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--- libmalloc/libmalloc-283.40.1/src/vm.c
+++ libmalloc/libmalloc-521.100.59/src/vm.c
@@ -23,13 +23,17 @@
 
 #include "internal.h"
 
+#if !MALLOC_TARGET_EXCLAVES
 static volatile uintptr_t entropic_address = 0;
+static volatile uintptr_t entropic_base = 0;
 static volatile uintptr_t entropic_limit = 0;
+#endif // !MALLOC_TARGET_EXCLAVES
 
 MALLOC_NOEXPORT
 uint64_t malloc_entropy[2] = {0, 0};
 
 #define ENTROPIC_KABILLION 0x10000000 /* 256Mb */
+#define ENTROPIC_USER_RANGE_SIZE 0x200000000ULL /* 8Gb */
 
 // <rdar://problem/22277891> align 64bit ARM shift to 32MB PTE entries
 #if MALLOC_TARGET_IOS && MALLOC_TARGET_64BIT
@@ -42,15 +46,17 @@
 mvm_aslr_init(void)
 {
 	// Prepare ASLR
-#if __i386__ || __x86_64__ || __arm64__ || (TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
-#if __i386__
+#if MALLOC_TARGET_EXCLAVES
+	arc4random_buf(malloc_entropy, sizeof(malloc_entropy));
+#elif defined(__i386__) || defined(__x86_64__) || defined(__arm64__) || TARGET_OS_DRIVERKIT || (TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
+#if defined(__i386__)
 	uintptr_t stackbase = 0x8fe00000;
 	int entropic_bits = 3;
-#elif __x86_64__
+#elif defined(__x86_64__)
 	uintptr_t stackbase = USRSTACK64;
 	int entropic_bits = 16;
-#elif __arm64__
-#if __LP64__
+#elif defined(__arm64__)
+#if defined(__LP64__)
 	uintptr_t stackbase = USRSTACK64;
 	int entropic_bits = 7;
 #else // __LP64__
@@ -65,7 +71,32 @@
 
 	if (mvm_aslr_enabled()) {
 		if (0 == entropic_address) {
-			uintptr_t t = stackbase - MAXSSIZ - ((uintptr_t)(malloc_entropy[1] & ((1 << entropic_bits) - 1)) << ENTROPIC_SHIFT);
+			uintptr_t t = stackbase - MAXSSIZ - ((uintptr_t)(malloc_entropy[1] &
+				((1 << entropic_bits) - 1)) << ENTROPIC_SHIFT);
+#if MALLOC_TARGET_IOS && MALLOC_TARGET_64BIT
+			uintptr_t addr = 0;
+
+			/* If kernel VM user ranges are enabled mach_vm_allocate/map will provide memory
+			 * in the upper VM address range. This range is randomized per process. For now
+			 * we do not have this metadata plumbed through so we make a single allocation
+			 * with the appropriate tag to determine where our heap is. If we are given an
+			 * allocation above where we expect then we can safely assume VM ranges are enabled.
+			 *
+			 * If so we do not need to apply further entropy but do need to ensure
+			 * we mask off the address to a PTE boundary.
+			 */ 
+			if (KERN_SUCCESS == mach_vm_allocate(mach_task_self(), (mach_vm_address_t *)&addr,
+					vm_page_quanta_size, VM_FLAGS_ANYWHERE | VM_MAKE_TAG(VM_MEMORY_MALLOC_TINY))) {
+				// Fall through and use existing base if addr < stackbase
+				if (addr > stackbase) {
+					t = (addr + ENTROPIC_USER_RANGE_SIZE) & ~((1 << ENTROPIC_SHIFT) - 1);
+					OSAtomicCompareAndSwapLong(0, addr, (volatile long *)&entropic_base);
+				}
+
+				mach_vm_deallocate(mach_task_self(), addr, vm_page_quanta_size);
+			}
+#endif // MALLOC_TARGET_IOS && MALLOC_TARGET_64BIT
+
 			OSAtomicCompareAndSwapLong(0, t, (volatile long *)&entropic_limit);
 			OSAtomicCompareAndSwapLong(0, t - ENTROPIC_KABILLION, (volatile long *)&entropic_address);
 		}
@@ -80,10 +111,77 @@
 }
 
