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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 <synch/spinlock.h>

#include <synch/mutex.h>

#include <adt/list.h>

#include <adt/btree.h>

#include <lib/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

/** Kernel address space. */

#define FLAG_AS_KERNEL          (1 << 0)    

/* Address space area attributes. */

#define AS_AREA_ATTR_NONE   0

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

/** The page fault was not resolved by as_page_fault(). */

#define AS_PF_FAULT     0

/** The page fault was resolved by as_page_fault(). */

#define AS_PF_OK        1

/** The page fault was caused by memcpy_from_uspace() or memcpy_to_uspace(). */

#define AS_PF_DEFER     2

/** 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.

 */

typedef struct as {

    /** Protected by asidlock. */

    link_t inactive_as_with_asid_link;

    /**

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

     * Protected by asidlock.

     */

    size_t cpu_refcount;

    /**

     * Address space identifier.

     * Constant on architectures that do not support ASIDs.

     * Protected by asidlock.

     */

    asid_t asid;

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

    atomic_t refcount;

    mutex_t lock;

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

    btree_t as_area_btree;

    /** Non-generic content. */

    as_genarch_t genarch;

    /** Architecture specific content. */

    as_arch_t arch;

} as_t;

typedef struct {

    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);

} as_operations_t;

/**

 * This structure contains information associated with the shared address space

 * area.

 */

typedef struct {

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

    mutex_t lock;      

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

    size_t refcount;

    /**

     * B+tree containing complete map of anonymous pages of the shared area.

     */

    btree_t pagemap;

} share_info_t;

/** Page fault access type. */

typedef enum {

    PF_ACCESS_READ,

    PF_ACCESS_WRITE,

    PF_ACCESS_EXEC

} pf_access_t;

struct mem_backend;

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

typedef union mem_backend_data {

    struct {    /**< elf_backend members */

        elf_header_t *elf;

        elf_segment_header_t *segment;

    };

    struct {    /**< phys_backend members */

        uintptr_t base;

        size_t frames;

    };

} mem_backend_data_t;

/** Address space area structure.

 *

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

 */

typedef struct {

    mutex_t lock;

    /** Containing address space. */

    as_t *as;      

    /**

     * Flags related to the memory represented by the address space area.

     */

    int flags;

    /** Attributes related to the address space area itself. */

    int attributes;

    /** Size of this area in multiples of PAGE_SIZE. */

    size_t pages;

    /** Base address of this area. */

    uintptr_t base;

    /** Map of used space. */

    btree_t used_space;

    /**

     * If the address space area has been shared, this pointer will

     * reference the share info structure.

     */

    share_info_t *sh_info;

    /** Memory backend backing this address space area. */

    struct mem_backend *backend;

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

    mem_backend_data_t backend_data;

} as_area_t;

/** Address space area backend structure. */

typedef struct mem_backend {

    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;

extern as_t *AS_KERNEL;

extern as_operations_t *as_operations;

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, as_t *new_as);

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_change_flags(as_t *as, int flags, uintptr_t address);

extern as_area_t *find_area_and_lock(as_t *, uintptr_t);

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_area_get_size(uintptr_t base);

#ifdef CONFIG_UDEBUG

extern int as_area_make_writeable(uintptr_t address);

extern int as_debug_write(uintptr_t va, void *data, size_t n);

#endif

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

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

/* Interface to be implemented by architectures. */

#ifndef as_constructor_arch

extern int as_constructor_arch(as_t *as, int flags);

#endif /* !def as_constructor_arch */

#ifndef as_destructor_arch

extern int as_destructor_arch(as_t *as);

#endif /* !def as_destructor_arch */

#ifndef as_create_arch

extern int as_create_arch(as_t *as, int flags);

#endif /* !def as_create_arch */

#ifndef as_install_arch

extern void as_install_arch(as_t *as);

#endif /* !def as_install_arch */

#ifndef as_deinstall_arch

extern void as_deinstall_arch(as_t *as);

#endif /* !def as_deinstall_arch */

/* Backend declarations and functions. */

extern mem_backend_t anon_backend;

extern mem_backend_t elf_backend;

extern mem_backend_t phys_backend;

/**

 * This flags is passed when running the loader, otherwise elf_load()

 * would return with a EE_LOADER error code.

 */

#define ELD_F_NONE  0

#define ELD_F_LOADER    1

extern unsigned int elf_load(elf_header_t *header, as_t *as, int flags);

/* 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_change_flags(uintptr_t address, int flags);

extern unative_t sys_as_area_destroy(uintptr_t address);

/* Introspection functions. */

extern void as_print(as_t *as);

#endif /* KERNEL */

#endif

/** @}

 */