michael@0: /*
michael@0:  * Copyright (C) 2008 Apple Inc. All rights reserved.
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1. Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
michael@0:  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
michael@0:  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
michael@0:  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
michael@0:  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
michael@0:  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
michael@0:  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
michael@0:  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0:  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: #include "assembler/jit/ExecutableAllocator.h"
michael@0: 
michael@0: #if ENABLE_ASSEMBLER && WTF_OS_UNIX && !WTF_OS_SYMBIAN
michael@0: 
michael@0: #include <sys/mman.h>
michael@0: #include <unistd.h>
michael@0: 
michael@0: #include "assembler/wtf/Assertions.h"
michael@0: #include "assembler/wtf/VMTags.h"
michael@0: #include "js/Utility.h"
michael@0: 
michael@0: namespace JSC {
michael@0: 
michael@0: size_t ExecutableAllocator::determinePageSize()
michael@0: {
michael@0:     return getpagesize();
michael@0: }
michael@0: 
michael@0: ExecutablePool::Allocation ExecutableAllocator::systemAlloc(size_t n)
michael@0: {
michael@0:     void *allocation = mmap(NULL, n, INITIAL_PROTECTION_FLAGS, MAP_PRIVATE | MAP_ANON, VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, 0);
michael@0:     if (allocation == MAP_FAILED)
michael@0:         allocation = NULL;
michael@0:     ExecutablePool::Allocation alloc = { reinterpret_cast<char*>(allocation), n };
michael@0:     return alloc;
michael@0: }
michael@0: 
michael@0: void ExecutableAllocator::systemRelease(const ExecutablePool::Allocation& alloc)
michael@0: {
michael@0:     int result = munmap(alloc.pages, alloc.size);
michael@0:     ASSERT_UNUSED(result, !result);
michael@0: }
michael@0: 
michael@0: #if WTF_ENABLE_ASSEMBLER_WX_EXCLUSIVE
michael@0: void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
michael@0: {
michael@0:     if (!pageSize)
michael@0:         intializePageSize();
michael@0: 
michael@0:     // Calculate the start of the page containing this region,
michael@0:     // and account for this extra memory within size.
michael@0:     intptr_t startPtr = reinterpret_cast<intptr_t>(start);
michael@0:     intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
michael@0:     void* pageStart = reinterpret_cast<void*>(pageStartPtr);
michael@0:     size += (startPtr - pageStartPtr);
michael@0: 
michael@0:     // Round size up
michael@0:     size += (pageSize - 1);
michael@0:     size &= ~(pageSize - 1);
michael@0: 
michael@0:     mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
michael@0: }
michael@0: #endif
michael@0: 
michael@0: #if WTF_CPU_ARM_TRADITIONAL && WTF_OS_LINUX && WTF_COMPILER_RVCT
michael@0: __asm void ExecutableAllocator::cacheFlush(void* code, size_t size)
michael@0: {
michael@0:     ARM
michael@0:     push {r7}
michael@0:     add r1, r1, r0
michael@0:     mov r7, #0xf0000
michael@0:     add r7, r7, #0x2
michael@0:     mov r2, #0x0
michael@0:     svc #0x0
michael@0:     pop {r7}
michael@0:     bx lr
michael@0: }
michael@0: #endif
michael@0: 
michael@0: void
michael@0: ExecutablePool::toggleAllCodeAsAccessible(bool accessible)
michael@0: {
michael@0:     char* begin = m_allocation.pages;
michael@0:     size_t size = m_freePtr - begin;
michael@0: 
michael@0:     if (size) {
michael@0:         // N.B. Some systems, like 32bit Mac OS 10.6, implicitly add PROT_EXEC
michael@0:         // when mprotect'ing memory with any flag other than PROT_NONE. Be
michael@0:         // sure to use PROT_NONE when making inaccessible.
michael@0:         int flags = accessible ? PROT_READ | PROT_WRITE | PROT_EXEC : PROT_NONE;
michael@0:         if (mprotect(begin, size, flags))
michael@0:             MOZ_CRASH();
michael@0:     }
michael@0: }
michael@0: 
michael@0: }
michael@0: 
michael@0: #endif // HAVE(ASSEMBLER)