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 /*

  * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "memory/resourceArea.hpp"

 #include "runtime/icache.hpp"

 // The flush stub function address

 AbstractICache::flush_icache_stub_t AbstractICache::_flush_icache_stub = NULL;

 void AbstractICache::initialize() {

   // Making this stub must be FIRST use of assembler

   ResourceMark rm;

   BufferBlob* b = BufferBlob::create("flush_icache_stub", ICache::stub_size);

   CodeBuffer c(b);

   ICacheStubGenerator g(&c);

   g.generate_icache_flush(&_flush_icache_stub);

   // The first use of flush_icache_stub must apply it to itself.

   // The StubCodeMark destructor in generate_icache_flush will

   // call Assembler::flush, which in turn will call invalidate_range,

   // which will in turn call the flush stub.  Thus we don't need an

   // explicit call to invalidate_range here.  This assumption is

   // checked in invalidate_range.

 }

 void AbstractICache::call_flush_stub(address start, int lines) {

   // The business with the magic number is just a little security.

   // We cannot call the flush stub when generating the flush stub

   // because it isn't there yet.  So, the stub also returns its third

   // parameter.  This is a cheap check that the stub was really executed.

   static int magic = 0xbaadbabe;

   int auto_magic = magic; // Make a local copy to avoid race condition

   int r = (*_flush_icache_stub)(start, lines, auto_magic);

   guarantee(r == auto_magic, "flush stub routine did not execute");

   ++magic;

 }

 void AbstractICache::invalidate_word(address addr) {

   // Because this is called for instruction patching on the fly, long after

   // bootstrapping, we execute the stub directly.  Account for a 4-byte word

   // spanning two cache lines by computing a start line address by rounding

   // addr down to a line_size boundary, and an end line address by adding

   // the word size - 1 and rounding the result down to a line_size boundary.

   // If we just added word size, we'd mistakenly flush the next cache line

   // if the word to be flushed started in the last 4 bytes of the line.

   // Doing that would segv if the next line weren't mapped.

   const int word_size_in_bytes = 4; // Always, regardless of platform

   intptr_t start_line = ((intptr_t)addr + 0) & ~(ICache::line_size - 1);

   intptr_t end_line   = ((intptr_t)addr + word_size_in_bytes - 1)

                                              & ~(ICache::line_size - 1);

   (*_flush_icache_stub)((address)start_line, start_line == end_line ? 1 : 2, 0);

 }

 void AbstractICache::invalidate_range(address start, int nbytes) {

   static bool firstTime = true;

   if (firstTime) {

     guarantee(start == CAST_FROM_FN_PTR(address, _flush_icache_stub),

               "first flush should be for flush stub");

     firstTime = false;

     return;

   }

   if (nbytes == 0) {

     return;

   }

   // Align start address to an icache line boundary and transform

   // nbytes to an icache line count.

   const uint line_offset = mask_address_bits(start, ICache::line_size-1);

   if (line_offset != 0) {

     start -= line_offset;

     nbytes += line_offset;

   }

   call_flush_stub(start, round_to(nbytes, ICache::line_size) >>

                          ICache::log2_line_size);

 }

 // For init.cpp

 void icache_init() {

   ICache::initialize();

 }