source: mainline/kernel/arch/arm32/include/barrier.h@ b55877d

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since b55877d was 6412909, checked in by Jan Vesely <jano.vesely@…>, 13 years ago

arm32: Implement ICache invalidation

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File size: 3.0 KB
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1/*
2 * Copyright (c) 2005 Jakub Jermar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup arm32
30 * @{
31 */
32/** @file
33 * @brief Memory barriers.
34 */
35
36#ifndef KERN_arm32_BARRIER_H_
37#define KERN_arm32_BARRIER_H_
38
39/*
40 * TODO: implement true ARM memory barriers for macros below.
41 */
42#define CS_ENTER_BARRIER() asm volatile ("" ::: "memory")
43#define CS_LEAVE_BARRIER() asm volatile ("" ::: "memory")
44
45#define memory_barrier() asm volatile ("" ::: "memory")
46#define read_barrier() asm volatile ("" ::: "memory")
47#define write_barrier() asm volatile ("" ::: "memory")
48
49/*
50 * There are multiple ways ICache can be implemented on ARM machines. Namely
51 * PIPT, VIPT, and ASID and VMID tagged VIVT (see ARM Architecture Reference
52 * Manual B3.11.2 (p. 1383). However, CortexA8 Manual states: "For maximum
53 * compatibility across processors, ARM recommends that operating systems target
54 * the ARMv7 base architecture that uses ASID-tagged VIVT instruction caches,
55 * and do not assume the presence of the IVIPT extension. Software that relies
56 * on the IVIPT extension might fail in an unpredictable way on an ARMv7
57 * implementation that does not include the IVIPT extension." (7.2.6 p. 245).
58 * Only PIPT invalidates cache for all VA aliases if one block is invalidated.
59 *
60 * @note: Supporting ASID and VMID tagged VIVT may need to add ICache
61 * maintenance to other places than just smc.
62 */
63
64/* Available on both all supported arms,
65 * invalidates entire ICache so the written value does not matter. */
66#define smc_coherence(a) asm volatile ( "mcr p15, 0, r0, c7, c5, 0")
67#define smc_coherence_block(a, l) smc_coherence(a)
68
69
70#endif
71
72/** @}
73 */
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