125 lines
3.9 KiB
C
125 lines
3.9 KiB
C
/* $XFree86: xc/programs/Xserver/hw/xfree86/os-support/sco/sco_iop.c,v 1.1 2002/06/03 21:22:10 dawes Exp $ */
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/*
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* Copyright 2001 by J. Kean Johnston <jkj@caldera.com>
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation, and that the name J. Kean Johnston not be used in
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* advertising or publicity pertaining to distribution of the software without
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* specific, written prior permission. J. Kean Johnston makes no
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* representations about the suitability of this software for any purpose.
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* It is provided "as is" without express or implied warranty.
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*
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* J. KEAN JOHNSTON DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL J. KEAN JOHNSTON BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
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* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/* $XConsortium$ */
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#include "X.h"
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#include "compiler.h"
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#define _NEED_SYSI86
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#include "xf86.h"
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#include "xf86Priv.h"
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#include "xf86OSpriv.h"
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#include "xf86_OSlib.h"
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/***************************************************************************/
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/* I/O Permissions section */
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/***************************************************************************/
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/*
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* There is a right way and a wrong way of doing this. Unfortunately, we
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* are forced to do it the wrong way. The right way is to be told the range
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* or ranges of I/O ports the driver(s) need access to, in order to use the
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* CONS_IOPERM ioctl() to grant access only to those ports we care about.
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* This way we can guarantee some small level of stability because a driver
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* does not have access to all ports (which would mean it could play with
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* the PIT and thus affect scheduling times, or a whole slew of other
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* nasty things). However, because XFree86 currently only enables or disables
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* ALL port access, we need to run at IOPL 3, which basically means the
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* X Server runs at the same level as the kernel. You can image why this is
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* unsafe. Oh, and this is not a problem unique to OSR5, other OSes are
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* affected by this as well.
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*
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* So, for the time being, we change our IOPL until such time as the XFree86
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* architecture is changed to allow for tighter control of I/O ports. If and
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* when it is, then the CONS_ADDIOP/DELIOP ioctl() should be used to enable
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* or disable access to the desired ports.
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*/
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extern long sysi86 (int cmd, ...);
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static Bool IOEnabled = FALSE;
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void xf86EnableIO(void)
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{
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if (IOEnabled)
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return;
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if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) < 0)
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FatalError("Failed to set IOPL for extended I/O\n");
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IOEnabled = TRUE;
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}
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void xf86DisableIO(void)
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{
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if (!IOEnabled)
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return;
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sysi86(SI86V86, V86SC_IOPL, 0);
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IOEnabled = FALSE;
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}
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/***************************************************************************/
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/* Interrupt Handling section */
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/***************************************************************************/
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Bool xf86DisableInterrupts()
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{
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if (!IOEnabled) {
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if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) < 0)
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return FALSE;
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}
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#ifdef __GNUC__
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__asm__ __volatile__("cli");
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#else
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asm("cli");
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#endif /* __GNUC__ */
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if (!IOEnabled) {
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sysi86(SI86V86, V86SC_IOPL, PS_IOPL);
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}
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return(TRUE);
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}
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void xf86EnableInterrupts()
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{
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if (!IOEnabled) {
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if (sysi86(SI86V86, V86SC_IOPL, PS_IOPL) < 0)
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return;
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}
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#ifdef __GNUC__
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__asm__ __volatile__("sti");
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#else
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asm("sti");
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#endif /* __GNUC__ */
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if (!IOEnabled) {
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sysi86(SI86V86, V86SC_IOPL, PS_IOPL);
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}
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}
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