Landing: Write protect executable pages in the VM.

runtime/vm/virtual_memory_linux.cc

Index: runtime/vm/virtual_memory_linux.cc
diff --git a/runtime/vm/virtual_memory_linux.cc b/runtime/vm/virtual_memory_linux.cc
index 7a0d02b8078cfcf5964a0772583031727bfb269b..518703835a0ea3b9214f583d4f62186fb79f99f2 100644
--- a/runtime/vm/virtual_memory_linux.cc
+++ b/runtime/vm/virtual_memory_linux.cc
@@ -76,7 +76,10 @@ bool VirtualMemory::Commit(uword addr, intptr_t size, bool executable) {
 }
 
 
-bool VirtualMemory::Protect(Protection mode) {
+bool VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
+  uword start_address = reinterpret_cast<uword>(address);
+  uword end_address = start_address + size;
+  uword page_address = start_address & ~(PageSize() - 1);

[Ivan Posva, 2014/02/03 05:44:35]

ditto

[Florian Schneider, 2014/02/10 11:56:17]

Done.

   int prot = 0;
   switch (mode) {
     case kNoAccess:
@@ -95,9 +98,12 @@ bool VirtualMemory::Protect(Protection mode) {
       prot = PROT_READ | PROT_WRITE | PROT_EXEC;
       break;
   }
-  return (mprotect(address(), size(), prot) == 0);
+  return (mprotect(reinterpret_cast<void*>(page_address),
+                   end_address - page_address,
+                   prot) == 0);
 }
 
+
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)