/*

 * 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.

 *

 *

 */

// Interface for updating the instruction cache.  Whenever the VM modifies

// code, part of the processor instruction cache potentially has to be flushed.

// Default implementation is in icache.cpp, and can be hidden per-platform.

// Most platforms must provide only ICacheStubGenerator::generate_icache_flush().

// Platforms that don't require icache flushing can just nullify the public

// members of AbstractICache in their ICache class.  AbstractICache should never

// be referenced other than by deriving the ICache class from it.

//

// The code for the ICache class and for generate_icache_flush() must be in

// architecture-specific files, i.e., icache_<arch>.hpp/.cpp

class AbstractICache : AllStatic {

 public:

  // The flush stub signature

  typedef int (*flush_icache_stub_t)(address addr, int lines, int magic);

 protected:

  // The flush stub function address

  static flush_icache_stub_t _flush_icache_stub;

  // Call the flush stub

  static void call_flush_stub(address start, int lines);

 public:

  enum {

    stub_size      = 0, // Size of the icache flush stub in bytes

    line_size      = 0, // Icache line size in bytes

    log2_line_size = 0  // log2(line_size)

  };

  static void initialize();

  static void invalidate_word(address addr);

  static void invalidate_range(address start, int nbytes);

};

// Must be included before the definition of ICacheStubGenerator

// because ICacheStubGenerator uses ICache definitions.

#include "incls/_icache_pd.hpp.incl"

class ICacheStubGenerator : public StubCodeGenerator {

 public:

  ICacheStubGenerator(CodeBuffer *c) : StubCodeGenerator(c) {}

  // Generate the icache flush stub.

  //

  // Since we cannot flush the cache when this stub is generated,

  // it must be generated first, and just to be sure, we do extra

  // work to allow a check that these instructions got executed.

  //

  // The flush stub has three parameters (see flush_icache_stub_t).

  //

  //   addr  - Start address, must be aligned at log2_line_size

  //   lines - Number of line_size icache lines to flush

  //   magic - Magic number copied to result register to make sure

  //           the stub executed properly

  //

  // A template for generate_icache_flush is

  //

  //    #define __ _masm->

  //

  //    void ICacheStubGenerator::generate_icache_flush(

  //      ICache::flush_icache_stub_t* flush_icache_stub

  //    ) {

  //      StubCodeMark mark(this, "ICache", "flush_icache_stub");

  //

  //      address start = __ pc();

  //

  //      // emit flush stub asm code

  //

  //      // Must be set here so StubCodeMark destructor can call the flush stub.

  //      *flush_icache_stub = (ICache::flush_icache_stub_t)start;

  //    };

  //

  //    #undef __

  //

  // 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 (see asm/assembler.cpp), which

  // in turn will call the flush stub *before* generate_icache_flush returns.

  // The usual method of having generate_icache_flush return the address of the

  // stub to its caller, which would then, e.g., store that address in

  // flush_icache_stub, won't work.  generate_icache_flush must itself set

  // flush_icache_stub to the address of the stub it generates before

  // the StubCodeMark destructor is invoked.

  void generate_icache_flush(ICache::flush_icache_stub_t* flush_icache_stub);

};