src/hotspot/os/bsd/os_bsd.cpp

@@ -1905,16 +1905,20 @@
 //       All it does is to check if there are enough free pages
 //       left at the time of mmap(). This could be a potential
 //       problem.
 bool os::pd_commit_memory(char* addr, size_t size, bool exec) {
   int prot = exec ? PROT_READ|PROT_WRITE|PROT_EXEC : PROT_READ|PROT_WRITE;
-#ifdef __OpenBSD__
+#if defined(__OpenBSD__)
   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
   Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with protection modes %x", p2i(addr), p2i(addr+size), prot);
   if (::mprotect(addr, size, prot) == 0) {
     return true;
   }
+#elif defined(__APPLE__)
+  if (::mprotect(addr, size, prot) == 0) {
+    return true;
+  }
 #else
   uintptr_t res = (uintptr_t) ::mmap(addr, size, prot,
                                      MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0);
   if (res != (uintptr_t) MAP_FAILED) {
     return true;

@@ -1993,15 +1997,26 @@
 char *os::scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found) {
   return end;
 }
 
 
-bool os::pd_uncommit_memory(char* addr, size_t size) {
-#ifdef __OpenBSD__
+bool os::pd_uncommit_memory(char* addr, size_t size, bool exec) {
+#if defined(__OpenBSD__)
   // XXX: Work-around mmap/MAP_FIXED bug temporarily on OpenBSD
   Events::log(NULL, "Protecting memory [" INTPTR_FORMAT "," INTPTR_FORMAT "] with PROT_NONE", p2i(addr), p2i(addr+size));
   return ::mprotect(addr, size, PROT_NONE) == 0;
+#elif defined(__APPLE__)
+  if (exec) {
+    if (::madvise(addr, size, MADV_FREE) != 0) {
+      return false;
+    }
+    return ::mprotect(addr, size, PROT_NONE) == 0;
+  } else {
+    uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
+        MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
+    return res  != (uintptr_t) MAP_FAILED;
+  }
 #else
   uintptr_t res = (uintptr_t) ::mmap(addr, size, PROT_NONE,
                                      MAP_PRIVATE|MAP_FIXED|MAP_NORESERVE|MAP_ANONYMOUS, -1, 0);
   return res  != (uintptr_t) MAP_FAILED;
 #endif

@@ -2012,24 +2027,30 @@
 }
 
 // If this is a growable mapping, remove the guard pages entirely by
 // munmap()ping them.  If not, just call uncommit_memory().
 bool os::remove_stack_guard_pages(char* addr, size_t size) {
-  return os::uncommit_memory(addr, size);
+  return os::uncommit_memory(addr, size, !ExecMem);
 }
 
 // If 'fixed' is true, anon_mmap() will attempt to reserve anonymous memory
 // at 'requested_addr'. If there are existing memory mappings at the same
 // location, however, they will be overwritten. If 'fixed' is false,
 // 'requested_addr' is only treated as a hint, the return value may or
 // may not start from the requested address. Unlike Bsd mmap(), this
 // function returns NULL to indicate failure.
-static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed) {
+static char* anon_mmap(char* requested_addr, size_t bytes, bool fixed, bool executable) {
   char * addr;
   int flags;
 
   flags = MAP_PRIVATE | MAP_NORESERVE | MAP_ANONYMOUS;
+#ifdef __APPLE__
+  if (executable) {
+    guarantee(!fixed, "MAP_JIT (for execute) is incompatible with MAP_FIXED");
+    flags |= MAP_JIT;
+  }
+#endif
   if (fixed) {
     assert((uintptr_t)requested_addr % os::Bsd::page_size() == 0, "unaligned address");
     flags |= MAP_FIXED;
   }
 

@@ -2045,12 +2066,13 @@
 static int anon_munmap(char * addr, size_t size) {
   return ::munmap(addr, size) == 0;
 }
 
 char* os::pd_reserve_memory(size_t bytes, char* requested_addr,
-                            size_t alignment_hint) {
-  return anon_mmap(requested_addr, bytes, (requested_addr != NULL));
+                            size_t alignment_hint,
+                            bool executable) {
+  return anon_mmap(requested_addr, bytes, (requested_addr != NULL), executable);
 }
 
 bool os::pd_release_memory(char* addr, size_t size) {
   return anon_munmap(addr, size);
 }

@@ -2156,11 +2178,11 @@
   // Repeatedly allocate blocks until the block is allocated at the
   // right spot.
 
   // Bsd mmap allows caller to pass an address as hint; give it a try first,
   // if kernel honors the hint then we can return immediately.
-  char * addr = anon_mmap(requested_addr, bytes, false);
+  char * addr = anon_mmap(requested_addr, bytes, false/*fixed*/, false/*executable*/);
   if (addr == requested_addr) {
     return requested_addr;
   }
 
   if (addr != NULL) {