 void *
-mvm_allocate_pages(size_t size, unsigned char align, unsigned debug_flags, int vm_page_label)
-{
-	boolean_t add_guard_pages = debug_flags & MALLOC_ADD_GUARD_PAGES;
+mvm_allocate_plat(uintptr_t addr, size_t size, uint8_t align, int flags, int debug_flags, int vm_page_label, plat_map_t *map_out)
+{
+	if (addr && (flags & VM_FLAGS_ANYWHERE)) {
+		// Pass MALLOC_ABORT_ON_ERROR to make this call abort
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR | debug_flags, false,
+			"Unsupported anywhere allocation at address 0x%lx of size 0x%lx with flags %d\n",
+			(unsigned long) addr, (unsigned long) size, flags);
+	}
+#if MALLOC_TARGET_EXCLAVES
+	// This call can have different behavior depending on `flags` and `map_out`:
+	// 1. If the input handle is invalid and MALLOC_NO_POPULATE is not present,
+	//	  the handle is initialized and memory is both reserved and populated
+	// 2. If the input handle is invalid and MALLOC_NO_POPULATE is present,
+	//	  the handle is initialized and memory is only reserved
+	// 3. If the input handle is valid and MALLOC_NO_POPULATE is not present,
+	//    memory is populated
+	const _liblibc_map_type_t type = LIBLIBC_MAP_TYPE_PRIVATE |
+		((flags & VM_FLAGS_ANYWHERE) ? LIBLIBC_MAP_TYPE_NONE : LIBLIBC_MAP_TYPE_FIXED) |
+		((debug_flags & MALLOC_NO_POPULATE) ? LIBLIBC_MAP_TYPE_NOCOMMIT : LIBLIBC_MAP_TYPE_NONE) |
+		((debug_flags & DISABLE_ASLR) ? LIBLIBC_MAP_TYPE_NORAND : LIBLIBC_MAP_TYPE_NONE);
+	const _liblibc_map_perm_t perm = LIBLIBC_MAP_PERM_READ | LIBLIBC_MAP_PERM_WRITE;
+	void * __unsafe_indexable map = mmap_plat(map_out, addr, size, perm,
+			type, align, (unsigned)vm_page_label);
+	if (!map) {
+		malloc_zone_error(debug_flags, false,
+			"Failed to allocate memory at address 0x%lx of size 0x%lx with flags %d\n", addr, size, flags);
+	}
+	return __unsafe_forge_bidi_indexable(void *, map, size);
+#else
+	(void)map_out;
+	if (debug_flags & MALLOC_NO_POPULATE) {
+		// Pass MALLOC_ABORT_ON_ERROR to make this call abort
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR | debug_flags, false,
+				"Unsupported unpopulated allocation at address 0x%lx of size 0x%lx with flags %d\n",
+				(unsigned long) addr, (unsigned long) size, flags);
+	}
+	mach_vm_address_t vm_addr = addr;
+	mach_vm_offset_t allocation_mask = ((mach_vm_offset_t)1 << align) - 1;
+	kern_return_t kr = mach_vm_map(mach_task_self(), &vm_addr,
+			(mach_vm_size_t)size, allocation_mask,
+			flags | VM_MAKE_TAG(vm_page_label), MEMORY_OBJECT_NULL, 0, FALSE,
+			VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+	if (kr) {
+		malloc_zone_error(debug_flags, false,
+				"Failed to allocate memory at address 0x%lx of size 0x%lx with flags %d\n",
+				(unsigned long) addr, (unsigned long) size, flags);
+		return NULL;
+	}
+	return __unsafe_forge_bidi_indexable(void *, vm_addr, size);
+#endif // MALLOC_TARGET_EXCLAVES
+}
+
+void *
+mvm_allocate_pages(size_t size, uint8_t align, uint32_t debug_flags,
+		int vm_page_label)
+{
+	return mvm_allocate_pages_plat(size, align, debug_flags, vm_page_label, NULL);
+}
+
+void *
+mvm_allocate_pages_plat(size_t size, uint8_t align, uint32_t debug_flags,
+		int vm_page_label, plat_map_t *map_out)
+{
+#if MALLOC_TARGET_EXCLAVES
+	return mvm_allocate_plat(0, size, align, VM_FLAGS_ANYWHERE, debug_flags, vm_page_label, map_out);
+#else
+	(void)map_out;
+	boolean_t add_prelude_guard_page = debug_flags & MALLOC_ADD_PRELUDE_GUARD_PAGE;
+	boolean_t add_postlude_guard_page = debug_flags & MALLOC_ADD_POSTLUDE_GUARD_PAGE;
 	boolean_t purgeable = debug_flags & MALLOC_PURGEABLE;
+	boolean_t use_entropic_range = !(debug_flags & DISABLE_ASLR);
 	mach_vm_address_t vm_addr;
 	uintptr_t addr;
 	mach_vm_size_t allocation_size = round_page_quanta(size);
@@ -94,12 +192,13 @@
 	if (!allocation_size) {
 		allocation_size = vm_page_quanta_size;
 	}
-	if (add_guard_pages) {
-		if (align > vm_page_quanta_shift) {
+	if (add_postlude_guard_page || add_prelude_guard_page) {
+		if (add_prelude_guard_page && align > vm_page_quanta_shift) {
 			/* <rdar://problem/16601499> alignment greater than pagesize needs more work */
-			allocation_size += (1 << align) + vm_page_quanta_size;
+			allocation_size += (1 << align) + large_vm_page_quanta_size;
 		} else {
-			allocation_size += 2 * vm_page_quanta_size;
+			allocation_size += add_prelude_guard_page && add_postlude_guard_page ?
+					2 * large_vm_page_quanta_size : large_vm_page_quanta_size;
 		}
 	}
 
