#ifndef _LINUX_MM_H
#define _LINUX_MM_H

#include <linux/sched.h>
#include <linux/errno.h>

#ifdef __KERNEL__

#include <linux/config.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/mmzone.h>

extern unsigned long max_mapnr;
extern unsigned long num_physpages;
extern void * high_memory;
extern int page_cluster;

#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/atomic.h>

/*
 * Linux kernel virtual memory manager primitives.
 * The idea being to have a "virtual" mm in the same way
 * we have a virtual fs - giving a cleaner interface to the
 * mm details, and allowing different kinds of memory mappings
 * (from shared memory to executable loading to arbitrary
 * mmap() functions).
 */

/*
 * This struct defines a memory VMM memory area. There is one of these
 * per VM-area/task.  A VM area is any part of the process virtual memory
 * space that has a special rule for the page-fault handlers (ie a shared
 * library, the executable area etc).
 */
struct vm_area_struct {
        struct mm_struct * vm_mm;       /* VM area parameters */
        unsigned long vm_start;
        unsigned long vm_end;

        /* linked list of VM areas per task, sorted by address */
        struct vm_area_struct *vm_next;

        pgprot_t vm_page_prot;
        unsigned long vm_flags;

        /* AVL tree of VM areas per task, sorted by address */
        short vm_avl_height;
        struct vm_area_struct * vm_avl_left;
        struct vm_area_struct * vm_avl_right;

        /* For areas with inode, the list inode->i_mmap, for shm areas,
         * the list of attaches, otherwise unused.
         */
        struct vm_area_struct *vm_next_share;
        struct vm_area_struct **vm_pprev_share;

        struct vm_operations_struct * vm_ops;
        unsigned long vm_pgoff;         /* offset in PAGE_SIZE units, *not* PAGE_CACHE_SIZE */
        struct file * vm_file;
        void * vm_private_data;         /* was vm_pte (shared mem) */
};

/*
 * vm_flags..
 */
#define VM_READ         0x00000001      /* currently active flags */
#define VM_WRITE        0x00000002
#define VM_EXEC         0x00000004
#define VM_SHARED       0x00000008

#define VM_MAYREAD      0x00000010      /* limits for mprotect() etc */
#define VM_MAYWRITE     0x00000020
#define VM_MAYEXEC      0x00000040
#define VM_MAYSHARE     0x00000080

#define VM_GROWSDOWN    0x00000100      /* general info on the segment */
#define VM_GROWSUP      0x00000200
#define VM_SHM          0x00000400      /* shared memory area, don't swap out */
#define VM_DENYWRITE    0x00000800      /* ETXTBSY on write attempts.. */

#define VM_EXECUTABLE   0x00001000
#define VM_LOCKED       0x00002000
#define VM_IO           0x00004000  /* Memory mapped I/O or similar */

#define VM_STACK_FLAGS  0x00000177

/*
 * mapping from the currently active vm_flags protection bits (the
 * low four bits) to a page protection mask..
 */
extern pgprot_t protection_map[16];


/*
 * These are the virtual MM functions - opening of an area, closing and
 * unmapping it (needed to keep files on disk up-to-date etc), pointer
 * to the functions called when a no-page or a wp-page exception occurs. 
 */
struct vm_operations_struct {
        void (*open)(struct vm_area_struct * area);
        void (*close)(struct vm_area_struct * area);
        void (*unmap)(struct vm_area_struct *area, unsigned long, size_t);
        void (*protect)(struct vm_area_struct *area, unsigned long, size_t, unsigned int newprot);
        int (*sync)(struct vm_area_struct *area, unsigned long, size_t, unsigned int flags);
        void (*advise)(struct vm_area_struct *area, unsigned long, size_t, unsigned int advise);
        struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int write_access);
        struct page * (*wppage)(struct vm_area_struct * area, unsigned long address, struct page * page);
        int (*swapout)(struct page *, struct file *);
};

