cacheflush.cpp revision 14b467e840f8735e050b1844731c7747a7130525 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
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 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28#include <unistd.h>
29#include <sys/cachectl.h>
30
31#ifdef DEBUG
32#include "private/libc_logging.h"
33#define  XLOG(...) __libc_format_log(ANDROID_LOG_DEBUG,"libc-cacheflush",__VA_ARGS__)
34#endif
35
36/*
37 * Linux historically defines a cacheflush(3) routine for MIPS
38 * with this signature:
39 * int cacheflush(char *addr, int nbytes, int cache);
40 *
41 * Android defines an alternate cacheflush routine which exposes the
42 * ARM system call interface:
43 * int cacheflush (long start, long end, long flags)
44 *
45 * This is an attempt to maintain compatibility between the historical MIPS
46 * usage for software previously ported to MIPS and Android specific
47 * uses of cacheflush()
48 *
49 * Use the gcc __clear_cache builtin if possible. This will generate inline synci
50 * instructions if available or call _flush_cache(start, len, BCACHE) directly
51 */
52
53#if defined (__GNUC__)
54#define GCC_VERSION ((__GNUC__*10000) + __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__)
55#endif
56
57/* This is the Android signature */
58int cacheflush (long start, long end, long /*flags*/) {
59	if (end < start) {
60		/*
61		 * It looks like this is really MIPS style cacheflush call
62		 * start => addr
63		 * end => nbytes
64		 */
65#ifdef DEBUG
66		static int warned = 0;
67		if (!warned) {
68			XLOG("called with (start,len) instead of (start,end)");
69			warned = 1;
70		}
71#endif
72		end += start;
73	}
74
75#if !defined(ARCH_MIPS_USE_FLUSHCACHE_SYSCALL) && \
76	defined(GCC_VERSION) && (GCC_VERSION >= 40300)
77
78#if (__mips_isa_rev >= 2) && (GCC_VERSION < 40403)
79	/*
80	 * Modify "start" and "end" to avoid GCC 4.3.0-4.4.2 bug in
81	 * mips_expand_synci_loop that may execute synci one more time.
82	 * "start" points to the first byte of the cache line.
83	 * "end" points to the last byte of the line before the last cache line.
84	 * Because size is always a multiple of 4, this is safe to set
85	 * "end" to the last byte.
86	 */
87	{
88		int lineSize;
89		asm("rdhwr %0, $1" : "=r" (lineSize));
90		start = start & (-lineSize);
91		end = (end & (-lineSize)) - 1;
92	}
93#endif
94	__builtin___clear_cache((char *)start, (char *)end);
95#else
96	_flush_cache((char *)start, end-start, BCACHE);
97#endif
98	return 0;
99}
100