@@ -110,17 +209,56 @@
 		return NULL;
 	}
 
-	vm_addr = vm_page_quanta_size;
-	kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size, allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
-					 VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+retry:
+	vm_addr = use_entropic_range ? entropic_address : vm_page_quanta_size;
+	kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size,
+			allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
+			VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+	if (kr == KERN_NO_SPACE && use_entropic_range) {
+		vm_addr = vm_page_quanta_size;
+		kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size,
+				allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
+				VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+	}
 	if (kr) {
-		malloc_zone_error(debug_flags, false, "can't allocate region\n*** mach_vm_map(size=%lu) failed (error code=%d)\n", size, kr);
+		if (kr != KERN_NO_SPACE) {
+			malloc_zone_error(debug_flags, false, "can't allocate region\n:"
+					"*** mach_vm_map(size=%lu, flags: %x) failed (error code=%d)\n",
+					size, debug_flags, kr);
+		}
 		return NULL;
 	}
 	addr = (uintptr_t)vm_addr;
 
-	if (add_guard_pages) {
-		if (align > vm_page_quanta_shift) {
+	if (use_entropic_range) {
+		// Don't allow allocation to rise above entropic_limit (for tidiness).
+		if (addr + allocation_size > entropic_limit) { // Exhausted current range?
+			uintptr_t t = entropic_address;
+			uintptr_t u = t - ENTROPIC_KABILLION;
+
+			// provided we don't wrap, deallocate and retry, in theexpanded
+			// entropic range
+			if (u < t && u >= entropic_base) {
+				mach_vm_deallocate(mach_task_self(), vm_addr, allocation_size);
+				OSAtomicCompareAndSwapLong(t, u,
+						(volatile long *)&entropic_address);  // Just one reduction please
+				goto retry;
+			}
+			// fall through to use what we got
+		}
+		
+		if (addr < entropic_address) { // we wrapped to find this allocation, expand the entropic range
+			uintptr_t t = entropic_address;
+			uintptr_t u = t - ENTROPIC_KABILLION;
+			if (u < t && u >= entropic_base) {
+				OSAtomicCompareAndSwapLong(t, u, (volatile long *)&entropic_address);  // Just one reduction please
+			}
+			// fall through to use what we got
+		}
+	}
+
+	if (add_postlude_guard_page || add_prelude_guard_page) {
+		if (add_prelude_guard_page && align > vm_page_quanta_shift) {
 			/* <rdar://problem/16601499> calculate the first address inside the alignment padding
 			 * where we can place the guard page and still be aligned.
 			 *
@@ -128,9 +266,9 @@
 			 * |leading|gp|                  alloc                  |gp| t |
 			 * |-----------------------------------------------------------|
 			 */
-			uintptr_t alignaddr = ((addr + vm_page_quanta_size) + (1 << align) - 1) & ~((1 << align) - 1);
-			size_t leading = alignaddr - addr - vm_page_quanta_size;
-			size_t trailing = (1 << align) - vm_page_quanta_size - leading;
+			uintptr_t alignaddr = ((addr + large_vm_page_quanta_size) + (1 << align) - 1) & ~((1 << align) - 1);
+			size_t leading = alignaddr - addr - large_vm_page_quanta_size;
+			size_t trailing = (1 << align) - large_vm_page_quanta_size - leading;
 
