diff options
Diffstat (limited to 'JavaScriptCore/jit/ExecutableAllocatorFixedVMPool.cpp')
| -rw-r--r-- | JavaScriptCore/jit/ExecutableAllocatorFixedVMPool.cpp | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/JavaScriptCore/jit/ExecutableAllocatorFixedVMPool.cpp b/JavaScriptCore/jit/ExecutableAllocatorFixedVMPool.cpp index 4d3c847..7846a25 100644 --- a/JavaScriptCore/jit/ExecutableAllocatorFixedVMPool.cpp +++ b/JavaScriptCore/jit/ExecutableAllocatorFixedVMPool.cpp @@ -27,25 +27,33 @@ #include "ExecutableAllocator.h" -#if ENABLE(ASSEMBLER) && OS(DARWIN) && CPU(X86_64) +#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED) #include <errno.h> #include "TCSpinLock.h" -#include <mach/mach_init.h> -#include <mach/vm_map.h> #include <sys/mman.h> #include <unistd.h> #include <wtf/AVLTree.h> #include <wtf/VMTags.h> +#if CPU(X86_64) + // These limits suitable on 64-bit platforms (particularly x86-64, where we require all jumps to have a 2Gb max range). + #define VM_POOL_SIZE (2u * 1024u * 1024u * 1024u) // 2Gb + #define COALESCE_LIMIT (16u * 1024u * 1024u) // 16Mb +#else + // These limits are hopefully sensible on embedded platforms. + #define VM_POOL_SIZE (32u * 1024u * 1024u) // 32Mb + #define COALESCE_LIMIT (4u * 1024u * 1024u) // 4Mb +#endif + +// ASLR currently only works on darwin (due to arc4random) & 64-bit (due to address space size). +#define VM_POOL_ASLR (OS(DARWIN) && CPU(X86_64)) + using namespace WTF; namespace JSC { -#define TWO_GB (2u * 1024u * 1024u * 1024u) -#define SIXTEEN_MB (16u * 1024u * 1024u) - // FreeListEntry describes a free chunk of memory, stored in the freeList. struct FreeListEntry { FreeListEntry(void* pointer, size_t size) @@ -291,9 +299,12 @@ public: // for now instead of 2^26 bits of ASLR lets stick with 25 bits of randomization plus // 2^24, which should put up somewhere in the middle of usespace (in the address range // 0x200000000000 .. 0x5fffffffffff). - intptr_t randomLocation = arc4random() & ((1 << 25) - 1); + intptr_t randomLocation = 0; +#if VM_POOL_ASLR + randomLocation = arc4random() & ((1 << 25) - 1); randomLocation += (1 << 24); randomLocation <<= 21; +#endif m_base = mmap(reinterpret_cast<void*>(randomLocation), m_totalHeapSize, INITIAL_PROTECTION_FLAGS, MAP_PRIVATE | MAP_ANON, VM_TAG_FOR_EXECUTABLEALLOCATOR_MEMORY, 0); if (!m_base) CRASH(); @@ -387,7 +398,7 @@ public: // 16MB of allocations have been freed, sweep m_freeList // coalescing any neighboring fragments. m_countFreedSinceLastCoalesce += size; - if (m_countFreedSinceLastCoalesce >= SIXTEEN_MB) { + if (m_countFreedSinceLastCoalesce >= COALESCE_LIMIT) { m_countFreedSinceLastCoalesce = 0; coalesceFreeSpace(); } @@ -429,7 +440,7 @@ ExecutablePool::Allocation ExecutablePool::systemAlloc(size_t size) SpinLockHolder lock_holder(&spinlock); if (!allocator) - allocator = new FixedVMPoolAllocator(JIT_ALLOCATOR_LARGE_ALLOC_SIZE, TWO_GB); + allocator = new FixedVMPoolAllocator(JIT_ALLOCATOR_LARGE_ALLOC_SIZE, VM_POOL_SIZE); ExecutablePool::Allocation alloc = {reinterpret_cast<char*>(allocator->alloc(size)), size}; return alloc; } @@ -444,4 +455,5 @@ void ExecutablePool::systemRelease(const ExecutablePool::Allocation& allocation) } + #endif // HAVE(ASSEMBLER) |