/*
 * A swap entry has to fit into a "unsigned long", as
 * the entry is hidden in the "index" field of the
 * swapper address space.
 */
typedef struct {
        unsigned long val;
} swp_entry_t;

/*
 * Try to keep the most commonly accessed fields in single cache lines
 * here (16 bytes or greater).  This ordering should be particularly
 * beneficial on 32-bit processors.
 *
 * The first line is data used in page cache lookup, the second line
 * is used for linear searches (eg. clock algorithm scans). 
 */
typedef struct page {
        struct list_head list;
        struct address_space *mapping;
        unsigned long index;
        struct page *next_hash;
        atomic_t count;
        unsigned long flags;    /* atomic flags, some possibly updated asynchronously */
        struct list_head lru;
        wait_queue_head_t wait;
        struct page **pprev_hash;
        struct buffer_head * buffers;
        unsigned long virtual; /* nonzero if kmapped */
        struct zone_struct *zone;
} mem_map_t;

#define get_page(p)             atomic_inc(&(p)->count)
#define put_page(p)             __free_page(p)
#define put_page_testzero(p)    atomic_dec_and_test(&(p)->count)
#define page_count(p)           atomic_read(&(p)->count)
#define set_page_count(p,v)     atomic_set(&(p)->count, v)

/* Page flag bit values */
#define PG_locked                0
#define PG_error                 1
#define PG_referenced            2
#define PG_uptodate              3
#define PG__unused_00            4
#define PG_decr_after            5
#define PG_unused_01             6
#define PG__unused_02            7
#define PG_slab                  8
#define PG_swap_cache            9
#define PG_skip                 10
#define PG_swap_entry           11
#define PG_highmem              12
                                /* bits 21-30 unused */
#define PG_reserved             31


/* Make it prettier to test the above... */
#define Page_Uptodate(page)     test_bit(PG_uptodate, &(page)->flags)
#define SetPageUptodate(page)   set_bit(PG_uptodate, &(page)->flags)
#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags)
#define PageLocked(page)        test_bit(PG_locked, &(page)->flags)
#define LockPage(page)          set_bit(PG_locked, &(page)->flags)
#define TryLockPage(page)       test_and_set_bit(PG_locked, &(page)->flags)
#define UnlockPage(page)        do { \
                                        clear_bit(PG_locked, &(page)->flags); \
                                        wake_up(&page->wait); \
                                } while (0)
#define PageError(page)         test_bit(PG_error, &(page)->flags)
#define SetPageError(page)      test_and_set_bit(PG_error, &(page)->flags)
#define ClearPageError(page)    clear_bit(PG_error, &(page)->flags)
#define PageReferenced(page)    test_bit(PG_referenced, &(page)->flags)
#define PageDecrAfter(page)     test_bit(PG_decr_after, &(page)->flags)
#define PageSlab(page)          test_bit(PG_slab, &(page)->flags)
#define PageSwapCache(page)     test_bit(PG_swap_cache, &(page)->flags)
#define PageReserved(page)      test_bit(PG_reserved, &(page)->flags)

#define PageSetSlab(page)       set_bit(PG_slab, &(page)->flags)
#define PageSetSwapCache(page)  set_bit(PG_swap_cache, &(page)->flags)

#define PageTestandSetSwapCache(page)   test_and_set_bit(PG_swap_cache, &(page)->flags)

#define PageClearSlab(page)             clear_bit(PG_slab, &(page)->flags)
#define PageClearSwapCache(page)        clear_bit(PG_swap_cache, &(page)->flags)

#define PageTestandClearSwapCache(page) test_and_clear_bit(PG_swap_cache, &(page)->flags)

#ifdef CONFIG_HIGHMEM
#define PageHighMem(page)               test_bit(PG_highmem, &(page)->flags)
#else
#define PageHighMem(page)               0 /* needed to optimize away at compile time */
#endif

#define SetPageReserved(page)           set_bit(PG_reserved, &(page)->flags)
#define ClearPageReserved(page)         clear_bit(PG_reserved, &(page)->flags)