 			/* Unmap the excess area. */
 			kr = mach_vm_deallocate(mach_task_self(), addr, leading);
@@ -141,134 +279,172 @@
 				return NULL;
 			}
 
-			kr = mach_vm_deallocate(mach_task_self(), addr + allocation_size - trailing, trailing);
-			if (kr) {
-				malloc_zone_error(debug_flags, false, "can't unmap excess trailing guard region\n"
-						"*** mach_vm_deallocate(addr=%p, size=%lu) failed (code=%d)\n",
-						(void *)(addr + allocation_size - trailing), trailing, kr);
-				return NULL;
+			if (trailing) {
+				kr = mach_vm_deallocate(mach_task_self(), addr + allocation_size - trailing, trailing);
+				if (kr) {
+					malloc_zone_error(debug_flags, false, "can't unmap excess trailing guard region\n"
+							"*** mach_vm_deallocate(addr=%p, size=%lu) failed (code=%d)\n",
+							(void *)(addr + allocation_size - trailing), trailing, kr);
+					return NULL;
+				}
 			}
 
 			addr = alignaddr;
-		} else {
-			addr += vm_page_quanta_size;
-		}
-		mvm_protect((void *)addr, size, PROT_NONE, debug_flags);
+		} else if (add_prelude_guard_page) {
+			addr += large_vm_page_quanta_size;
+		}
+		mvm_protect_plat((void *)addr, size, PROT_NONE, debug_flags, map_out);
 	}
 	return (void *)addr;
-}
-
-void *
-mvm_allocate_pages_securely(size_t size, unsigned char align, int vm_page_label, uint32_t debug_flags)
-{
-	mach_vm_address_t vm_addr;
-	uintptr_t addr;
-	mach_vm_size_t allocation_size = round_page_quanta(size);
-	mach_vm_offset_t allocation_mask = ((mach_vm_offset_t)1 << align) - 1;
-	int alloc_flags = VM_FLAGS_ANYWHERE | VM_MAKE_TAG(vm_page_label);
-	kern_return_t kr;
-
-	if (debug_flags & DISABLE_ASLR) {
-		return mvm_allocate_pages(size, align, 0, vm_page_label);
-	}
-
-	if (!allocation_size) {
-		allocation_size = vm_page_quanta_size;
-	}
-	if (allocation_size < size) { // size_t arithmetic wrapped!
-		return NULL;
-	}
-
-retry:
-	vm_addr = entropic_address;
-	kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size, allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
-					 VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
-	if (kr == KERN_NO_SPACE) {
-		vm_addr = vm_page_quanta_size;
-		kr = mach_vm_map(mach_task_self(), &vm_addr, allocation_size, allocation_mask, alloc_flags, MEMORY_OBJECT_NULL, 0, FALSE,
-						 VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
-	}
+#endif // MALLOC_TARGET_EXCLAVES
+}
+
+void
+mvm_deallocate_plat(void * __sized_by(size) addr, size_t size, int debug_flags, plat_map_t *map)
+{
+#if MALLOC_TARGET_EXCLAVES
+	if (!munmap_plat(map, addr, size)) {
+		malloc_zone_error(debug_flags, false,
+			"Failed to deallocate at address %p of size 0x%lx\n", addr, size);
+	}
+#else
+	(void)map;
+	kern_return_t kr = mach_vm_deallocate(mach_task_self(),
+		(mach_vm_address_t)addr, (mach_vm_size_t)size);
 	if (kr) {
-		malloc_zone_error(debug_flags, false, "can't allocate region securely\n",
-				"*** mach_vm_map(size=%lu) failed (error code=%d)\n", size, kr);
-		return NULL;
-	}
-	addr = (uintptr_t)vm_addr;
-
-	// Don't allow allocation to rise above entropic_limit (for tidiness).
-	if (addr + allocation_size > entropic_limit) { // Exhausted current range?
-		uintptr_t t = entropic_address;
-		uintptr_t u = t - ENTROPIC_KABILLION;
-
-		if (u < t) { // provided we don't wrap, deallocate and retry, in the expanded entropic range
-			mach_vm_deallocate(mach_task_self(), vm_addr, allocation_size);
-			OSAtomicCompareAndSwapLong(t, u, (volatile long *)&entropic_address);  // Just one reduction please
-			goto retry;
-		}
-		// fall through to use what we got
-	}
-
-	if (addr < entropic_address) { // we wrapped to find this allocation, expand the entropic range
-		uintptr_t t = entropic_address;
-		uintptr_t u = t - ENTROPIC_KABILLION;
-		if (u < t) {
-			OSAtomicCompareAndSwapLong(t, u, (volatile long *)&entropic_address);  // Just one reduction please
-		}
-		// fall through to use what we got
-	}
-	return (void *)addr;
+		malloc_zone_error(debug_flags, false,
+			"Failed to deallocate at address %p of size 0x%lx\n", addr, size);
+	}
+#endif // MALLOC_TARGET_EXCLAVES
 }
 
