_shared_vm_struct(struct vm_area_struct *);
 216 extern void build_mmap_avl(struct mm_struct *);
 217 extern void exit_mmap(struct mm_struct *);
 218 extern int do_munmap(unsigned long, size_t);
 219 extern unsigned long get_unmapped_area(unsigned long, unsigned long);
 221 /* filemap.c */
 222 extern unsigned long page_unuse(unsigned long);
 223 extern int shrink_mmap(int, unsigned long);
 225 #define read_swap_page(nr,buf) \
rw_swap_page(READ,(nr),(buf))
 227 #define write_swap_page(nr,buf) \
rw_swap_page(WRITE,(nr),(buf))
 230 #define GFP_BUFFER      0x00
 231 #define GFP_ATOMIC      0x01
 232 #define GFP_USER        0x02
 233 #define GFP_KERNEL      0x03
 234 #define GFP_NOBUFFER    0x04
 235 #define GFP_NFS         0x05
 237 /* Flag - indicates that the buffer will be suitable for DMA.  Ignored on some
 238    platforms, used as appropriate on others */
 240 #define GFP_DMA         0x80
 242 #define GFP_LEVEL_MASK 0xf
 244 #define avl_empty       (struct vm_area_struct *) NULL
 246 static inline int expand_stack(struct vm_area_struct * vma, unsigned long address)
     /* [<][>][^][v][top][bottom][index][help] */
 247 {
 248         unsigned long grow;
address &= PAGE_MASK;
 251         if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur)
 252                 return -ENOMEM;
grow = vma->vm_start - address;
vma->vm_start = address;
vma->vm_offset -= grow;
vma->vm_mm->total_vm += grow >> PAGE_SHIFT;
 257         if (vma->vm_flags & VM_LOCKED)
vma->vm_mm->locked_vm += grow >> PAGE_SHIFT;
 259         return 0;
 260 }
 262 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
 263 static inline struct vm_area_struct * find_vma (struct task_struct * task, unsigned long addr)
     /* [<][>][^][v][top][bottom][index][help] */
 264 {
 265         struct vm_area_struct * result = NULL;
 266         struct vm_area_struct * tree;
 268         if (!task->mm)
 269                 return NULL;
 270         for (tree = task->mm->mmap_avl ; ; ) {
 271                 if (tree == avl_empty)
 272                         return result;
 273                 if (tree->vm_end > addr) {
 274                         if (tree->vm_start <= addr)
 275                                 return tree;
result = tree;
tree = tree->vm_avl_left;
 278                 } else
tree = tree->vm_avl_right;
 280         }
 281 }
 283 /* Look up the first VMA which intersects the interval start_addr..end_addr-1,
 284    NULL if none.  Assume start_addr < end_addr. */
 285 static inline struct vm_area_struct * find_vma_intersection (struct task_struct * task, unsigned long start_addr, unsigned long end_addr)
     /* [<][>][^][v][top][bottom][index][help] */
 286 {
 287         struct vm_area_struct * vma;
vma = find_vma(task,start_addr);
 290         if (!vma || end_addr <= vma->vm_start)
 291                 return NULL;
 292         return vma;
 293 }
 295 /*
 296  * vm_ops not present page codes for shared memory.
 297  *
 298  * Will go away eventually..
 299  */
 300 #define SHM_SWP_TYPE 0x40
 302 extern void shm_no_page (ulong *);
 304 /*
 305  * swap cache stuff (in swap.c)
 306  */
 307 #define SWAP_CACHE_INFO
 309 extern unsigned long * swap_cache;
 311 #ifdef SWAP_CACHE_INFO
 312 extern unsigned long swap_cache_add_total;
 313 extern unsigned long swap_cache_add_success;
 314 extern unsigned long swap_cache_del_total;
 315 extern unsigned long swap_cache_del_success;
 316 extern unsigned long swap_cache_find_total;
 317 extern unsigned long swap_cache_find_success;
 318 #endif
 320 extern inline unsigned long in_swap_cache(unsigned long addr)
     /* [<][>][^][v][top][bottom][index][help] */
 321 {
 322         return swap_cache[MAP_NR(addr)]; 
 323 }
 325 extern inline long find_in_swap_cache (unsigned long addr)
     /* [<][>][^][v][top][bottom][index][help] */
 326 {
 327         unsigned long entry;
 329 #ifdef SWAP_CACHE_INFO
swap_cache_find_total++;
 331 #endif
entry = xchg(swap_cache + MAP_NR(addr), 0);
 333 #ifdef SWAP_CACHE_INFO
 334         if (entry)
swap_cache_find_success++;
 336 #endif  
 337         return entry;
 338 }
 340 extern inline int delete_from_swap_cache(unsigned long addr)
     /* [<][>][^][v][top][bottom][index][help] */
 341 {
 342         unsigned long entry;
 344 #ifdef SWAP_CACHE_INFO
swap_cache_del_total++;
 346 #endif  
entry= xchg(swap_cache + MAP_NR(addr), 0);
 348         if (entry)  {
 349 #ifdef SWAP_CACHE_INFO
swap_cache_del_success++;
 351 #endif
swap_free(entry);
 353                 return 1;
 354         }
 355         return 0;
 356 }
 358 #endif /* __KERNEL__ */
 360 #endif