/*
 * Error return values for the *_nopage functions
 */
#define NOPAGE_SIGBUS   (NULL)
#define NOPAGE_OOM      ((struct page *) (-1))


/*
 * Various page->flags bits:
 *
 * PG_reserved is set for a page which must never be accessed (which
 * may not even be present).
 *
 * PG_DMA has been removed, page->zone now tells exactly wether the
 * page is suited to do DMAing into.
 *
 * Multiple processes may "see" the same page. E.g. for untouched
 * mappings of /dev/null, all processes see the same page full of
 * zeroes, and text pages of executables and shared libraries have
 * only one copy in memory, at most, normally.
 *
 * For the non-reserved pages, page->count denotes a reference count.
 *   page->count == 0 means the page is free.
 *   page->count == 1 means the page is used for exactly one purpose
 *   (e.g. a private data page of one process).
 *
 * A page may be used for kmalloc() or anyone else who does a
 * __get_free_page(). In this case the page->count is at least 1, and
 * all other fields are unused but should be 0 or NULL. The
 * management of this page is the responsibility of the one who uses
 * it.
 *
 * The other pages (we may call them "process pages") are completely
 * managed by the Linux memory manager: I/O, buffers, swapping etc.
 * The following discussion applies only to them.
 *
 * A page may belong to an inode's memory mapping. In this case,
 * page->inode is the pointer to the inode, and page->offset is the
 * file offset of the page (not necessarily a multiple of PAGE_SIZE).
 *
 * A page may have buffers allocated to it. In this case,
 * page->buffers is a circular list of these buffer heads. Else,
 * page->buffers == NULL.
 *
 * For pages belonging to inodes, the page->count is the number of
 * attaches, plus 1 if buffers are allocated to the page.
 *
 * All pages belonging to an inode make up a doubly linked list
 * inode->i_pages, using the fields page->next and page->prev. (These
 * fields are also used for freelist management when page->count==0.)
 * There is also a hash table mapping (inode,offset) to the page
 * in memory if present. The lists for this hash table use the fields
 * page->next_hash and page->pprev_hash.
 *
 * All process pages can do I/O:
 * - inode pages may need to be read from disk,
 * - inode pages which have been modified and are MAP_SHARED may need
 *   to be written to disk,
 * - private pages which have been modified may need to be swapped out
 *   to swap space and (later) to be read back into memory.
 * During disk I/O, PG_locked is used. This bit is set before I/O
 * and reset when I/O completes. page->wait is a wait queue of all
 * tasks waiting for the I/O on this page to complete.
 * PG_uptodate tells whether the page's contents is valid.
 * When a read completes, the page becomes uptodate, unless a disk I/O
 * error happened.
 *
 * For choosing which pages to swap out, inode pages carry a
 * PG_referenced bit, which is set any time the system accesses
 * that page through the (inode,offset) hash table.
 *
 * PG_skip is used on sparc/sparc64 architectures to "skip" certain
 * parts of the address space.
 *
 * PG_error is set to indicate that an I/O error occurred on this page.
 */

extern mem_map_t * mem_map;

/*
 * There is only one page-allocator function, and two main namespaces to
 * it. The alloc_page*() variants return 'struct page *' and as such
 * can allocate highmem pages, the *get*page*() variants return
 * virtual kernel addresses to the allocated page(s).
 */
extern struct page * FASTCALL(__alloc_pages(zonelist_t *zonelist, unsigned long order));
extern struct page * alloc_pages_node(int nid, int gfp_mask, unsigned long order);

#ifndef CONFIG_DISCONTIGMEM
extern inline struct page * alloc_pages(int gfp_mask, unsigned long order)
{
        /*  temporary check. */
        if (contig_page_data.node_zonelists[gfp_mask].gfp_mask != (gfp_mask))
                BUG();
        /*
         * Gets optimized away by the compiler.
         */
        if (order >= MAX_ORDER)
                return NULL;
        return __alloc_pages(contig_page_data.node_zonelists+(gfp_mask), order);
}
#else /* !CONFIG_DISCONTIGMEM */
extern struct page * alloc_pages(int gfp_mask, unsigned long order);
#endif /* !CONFIG_DISCONTIGMEM */

