xnu-6153.101.6.tar.gz

[apple/xnu.git] / osfmk / i386 / iopb.h

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/*
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/*
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
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 * Permission to use, copy, modify and distribute this software and its
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/*
 */

#ifndef _I386_IOPB_H_
#define _I386_IOPB_H_

#include <i386/tss.h>
#include <kern/queue.h>

/*
 * IO permission bitmap.
 *
 * Allows only IO ports 0 .. 0xffff: for ISA machines.
 */

#define iopb_howmany(a, b)       (((a)+(b)-1)/(b))

#define IOPB_MAX        0xffff          /* x86 allows ports 0..ffff */
#define IOPB_BYTES      (iopb_howmany(IOPB_MAX+1,8))

typedef unsigned char   isa_iopb[IOPB_BYTES];

/*
 * An IO permission map is a task segment with an IO permission bitmap.
 */

struct iopb_tss {
	struct i386_tss tss;            /* task state segment */
	isa_iopb        bitmap;         /* bitmap of mapped IO ports */
	unsigned int    barrier;        /* bitmap barrier for CPU slop */
	queue_head_t    io_port_list;   /* list of mapped IO ports */
	int             iopb_desc[2];   /* descriptor for this TSS */
};

typedef struct iopb_tss *iopb_tss_t;

#endif  /* _I386_IOPB_H_ */