usr/src/sys/i386/include/pmap.h

/*
 * Copyright (c) 1991 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department and William Jolitz of UUNET Technologies Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 *      @(#)pmap.h      7.4 (Berkeley) 5/12/91
 */

/*
 * Derived from hp300 version by Mike Hibler, this version by William
 * Jolitz uses a recursive map [a pde points to the page directory] to
 * map the page tables using the pagetables themselves. This is done to
 * reduce the impact on kernel virtual memory for lots of sparse address
 * space, and to reduce the cost of memory to each process.
 *
 * from hp300:  @(#)pmap.h      7.2 (Berkeley) 12/16/90
 */

#ifndef _PMAP_MACHINE_
#define _PMAP_MACHINE_  1

/*
 * 386 page table entry and page table directory
 * W.Jolitz, 8/89
 */

struct pde
{
unsigned int
                pd_v:1,                 /* valid bit */
                pd_prot:2,              /* access control */
                pd_mbz1:2,              /* reserved, must be zero */
                pd_u:1,                 /* hardware maintained 'used' bit */
                :1,                     /* not used */
                pd_mbz2:2,              /* reserved, must be zero */
                :3,                     /* reserved for software */
                pd_pfnum:20;            /* physical page frame number of pte's*/
};

#define PD_MASK         0xffc00000      /* page directory address bits */
#define PT_MASK         0x003ff000      /* page table address bits */
#define PD_SHIFT        22              /* page directory address shift */
#define PG_SHIFT        12              /* page table address shift */

struct pte
{
unsigned int
                pg_v:1,                 /* valid bit */
                pg_prot:2,              /* access control */
                pg_mbz1:2,              /* reserved, must be zero */
                pg_u:1,                 /* hardware maintained 'used' bit */
                pg_m:1,                 /* hardware maintained modified bit */
                pg_mbz2:2,              /* reserved, must be zero */
                pg_w:1,                 /* software, wired down page */
                :1,                     /* software (unused) */
                pg_nc:1,                /* 'uncacheable page' bit */
                pg_pfnum:20;            /* physical page frame number */
};

#define PG_V            0x00000001
#define PG_RO           0x00000000
#define PG_RW           0x00000002
#define PG_u            0x00000004
#define PG_PROT         0x00000006 /* all protection bits . */
#define PG_W            0x00000200
#define PG_N            0x00000800 /* Non-cacheable */
#define PG_M            0x00000040
#define PG_U            0x00000020
#define PG_FRAME        0xfffff000

#define PG_NOACC        0
#define PG_KR           0x00000000
#define PG_KW           0x00000002
#define PG_URKR         0x00000004
#define PG_URKW         0x00000004
#define PG_UW           0x00000006

/* Garbage for current bastardized pager that assumes a hp300 */
#define PG_NV   0
#define PG_CI   0
/*
 * Page Protection Exception bits
 */

#define PGEX_P          0x01    /* Protection violation vs. not present */
#define PGEX_W          0x02    /* during a Write cycle */
#define PGEX_U          0x04    /* access from User mode (UPL) */

typedef struct pde      pd_entry_t;     /* page directory entry */
typedef struct pte      pt_entry_t;     /* Mach page table entry */

/*
 * One page directory, shared between
 * kernel and user modes.
 */
#define I386_PAGE_SIZE  NBPG
#define I386_PDR_SIZE   NBPDR

#define I386_KPDES      8 /* KPT page directory size */
#define I386_UPDES      NBPDR/sizeof(struct pde)-8 /* UPT page directory size */

#define UPTDI           0x3f6           /* ptd entry for u./kernel&user stack */
#define PTDPTDI         0x3f7           /* ptd entry that points to ptd! */
#define KPTDI_FIRST     0x3f8           /* start of kernel virtual pde's */
#define KPTDI_LAST      0x3fA           /* last of kernel virtual pde's */

/*
 * Address of current and alternate address space page table maps
 * and directories.
 */
#ifdef KERNEL
extern struct pte       PTmap[], APTmap[], Upte;
extern struct pde       PTD[], APTD[], PTDpde, APTDpde, Upde;
extern  pt_entry_t      *Sysmap;

extern int      IdlePTD;        /* physical address of "Idle" state directory */
#endif

/*
 * virtual address to page table entry and
 * to physical address. Likewise for alternate address space.
 * Note: these work recursively, thus vtopte of a pte will give
 * the corresponding pde that in turn maps it.
 */
#define vtopte(va)      (PTmap + i386_btop(va))
#define kvtopte(va)     vtopte(va)
#define ptetov(pt)      (i386_ptob(pt - PTmap))
#define vtophys(va)  (i386_ptob(vtopte(va)->pg_pfnum) | ((int)(va) & PGOFSET))
#define ispt(va)        ((va) >= UPT_MIN_ADDRESS && (va) <= KPT_MAX_ADDRESS)

#define avtopte(va)     (APTmap + i386_btop(va))
#define ptetoav(pt)     (i386_ptob(pt - APTmap))
#define avtophys(va)  (i386_ptob(avtopte(va)->pg_pfnum) | ((int)(va) & PGOFSET))

/*
 * macros to generate page directory/table indicies
 */

#define pdei(va)        (((va)&PD_MASK)>>PD_SHIFT)
#define ptei(va)        (((va)&PT_MASK)>>PT_SHIFT)

/*
 * Pmap stuff
 */

struct pmap {
        pd_entry_t              *pm_pdir;       /* KVA of page directory */
        boolean_t               pm_pdchanged;   /* pdir changed */
        short                   pm_dref;        /* page directory ref count */
        short                   pm_count;       /* pmap reference count */
        simple_lock_data_t      pm_lock;        /* lock on pmap */
        struct pmap_statistics  pm_stats;       /* pmap statistics */
        long                    pm_ptpages;     /* more stats: PT pages */
};

typedef struct pmap     *pmap_t;

#ifdef KERNEL
extern pmap_t           kernel_pmap;
#endif

/*
 * Macros for speed
 */
#define PMAP_ACTIVATE(pmapp, pcbp) \
        if ((pmapp) != NULL /*&& (pmapp)->pm_pdchanged */) {  \
                (pcbp)->pcb_cr3 = \
                    pmap_extract(kernel_pmap, (pmapp)->pm_pdir); \
                if ((pmapp) == &curproc->p_vmspace->vm_pmap) \
                        load_cr3((pcbp)->pcb_cr3); \
                (pmapp)->pm_pdchanged = FALSE; \
        }

#define PMAP_DEACTIVATE(pmapp, pcbp)

/*
 * For each vm_page_t, there is a list of all currently valid virtual
 * mappings of that page.  An entry is a pv_entry_t, the list is pv_table.
 */
typedef struct pv_entry {
        struct pv_entry *pv_next;       /* next pv_entry */
        pmap_t          pv_pmap;        /* pmap where mapping lies */
        vm_offset_t     pv_va;          /* virtual address for mapping */
        int             pv_flags;       /* flags */
} *pv_entry_t;

#define PV_ENTRY_NULL   ((pv_entry_t) 0)

#define PV_CI           0x01    /* all entries must be cache inhibited */
#define PV_PTPAGE       0x02    /* entry maps a page table page */

#ifdef  KERNEL

pv_entry_t      pv_table;               /* array of entries, one per page */

#define pa_index(pa)            atop(pa - vm_first_phys)
#define pa_to_pvh(pa)           (&pv_table[pa_index(pa)])

#define pmap_resident_count(pmap)       ((pmap)->pm_stats.resident_count)

#endif  KERNEL

#endif  _PMAP_MACHINE_