#define alloc_page(gfp_mask) \
                alloc_pages(gfp_mask, 0)

extern inline unsigned long __get_free_pages (int gfp_mask, unsigned long order)
{
        struct page * page;

        page = alloc_pages(gfp_mask, order);
        if (!page)
                return 0;
        return page_address(page);
}

#define __get_free_page(gfp_mask) \
                __get_free_pages((gfp_mask),0)

#define __get_dma_pages(gfp_mask, order) \
                __get_free_pages((gfp_mask) | GFP_DMA,(order))

extern inline unsigned long get_zeroed_page(int gfp_mask)
{
        unsigned long page;

        page = __get_free_page(gfp_mask);
        if (page)
                clear_page((void *)page);
        return page;
}

/*
 * The old interface name will be removed in 2.5:
 */
#define get_free_page get_zeroed_page

/*
 * There is only one 'core' page-freeing function.
 */
extern void FASTCALL(__free_pages_ok(struct page * page, unsigned long order));

extern inline void __free_pages(struct page *page, unsigned long order)
{
        if (!put_page_testzero(page))
                return;
        __free_pages_ok(page, order);
}

#define __free_page(page) __free_pages(page, 0)

extern inline void free_pages(unsigned long addr, unsigned long order)
{
        unsigned long map_nr;

#ifdef CONFIG_DISCONTIGMEM
        if (addr == 0) return;
#endif
        map_nr = MAP_NR(addr);
        if (map_nr < max_mapnr)
                __free_pages(mem_map + map_nr, order);
}

#define free_page(addr) free_pages((addr),0)

extern void show_free_areas(void);
extern void show_free_areas_node(int nid);

extern void clear_page_tables(struct mm_struct *, unsigned long, int);

extern int map_zero_setup(struct vm_area_struct *);

extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma);
extern int remap_page_range(unsigned long from, unsigned long to, unsigned long size, pgprot_t prot);
extern int zeromap_page_range(unsigned long from, unsigned long size, pgprot_t prot);

extern void vmtruncate(struct inode * inode, loff_t offset);
extern int handle_mm_fault(struct task_struct *tsk,struct vm_area_struct *vma, unsigned long address, int write_access);
extern int make_pages_present(unsigned long addr, unsigned long end);
extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char *dst, int len);
extern int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst, int len);

extern int pgt_cache_water[2];
extern int check_pgt_cache(void);

extern void free_area_init(unsigned long * zones_size);
extern void free_area_init_node(int nid, pg_data_t *pgdat, 
                unsigned long * zones_size, unsigned long zone_start_paddr);
extern void mem_init(void);
extern void show_mem(void);
extern void si_meminfo(struct sysinfo * val);
extern void swapin_readahead(swp_entry_t);

/* mmap.c */
extern void vma_init(void);
extern void merge_segments(struct mm_struct *, unsigned long, unsigned long);
extern void insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
extern void build_mmap_avl(struct mm_struct *);
extern void exit_mmap(struct mm_struct *);
extern unsigned long get_unmapped_area(unsigned long, unsigned long);

extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
        unsigned long len, unsigned long prot,
        unsigned long flag, unsigned long pgoff);

extern inline unsigned long do_mmap(struct file *file, unsigned long addr,
        unsigned long len, unsigned long prot,
        unsigned long flag, unsigned long offset)
{
        unsigned long ret = -EINVAL;
        if ((offset + PAGE_ALIGN(len)) < offset)
                goto out;
        if (!(offset & ~PAGE_MASK))
                ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
out:
        return ret;
}

extern int do_munmap(unsigned long, size_t);
extern unsigned long do_brk(unsigned long, unsigned long);

struct zone_t;
/* filemap.c */
extern void remove_inode_page(struct page *);
extern unsigned long page_unuse(struct page *);
extern int shrink_mmap(int, int, zone_t *);
extern void truncate_inode_pages(struct address_space *, loff_t);

