diff --git a/libc/Android.mk b/libc/Android.mk
index 2ea96d4..4ffdf57 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -47,7 +47,6 @@
     bionic/if_indextoname.c \
     bionic/if_nametoindex.c \
     bionic/initgroups.c \
-    bionic/ioctl.c \
     bionic/isatty.c \
     bionic/memmem.c \
     bionic/pututline.c \
@@ -151,6 +150,7 @@
     bionic/gettid.cpp \
     bionic/__gnu_basename.cpp \
     bionic/inotify_init.cpp \
+    bionic/ioctl.cpp \
     bionic/lchown.cpp \
     bionic/lfs64_support.cpp \
     bionic/__libc_current_sigrtmax.cpp \
@@ -170,6 +170,7 @@
     bionic/mkfifo.cpp \
     bionic/mknod.cpp \
     bionic/mntent.cpp \
+    bionic/mremap.cpp \
     bionic/NetdClientDispatch.cpp \
     bionic/open.cpp \
     bionic/pathconf.cpp \
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 4188c15..526b6d0 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -107,7 +107,7 @@
 int         ___close:close(int)  all
 pid_t       __getpid:getpid()  all
 int         munmap(void*, size_t)  all
-void*       mremap(void*, size_t, size_t, unsigned long)  all
+void*       ___mremap:mremap(void*, size_t, size_t, int, void*)  all
 int         msync(const void*, size_t, int)    all
 int         mprotect(const void*, size_t, int)  all
 int         madvise(void*, size_t, int)  all
diff --git a/libc/arch-arm/syscalls/___mremap.S b/libc/arch-arm/syscalls/___mremap.S
new file mode 100644
index 0000000..ade8d78
--- /dev/null
+++ b/libc/arch-arm/syscalls/___mremap.S
@@ -0,0 +1,23 @@
+/* Generated by gensyscalls.py. Do not edit. */
+
+#include <private/bionic_asm.h>
+
+ENTRY(___mremap)
+    mov     ip, sp
+    stmfd   sp!, {r4, r5, r6, r7}
+    .cfi_def_cfa_offset 16
+    .cfi_rel_offset r4, 0
+    .cfi_rel_offset r5, 4
+    .cfi_rel_offset r6, 8
+    .cfi_rel_offset r7, 12
+    ldmfd   ip, {r4, r5, r6}
+    ldr     r7, =__NR_mremap
+    swi     #0
+    ldmfd   sp!, {r4, r5, r6, r7}
+    .cfi_def_cfa_offset 0
+    cmn     r0, #(MAX_ERRNO + 1)
+    bxls    lr
+    neg     r0, r0
+    b       __set_errno_internal
+END(___mremap)
+.hidden ___mremap
diff --git a/libc/arch-arm/syscalls/mremap.S b/libc/arch-arm/syscalls/mremap.S
deleted file mode 100644
index 505ea3c..0000000
--- a/libc/arch-arm/syscalls/mremap.S
+++ /dev/null
@@ -1,14 +0,0 @@
-/* Generated by gensyscalls.py. Do not edit. */
-
-#include <private/bionic_asm.h>
-
-ENTRY(mremap)
-    mov     ip, r7
-    ldr     r7, =__NR_mremap
-    swi     #0
-    mov     r7, ip
-    cmn     r0, #(MAX_ERRNO + 1)
-    bxls    lr
-    neg     r0, r0
-    b       __set_errno_internal
-END(mremap)
diff --git a/libc/arch-arm64/syscalls/mremap.S b/libc/arch-arm64/syscalls/___mremap.S
similarity index 81%
rename from libc/arch-arm64/syscalls/mremap.S
rename to libc/arch-arm64/syscalls/___mremap.S
index 69b91d6..aeb93bc 100644
--- a/libc/arch-arm64/syscalls/mremap.S
+++ b/libc/arch-arm64/syscalls/___mremap.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(mremap)
+ENTRY(___mremap)
     mov     x8, __NR_mremap
     svc     #0
 
