GENWiki

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

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  nowa-
     days, Linux provides a cacheflush() system call on some other architec-
     tures, 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 4.16 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/.

Linux 2017-09-15 CACHEFLUSH(2)