--- libmalloc/libmalloc-521.100.59/src/internal.h
+++ libmalloc/libmalloc-646.40.3/src/internal.h
@@ -110,6 +110,9 @@
 # if !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 typedef void plat_map_t;
 # else
+#  if !defined(__x86_64__)
+#   include <l4/l4.h>
+#  endif // !defined(__x86_64__)
 typedef plat_map_exclaves_t plat_map_t;
 # endif // !MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 #else
@@ -202,11 +205,13 @@
 #include <sys/mman.h>
 #include <sys/queue.h>
 #if !MALLOC_TARGET_EXCLAVES
+# include <sys/codesign.h>
 # include <sys/event.h>
 # include <sys/param.h>
 # include <sys/stat.h>
 # include <sys/sysctl.h>
 # include <sys/random.h>
+# include <sys/csr.h>
 #else
 # include <vas/vas.h>
 # define howmany(x, y)   ((((x) % (y)) == 0) ? ((x) / (y)) : (((x) / (y)) + 1))
@@ -214,6 +219,7 @@
 # define roundup(x, y) ((((x) % (y)) == 0) ? \
 					   (x) : ((x) + ((y) - ((x) % (y)))))
 #endif // !MALLOC_TARGET_EXCLAVES
+#define rounddown(x,y)  (((x)/(y))*(y))
 #include <sys/types.h>
 #if !MALLOC_TARGET_EXCLAVES
 # include <sys/ulock.h>
@@ -284,7 +290,9 @@
 #endif // !MALLOC_TARGET_EXCLAVES && MALLOC_TARGET_EXCLAVES_INTROSPECTOR
 #include "xzone/xzone_introspect.h"
 #include "xzone/xzone_malloc.h"
-#include "xzone/xzone_inline_internal.h"
+#if !(MALLOC_TARGET_EXCLAVES_INTROSPECTOR && defined(__x86_64__))
+# include "xzone/xzone_inline_internal.h"
+#endif // !(MALLOC_TARGET_EXCLAVES_INTROSPECTOR && defined(__x86_64__))
 #if !MALLOC_TARGET_EXCLAVES
 # include "stack_logging.h"
 # include "stack_trace.h"
@@ -377,31 +385,31 @@
 #endif
 
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(size)
 _malloc_zone_malloc(malloc_zone_t *zone, size_t size, malloc_zone_options_t mzo) __alloc_size(2);
 
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(num_items * size)
 _malloc_zone_calloc(malloc_zone_t *zone, size_t num_items, size_t size, malloc_zone_options_t mzo) __alloc_size(2,3);
 
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(size)
 _malloc_zone_valloc(malloc_zone_t *zone, size_t size, malloc_zone_options_t mzo) __alloc_size(2);
 
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(size)
 _malloc_zone_realloc(malloc_zone_t *zone, void * __unsafe_indexable ptr,
 		size_t size, malloc_type_descriptor_t type_desc) __alloc_size(3);
 
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(size)
 _malloc_zone_memalign(malloc_zone_t *zone, size_t alignment, size_t size,
 		malloc_zone_options_t mzo, malloc_type_descriptor_t type_desc)
 		 __alloc_align(2) __alloc_size(3);
 
 #if !MALLOC_TARGET_EXCLAVES
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(size)
 _malloc_zone_malloc_with_options_np_outlined(malloc_zone_t *zone, size_t align,
 		size_t size, malloc_options_np_t options)
 		__alloc_align(2) __alloc_size(3);
@@ -419,8 +427,13 @@
 #endif // DARWINTEST || MALLOC_BUILDING_XCTESTS
 
 MALLOC_NOEXPORT
-void *
+void * __sized_by_or_null(new_size)
 _realloc(void * __unsafe_indexable in_ptr, size_t new_size) __alloc_size(2);
+
+MALLOC_NOEXPORT
+malloc_zone_t *
+find_registered_zone(const void * __unsafe_indexable ptr, size_t *returned_size,
+		bool known_non_default);
 
 MALLOC_NOEXPORT
 int
@@ -542,7 +555,6 @@
 typedef void (*set_msl_lite_hooks_callout_t) (struct _malloc_msl_lite_hooks_s *hooksp, size_t size);
 void set_msl_lite_hooks(set_msl_lite_hooks_callout_t callout);
 
-
 static MALLOC_INLINE void
 yield(void)
 {
@@ -554,4 +566,19 @@
 #endif // !MALLOC_TARGET_EXCLAVES
 }
 
+#if CONFIG_FEATUREFLAGS_SIMPLE
+#if TARGET_OS_SIMULATOR
+#define malloc_secure_feature_enabled(name, fallback, simulator_default) \
+	(simulator_default)
+#elif CONFIG_CHECK_SECURITY_POLICY
+// TODO: Do we want the secure fallback to be the same as the no-ff fallback?
+#define malloc_secure_feature_enabled(name, fallback, simulator_default) \
+	(malloc_internal_security_policy ? \
+			os_feature_enabled_simple(libmalloc, name, fallback) : (fallback))
+#else
+#define malloc_secure_feature_enabled(name, fallback, simulator_default) \
+	os_feature_enabled_simple(libmalloc, name, fallback)
+#endif // TARGET_OS_SIMULATOR
+#endif // CONFIG_FEATUREFLAGS_SIMPLE
+
 #endif // __INTERNAL_H