.\"	$OpenBSD: cacheflush.3,v 1.1 2009/09/27 18:20:13 miod Exp $
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.\" Copyright (c) 2009 Miodrag Vallat.
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.Dd $Mdocdate: September 27 2009 $
.Dt CACHEFLUSH 3
.Os
.Sh NAME
.Nm cacheflush ,
.Nm _flush_cache
.Nd CPU cache synchronization functions
.Sh SYNOPSIS
.In machine/sysarch.h
.Ft int
.Fn cacheflush "void *addr" "int nbytes" "int cache"
.Ft int
.Fn _flush_cache "char *addr" "int nbytes" "int cache"
.Sh DESCRIPTION
.Fn cacheflush
allows a process to synchronize the contents of the processor caches with
main memory.
Since MIPS processors have separate instruction and data caches, this
function allows for dynamically generated code to run correctly.
.Pp
.Nm
operates on a contiguous memory range in the current process address space,
starting at address
.Fa addr
and
.Fa nbytes
bytes long.
The caches to be synchronized are specified in the
.Fa cache
argument with one of the following values:
.Pp
.Bl -tag -width "ICACHEXXX" -compact -offset ind
.It Dv ICACHE
synchronize the instruction cache
.It Dv DCACHE
synchronize the data cache
.It Dv BCACHE
synchronize both the instruction and data caches
.El
.Pp
.Nm _flush_cache
is an alias for the
.Nm cacheflush
function.
.Sh RETURN VALUES
Upon successful completion,
.Nm
returns zero.
Otherwise, a value of \-1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
.Nm
will fail if:
.Bl -tag -width Er
.It Bq Er EFAULT
The address range specified by
.Fa addr
and
.Fa nbytes
is not part of the process allocated address space.
.It Bq Er EINVAL
.Fa cache
is not valid.
.El