diff -r cd8b8f500fac -r 9a5271881bc0 hotspot/src/os/windows/vm/os_windows.cpp --- a/hotspot/src/os/windows/vm/os_windows.cpp Wed Jul 05 16:39:00 2017 +0200 +++ b/hotspot/src/os/windows/vm/os_windows.cpp Sat Jul 19 17:38:22 2008 -0400 @@ -2170,6 +2170,7 @@ // Windows 98 reports faulting addresses incorrectly if (!MacroAssembler::needs_explicit_null_check((intptr_t)addr) || !os::win32::is_nt()) { + return Handle_Exception(exceptionInfo, SharedRuntime::continuation_for_implicit_exception(thread, pc, SharedRuntime::IMPLICIT_NULL)); } @@ -2563,9 +2564,33 @@ return VirtualFree(addr, 0, MEM_RELEASE) != 0; } -bool os::protect_memory(char* addr, size_t bytes) { +// Set protections specified +bool os::protect_memory(char* addr, size_t bytes, ProtType prot, + bool is_committed) { + unsigned int p = 0; + switch (prot) { + case MEM_PROT_NONE: p = PAGE_NOACCESS; break; + case MEM_PROT_READ: p = PAGE_READONLY; break; + case MEM_PROT_RW: p = PAGE_READWRITE; break; + case MEM_PROT_RWX: p = PAGE_EXECUTE_READWRITE; break; + default: + ShouldNotReachHere(); + } + DWORD old_status; - return VirtualProtect(addr, bytes, PAGE_READONLY, &old_status) != 0; + + // Strange enough, but on Win32 one can change protection only for committed + // memory, not a big deal anyway, as bytes less or equal than 64K + if (!is_committed && !commit_memory(addr, bytes)) { + fatal("cannot commit protection page"); + } + // One cannot use os::guard_memory() here, as on Win32 guard page + // have different (one-shot) semantics, from MSDN on PAGE_GUARD: + // + // Pages in the region become guard pages. Any attempt to access a guard page + // causes the system to raise a STATUS_GUARD_PAGE exception and turn off + // the guard page status. Guard pages thus act as a one-time access alarm. + return VirtualProtect(addr, bytes, p, &old_status) != 0; } bool os::guard_memory(char* addr, size_t bytes) {