diff --git a/bindings/go/unicorn/unicorn.go b/bindings/go/unicorn/unicorn.go
index ca210c43..a9aeca2d 100644
--- a/bindings/go/unicorn/unicorn.go
+++ b/bindings/go/unicorn/unicorn.go
@@ -28,7 +28,7 @@ func errReturn(err C.uc_err) error {
 type Unicorn interface {
 	MemMap(addr, size uint64) error
 	MemMapProt(addr, size uint64, prot int) error
-	MemMapPtr(addr, size uint64, ptr unsafe.Pointer) error
+	MemMapPtr(addr, size uint64, prot int, ptr unsafe.Pointer) error
 	MemUnmap(addr, size uint64) error
 	MemRead(addr, size uint64) ([]byte, error)
 	MemReadInto(dst []byte, addr uint64) error
@@ -129,8 +129,8 @@ func (u *uc) MemMap(addr, size uint64) error {
 	return u.MemMapProt(addr, size, PROT_ALL)
 }
 
-func (u *uc) MemMapPtr(addr, size uint64, ptr unsafe.Pointer) error {
-	return errReturn(C.uc_mem_map_ptr(u.handle, C.uint64_t(addr), C.size_t(size), ptr))
+func (u *uc) MemMapPtr(addr, size uint64, prot int, ptr unsafe.Pointer) error {
+	return errReturn(C.uc_mem_map_ptr(u.handle, C.uint64_t(addr), C.size_t(size), C.uint32_t(prot), ptr))
 }
 
 func (u *uc) MemUnmap(addr, size uint64) error {
diff --git a/bindings/python/unicorn/unicorn.py b/bindings/python/unicorn/unicorn.py
index 2ccb02ae..08be9632 100644
--- a/bindings/python/unicorn/unicorn.py
+++ b/bindings/python/unicorn/unicorn.py
@@ -104,7 +104,7 @@ _setup_prototype(_uc, "uc_emu_start", ucerr, uc_engine, ctypes.c_uint64, ctypes.
 _setup_prototype(_uc, "uc_emu_stop", ucerr, uc_engine)
 _setup_prototype(_uc, "uc_hook_del", ucerr, uc_engine, uc_hook_h)
 _setup_prototype(_uc, "uc_mem_map", ucerr, uc_engine, ctypes.c_uint64, ctypes.c_size_t, ctypes.c_uint32)
-_setup_prototype(_uc, "uc_mem_map_ptr", ucerr, uc_engine, ctypes.c_uint64, ctypes.c_size_t, ctypes.c_void_p)
+_setup_prototype(_uc, "uc_mem_map_ptr", ucerr, uc_engine, ctypes.c_uint64, ctypes.c_size_t, ctypes.c_uint32, ctypes.c_void_p)
 _setup_prototype(_uc, "uc_mem_unmap", ucerr, uc_engine, ctypes.c_uint64, ctypes.c_size_t)
 _setup_prototype(_uc, "uc_mem_protect", ucerr, uc_engine, ctypes.c_uint64, ctypes.c_size_t, ctypes.c_uint32)
 
@@ -243,8 +243,8 @@ class Uc(object):
 
 
     # map a range of memory from a raw host memory address
-    def mem_map_ptr(self, address, size, ptr):
-        status = _uc.uc_mem_map_ptr(self._uch, address, size, ptr)
+    def mem_map_ptr(self, address, size, perms, ptr):
+        status = _uc.uc_mem_map_ptr(self._uch, address, size, perms, ptr)
         if status != UC_ERR_OK:
             raise UcError(status)
 
diff --git a/include/uc_priv.h b/include/uc_priv.h
index c24a21f9..5cdf6557 100644
--- a/include/uc_priv.h
+++ b/include/uc_priv.h
@@ -48,7 +48,7 @@ typedef void (*uc_args_uc_u64_t)(struct uc_struct *, uint64_t addr);
 
 typedef MemoryRegion* (*uc_args_uc_ram_size_t)(struct uc_struct*,  ram_addr_t begin, size_t size, uint32_t perms);
 
-typedef MemoryRegion* (*uc_args_uc_ram_size_ptr_t)(struct uc_struct*,  ram_addr_t begin, size_t size, void *ptr);
+typedef MemoryRegion* (*uc_args_uc_ram_size_ptr_t)(struct uc_struct*,  ram_addr_t begin, size_t size, uint32_t perms, void *ptr);
 
 typedef void (*uc_mem_unmap_t)(struct uc_struct*, MemoryRegion *mr);
 
diff --git a/include/unicorn/unicorn.h b/include/unicorn/unicorn.h
index 561e48b6..719cbcf6 100644
--- a/include/unicorn/unicorn.h
+++ b/include/unicorn/unicorn.h
@@ -455,14 +455,18 @@ uc_err uc_mem_map(uc_engine *uc, uint64_t address, size_t size, uint32_t perms);
     This address must be aligned to 4KB, or this will return with UC_ERR_ARG error.
  @size: size of the new memory region to be mapped in.
     This size must be multiple of 4KB, or this will return with UC_ERR_ARG error.
- @ptr: pointer to host memory backing the newly mapped memory. Existing host
-    memory permissions are preserved.
+ @perms: Permissions for the newly mapped region.
+    This must be some combination of UC_PROT_READ | UC_PROT_WRITE | UC_PROT_EXEC,
+    or this will return with UC_ERR_ARG error.
+ @ptr: pointer to host memory backing the newly mapped memory. This host memory is
+    expected to be an equal or larger size than provided, and be mapped with at
+    least PROT_READ | PROT_WRITE. If it is not, the resulting behavior is undefined.
 
