NAME

       cacheflush - flush contents of instruction and/or data cache

SYNOPSIS

       #include <asm/cachectl.h>

       int cacheflush(char *addr, int nbytes, int cache);

DESCRIPTION

       cacheflush()  flushes the contents of the indicated cache(s) for the user addresses in the
       range addr to (addr+nbytes-1).  cache may be one of:

       ICACHE Flush the instruction cache.

       DCACHE Write back to memory and invalidate the affected valid cache lines.

       BCACHE Same as (ICACHE|DCACHE).

RETURN VALUE

       cacheflush() returns 0 on success or -1 on error.  If  errors  are  detected,  errno  will
       indicate the error.

ERRORS

       EFAULT Some or all of the address range addr to (addr+nbytes-1) is not accessible.

       EINVAL cache is not one of ICACHE, DCACHE, or BCACHE (but see BUGS).

CONFORMING TO

       Historically,  this system call was available on all MIPS UNIX variants including RISC/os,
       IRIX, Ultrix, NetBSD, OpenBSD, and FreeBSD (and  also  on  some  non-UNIX  MIPS  operating
       systems),  so  that  the  existence  of  this call in MIPS operating systems is a de-facto
       standard.

   Caveat
       cacheflush() should not be used in programs intended to be portable.  On Linux, this  call
       first  appeared  on  the  MIPS  architecture,  but nowadays, Linux provides a cacheflush()
       system call on some other architectures, but with different arguments.

BUGS

       Linux kernels older than version 2.6.11 ignore the addr and nbytes arguments, making  this
       function fairly expensive.  Therefore, the whole cache is always flushed.

       This  function always behaves as if BCACHE has been passed for the cache argument and does
       not do any error checking on the cache argument.

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.