1 /*
2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/resourceArea.hpp"
27 #include "runtime/icache.hpp"
28 #include "utilities/align.hpp"
29
30 // The flush stub function address
31 AbstractICache::flush_icache_stub_t AbstractICache::_flush_icache_stub = NULL;
32
33 void AbstractICache::initialize() {
34 // Making this stub must be FIRST use of assembler
35 ResourceMark rm;
36
37 BufferBlob* b = BufferBlob::create("flush_icache_stub", ICache::stub_size);
38 if (b == NULL) {
39 vm_exit_out_of_memory(ICache::stub_size, OOM_MALLOC_ERROR, "CodeCache: no space for flush_icache_stub");
40 }
41 CodeBuffer c(b);
42
43 ICacheStubGenerator g(&c);
44 g.generate_icache_flush(&_flush_icache_stub);
45
46 // The first use of flush_icache_stub must apply it to itself.
47 // The StubCodeMark destructor in generate_icache_flush will
48 // call Assembler::flush, which in turn will call invalidate_range,
49 // which will in turn call the flush stub. Thus we don't need an
50 // explicit call to invalidate_range here. This assumption is
51 // checked in invalidate_range.
52 }
53
54 void AbstractICache::call_flush_stub(address start, int lines) {
55 // The business with the magic number is just a little security.
56 // We cannot call the flush stub when generating the flush stub
57 // because it isn't there yet. So, the stub also returns its third
58 // parameter. This is a cheap check that the stub was really executed.
59 static int magic = 0xbaadbabe;
60
61 int auto_magic = magic; // Make a local copy to avoid race condition
62 int r = (*_flush_icache_stub)(start, lines, auto_magic);
63 guarantee(r == auto_magic, "flush stub routine did not execute");
64 ++magic;
65 }
66
67 void AbstractICache::invalidate_word(address addr) {
68 // Because this is called for instruction patching on the fly, long after
69 // bootstrapping, we execute the stub directly. Account for a 4-byte word
70 // spanning two cache lines by computing a start line address by rounding
71 // addr down to a line_size boundary, and an end line address by adding
72 // the word size - 1 and rounding the result down to a line_size boundary.
73 // If we just added word size, we'd mistakenly flush the next cache line
74 // if the word to be flushed started in the last 4 bytes of the line.
75 // Doing that would segv if the next line weren't mapped.
76
77 const int word_size_in_bytes = 4; // Always, regardless of platform
78
79 intptr_t start_line = ((intptr_t)addr + 0) & ~(ICache::line_size - 1);
80 intptr_t end_line = ((intptr_t)addr + word_size_in_bytes - 1)
81 & ~(ICache::line_size - 1);
82 (*_flush_icache_stub)((address)start_line, start_line == end_line ? 1 : 2, 0);
83 }
84
85 void AbstractICache::invalidate_range(address start, int nbytes) {
86 static bool firstTime = true;
87 if (firstTime) {
88 guarantee(start == CAST_FROM_FN_PTR(address, _flush_icache_stub),
89 "first flush should be for flush stub");
90 firstTime = false;
91 return;
92 }
93 if (nbytes == 0) {
94 return;
95 }
96 // Align start address to an icache line boundary and transform
97 // nbytes to an icache line count.
98 const uint line_offset = mask_address_bits(start, ICache::line_size-1);
99 if (line_offset != 0) {
100 start -= line_offset;
101 nbytes += line_offset;
102 }
103 call_flush_stub(start, align_up(nbytes, (int)ICache::line_size) >>
104 ICache::log2_line_size);
105 }
106
107 // For init.cpp
108 void icache_init() {
109 ICache::initialize();
110 }