@@ -11,4 +11,5 @@
     b.hi    __set_errno_internal
 
     ret
-END(mremap)
+END(___mremap)
+.hidden ___mremap
diff --git a/libc/arch-mips/syscalls/mremap.S b/libc/arch-mips/syscalls/___mremap.S
similarity index 84%
rename from libc/arch-mips/syscalls/mremap.S
rename to libc/arch-mips/syscalls/___mremap.S
index 7cbb94e..82e2eb3 100644
--- a/libc/arch-mips/syscalls/mremap.S
+++ b/libc/arch-mips/syscalls/___mremap.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(mremap)
+ENTRY(___mremap)
     .set noreorder
     .cpload t9
     li v0, __NR_mremap
@@ -16,4 +16,5 @@
     j t9
     nop
     .set reorder
-END(mremap)
+END(___mremap)
+.hidden ___mremap
diff --git a/libc/arch-mips64/syscalls/mremap.S b/libc/arch-mips64/syscalls/___mremap.S
similarity index 87%
rename from libc/arch-mips64/syscalls/mremap.S
rename to libc/arch-mips64/syscalls/___mremap.S
index cf7f1de..5004d50 100644
--- a/libc/arch-mips64/syscalls/mremap.S
+++ b/libc/arch-mips64/syscalls/___mremap.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(mremap)
+ENTRY(___mremap)
     .set push
     .set noreorder
     li v0, __NR_mremap
@@ -22,4 +22,5 @@
     j t9
     move ra, t0
     .set pop
-END(mremap)
+END(___mremap)
+.hidden ___mremap
diff --git a/libc/arch-x86/syscalls/mremap.S b/libc/arch-x86/syscalls/___mremap.S
similarity index 69%
rename from libc/arch-x86/syscalls/mremap.S
rename to libc/arch-x86/syscalls/___mremap.S
index 869ef5d..e5e9c54 100644
--- a/libc/arch-x86/syscalls/mremap.S
+++ b/libc/arch-x86/syscalls/___mremap.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(mremap)
+ENTRY(___mremap)
     pushl   %ebx
     .cfi_def_cfa_offset 8
     .cfi_rel_offset ebx, 0
@@ -15,10 +15,14 @@
     pushl   %esi
     .cfi_adjust_cfa_offset 4
     .cfi_rel_offset esi, 0
-    mov     20(%esp), %ebx
-    mov     24(%esp), %ecx
-    mov     28(%esp), %edx
-    mov     32(%esp), %esi
+    pushl   %edi
+    .cfi_adjust_cfa_offset 4
+    .cfi_rel_offset edi, 0
+    mov     24(%esp), %ebx
+    mov     28(%esp), %ecx
+    mov     32(%esp), %edx
+    mov     36(%esp), %esi
+    mov     40(%esp), %edi
     movl    $__NR_mremap, %eax
     int     $0x80
     cmpl    $-MAX_ERRNO, %eax
@@ -28,9 +32,11 @@
     call    __set_errno_internal
     addl    $4, %esp
 1:
+    popl    %edi
     popl    %esi
     popl    %edx
     popl    %ecx
     popl    %ebx
     ret
-END(mremap)
+END(___mremap)
+.hidden ___mremap
diff --git a/libc/arch-x86_64/syscalls/mremap.S b/libc/arch-x86_64/syscalls/___mremap.S
similarity index 84%
rename from libc/arch-x86_64/syscalls/mremap.S
rename to libc/arch-x86_64/syscalls/___mremap.S
index a6042cb..cc6dee9 100644
--- a/libc/arch-x86_64/syscalls/mremap.S
+++ b/libc/arch-x86_64/syscalls/___mremap.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(mremap)
+ENTRY(___mremap)
     movq    %rcx, %r10
     movl    $__NR_mremap, %eax
     syscall
@@ -13,4 +13,5 @@
     call    __set_errno_internal
 1:
     ret
-END(mremap)
+END(___mremap)
+.hidden ___mremap
diff --git a/libc/bionic/ioctl.c b/libc/bionic/ioctl.cpp
similarity index 85%
rename from libc/bionic/ioctl.c
rename to libc/bionic/ioctl.cpp
index 6dd95d0..db85132 100644
--- a/libc/bionic/ioctl.c
+++ b/libc/bionic/ioctl.cpp
@@ -25,19 +25,16 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+
+#include <sys/ioctl.h>
 #include <stdarg.h>
 
-extern int __ioctl(int, int, void *);
+extern "C" int __ioctl(int, int, void *);
 
-int ioctl(int fd, int request, ...)
-{
-    va_list ap;
-    void * arg;
-
-    va_start(ap, request);
-    arg = va_arg(ap, void *);
-    va_end(ap);
-
-    return __ioctl(fd, request, arg);
+int ioctl(int fd, int request, ...) {
+  va_list ap;
+  va_start(ap, request);
+  void* arg = va_arg(ap, void*);
+  va_end(ap);
+  return __ioctl(fd, request, arg);
 }
-
diff --git a/libc/bionic/ioctl.c b/libc/bionic/mremap.cpp
similarity index 71%
copy from libc/bionic/ioctl.c
copy to libc/bionic/mremap.cpp
index 6dd95d0..4892b1d 100644
--- a/libc/bionic/ioctl.c
+++ b/libc/bionic/mremap.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 The Android Open Source Project
+ * Copyright (C) 2015 The Android Open Source Project
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -25,19 +25,21 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+
+#include <sys/mman.h>
 #include <stdarg.h>
 
-extern int __ioctl(int, int, void *);
+extern "C" void* ___mremap(void*, size_t, size_t, int, void*);
 
-int ioctl(int fd, int request, ...)
-{
+void* mremap(void* old_address, size_t old_size, size_t new_size, int flags, ...) {
+  void* new_address = nullptr;
+  // The optional argument is only valid if the MREMAP_FIXED flag is set,
+  // so we assume it's not present otherwise.
+  if ((flags & MREMAP_FIXED) != 0) {
     va_list ap;
-    void * arg;
-
-    va_start(ap, request);
-    arg = va_arg(ap, void *);
+    va_start(ap, flags);
+    new_address = va_arg(ap, void*);
     va_end(ap);
-
-    return __ioctl(fd, request, arg);
+  }
+  return ___mremap(old_address, old_size, new_size, flags, new_address);
 }
-
diff --git a/libc/include/sys/mman.h b/libc/include/sys/mman.h
index 6857f60..a19ceb5 100644
--- a/libc/include/sys/mman.h
+++ b/libc/include/sys/mman.h
@@ -59,7 +59,7 @@
 extern int munmap(void*, size_t);
 extern int msync(const void*, size_t, int);
 extern int mprotect(const void*, size_t, int);
-extern void* mremap(void*, size_t, size_t, unsigned long);
+extern void* mremap(void*, size_t, size_t, int, ...);
 
 extern int mlockall(int);
 extern int munlockall(void);