source: mainline/kernel/arch/ia32/include/mm/page.h@ 3a2f8aa

/*
 * 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 KERN_ia32_PAGE_H_
#define KERN_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.
 */

/* Number of entries in each level. */
#define PTL0_ENTRIES_ARCH       1024
#define PTL1_ENTRIES_ARCH       0
#define PTL2_ENTRIES_ARCH       0
#define PTL3_ENTRIES_ARCH       1024

/* Page table sizes for each level. */
#define PTL0_SIZE_ARCH          ONE_FRAME
#define PTL1_SIZE_ARCH          0
#define PTL2_SIZE_ARCH          0
#define PTL3_SIZE_ARCH          ONE_FRAME

/* Macros calculating indices for each level. */
#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)

/* Get PTE address accessors for each level. */
#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))

/* Set PTE address accessors for each level. */
#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)

/* Get PTE flags accessors for each level. */
#define GET_PTL1_FLAGS_ARCH(ptl0, i) \
        get_pt_flags((pte_t *) (ptl0), (size_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), (size_t) (i))

/* Set PTE flags accessors for each level. */
#define SET_PTL1_FLAGS_ARCH(ptl0, i, x) \
        set_pt_flags((pte_t *) (ptl0), (size_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), (size_t) (i), (x))

/* Macros for querying the last level entries. */
#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/mm.h>
#include <arch/interrupt.h>
#include <arch/types.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. */
typedef struct {
        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)) pte_t;

static inline unsigned int get_pt_flags(pte_t *pt, size_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, size_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

/** @}
 */