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 
29 #include <unistd.h>
30 #include <sys/cachectl.h>
31 
32 #include "private/libc_logging.h"
33 
34 // Linux historically defines a cacheflush(3) routine for MIPS
35 // with this signature:
36 
37 //   int cacheflush(char *addr, int nbytes, int cache);
38 
39 // Android defines an alternate cacheflush routine which exposes the
40 // ARM system call interface:
41 
42 //   int cacheflush (long start, long end, long flags)
43 
44 // This is an attempt to maintain compatibility between the historical MIPS
45 // usage for software previously ported to MIPS and Android specific
46 // uses of cacheflush().
47 
cacheflush(long start,long end,long)48 int cacheflush(long start, long end, long /*flags*/) {
49   if (end < start) {
50     // It looks like this is really a MIPS-style cacheflush call.
51     static bool warned = false;
52     if (!warned) {
53       __libc_format_log(ANDROID_LOG_WARN, "libc", "cacheflush called with (start,len) instead of (start,end)");
54       warned = true;
55     }
56     end += start;
57   }
58 
59   // Use the GCC builtin. This will generate inline synci instructions if available,
60   // or call _flush_cache(start, len, BCACHE) directly.
61   __builtin___clear_cache(reinterpret_cast<char*>(start), reinterpret_cast<char*>(end));
62   return 0;
63 }
64