  @return UC_ERR_OK on success, or other value on failure (refer to uc_err enum
  for detailed error).
 */
 UNICORN_EXPORT
-uc_err uc_mem_map_ptr(uc_engine *uc, uint64_t address, size_t size, void *ptr);
+uc_err uc_mem_map_ptr(uc_engine *uc, uint64_t address, size_t size, uint32_t perms, void *ptr);
 
 /*
  Unmap a region of emulation memory.
diff --git a/qemu/include/exec/memory.h b/qemu/include/exec/memory.h
index b6f7d1b3..3a707522 100644
--- a/qemu/include/exec/memory.h
+++ b/qemu/include/exec/memory.h
@@ -939,7 +939,7 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
 void memory_register_types(struct uc_struct *uc);
 
 MemoryRegion *memory_map(struct uc_struct *uc, ram_addr_t begin, size_t size, uint32_t perms);
-MemoryRegion *memory_map_ptr(struct uc_struct *uc, ram_addr_t begin, size_t size, void *ptr);
+MemoryRegion *memory_map_ptr(struct uc_struct *uc, ram_addr_t begin, size_t size, uint32_t perms, void *ptr);
 void memory_unmap(struct uc_struct *uc, MemoryRegion *mr);
 int memory_free(struct uc_struct *uc);
 
diff --git a/qemu/memory.c b/qemu/memory.c
index 36672f9b..2d2e21a4 100644
--- a/qemu/memory.c
+++ b/qemu/memory.c
@@ -48,12 +48,12 @@ MemoryRegion *memory_map(struct uc_struct *uc, ram_addr_t begin, size_t size, ui
     return ram;
 }
 
-MemoryRegion *memory_map_ptr(struct uc_struct *uc, ram_addr_t begin, size_t size, void *ptr)
+MemoryRegion *memory_map_ptr(struct uc_struct *uc, ram_addr_t begin, size_t size, uint32_t perms, void *ptr)
 {
     MemoryRegion *ram = g_new(MemoryRegion, 1);
 
     memory_region_init_ram_ptr(uc, ram, NULL, "pc.ram", size, ptr);
-    ram->perms = UC_PROT_ALL;
+    ram->perms = perms;
     if (ram->ram_addr == -1)
         // out of memory
         return NULL;
diff --git a/samples/sample_x86.c b/samples/sample_x86.c
index c5fb540c..910af989 100644
--- a/samples/sample_x86.c
+++ b/samples/sample_x86.c
@@ -256,7 +256,7 @@ static void test_i386_map_ptr(void)
         return;
     }
 
-    uc_mem_map_ptr(uc, ADDRESS, 2 * 1024 * 1024, mem);
+    uc_mem_map_ptr(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL, mem);
 
     // write machine code to be emulated to memory
     if (!memcpy(mem, X86_CODE32, sizeof(X86_CODE32) - 1)) {
diff --git a/tests/unit/test_mem_map_ptr.c b/tests/unit/test_mem_map_ptr.c
index 1b91211f..fff4e6c7 100644
--- a/tests/unit/test_mem_map_ptr.c
+++ b/tests/unit/test_mem_map_ptr.c
@@ -45,7 +45,7 @@ static void test_basic(void **state)
     void *host_mem = calloc(1, mem_len);
 
     /* Map a region */
-    uc_assert_success(uc_mem_map_ptr(uc, mem_start, mem_len, host_mem));
+    uc_assert_success(uc_mem_map_ptr(uc, mem_start, mem_len, UC_PROT_ALL, host_mem));
 
     /* Write some data to it */
     uc_assert_success(uc_mem_write(uc, test_addr, "test", 4));
diff --git a/uc.c b/uc.c
index 25ff1fb9..603cf068 100644
--- a/uc.c
+++ b/uc.c
@@ -616,12 +616,12 @@ uc_err uc_mem_map(uc_engine *uc, uint64_t address, size_t size, uint32_t perms)
 }
 
 UNICORN_EXPORT
-uc_err uc_mem_map_ptr(uc_engine *uc, uint64_t address, size_t size, void *ptr)
+uc_err uc_mem_map_ptr(uc_engine *uc, uint64_t address, size_t size, uint32_t perms, void *ptr)
 {
     if (ptr == NULL)
         return UC_ERR_ARG;
 
-    return mem_map(uc, address, size, UC_PROT_ALL, uc->memory_map_ptr(uc, address, size, ptr));
+    return mem_map(uc, address, size, UC_PROT_ALL, uc->memory_map_ptr(uc, address, size, perms, ptr));
 }
 
 // Create a backup copy of the indicated MemoryRegion.