 void
-mvm_deallocate_pages(void *addr, size_t size, unsigned debug_flags)
-{
-	boolean_t add_guard_pages = debug_flags & MALLOC_ADD_GUARD_PAGES;
+mvm_deallocate_pages(void * __sized_by(size) addr, size_t size,
+		unsigned debug_flags)
+{
+	mvm_deallocate_pages_plat(addr, size, debug_flags, NULL);
+}
+
+void
+mvm_deallocate_pages_plat(void * __sized_by(size) addr, size_t size,
+		unsigned debug_flags, plat_map_t *map)
+{
+#if MALLOC_TARGET_EXCLAVES
+	if (debug_flags & (MALLOC_ADD_GUARD_PAGE_FLAGS | MALLOC_PURGEABLE)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR | debug_flags, true,
+			"Unsupported deallocation debug flags %u\n", debug_flags);
+	}
+	mvm_deallocate_plat(addr, size, debug_flags, map);
+#else
+	(void)map;
+	boolean_t added_prelude_guard_page = debug_flags & MALLOC_ADD_PRELUDE_GUARD_PAGE;
+	boolean_t added_postlude_guard_page = debug_flags & MALLOC_ADD_POSTLUDE_GUARD_PAGE;
 	mach_vm_address_t vm_addr = (mach_vm_address_t)addr;
 	mach_vm_size_t allocation_size = size;
-	kern_return_t kr;
-
-	if (add_guard_pages) {
-		vm_addr -= vm_page_quanta_size;
-		allocation_size += 2 * vm_page_quanta_size;
-	}
-	kr = mach_vm_deallocate(mach_task_self(), vm_addr, allocation_size);
-	if (kr) {
-		malloc_zone_error(debug_flags, false, "Can't deallocate_pages region at %p\n", addr);
-	}
+
+	if (added_prelude_guard_page) {
+		vm_addr -= large_vm_page_quanta_size;
+		allocation_size += large_vm_page_quanta_size;
+	}
+	if (added_postlude_guard_page) {
+		allocation_size += large_vm_page_quanta_size;
+	}
+	mvm_deallocate_plat(__unsafe_forge_bidi_indexable(void *, vm_addr,
+			allocation_size), (size_t)allocation_size, debug_flags, NULL);
+#endif // MALLOC_TARGET_EXCLAVES
 }
 
 void
-mvm_protect(void *address, size_t size, unsigned protection, unsigned debug_flags)
-{
+mvm_protect(void * __sized_by(size) address, size_t size, unsigned protection,
+		unsigned debug_flags)
+{
+	mvm_protect_plat(address, size, protection, debug_flags, NULL);
+}
+
+void
+mvm_protect_plat(void * __sized_by(size) address, size_t size, unsigned protection,
+		unsigned debug_flags, plat_map_t *map)
+{
+#if MALLOC_TARGET_EXCLAVES
+	const _liblibc_map_perm_t perm =
+		((protection & PROT_READ) ? LIBLIBC_MAP_PERM_READ : LIBLIBC_MAP_PERM_NONE) |
+		((protection & PROT_WRITE) ? LIBLIBC_MAP_PERM_WRITE : LIBLIBC_MAP_PERM_NONE) |
+		((protection & PROT_EXEC) ? LIBLIBC_MAP_PERM_EXECUTE : LIBLIBC_MAP_PERM_NONE);
+	if (debug_flags & (MALLOC_ADD_GUARD_PAGE_FLAGS | MALLOC_PURGEABLE)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR | debug_flags, true,
+			"Unsupported deallocation debug flags %u\n", debug_flags);
+	}
+	if (!mprotect_plat(map, address, size, perm)) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR | debug_flags, true,
+			"Unsupported deallocation address %p or size %lu\n", address, size);
+	}
+#else
+	(void)map;
 	kern_return_t err;
 
