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

/*
 * Copyright (c) 1987 Carnegie-Mellon University
 * Copyright (c) 1992 Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)pmap.h      7.3 (Berkeley) %G%
 */

#ifndef _PMAP_MACHINE_
#define _PMAP_MACHINE_

/*
 * TLB hash table values.
 * SHIFT2 should shift virtual address bit 22 to the high bit of the index.
 *                      address:        index:
 *      USRTEXT         0x00400000      10xxxxxxx
 *      USRDATA         0x10000000      00xxxxxxx
 *      USRSTACK        0x7FFFFFFF      11xxxxxxx
 * This gives 1/2 the table to data, 1/4 for text and 1/4 for stack.
 * Note: the current process has its hash table mapped at PMAP_HASH_UADDR.
 *      the kernel's hash table is mapped at PMAP_HASH_KADDR.
 *      The size of the hash table is known in locore.s.
 * The wired entries in the TLB will contain the following:
 *      UPAGES                  (for curproc)
 *      PMAP_HASH_UPAGES        (for curproc)
 *      PMAP_HASH_KPAGES        (for kernel)
 * The kernel doesn't actual use a pmap_hash_t, the pm_hash field is NULL and
 * all the PTE entries are stored in a single array at PMAP_HASH_KADDR.
 * If we need more KPAGES that the TLB has wired entries, then we can switch
 * to a global pointer for the kernel TLB table.
 * If we try to use a hash table for the kernel, wired TLB entries become a
 * problem.
 * Note: PMAP_HASH_UPAGES should be a multiple of MACH pages (see pmap_enter()).
 */
#define PMAP_HASH_UPAGES        1
#define PMAP_HASH_KPAGES        3
#define PMAP_HASH_UADDR         (UADDR - PMAP_HASH_UPAGES * NBPG)
#define PMAP_HASH_KADDR         (UADDR - (PMAP_HASH_UPAGES + PMAP_HASH_KPAGES) * NBPG)
#define PMAP_HASH_NUM_ENTRIES   512
#define PMAP_HASH_SIZE_SHIFT    3
#define PMAP_HASH_SHIFT1        12
#define PMAP_HASH_SHIFT2        14
#define PMAP_HASH_MASK1         0x07f
#define PMAP_HASH_MASK2         0x180
#define PMAP_HASH_SIZE          (PMAP_HASH_NUM_ENTRIES*sizeof(struct pmap_hash))

/* compute pointer to pmap hash table */
#define PMAP_HASH(va) \
        ((((va) >> PMAP_HASH_SHIFT1) & PMAP_HASH_MASK1) | \
         (((va) >> PMAP_HASH_SHIFT2) & PMAP_HASH_MASK2))

/*
 * A TLB hash entry.
 */
typedef struct pmap_hash {
        u_int   low;            /* The TLB low register value. */
        u_int   high;           /* The TLB high register value. */
} *pmap_hash_t;

/*
 * Machine dependent pmap structure.
 */
typedef struct pmap {
        int                     pm_count;       /* pmap reference count */
        simple_lock_data_t      pm_lock;        /* lock on pmap */
        struct pmap_statistics  pm_stats;       /* pmap statistics */
        int                     pm_flags;       /* see below */
        int                     pm_tlbpid;      /* address space tag */
        pmap_hash_t             pm_hash;        /* TLB cache */
        unsigned                pm_hash_ptes[PMAP_HASH_UPAGES];
} *pmap_t;

#define PM_MODIFIED     1               /* flush tlbpid before resume() */

/*
 * Defines for pmap_attributes[phys_mach_page];
 */
#define PMAP_ATTR_MOD   0x01    /* page has been modified */
#define PMAP_ATTR_REF   0x02    /* page has been referenced */

#ifdef  KERNEL
extern struct pmap kernel_pmap_store;
#define kernel_pmap (&kernel_pmap_store)
extern  char *pmap_attributes;          /* reference and modify bits */
#endif  KERNEL
#endif  _PMAP_MACHINE_