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Make this a bit more verbose.

This commit is contained in:
fvdl 2001-11-10 19:06:54 +00:00
parent 33e8c8e58d
commit 88de3daceb
1 changed files with 56 additions and 9 deletions
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65
lib/libarch/i386/i386_get_mtrr.2
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@ -1,4 +1,4 @@
.\" $NetBSD: i386_get_mtrr.2,v 1.2 2001/11/10 08:10:49 wiz Exp $
.\" $NetBSD: i386_get_mtrr.2,v 1.3 2001/11/10 19:06:54 fvdl Exp $
.\"
.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -40,7 +40,7 @@
.Sh NAME
.Nm i386_get_mtrr ,
.Nm i386_set_mtrr
.Nd access MTRR registers
.Nd access Memory Type Range Registers
.Sh LIBRARY
.Lb libi386
.Sh SYNOPSIS
@ -55,6 +55,30 @@
These functions provide an interface to the MTRR registers found on
686-class processors.
.Pp
.Fa mtrrp
is a pointer to one or more mtrr structures, as described below. The
.Fa n
argument is a pointer to an integer containing the number of structures
pointed to by
.Fa mtrrp .
For
.Fn i386_set_mtrr
the integer pointed to by
.Fa n
will be updated to reflect the actual number of MTRRs successfully set.
For
.Fn i386_get_mtrr no more than
.Fa n
structures will be copied out, and the integer value pointed to by
.Fa n
will be updated to reflect the actual number of valid structures
retrieved.
A NULL argument to
.Fa mtrrp
will result in just the number of MTRRs available being returned
in the integer pointed to by
.Fa n .
.Pp
The argument
.Fa mtrrp
has the following structure:
@ -68,7 +92,7 @@ struct mtrr {
};
.Ed
.Pp
The location of the mapping is described by its base address
The location of the mapping is described by its physical base address
.Em base
and length
.Em len .
@ -78,12 +102,15 @@ are:
.Pp
.Bl -tag -offset indent -width MTRR_TYPE_UNDEF1 -compact
.It MTRR_TYPE_UC
uncached memory.
.It MTRR_TYPE_WC
.It MTRR_TYPE_UNDEF1
.It MTRR_TYPE_UNDEF2
use write-combining.
.It MTRR_TYPE_WT
use write-through caching.
.It MTRR_TYPE_WP
write-protected memory.
.It MTRR_TYPE_WB
use write-back caching.
.El
.Pp
Valid values for
@ -92,11 +119,11 @@ are:
.Pp
.Bl -tag -offset indent -width MTRR_PRIVATE -compact
.It MTRR_PRIVATE
own range, reset at exit
own range, reset the MTRR when the current process exits.
.It MTRR_FIXED
use fixed range MTRR
use fixed range MTRR.
.It MTRR_VALID
entry is valid
entry is valid.
.El
.Pp
The
@ -104,6 +131,26 @@ The
member the PID of the user process which claims the mapping. It is
only valid if MTRR_PRIVATE is set in
.Em flags .
To clear/reset MTRRs, use a
.Em flags
field without MTRR_VALID set.
.Sh RETURN VALUES
Upon successful completion zero is returned, otherwise -1 is returned
on failure.
on failure, and the global variable
.Va errno
is set to indicate the error. The integer value pointed to by
.Fa n
will be container the number of successfully processed mtrr structures
in both cases.
.Sh ERRORS
.Bl -tag -width [EINVAL]
.It Bq Er ENOSYS
The currently running kernel or CPU has no MTRR support.
.It Bq Er EINVAL
The currently running kernel has no MTRR support, or one of the mtrr
structures pointed to by
.Fa mtrrp
is invalid.
.It Bq Er EBUSY
No unused MTRRs are available.
.El