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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 ia32mm 
 * @{
 */
/** @file
 */

#ifndef __ia32_PAGE_H__
#define __ia32_PAGE_H__

#include <arch/mm/frame.h>

#define PAGE_WIDTH  FRAME_WIDTH
#define PAGE_SIZE   FRAME_SIZE

#ifdef KERNEL

#ifndef __ASM__
#   define KA2PA(x) (((uintptr_t) (x)) - 0x80000000)
#   define PA2KA(x) (((uintptr_t) (x)) + 0x80000000)
#else
#   define KA2PA(x) ((x) - 0x80000000)
#   define PA2KA(x) ((x) + 0x80000000)
#endif

/*
 * Implementation of generic 4-level page table interface.
 * IA-32 has 2-level page tables, so PTL1 and PTL2 are left out.
 */
#define PTL0_ENTRIES_ARCH   1024
#define PTL1_ENTRIES_ARCH   0
#define PTL2_ENTRIES_ARCH   0
#define PTL3_ENTRIES_ARCH   1024

#define PTL0_INDEX_ARCH(vaddr)  (((vaddr)>>22)&0x3ff)
#define PTL1_INDEX_ARCH(vaddr)  0
#define PTL2_INDEX_ARCH(vaddr)  0
#define PTL3_INDEX_ARCH(vaddr)  (((vaddr)>>12)&0x3ff)

#define GET_PTL1_ADDRESS_ARCH(ptl0, i)      ((pte_t *)((((pte_t *)(ptl0))[(i)].frame_address)<<12))
#define GET_PTL2_ADDRESS_ARCH(ptl1, i)      (ptl1)
#define GET_PTL3_ADDRESS_ARCH(ptl2, i)      (ptl2)
#define GET_FRAME_ADDRESS_ARCH(ptl3, i)     ((uintptr_t)((((pte_t *)(ptl3))[(i)].frame_address)<<12))

#define SET_PTL0_ADDRESS_ARCH(ptl0)     (write_cr3((uintptr_t) (ptl0)))
#define SET_PTL1_ADDRESS_ARCH(ptl0, i, a)   (((pte_t *)(ptl0))[(i)].frame_address = (a)>>12)
#define SET_PTL2_ADDRESS_ARCH(ptl1, i, a)
#define SET_PTL3_ADDRESS_ARCH(ptl2, i, a)
#define SET_FRAME_ADDRESS_ARCH(ptl3, i, a)  (((pte_t *)(ptl3))[(i)].frame_address = (a)>>12)

#define GET_PTL1_FLAGS_ARCH(ptl0, i)        get_pt_flags((pte_t *)(ptl0), (index_t)(i))
#define GET_PTL2_FLAGS_ARCH(ptl1, i)        PAGE_PRESENT
#define GET_PTL3_FLAGS_ARCH(ptl2, i)        PAGE_PRESENT
#define GET_FRAME_FLAGS_ARCH(ptl3, i)       get_pt_flags((pte_t *)(ptl3), (index_t)(i))

#define SET_PTL1_FLAGS_ARCH(ptl0, i, x)     set_pt_flags((pte_t *)(ptl0), (index_t)(i), (x))
#define SET_PTL2_FLAGS_ARCH(ptl1, i, x)
#define SET_PTL3_FLAGS_ARCH(ptl2, i, x)
#define SET_FRAME_FLAGS_ARCH(ptl3, i, x)    set_pt_flags((pte_t *)(ptl3), (index_t)(i), (x))

#define PTE_VALID_ARCH(p)           (*((uint32_t *) (p)) != 0)
#define PTE_PRESENT_ARCH(p)         ((p)->present != 0)
#define PTE_GET_FRAME_ARCH(p)           ((p)->frame_address<<FRAME_WIDTH)
#define PTE_WRITABLE_ARCH(p)            ((p)->writeable != 0)
#define PTE_EXECUTABLE_ARCH(p)          1

#ifndef __ASM__

#include <mm/page.h>
#include <arch/types.h>
#include <arch/mm/frame.h>
#include <typedefs.h>

/* Page fault error codes. */

/** When bit on this position is 0, the page fault was caused by a not-present page. */
#define PFERR_CODE_P        (1<<0)

/** When bit on this position is 1, the page fault was caused by a write. */
#define PFERR_CODE_RW       (1<<1)

/** When bit on this position is 1, the page fault was caused in user mode. */
#define PFERR_CODE_US       (1<<2)

/** When bit on this position is 1, a reserved bit was set in page directory. */ 
#define PFERR_CODE_RSVD     (1<<3)  

/** Page Table Entry. */
struct page_specifier {
    unsigned present : 1;
    unsigned writeable : 1;
    unsigned uaccessible : 1;
    unsigned page_write_through : 1;
    unsigned page_cache_disable : 1;
    unsigned accessed : 1;
    unsigned dirty : 1;
    unsigned pat : 1;
    unsigned global : 1;
    unsigned soft_valid : 1;    /**< Valid content even if the present bit is not set. */
    unsigned avl : 2;
    unsigned frame_address : 20;
} __attribute__ ((packed));

static inline int get_pt_flags(pte_t *pt, index_t i)
{
    pte_t *p = &pt[i];
    
    return (
        (!p->page_cache_disable)<<PAGE_CACHEABLE_SHIFT |
        (!p->present)<<PAGE_PRESENT_SHIFT |
        p->uaccessible<<PAGE_USER_SHIFT |
        1<<PAGE_READ_SHIFT |
        p->writeable<<PAGE_WRITE_SHIFT |
        1<<PAGE_EXEC_SHIFT |
        p->global<<PAGE_GLOBAL_SHIFT
    );
}

static inline void set_pt_flags(pte_t *pt, index_t i, int flags)
{
    pte_t *p = &pt[i];
    
    p->page_cache_disable = !(flags & PAGE_CACHEABLE);
    p->present = !(flags & PAGE_NOT_PRESENT);
    p->uaccessible = (flags & PAGE_USER) != 0;
    p->writeable = (flags & PAGE_WRITE) != 0;
    p->global = (flags & PAGE_GLOBAL) != 0;
    
    /*
     * Ensure that there is at least one bit set even if the present bit is cleared.
     */
    p->soft_valid = true;
}

extern void page_arch_init(void);
extern void page_fault(int n, istate_t *istate);

#endif /* __ASM__ */

#endif /* KERNEL */

#endif

 /** @}
 */