/* generic vm_area_ops exported for stackable file systems */
extern int filemap_swapout(struct page * page, struct file *file);
extern pte_t filemap_swapin(struct vm_area_struct * vma,
                            unsigned long offset, unsigned long entry);
extern int filemap_sync(struct vm_area_struct * vma, unsigned long address,
                        size_t size, unsigned int flags);
extern struct page *filemap_nopage(struct vm_area_struct * area,
                                    unsigned long address, int no_share);

/*
 * GFP bitmasks..
 */
#define __GFP_WAIT      0x01
#define __GFP_HIGH      0x02
#define __GFP_IO        0x04
#define __GFP_DMA       0x08
#ifdef CONFIG_HIGHMEM
#define __GFP_HIGHMEM   0x10
#else
#define __GFP_HIGHMEM   0x0 /* noop */
#endif


#define GFP_BUFFER      (__GFP_HIGH | __GFP_WAIT)
#define GFP_ATOMIC      (__GFP_HIGH)
#define GFP_USER        (__GFP_WAIT | __GFP_IO)
#define GFP_HIGHUSER    (GFP_USER | __GFP_HIGHMEM)
#define GFP_KERNEL      (__GFP_HIGH | __GFP_WAIT | __GFP_IO)
#define GFP_NFS         (__GFP_HIGH | __GFP_WAIT | __GFP_IO)
#define GFP_KSWAPD      (__GFP_IO)

/* Flag - indicates that the buffer will be suitable for DMA.  Ignored on some
   platforms, used as appropriate on others */

#define GFP_DMA         __GFP_DMA

/* Flag - indicates that the buffer can be taken from high memory which is not
   permanently mapped by the kernel */

#define GFP_HIGHMEM     __GFP_HIGHMEM

/* vma is the first one with  address < vma->vm_end,
 * and even  address < vma->vm_start. Have to extend vma. */
static inline int expand_stack(struct vm_area_struct * vma, unsigned long address)
{
        unsigned long grow;

        address &= PAGE_MASK;
        grow = (vma->vm_start - address) >> PAGE_SHIFT;
        if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur ||
            ((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->rlim[RLIMIT_AS].rlim_cur)
                return -ENOMEM;
        vma->vm_start = address;
        vma->vm_pgoff -= grow;
        vma->vm_mm->total_vm += grow;
        if (vma->vm_flags & VM_LOCKED)
                vma->vm_mm->locked_vm += grow;
        return 0;
}

/* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr);
extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,
                                             struct vm_area_struct **pprev);

/* Look up the first VMA which intersects the interval start_addr..end_addr-1,
   NULL if none.  Assume start_addr < end_addr. */
static inline struct vm_area_struct * find_vma_intersection(struct mm_struct * mm, unsigned long start_addr, unsigned long end_addr)
{
        struct vm_area_struct * vma = find_vma(mm,start_addr);

        if (vma && end_addr <= vma->vm_start)
                vma = NULL;
        return vma;
}

extern struct vm_area_struct *find_extend_vma(struct task_struct *tsk, unsigned long addr);

#define buffer_under_min()      (atomic_read(&buffermem_pages) * 100 < \
                                buffer_mem.min_percent * num_physpages)
#define pgcache_under_min()     (atomic_read(&page_cache_size) * 100 < \
                                page_cache.min_percent * num_physpages)

#define vmlist_access_lock(mm)          spin_lock(&mm->page_table_lock)
#define vmlist_access_unlock(mm)        spin_unlock(&mm->page_table_lock)
#define vmlist_modify_lock(mm)          vmlist_access_lock(mm)
#define vmlist_modify_unlock(mm)        vmlist_access_unlock(mm)

#endif /* __KERNEL__ */

#endif