/*

 * 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();

}