#ifndef _LINUX_MM_H
#define _LINUX_MM_H

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

#ifdef __KERNEL__

#include <linux/config.h>
#include <linux/gfp.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/mmzone.h>
#include <linux/swap.h>
#include <linux/rbtree.h>
#include <linux/fs.h>

extern unsigned long max_mapnr;
extern unsigned long num_physpages;
extern void * high_memory;
extern int page_cluster;
/* The inactive_clean lists are per zone. */
extern struct list_head active_list;
extern struct list_head inactive_list;

#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;       /* The address space we belong to. */
        unsigned long vm_start;         /* Our start address within vm_mm. */
        unsigned long vm_end;           /* The first byte after our end address
                                           within vm_mm. */

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

        pgprot_t vm_page_prot;          /* Access permissions of this VMA. */
        unsigned long vm_flags;         /* Flags, listed below. */

        rb_node_t vm_rb;

        /*
         * For areas with an address space and backing store,
         * one of the address_space->i_mmap{,shared} lists,
         * for shm areas, the list of attaches, otherwise unused.
         */
        list_t shared;

        /* Function pointers to deal with this struct. */
        struct vm_operations_struct * vm_ops;

        /* Information about our backing store: */
        unsigned long vm_pgoff;         /* Offset (within vm_file) in PAGE_SIZE
                                           units, *not* PAGE_CACHE_SIZE */
        struct file * vm_file;          /* File we map to (can be NULL). */
        unsigned long vm_raend;         /* XXX: put full readahead info here. */
        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 */

                                        /* Used by sys_madvise() */
#define VM_SEQ_READ     0x00008000      /* App will access data sequentially */
#define VM_RAND_READ    0x00010000      /* App will not benefit from clustered reads */

#define VM_DONTCOPY     0x00020000      /* Do not copy this vma on fork */
#define VM_DONTEXPAND   0x00040000      /* Cannot expand with mremap() */
#define VM_RESERVED     0x00080000      /* Don't unmap it from swap_out */

#define VM_STACK_FLAGS  (0x00000100 | VM_DATA_DEFAULT_FLAGS)

#define VM_READHINTMASK                 (VM_SEQ_READ | VM_RAND_READ)
#define VM_ClearReadHint(v)             (v)->vm_flags &= ~VM_READHINTMASK
#define VM_NormalReadHint(v)            (!((v)->vm_flags & VM_READHINTMASK))
#define VM_SequentialReadHint(v)        ((v)->vm_flags & VM_SEQ_READ)
#define VM_RandomReadHint(v)            ((v)->vm_flags & VM_RAND_READ)

/*
 * 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);
        struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int unused);
};

/* forward declaration; pte_chain is meant to be internal to rmap.c */
struct pte_chain;

/*
 * Each physical page in the system has a struct page associated with
 * it to keep track of whatever it is we are using the page for at the
 * moment. Note that we have no way to track which tasks are using
 * a page.
 *
 * 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). 
 *
 * TODO: make this structure smaller, it could be as small as 32 bytes.
 */
struct page {
        struct list_head list;          /* ->mapping has some page lists. */
        struct address_space *mapping;  /* The inode (or ...) we belong to. */
        unsigned long index;            /* Our offset within mapping. */
        atomic_t count;                 /* Usage count, see below. */
        unsigned long flags;            /* atomic flags, some possibly
                                           updated asynchronously */
        struct list_head lru;           /* Pageout list, eg. active_list;
                                           protected by pagemap_lru_lock !! */
        union {
                struct pte_chain * chain;       /* Reverse pte mapping pointer.
                                         * protected by PG_chainlock */
                pte_t            * direct;
        } pte;
        unsigned long private;          /* mapping-private opaque data */

        /*
         * On machines where all RAM is mapped into kernel address space,
         * we can simply calculate the virtual address. On machines with
         * highmem some memory is mapped into kernel virtual memory
         * dynamically, so we need a place to store that address.
         * Note that this field could be 16 bits on x86 ... ;)
         *
         * Architectures with slow multiplication can define
         * WANT_PAGE_VIRTUAL in asm/page.h
         */
#if defined(CONFIG_HIGHMEM) || defined(WANT_PAGE_VIRTUAL)
        void *virtual;                  /* Kernel virtual address (NULL if
                                           not kmapped, ie. highmem) */
#endif /* CONFIG_HIGMEM || WANT_PAGE_VIRTUAL */
};

