xref: /freebsd/lib/libc/arm/gen/arm_sync_icache.2 (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1.\" Copyright (c) 2019 Ian Lepore <ian@FreeBSD.org>
2.\"
3.\" Redistribution and use in source and binary forms, with or without
4.\" modification, are permitted provided that the following conditions
5.\" are met:
6.\" 1. Redistributions of source code must retain the above copyright
7.\"    notice, this list of conditions and the following disclaimer.
8.\" 2. Redistributions in binary form must reproduce the above copyright
9.\"    notice, this list of conditions and the following disclaimer in the
10.\"    documentation and/or other materials provided with the distribution.
11.\"
12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
15.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
22.\" SUCH DAMAGE.
23.\"
24.\" $FreeBSD$
25.\"
26.Dd July 10, 2019
27.Dt ARM_sync_icache 2
28.Os
29.Sh NAME
30.Nm arm_sync_icache
31.Nd synchronize the data and instruction caches
32.Sh LIBRARY
33.Lb libc
34.Sh SYNOPSIS
35.In machine/sysarch.h
36.Ft int
37.Fn arm_sync_icache "u_int addr" "int len"
38.Sh DESCRIPTION
39The
40.Nm
41system call synchronizes the contents of any data and instructions caches
42with the contents of main memory for the given range.
43Use this after loading executable code or modifying existing code in memory,
44before attempting to execute that code.
45.Pp
46The
47.Va addr
48and
49.Va len
50arguments do not need to be aligned to any particular boundary, but
51cache operations will affect entire cache lines, even those which are only
52partially overlapped by the given range.
53.Pp
54This takes one or more of the following actions, depending on the requirements
55of the hardware:
56.Bl -bullet
57.It
58Write dirty data cache lines within the range back to main memory.
59.It
60Invalidate existing instruction cache contents for the range.
61.It
62Invalidate branch prediction caches for the range.
63.El
64.Pp
65On hardware which supports multiple synchronization points for cache
66operations, the caches are maintained to the point of unification,
67making the data in the range coherent amongst all cores.
68.Sh RETURN VALUES
69The
70.Nm
71system call always returns 0.
72.Sh ERRORS
73If a call refers to memory which the calling process does not have rights
74to access, or if the
75.Va len
76argument is negative, a SIGSEGV signal is delivered to the calling thread.
77.Sh AUTHORS
78This man page was written by
79.An Ian Lepore .
80