src/mem/page_table.hh

   1 /*
   2  * Copyright (c) 2003 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Steve Reinhardt
  29  */
  30
  31 /**
  32  * @file
  33  * Declaration of a non-full system Page Table.
  34  */
  35
  36 #ifndef __MEM_PAGE_TABLE_HH__
  37 #define __MEM_PAGE_TABLE_HH__
  38
  39 #include <string>
  40
  41 #include "arch/isa_traits.hh"
  42 #include "arch/tlb.hh"
  43 #include "base/hashmap.hh"
  44 #include "base/types.hh"
  45 #include "config/the_isa.hh"
  46 #include "mem/request.hh"
  47 #include "sim/serialize.hh"
  48
  49 class Process;
  50
  51 /**
  52  * Page Table Declaration.
  53  */
  54 class PageTable
  55 {
  56   protected:
  57     typedef m5::hash_map<Addr, TheISA::TlbEntry> PTable;
  58     typedef PTable::iterator PTableItr;
  59     PTable pTable;
  60
  61     struct cacheElement {
  62         Addr vaddr;
  63         TheISA::TlbEntry entry;
  64     };
  65
  66     struct cacheElement pTableCache[3];
  67
  68     const Addr pageSize;
  69     const Addr offsetMask;
  70
  71     Process *process;
  72
  73   public:
  74
  75     PageTable(Process *_process, Addr _pageSize = TheISA::VMPageSize);
  76
  77     ~PageTable();
  78
  79     Addr pageAlign(Addr a)  { return (a & ~offsetMask); }
  80     Addr pageOffset(Addr a) { return (a &  offsetMask); }
  81
  82     void allocate(Addr vaddr, int64_t size, bool clobber = false);
  83     void remap(Addr vaddr, int64_t size, Addr new_vaddr);
  84     void deallocate(Addr vaddr, int64_t size);
  85
  86     /**
  87      * Check if any pages in a region are already allocated
  88      * @param vaddr The starting virtual address of the region.
  89      * @param size The length of the region.
  90      * @return True if no pages in the region are mapped.
  91      */
  92     bool isUnmapped(Addr vaddr, int64_t size);
  93
  94     /**
  95      * Lookup function
  96      * @param vaddr The virtual address.
  97      * @return entry The page table entry corresponding to vaddr.
  98      */
  99     bool lookup(Addr vaddr, TheISA::TlbEntry &entry);
 100
 101     /**
 102      * Translate function
 103      * @param vaddr The virtual address.
 104      * @param paddr Physical address from translation.
 105      * @return True if translation exists
 106      */
 107     bool translate(Addr vaddr, Addr &paddr);
 108
 109     /**
 110      * Simplified translate function (just check for translation)
 111      * @param vaddr The virtual address.
 112      * @return True if translation exists
 113      */
 114     bool translate(Addr vaddr) { Addr dummy; return translate(vaddr, dummy); }
 115
 116     /**
 117      * Perform a translation on the memory request, fills in paddr
 118      * field of req.
 119      * @param req The memory request.
 120      */
 121     Fault translate(RequestPtr req);
 122
 123     /**
 124      * Update the page table cache.
 125      * @param vaddr virtual address (page aligned) to check
 126      * @param pte page table entry to return
 127      */
 128     inline void updateCache(Addr vaddr, TheISA::TlbEntry entry)
 129     {
 130         pTableCache[2].entry = pTableCache[1].entry;
 131         pTableCache[2].vaddr = pTableCache[1].vaddr;
 132         pTableCache[1].entry = pTableCache[0].entry;
 133         pTableCache[1].vaddr = pTableCache[0].vaddr;
 134         pTableCache[0].entry = entry;
 135         pTableCache[0].vaddr = vaddr;
 136     }
 137
 138
 139     void serialize(std::ostream &os);
 140
 141     void unserialize(Checkpoint *cp, const std::string &section);
 142 };
 143
 144 #endif // __MEM_PAGE_TABLE_HH__