/*
 * Methods to modify the page usage count.
 *
 * What counts for a page usage:
 * - cache mapping   (page->mapping)
 * - private data    (page->private)
 * - page mapped in a task's page tables, each mapping
 *   is counted separately
 *
 * Also, many kernel routines increase the page count before a critical
 * routine so they can be sure the page doesn't go away from under them.
 */
#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)

/*
 * 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->mapping is the pointer to the inode, and page->index is the
 * file offset of the page, in units of PAGE_CACHE_SIZE.
 *
 * A page contains an opaque `private' member, which belongs to the
 * page's address_space.  Usually, this is the address of a circular
 * list of the page's disk buffers.
 *
 * For pages belonging to inodes, the page->count is the number of
 * attaches, plus 1 if `private' contains something, plus one for
 * the page cache itself.
 *
 * All pages belonging to an inode are in these doubly linked lists:
 * mapping->clean_pages, mapping->dirty_pages and mapping->locked_pages;
 * using the page->list list_head. These fields are also used for
 * freelist managemet (when page->count==0).
 *
 * There is also a per-mapping radix tree mapping index to the page
 * in memory if present. The tree is rooted at mapping->root.  
 *
 * 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.
 */

/*
 * FIXME: take this include out, include page-flags.h in
 * files which need it (119 of them)
 */
#include <linux/page-flags.h>

/*
 * The zone field is never updated after free_area_init_core()
 * sets it, so none of the operations on it need to be atomic.
 */
#define NODE_SHIFT 4
#define ZONE_SHIFT (BITS_PER_LONG - 8)

struct zone_struct;
extern struct zone_struct *zone_table[];

static inline zone_t *page_zone(struct page *page)
{
        return zone_table[page->flags >> ZONE_SHIFT];
}

static inline void set_page_zone(struct page *page, unsigned long zone_num)
{
        page->flags &= ~(~0UL << ZONE_SHIFT);
        page->flags |= zone_num << ZONE_SHIFT;
}

/*
 * In order to avoid #ifdefs within C code itself, we define
 * set_page_address to a noop for non-highmem machines, where
 * the field isn't useful.
 * The same is true for page_address() in arch-dependent code.
 */
#if defined(CONFIG_HIGHMEM) || defined(WANT_PAGE_VIRTUAL)

#define set_page_address(page, address)                 \
        do {                                            \
                (page)->virtual = (address);            \
        } while(0)

#else /* CONFIG_HIGHMEM || WANT_PAGE_VIRTUAL */
#define set_page_address(page, address)  do { } while(0)
#endif /* CONFIG_HIGHMEM || WANT_PAGE_VIRTUAL */

/*
 * Permanent address of a page. Obviously must never be
 * called on a highmem page.
 */
#if defined(CONFIG_HIGHMEM) || defined(WANT_PAGE_VIRTUAL)

#define page_address(page) ((page)->virtual)

#else /* CONFIG_HIGHMEM || WANT_PAGE_VIRTUAL */

#define page_address(page)                                              \
        __va( (((page) - page_zone(page)->zone_mem_map) << PAGE_SHIFT)  \
                        + page_zone(page)->zone_start_paddr)

#endif /* CONFIG_HIGHMEM || WANT_PAGE_VIRTUAL */

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

/*
 * Different kinds of faults, as returned by handle_mm_fault().
 * Used to decide whether a process gets delivered SIGBUS or
 * just gets major/minor fault counters bumped up.
 */
#define VM_FAULT_OOM    (-1)
#define VM_FAULT_SIGBUS 0
#define VM_FAULT_MINOR  1
#define VM_FAULT_MAJOR  2

