[project @ 2005-07-12 11:51:31 by simonmar]

[ghc-hetmet.git] / ghc / rts / RtsUtils.c

diff --git a/ghc/rts/RtsUtils.c b/ghc/rts/RtsUtils.c
index 646fba9..23bd10e 100644 (file)
--- a/ghc/rts/RtsUtils.c
+++ b/ghc/rts/RtsUtils.c
@@ -40,6 +40,20 @@
 #include <pthread.h>
 #endif
 
+#if defined(openbsd_HOST_OS) || defined(linux_HOST_OS)
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+
+/* no C99 header stdint.h on OpenBSD? */
+#if defined(openbsd_HOST_OS)
+typedef unsigned long my_uintptr_t;
+#else
+#include <stdint.h>
+typedef uintptr_t my_uintptr_t;
+#endif
+#endif
+
 /* -----------------------------------------------------------------------------
    Result-checking malloc wrappers.
    -------------------------------------------------------------------------- */
@@ -301,3 +315,42 @@ int genericRaise(int sig) {
         return raise(sig);
 #endif
 }
+
+/* -----------------------------------------------------------------------------
+   Allocating executable memory
+   -------------------------------------------------------------------------- */
+
+/* Heavily arch-specific, I'm afraid.. */
+
+/*
+ * Allocate len bytes which are readable, writable, and executable.
+ *
+ * ToDo: If this turns out to be a performance bottleneck, one could
+ * e.g. cache the last VirtualProtect/mprotect-ed region and do
+ * nothing in case of a cache hit.
+ */
+void*
+stgMallocBytesRWX(int len)
+{
+  void *addr = stgMallocBytes(len, "mallocBytesRWX");
+#if defined(i386_HOST_ARCH) && defined(_WIN32)
+  /* This could be necessary for processors which distinguish between READ and
+     EXECUTE memory accesses, e.g. Itaniums. */
+  DWORD dwOldProtect = 0;
+  if (VirtualProtect (addr, len, PAGE_EXECUTE_READWRITE, &dwOldProtect) == 0) {
+    barf("mallocBytesRWX: failed to protect 0x%p; error=%lu; old protection: %lu\n",
+         addr, (unsigned long)GetLastError(), (unsigned long)dwOldProtect);
+  }
+#elif defined(openbsd_HOST_OS) || defined(linux_HOST_OS)
+  /* malloced memory isn't executable by default on OpenBSD */
+  my_uintptr_t pageSize         = sysconf(_SC_PAGESIZE);
+  my_uintptr_t mask             = ~(pageSize - 1);
+  my_uintptr_t startOfFirstPage = ((my_uintptr_t)addr          ) & mask;
+  my_uintptr_t startOfLastPage  = ((my_uintptr_t)addr + len - 1) & mask;
+  my_uintptr_t size             = startOfLastPage - startOfFirstPage + pageSize;
+  if (mprotect((void*)startOfFirstPage, (size_t)size, PROT_EXEC | PROT_READ | PROT_WRITE) != 0) {
+    barf("mallocBytesRWX: failed to protect 0x%p\n", addr);
+  }
+#endif
+  return addr;
+}