/* 
 * Copyright (c) 1987 Carnegie-Mellon University
 * Copyright (c) 1992, 1993
 *	The 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	8.1 (Berkeley) 06/10/93
 */

#ifndef	_PMAP_MACHINE_
#define	_PMAP_MACHINE_

/*
 * The user address space is 2Gb (0x0 - 0x80000000).
 * User programs are laid out in memory as follows:
 *			address
 *	USRTEXT		0x00001000
 *	USRDATA		USRTEXT + text_size
 *	USRSTACK	0x7FFFFFFF
 *
 * The user address space is mapped using a two level structure where
 * virtual address bits 30..22 are used to index into a segment table which
 * points to a page worth of PTEs (4096 page can hold 1024 PTEs).
 * Bits 21..12 are then used to index a PTE which describes a page within 
 * a segment.
 *
 * The wired entries in the TLB will contain the following:
 *	0-1	(UPAGES)	for curproc user struct and kernel stack.
 *
 * Note: The kernel doesn't use the same data structures as user programs.
 * All the PTE entries are stored in a single array in Sysmap which is
 * dynamically allocated at boot time.
 */

#define pmax_trunc_seg(x)	((vm_offset_t)(x) & ~SEGOFSET)
#define pmax_round_seg(x)	(((vm_offset_t)(x) + SEGOFSET) & ~SEGOFSET)
#define pmap_segmap(m, v)	((m)->pm_segtab->seg_tab[((v) >> SEGSHIFT)])

#define PMAP_SEGTABSIZE		512

union pt_entry;

struct segtab {
	union pt_entry	*seg_tab[PMAP_SEGTABSIZE];
};

/*
 * 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_tlbpid;	/* address space tag */
	u_int			pm_tlbgen;	/* TLB PID generation number */
	struct segtab		*pm_segtab;	/* pointers to pages of PTEs */
} *pmap_t;

/*
 * 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	char *pmap_attributes;		/* reference and modify bits */
extern	struct pmap kernel_pmap_store;
#define kernel_pmap (&kernel_pmap_store)
#define	pmap_wired_count(pmap) 	((pmap)->pm_stats.wired_count)
#endif	/* KERNEL */

#endif	/* _PMAP_MACHINE_ */