1 /*
   2  * Copyright (c) 1997, 2016, 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
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  24 
  25 #ifndef SHARE_VM_RUNTIME_ICACHE_HPP
  26 #define SHARE_VM_RUNTIME_ICACHE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "runtime/stubCodeGenerator.hpp"
  30 #include "utilities/macros.hpp"
  31 
  32 // Interface for updating the instruction cache.  Whenever the VM modifies
  33 // code, part of the processor instruction cache potentially has to be flushed.
  34 
  35 // Default implementation is in icache.cpp, and can be hidden per-platform.
  36 // Most platforms must provide only ICacheStubGenerator::generate_icache_flush().
  37 // Platforms that don't require icache flushing can just nullify the public
  38 // members of AbstractICache in their ICache class.  AbstractICache should never
  39 // be referenced other than by deriving the ICache class from it.
  40 //
  41 // The code for the ICache class and for generate_icache_flush() must be in
  42 // architecture-specific files, i.e., icache_<arch>.hpp/.cpp
  43 
  44 class AbstractICache : AllStatic {
  45  public:
  46   // The flush stub signature
  47   typedef int (*flush_icache_stub_t)(address addr, int lines, int magic);
  48 
  49  protected:
  50   // The flush stub function address
  51   static flush_icache_stub_t _flush_icache_stub;
  52 
  53   // Call the flush stub
  54   static void call_flush_stub(address start, int lines);
  55 
  56  public:
  57   enum {
  58     stub_size      = 0, // Size of the icache flush stub in bytes
  59     line_size      = 0, // Icache line size in bytes
  60     log2_line_size = 0  // log2(line_size)
  61   };
  62 
  63   static void initialize();
  64   static void invalidate_word(address addr);
  65   static void invalidate_range(address start, int nbytes);
  66 };
  67 
  68 
  69 // Must be included before the definition of ICacheStubGenerator
  70 // because ICacheStubGenerator uses ICache definitions.
  71 
  72 #include CPU_HEADER(icache)
  73 
  74 class ICacheStubGenerator : public StubCodeGenerator {
  75  public:
  76   ICacheStubGenerator(CodeBuffer *c) : StubCodeGenerator(c) {}
  77 
  78   // Generate the icache flush stub.
  79   //
  80   // Since we cannot flush the cache when this stub is generated,
  81   // it must be generated first, and just to be sure, we do extra
  82   // work to allow a check that these instructions got executed.
  83   //
  84   // The flush stub has three parameters (see flush_icache_stub_t).
  85   //
  86   //   addr  - Start address, must be aligned at log2_line_size
  87   //   lines - Number of line_size icache lines to flush
  88   //   magic - Magic number copied to result register to make sure
  89   //           the stub executed properly
  90   //
  91   // A template for generate_icache_flush is
  92   //
  93   //    #define __ _masm->
  94   //
  95   //    void ICacheStubGenerator::generate_icache_flush(
  96   //      ICache::flush_icache_stub_t* flush_icache_stub
  97   //    ) {
  98   //      StubCodeMark mark(this, "ICache", "flush_icache_stub");
  99   //
 100   //      address start = __ pc();
 101   //
 102   //      // emit flush stub asm code
 103   //
 104   //      // Must be set here so StubCodeMark destructor can call the flush stub.
 105   //      *flush_icache_stub = (ICache::flush_icache_stub_t)start;
 106   //    };
 107   //
 108   //    #undef __
 109   //
 110   // The first use of flush_icache_stub must apply it to itself.  The
 111   // StubCodeMark destructor in generate_icache_flush will call Assembler::flush,
 112   // which in turn will call invalidate_range (see asm/assembler.cpp), which
 113   // in turn will call the flush stub *before* generate_icache_flush returns.
 114   // The usual method of having generate_icache_flush return the address of the
 115   // stub to its caller, which would then, e.g., store that address in
 116   // flush_icache_stub, won't work.  generate_icache_flush must itself set
 117   // flush_icache_stub to the address of the stub it generates before
 118   // the StubCodeMark destructor is invoked.
 119 
 120   void generate_icache_flush(ICache::flush_icache_stub_t* flush_icache_stub);
 121 };
 122 
 123 #endif // SHARE_VM_RUNTIME_ICACHE_HPP