MEMCONFIG(8)            OpenBSD System Manager's Manual           MEMCONFIG(8)

NAME
     memconfig - control system cache behaviour with respect to memory

SYNOPSIS
     memconfig list [-a]
     memconfig set -b base -l length -o owner attribute
     memconfig clear -o owner
     memconfig clear -b base -l length

DESCRIPTION
     A number of supported system architectures allow the behaviour of the CPU
     cache to be programmed to behave differently depending on the region be-
     ing written.

     memconfig provides an interface to this facility, allowing CPU cache be-
     havior to be altered for ranges of system physical memory.

     These ranges are typically power-of-2 aligned and sized, however the spe-
     cific rules governing their layout vary between architectures.  The mem-
     config program does not attempt to enforce these rules, however the sys-
     tem will reject any attempt to set an illegal combination.

     The operands and their options are as follows:

     list   List range slots.

            [-a]    List all range slots, even those that are inactive.

     set    Set memory range attributes.

            -b base
                    Memory range base address.

            -l length
                    Length of memory range in bytes, power of 2.

            -o owner
                    Text identifier for this setting (7 char max).

            attribute
                    Attributes applied to this range; one of uncacheable,
                    write-combine, write-through, write-back, or write-
                    protect.

     clear  Clear memory range attributes.  Ranges may be cleared by owner or
            by base/length combination.

            To clear based on ownership:

            -o owner
                    All ranges with this owner will be cleared.

            To clear based on the base/length combination:

            -b base
                    Memory range base address.

            -l length
                    Length of memory range in bytes, power of 2.

            Base and length must exactly match an existing range.

SEE ALSO
     mtrr(4)

HISTORY
     memconfig was originally introduced in FreeBSD 3.3 as memcontrol(8).

OpenBSD 2.9                    November 14, 1999                             2