/* The array of struct pages */
extern struct page *mem_map;

extern void show_free_areas(void);
extern void show_free_areas_node(pg_data_t *pgdat);

extern int fail_writepage(struct page *);
struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int unused);
struct file *shmem_file_setup(char * name, loff_t size);
extern void shmem_lock(struct file * file, int lock);
extern int shmem_zero_setup(struct vm_area_struct *);

extern void zap_page_range(struct vm_area_struct *vma, 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(struct vm_area_struct *vma, unsigned long from, unsigned long to, unsigned long size, pgprot_t prot);
extern int zeromap_page_range(struct vm_area_struct *vma, unsigned long from, unsigned long size, pgprot_t prot);

extern int vmtruncate(struct inode * inode, loff_t offset);
extern pmd_t *FASTCALL(__pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address));
extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
extern int handle_mm_fault(struct mm_struct *mm,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 ptrace_attach(struct task_struct *tsk);
extern int ptrace_detach(struct task_struct *, unsigned int);
extern void ptrace_disable(struct task_struct *);
extern int ptrace_check_attach(struct task_struct *task, int kill);

int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
                int len, int write, int force, struct page **pages, struct vm_area_struct **vmas);

int __set_page_dirty_buffers(struct page *page);
int __set_page_dirty_nobuffers(struct page *page);

/*
 * If the mapping doesn't provide a set_page_dirty a_op, then
 * just fall through and assume that it wants buffer_heads.
 * FIXME: make the method unconditional.
 */
static inline int set_page_dirty(struct page *page)
{
        if (page->mapping) {
                int (*spd)(struct page *);

                spd = page->mapping->a_ops->set_page_dirty;
                if (spd)
                        return (*spd)(page);
        }
        return __set_page_dirty_buffers(page);
}

/*
 * On a two-level page table, this ends up being trivial. Thus the
 * inlining and the symmetry break with pte_alloc_map() that does all
 * of this out-of-line.
 */
static inline pmd_t *pmd_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
{
        if (pgd_none(*pgd))
                return __pmd_alloc(mm, pgd, address);
        return pmd_offset(pgd, address);
}

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

extern int can_share_swap_page(struct page *);
extern int remove_exclusive_swap_page(struct page *);

extern void __free_pte(pte_t);

/* mmap.c */
extern void lock_vma_mappings(struct vm_area_struct *);
extern void unlock_vma_mappings(struct vm_area_struct *);
extern void insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
extern void __insert_vm_struct(struct mm_struct *, struct vm_area_struct *);
extern void build_mmap_rb(struct mm_struct *);
extern void exit_mmap(struct mm_struct *);

extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, 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);

static 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(struct mm_struct *, unsigned long, size_t);

extern unsigned long do_brk(unsigned long, unsigned long);

static inline void __vma_unlink(struct mm_struct * mm, struct vm_area_struct * vma, struct vm_area_struct * prev)
{
        prev->vm_next = vma->vm_next;
        rb_erase(&vma->vm_rb, &mm->mm_rb);
        if (mm->mmap_cache == vma)
                mm->mmap_cache = prev;
}

static inline int can_vma_merge(struct vm_area_struct * vma, unsigned long vm_flags)
{
        if (!vma->vm_file && vma->vm_flags == vm_flags)
                return 1;
        else
                return 0;
}

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

/* generic vm_area_ops exported for stackable file systems */
extern int filemap_sync(struct vm_area_struct *, unsigned long, size_t, unsigned int);
extern struct page *filemap_nopage(struct vm_area_struct *, unsigned long, int);

/* mm/page-writeback.c */
int write_one_page(struct page *page, int wait);

/* readahead.c */
#define VM_MAX_READAHEAD        128     /* kbytes */
#define VM_MIN_READAHEAD        16      /* kbytes (includes current page) */
int do_page_cache_readahead(struct file *file,
                        unsigned long offset, unsigned long nr_to_read);
void page_cache_readahead(struct file *file, unsigned long offset);
void page_cache_readaround(struct file *file, unsigned long offset);
void handle_ra_miss(struct file *file);

/* 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;

        /*
         * vma->vm_start/vm_end cannot change under us because the caller is required
         * to hold the mmap_sem in write mode. We need to get the spinlock only
         * before relocating the vma range ourself.
         */
        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;
        spin_lock(&vma->vm_mm->page_table_lock);
        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;
        spin_unlock(&vma->vm_mm->page_table_lock);
        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 mm_struct *mm, unsigned long addr);

extern struct page * vmalloc_to_page(void *addr);
extern unsigned long get_page_cache_size(void);

#endif /* __KERNEL__ */

#endif