CACHEFLUSH(2)             Linux Programmer's Manual            CACHEFLUSH(2)

NAME         top

       cacheflush - flush contents of instruction and/or data cache

SYNOPSIS         top

       #include <asm/cachectl.h>

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

DESCRIPTION         top

       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

       BCACHE Same as (ICACHE|DCACHE).

RETURN VALUE         top

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

ERRORS         top

       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         top

       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

       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         top

       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

COLOPHON         top

       This page is part of release 4.10 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

Linux                            2015-02-21                    CACHEFLUSH(2)