jit/ExecutableAllocator.cpp

   1 /*
   2  * Copyright (C) 2008 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. 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  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27
  28 #include "ExecutableAllocator.h"
  29
  30 #if ENABLE(ASSEMBLER)
  31
  32 namespace JSC {
  33
  34 size_t ExecutableAllocator::pageSize = 0;
  35
  36 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
  37 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSeting setting)
  38 {
  39     if (!pageSize)
  40         intializePageSize();
  41
  42     // Calculate the start of the page containing this region,
  43     // and account for this extra memory within size.
  44     intptr_t startPtr = reinterpret_cast<intptr_t>(start);
  45     intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
  46     void* pageStart = reinterpret_cast<void*>(pageStartPtr);
  47     size += (startPtr - pageStartPtr);
  48
  49     // Round size up
  50     size += (pageSize - 1);
  51     size &= ~(pageSize - 1);
  52
  53     mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
  54 }
  55 #endif
  56
  57 #if CPU(ARM_TRADITIONAL) && OS(LINUX) && COMPILER(RVCT)
  58 __asm void ExecutableAllocator::cacheFlush(void* code, size_t size)
  59 {
  60     ARM
  61     push {r7}
  62     add r1, r1, r0
  63     mov r7, #0xf0000
  64     add r7, r7, #0x2
  65     mov r2, #0x0
  66     svc #0x0
  67     pop {r7}
  68     bx lr
  69 }
  70 #endif
  71
  72 }
  73
  74 #endif // HAVE(ASSEMBLER)