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/*

 * Copyright (C) 2001-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup genericmm

 * @{

 */

/** @file

 */

#ifndef KERN_AS_H_

#define KERN_AS_H_

/** Address space area flags. */

#define AS_AREA_READ        1

#define AS_AREA_WRITE       2

#define AS_AREA_EXEC        4

#define AS_AREA_CACHEABLE   8

#ifdef KERNEL

#include <arch/mm/page.h>

#include <arch/mm/as.h>

#include <arch/mm/asid.h>

#include <arch/types.h>

#include <typedefs.h>

#include <synch/spinlock.h>

#include <synch/mutex.h>

#include <adt/list.h>

#include <adt/btree.h>

#include <elf.h>

/** Defined to be true if user address space and kernel address space shadow each other. */

#define KERNEL_ADDRESS_SPACE_SHADOWED   KERNEL_ADDRESS_SPACE_SHADOWED_ARCH

#define KERNEL_ADDRESS_SPACE_START  KERNEL_ADDRESS_SPACE_START_ARCH

#define KERNEL_ADDRESS_SPACE_END    KERNEL_ADDRESS_SPACE_END_ARCH

#define USER_ADDRESS_SPACE_START    USER_ADDRESS_SPACE_START_ARCH

#define USER_ADDRESS_SPACE_END      USER_ADDRESS_SPACE_END_ARCH

#define USTACK_ADDRESS  USTACK_ADDRESS_ARCH

#define FLAG_AS_KERNEL      (1 << 0)    /**< Kernel address space. */

/** Address space structure.

 *

 * as_t contains the list of as_areas of userspace accessible

 * pages for one or more tasks. Ranges of kernel memory pages are not

 * supposed to figure in the list as they are shared by all tasks and

 * set up during system initialization.

 */

struct as {

    /** Protected by asidlock. */

    link_t inactive_as_with_asid_link;

    mutex_t lock;

    /** Number of references (i.e tasks that reference this as). */

    count_t refcount;

    /** Number of processors on wich is this address space active. */

    count_t cpu_refcount;

    /** B+tree of address space areas. */

    btree_t as_area_btree;

    /** Page table pointer. Constant on architectures that use global page hash table. */

    pte_t *page_table;

    /** Address space identifier. Constant on architectures that do not support ASIDs.*/

    asid_t asid;

};

struct as_operations {

    pte_t *(* page_table_create)(int flags);

    void (* page_table_destroy)(pte_t *page_table);

    void (* page_table_lock)(as_t *as, bool lock);

    void (* page_table_unlock)(as_t *as, bool unlock);

};

typedef struct as_operations as_operations_t;

/** Address space area attributes. */

#define AS_AREA_ATTR_NONE   0

#define AS_AREA_ATTR_PARTIAL    1   /**< Not fully initialized area. */

#define AS_PF_FAULT     0   /**< The page fault was not resolved by as_page_fault(). */

#define AS_PF_OK        1   /**< The page fault was resolved by as_page_fault(). */

#define AS_PF_DEFER     2   /**< The page fault was caused by memcpy_from_uspace()

                         or memcpy_to_uspace(). */

/** This structure contains information associated with the shared address space area. */

typedef struct {

    mutex_t lock;       /**< This lock must be acquired only when the as_area lock is held. */

    count_t refcount;   /**< This structure can be deallocated if refcount drops to 0. */

    btree_t pagemap;    /**< B+tree containing complete map of anonymous pages of the shared area. */

} share_info_t;

/** Address space area backend structure. */

typedef struct {

    int (* page_fault)(as_area_t *area, uintptr_t addr, pf_access_t access);

    void (* frame_free)(as_area_t *area, uintptr_t page, uintptr_t frame);

    void (* share)(as_area_t *area);

} mem_backend_t;

/** Backend data stored in address space area. */

typedef union {

    struct {    /**< elf_backend members */

        elf_header_t *elf;

        elf_segment_header_t *segment;

    };

    struct {    /**< phys_backend members */

        uintptr_t base;

        count_t frames;

    };

} mem_backend_data_t;

/** Address space area structure.

 *

 * Each as_area_t structure describes one contiguous area of virtual memory.

 * In the future, it should not be difficult to support shared areas.

 */

struct as_area {

    mutex_t lock;

    as_t *as;       /**< Containing address space. */

    int flags;      /**< Flags related to the memory represented by the address space area. */

    int attributes;     /**< Attributes related to the address space area itself. */

    count_t pages;      /**< Size of this area in multiples of PAGE_SIZE. */

    uintptr_t base;     /**< Base address of this area. */

    btree_t used_space; /**< Map of used space. */

    share_info_t *sh_info;  /**< If the address space area has been shared, this pointer will

                         reference the share info structure. */

    mem_backend_t *backend; /**< Memory backend backing this address space area. */

    /** Data to be used by the backend. */

    mem_backend_data_t backend_data;

};

extern as_t *AS_KERNEL;

extern as_operations_t *as_operations;

extern spinlock_t inactive_as_with_asid_lock;

extern link_t inactive_as_with_asid_head;

extern void as_init(void);

extern as_t *as_create(int flags);

extern void as_destroy(as_t *as);

extern void as_switch(as_t *old, as_t *new);

extern int as_page_fault(uintptr_t page, pf_access_t access, istate_t *istate);

extern as_area_t *as_area_create(as_t *as, int flags, size_t size, uintptr_t base, int attrs,

    mem_backend_t *backend, mem_backend_data_t *backend_data);

extern int as_area_destroy(as_t *as, uintptr_t address);   

extern int as_area_resize(as_t *as, uintptr_t address, size_t size, int flags);

int as_area_share(as_t *src_as, uintptr_t src_base, size_t acc_size,

          as_t *dst_as, uintptr_t dst_base, int dst_flags_mask);

extern int as_area_get_flags(as_area_t *area);

extern bool as_area_check_access(as_area_t *area, pf_access_t access);

extern size_t as_get_size(uintptr_t base);

extern int used_space_insert(as_area_t *a, uintptr_t page, count_t count);

extern int used_space_remove(as_area_t *a, uintptr_t page, count_t count);

/* Interface to be implemented by architectures. */

#ifndef as_install_arch

extern void as_install_arch(as_t *as);

#endif /* !def as_install_arch */

/* Backend declarations. */

extern mem_backend_t anon_backend;

extern mem_backend_t elf_backend;

extern mem_backend_t phys_backend;

/* Address space area related syscalls. */

extern unative_t sys_as_area_create(uintptr_t address, size_t size, int flags);

extern unative_t sys_as_area_resize(uintptr_t address, size_t size, int flags);

extern unative_t sys_as_area_destroy(uintptr_t address);

#endif /* KERNEL */

#endif

/** @}

 */