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* Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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#include "precompiled.hpp"
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#include "code/codeBlob.hpp"
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#include "memory/resourceArea.hpp"
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#include "runtime/icache.hpp"
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#include "utilities/align.hpp"
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// The flush stub function address
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AbstractICache::flush_icache_stub_t AbstractICache::_flush_icache_stub = nullptr;
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void AbstractICache::initialize() {
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// Making this stub must be FIRST use of assembler
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BufferBlob* b = BufferBlob::create("flush_icache_stub", ICache::stub_size);
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vm_exit_out_of_memory(ICache::stub_size, OOM_MALLOC_ERROR, "CodeCache: no space for flush_icache_stub");
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ICacheStubGenerator g(&c);
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g.generate_icache_flush(&_flush_icache_stub);
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// The first use of flush_icache_stub must apply it to itself.
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// The StubCodeMark destructor in generate_icache_flush will
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// call Assembler::flush, which in turn will call invalidate_range,
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// which will in turn call the flush stub. Thus we don't need an
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// explicit call to invalidate_range here. This assumption is
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// checked in invalidate_range.
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void AbstractICache::call_flush_stub(address start, int lines) {
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// The business with the magic number is just a little security.
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// We cannot call the flush stub when generating the flush stub
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// because it isn't there yet. So, the stub also returns its third
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// parameter. This is a cheap check that the stub was really executed.
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static int magic = 0xbaadbabe;
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int auto_magic = magic; // Make a local copy to avoid race condition
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int r = (*_flush_icache_stub)(start, lines, auto_magic);
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guarantee(r == auto_magic, "flush stub routine did not execute");
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void AbstractICache::invalidate_word(address addr) {
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// Because this is called for instruction patching on the fly, long after
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// bootstrapping, we execute the stub directly. Account for a 4-byte word
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// spanning two cache lines by computing a start line address by rounding
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// addr down to a line_size boundary, and an end line address by adding
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// the word size - 1 and rounding the result down to a line_size boundary.
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// If we just added word size, we'd mistakenly flush the next cache line
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// if the word to be flushed started in the last 4 bytes of the line.
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// Doing that would segv if the next line weren't mapped.
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const int word_size_in_bytes = 4; // Always, regardless of platform
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intptr_t start_line = ((intptr_t)addr + 0) & ~(ICache::line_size - 1);
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intptr_t end_line = ((intptr_t)addr + word_size_in_bytes - 1)
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& ~(ICache::line_size - 1);
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(*_flush_icache_stub)((address)start_line, start_line == end_line ? 1 : 2, 0);
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void AbstractICache::invalidate_range(address start, int nbytes) {
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static bool firstTime = true;
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guarantee(start == CAST_FROM_FN_PTR(address, _flush_icache_stub),
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"first flush should be for flush stub");
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// Align start address to an icache line boundary and transform
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// nbytes to an icache line count.
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const uint line_offset = uintptr_t(start) & (ICache::line_size-1);
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if (line_offset != 0) {
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start -= line_offset;
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nbytes += line_offset;
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call_flush_stub(start, align_up(nbytes, (int)ICache::line_size) >>
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ICache::log2_line_size);
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ICache::initialize();