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Diffstat (limited to 'static/openbsd/man4/man4.i386/mtrr.4')
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diff --git a/static/openbsd/man4/man4.i386/mtrr.4 b/static/openbsd/man4/man4.i386/mtrr.4 new file mode 100644 index 00000000..6636011e --- /dev/null +++ b/static/openbsd/man4/man4.i386/mtrr.4 @@ -0,0 +1,147 @@ +.\" $OpenBSD: mtrr.4,v 1.17 2014/02/15 23:41:19 schwarze Exp $ +.\" +.\" Pentium MTRR driver for OpenBSD. +.\" Copyright 1999 Matthieu Herrb <matthieu@openbsd.org> +.\" +.\" Modification and redistribution in source and binary forms is +.\" permitted provided that due credit is given to the author and the +.\" OpenBSD project (for instance by leaving this copyright notice +.\" intact). +.\" +.Dd $Mdocdate: February 15 2014 $ +.Dt MTRR 4 i386 +.Os +.Sh NAME +.Nm mtrr +.Nd driver for CPU memory range attributes +.Sh SYNOPSIS +.Cd "pseudo-device mtrr 1" +.Sh DESCRIPTION +The +.Nm +device provides access to the memory range attributes supported by the +MTRRs on Pentiums. +.Ss IOCTL INTERFACE +Several architectures allow attributes to be associated with ranges of physical +memory. +These attributes can be manipulated via +.Fn ioctl +calls performed on +.Pa /dev/mem +or +.Pa /dev/xf86 . +Declarations and data types are to be found in +.In sys/memrange.h . +.Pp +The specific attributes, and number of programmable ranges may vary between +architectures. +The full set of supported attributes is: +.Bl -tag -width MDF_WRITECOMBINE +.It Dv MDF_UNCACHEABLE +The region is not cached. +.It Dv MDF_WRITECOMBINE +Writes to the region may be combined or performed out of order. +.It Dv MDF_WRITETHROUGH +Writes to the region are committed synchronously. +.It Dv MDF_WRITEBACK +Writes to the region are committed asynchronously. +.It Dv MDF_WRITEPROTECT +The region cannot be written to. +.El +.Pp +Memory ranges are described by +.Bd -literal -offset xxxx +struct mem_range_desc { + u_int64_t mr_base; /\(** physical base address \(**/ + u_int64_t mr_len; /\(** physical length of region \(**/ + int mr_flags; /\(** attributes of region \(**/ + char mr_owner[8]; +}; +.Ed +.Pp +In addition to the region attributes listed above, the following flags +may also be set in the +.Fa mr_flags +field: +.Bl -tag -width MDF_FIXACTIVE +.It Dv MDF_FIXBASE +The region's base address cannot be changed. +.It Dv MDF_FIXLEN +The region's length cannot be changed. +.It Dv MDF_FIRMWARE +The region is believed to have been established by the system firmware. +.It Dv MDF_ACTIVE +The region is currently active. +.It Dv MDF_BOGUS +We believe the region to be invalid or otherwise erroneous. +.It Dv MDF_FIXACTIVE +The region cannot be disabled. +.El +.Pp +Operations are performed using +.Bd -literal -offset xxxx +struct mem_range_op { + struct mem_range_desc *mo_desc; + int mo_arg[2]; +}; +.Ed +.Pp +The +.Fa MEMRANGE_GET +ioctl is used to retrieve current memory range attributes. +If +.Fa mo_arg[0] +is set to 0, it will be updated with the total number of memory range +descriptors. +If greater than 0, the array at +.Fa mo_desc +will be filled with a corresponding number of descriptor structures, +or the maximum, whichever is less. +.Pp +The +.Fa MEMRANGE_SET +ioctl is used to add, alter and remove memory range attributes. +A range with the +.Dv MDF_FIXACTIVE +flag may not be removed. +.Pp +.Fa mo_arg[0] +should be set to MEMRANGE_SET_UPDATE to update an existing +or establish a new range, or to MEMRANGE_SET_REMOVE to remove a range. +.Sh ERRORS +On +.Xr ioctl 2 +failure, +.Xr errno 2 +will be set as follows: +.Bl -tag -width Er +.It Bq Er EOPNOTSUPP +Memory range operations are not supported on this architecture. +.It Bq Er ENXIO +No memory range descriptors are available (e.g., firmware has not enabled +any). +.It Bq Er EINVAL +The memory range supplied as an argument is invalid or overlaps another +range in a fashion not supported by this architecture. +.It Bq Er EBUSY +An attempt to remove or update a range failed because the range is busy. +.It Bq Er ENOSPC +An attempt to create a new range failed due to a shortage of hardware +resources (e.g., descriptor slots). +.It Bq Er ENOENT +An attempt to remove a range failed because no range matches the descriptor +base/length supplied. +.It Bq Er EPERM +An attempt to remove a range failed because the range is permanently +enabled. +.El +.Sh SEE ALSO +.Xr ioctl 2 , +.Xr mem 4 , +.Xr pctr 4 , +.Xr xf86 4 , +.Xr memconfig 8 +.Sh HISTORY +.Nm +support was originally included in +.Fx 3.3 . |