-	if (!(debug_flags & MALLOC_DONT_PROTECT_PRELUDE)) {
-		err = mprotect((void *)((uintptr_t)address - vm_page_quanta_size), vm_page_quanta_size, protection);
+	if ((debug_flags & MALLOC_ADD_PRELUDE_GUARD_PAGE) && !(debug_flags & MALLOC_DONT_PROTECT_PRELUDE)) {
+		err = mprotect((void *)((uintptr_t)address - large_vm_page_quanta_size), large_vm_page_quanta_size, protection);
 		if (err) {
 			malloc_report(ASL_LEVEL_ERR, "*** can't mvm_protect(%u) region for prelude guard page at %p\n", protection,
-					(void *)((uintptr_t)address - vm_page_quanta_size));
-		}
-	}
-	if (!(debug_flags & MALLOC_DONT_PROTECT_POSTLUDE)) {
-		err = mprotect((void *)(round_page_quanta(((uintptr_t)address + size))), vm_page_quanta_size, protection);
+					(void *)((uintptr_t)address - large_vm_page_quanta_size));
+		}
+	}
+	if ((debug_flags & MALLOC_ADD_POSTLUDE_GUARD_PAGE) && !(debug_flags & MALLOC_DONT_PROTECT_POSTLUDE)) {
+		err = mprotect((void *)(round_page_quanta(((uintptr_t)address + size))), large_vm_page_quanta_size, protection);
 		if (err) {
 			malloc_report(ASL_LEVEL_ERR, "*** can't mvm_protect(%u) region for postlude guard page at %p\n", protection,
 					(void *)((uintptr_t)address + size));
 		}
 	}
+#endif // MALLOC_TARGET_EXCLAVES
+}
+
+int
+mvm_madvise(void * __sized_by(sz) addr, size_t sz, int advice, unsigned debug_flags)
+{
+	return mvm_madvise_plat(addr, sz, advice, debug_flags, NULL);
+}
+
+int
+mvm_madvise_plat(void * __sized_by(sz) addr, size_t sz, int advice, unsigned debug_flags, plat_map_t *map)
+{
+#if MALLOC_TARGET_EXCLAVES
+	if (!(advice == MADV_FREE || advice == MADV_FREE_REUSABLE) ||
+		(debug_flags & (MALLOC_ADD_GUARD_PAGE_FLAGS | MALLOC_PURGEABLE))) {
+		malloc_zone_error(MALLOC_ABORT_ON_ERROR | debug_flags, true,
+			"Unsupported allocation advice %d or debug flags %u\n", advice, debug_flags);
+	}
+
+	if (!madvise_plat(map, addr, sz, LIBLIBC_MAP_HINT_UNUSED)) {
+		return 1;
+	}
+#else
+	(void)map;
+	if (madvise(addr, sz, advice) == -1) {
+		return 1;
+	}
+#endif // MALLOC_TARGET_EXCLAVES
+	return 0;
 }
 
 int
 mvm_madvise_free(void *rack, void *r, uintptr_t pgLo, uintptr_t pgHi, uintptr_t *last, boolean_t scribble)
 {
+	return mvm_madvise_free_plat(rack, r, pgLo, pgHi, last, scribble, NULL);
+}
+
+int
+mvm_madvise_free_plat(void *rack, void *r, uintptr_t pgLo, uintptr_t pgHi, uintptr_t *last, boolean_t scribble, plat_map_t *map)
+{
 	if (pgHi > pgLo) {
 		size_t len = pgHi - pgLo;
-
-		if (scribble) {
-			memset((void *)pgLo, SCRUBBLE_BYTE, len); // Scribble on MADV_FREEd memory
-		}
-
-#if TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
+		void *ptr = __unsafe_forge_bidi_indexable(void *, pgLo, len);
+
+		if (scribble && malloc_zero_policy != MALLOC_ZERO_ON_FREE) {
+			memset(ptr, SCRUBBLE_BYTE, len); // Scribble on MADV_FREEd memory
+		}
+
+#if MALLOC_TARGET_IOS
 		if (last) {
 			if (*last == pgLo) {
 				return 0;
@@ -276,20 +452,81 @@
 
