/js/src/nanojit/VMPI.cpp

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  4 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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  6 * The contents of this file are subject to the Mozilla Public License Version 1.1 (the
  7 * "License"); you may not use this file except in compliance with the License. You may obtain
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 10 * Software distributed under the License is distributed on an "AS IS" basis, WITHOUT
 11 * WARRANTY OF ANY KIND, either express or implied. See the License for the specific
 12 * language governing rights and limitations under the License.
 13 *
 14 * The Original Code is [Open Source Virtual Machine.]
 15 *
 16 * The Initial Developer of the Original Code is Adobe System Incorporated.  Portions created
 17 * by the Initial Developer are Copyright (C)[ 2004-2006 ] Adobe Systems Incorporated. All Rights
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 20 * Contributor(s): Adobe AS3 Team
 21 *                 Andreas Gal <gal@mozilla.com>
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 34
 35#include "nanojit.h"
 36
 37#ifdef SOLARIS
 38    typedef caddr_t maddr_ptr;
 39#else
 40    typedef void *maddr_ptr;
 41#endif
 42
 43using namespace avmplus;
 44
 45size_t
 46VMPI_getVMPageSize()
 47{
 48    return 4096;
 49}
 50
 51#ifdef WIN32
 52void
 53VMPI_setPageProtection(void *address,
 54                       size_t size,
 55                       bool executableFlag,
 56                       bool writeableFlag)
 57{
 58    DWORD oldProtectFlags = 0;
 59    DWORD newProtectFlags = 0;
 60    if ( executableFlag && writeableFlag ) {
 61        newProtectFlags = PAGE_EXECUTE_READWRITE;
 62    } else if ( executableFlag ) {
 63        newProtectFlags = PAGE_EXECUTE_READ;
 64    } else if ( writeableFlag ) {
 65        newProtectFlags = PAGE_READWRITE;
 66    } else {
 67        newProtectFlags = PAGE_READONLY;
 68    }
 69
 70    BOOL retval;
 71    MEMORY_BASIC_INFORMATION mbi;
 72    do {
 73        VirtualQuery(address, &mbi, sizeof(MEMORY_BASIC_INFORMATION));
 74        size_t markSize = size > mbi.RegionSize ? mbi.RegionSize : size;
 75
 76        retval = VirtualProtect(address, markSize, newProtectFlags, &oldProtectFlags);
 77        NanoAssert(retval);
 78
 79        address = (char*) address + markSize;
 80        size -= markSize;
 81    } while(size > 0 && retval);
 82
 83    // We should not be clobbering PAGE_GUARD protections
 84    NanoAssert((oldProtectFlags & PAGE_GUARD) == 0);
 85}
 86
 87#elif defined(AVMPLUS_OS2)
 88
 89void
 90VMPI_setPageProtection(void *address,
 91                       size_t size,
 92                       bool executableFlag,
 93                       bool writeableFlag)
 94{
 95    ULONG flags = PAG_READ;
 96    if (executableFlag) {
 97        flags |= PAG_EXECUTE;
 98    }
 99    if (writeableFlag) {
100        flags |= PAG_WRITE;
101    }
102    address = (void*)((size_t)address & ~(0xfff));
103    size = (size + 0xfff) & ~(0xfff);
104
105    ULONG attribFlags = PAG_FREE;
106    while (size) {
107        ULONG attrib;
108        ULONG range = size;
109        ULONG retval = DosQueryMem(address, &range, &attrib);
110        NanoAssert(retval == 0);
111
112        // exit if this is the start of the next memory object
113        if (attrib & attribFlags) {
114            break;
115        }
116        attribFlags |= PAG_BASE;
117
118        range = size > range ? range : size;
119        retval = DosSetMem(address, range, flags);
120        NanoAssert(retval == 0);
121
122        address = (char*)address + range;
123        size -= range;
124    }
125}
126
127#else // !WIN32 && !AVMPLUS_OS2
128
129void VMPI_setPageProtection(void *address,
130                            size_t size,
131                            bool executableFlag,
132                            bool writeableFlag)
133{
134  int bitmask = sysconf(_SC_PAGESIZE) - 1;
135  // mprotect requires that the addresses be aligned on page boundaries
136  void *endAddress = (void*) ((char*)address + size);
137  void *beginPage = (void*) ((size_t)address & ~bitmask);
138  void *endPage   = (void*) (((size_t)endAddress + bitmask) & ~bitmask);
139  size_t sizePaged = (size_t)endPage - (size_t)beginPage;
140
141  int flags = PROT_READ;
142  if (executableFlag) {
143    flags |= PROT_EXEC;
144  }
145  if (writeableFlag) {
146    flags |= PROT_WRITE;
147  }
148  int retval = mprotect((maddr_ptr)beginPage, (unsigned int)sizePaged, flags);
149  NanoAssert(retval == 0);
150  (void)retval;
151}
152
153#endif // WIN32