 			*last = pgLo;
 		}
-#endif // TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR
-
+#endif // MALLOC_TARGET_IOS
+
+#if MALLOC_TARGET_EXCLAVES
+		if (mvm_madvise_plat(ptr, len, CONFIG_MADVISE_STYLE, 0, map)) {
+			return 1;
+		}
+#else
 		MAGMALLOC_MADVFREEREGION(rack, r, (void *)pgLo, (int)len); // DTrace USDT Probe
-		if (-1 == madvise((void *)pgLo, len, CONFIG_MADVISE_STYLE)) {
+		if (mvm_madvise(ptr, len, CONFIG_MADVISE_STYLE, 0)) {
 			/* -1 return: VM map entry change makes this unfit for reuse. Something evil lurks. */
 #if DEBUG_MADVISE
 			malloc_zone_error(NULL, false,
 					"madvise_free_range madvise(..., MADV_FREE_REUSABLE) failed for %p, length=%d\n",
 					(void *)pgLo, len);
-#endif
+#endif // DEBUG_MADVISE
 			return 1;
 		} else {
 			MALLOC_TRACE(TRACE_madvise, (uintptr_t)r, (uintptr_t)pgLo, len, CONFIG_MADVISE_STYLE);
 		}
+#endif // MALLOC_TARGET_EXCLAVES
 	}
 	return 0;
 }
+
+#if CONFIG_DEFERRED_RECLAIM
+static struct mach_vm_reclaim_ringbuffer_v1_s reclaim_buffer;
+static _malloc_lock_s reclaim_buffer_lock = _MALLOC_LOCK_INIT;
+
+kern_return_t
+mvm_deferred_reclaim_init(void)
+{
+	return mach_vm_reclaim_ringbuffer_init(&reclaim_buffer);
+}
+
+
+bool
+mvm_reclaim_mark_used(uint64_t id, mach_vm_address_t ptr, uint32_t size, unsigned int debug_flags)
+{
+	bool used;
+	if (debug_flags & MALLOC_ADD_GUARD_PAGE_FLAGS) {
+		if (os_add_overflow(size, 2 * large_vm_page_quanta_size, &size)) {
+			return false;
+		}
+		ptr -= large_vm_page_quanta_size;
+	}
+	_malloc_lock_lock(&reclaim_buffer_lock);
+	used = mach_vm_reclaim_mark_used(&reclaim_buffer, id, ptr, size);
+	_malloc_lock_unlock(&reclaim_buffer_lock);
+	return used;
+}
+
+uint64_t
+mvm_reclaim_mark_free(vm_address_t ptr, uint32_t size, unsigned int debug_flags)
+{
+	uint64_t id;
+	bool should_update_kernel_accounting = false;
+	if (debug_flags & MALLOC_ADD_GUARD_PAGE_FLAGS) {
+		if (os_add_overflow(size, 2 * large_vm_page_quanta_size, &size)) {
+			return VM_RECLAIM_INDEX_NULL;
+		}
+		ptr -= large_vm_page_quanta_size;
+	}
+	_malloc_lock_lock(&reclaim_buffer_lock);
+	id = mach_vm_reclaim_mark_free(&reclaim_buffer, ptr, size,
+			MACH_VM_RECLAIM_DEALLOCATE, &should_update_kernel_accounting);
+	_malloc_lock_unlock(&reclaim_buffer_lock);
+	if (should_update_kernel_accounting) {
+		mach_vm_reclaim_update_kernel_accounting(&reclaim_buffer);
+	}
+	return id;
+}
+
+bool
+mvm_reclaim_is_available(uint64_t id)
+{
+	return mach_vm_reclaim_is_available(&reclaim_buffer, id);
+}
+#endif // CONFIG_DEFERRED_RECLAIM