diff --git a/libc/arch-arm/include/machine/asm.h b/libc/arch-arm/include/machine/asm.h
index 7b8f053..047e54d 100644
--- a/libc/arch-arm/include/machine/asm.h
+++ b/libc/arch-arm/include/machine/asm.h
@@ -97,6 +97,12 @@
 #define	ASENTRY_NP(y)	_ENTRY(_ASM_LABEL(y))
 #define	ASEND(y)	_END(_ASM_LABEL(y))
 
+#ifdef __ELF__
+#define ENTRY_PRIVATE(y)  ENTRY(y); .hidden _C_LABEL(y)
+#else
+#define ENTRY_PRIVATE(y)  ENTRY(y)
+#endif
+
 #define	ASMSTR		.asciz
 
 #if defined(__ELF__) && defined(PIC)
diff --git a/libc/arch-x86/include/machine/asm.h b/libc/arch-x86/include/machine/asm.h
index 7a23060..49d3ea8 100644
--- a/libc/arch-x86/include/machine/asm.h
+++ b/libc/arch-x86/include/machine/asm.h
@@ -103,6 +103,12 @@
 #define _ENTRY(x) \
 	.text; _ALIGN_TEXT; .globl x; .type x,@function; x:
 
+#define _ASM_SIZE(x)    .size x, .-x;
+
+#define _END(x) \
+	.fnend; \
+	_ASM_SIZE(x)
+
 #ifdef GPROF
 # define _PROF_PROLOGUE	\
 	pushl %ebp; movl %esp,%ebp; call PIC_PLT(mcount); popl %ebp
@@ -112,8 +118,12 @@
 
 #define	ENTRY(y)	_ENTRY(_C_LABEL(y)); _PROF_PROLOGUE
 #define	NENTRY(y)	_ENTRY(_C_LABEL(y))
+#define	END(y)		_END(_C_LABEL(y))
 #define	ASENTRY(y)	_ENTRY(_ASM_LABEL(y)); _PROF_PROLOGUE
 
+#define ENTRY_PRIVATE(y)  ENTRY(y); .hidden _C_LABEL(y)
+
+
 #define	ALTENTRY(name)	.globl _C_LABEL(name); _C_LABEL(name):
 
 #define	ASMSTR		.asciz
diff --git a/libc/include/sys/cdefs_elf.h b/libc/include/sys/cdefs_elf.h
index 1e57470..0887fa5 100644
--- a/libc/include/sys/cdefs_elf.h
+++ b/libc/include/sys/cdefs_elf.h
@@ -96,9 +96,24 @@
 #endif
 
 /* GCC visibility helper macro */
+/* This must be used to tag non-static functions that are private, i.e.
+ * never exposed by the shared library. */
 #define __LIBC_HIDDEN__							\
 	__attribute__ ((visibility ("hidden")))
 
+/* This must be used to tag non-static functions that are public, i.e.
+ * exposed by the shared library, and part of the stable NDK ABI */
+#define __LIBC_ABI_PUBLIC__ \
+        __attribute__ ((visibility ("default")))
+
+/* This must be used to tag non-static functions that must be exported
+ * by the shared library, but whose implementation is private to the
+ * platform. For now this is equivalent to __LIBC_ABI_PUBLIC__, but we
+ * may want to change this later.
+ */
+#define __LIBC_ABI_PRIVATE__ \
+        __attribute__ ((visibility ("default")))
+
 #define	__IDSTRING(_n,_s)		__SECTIONSTRING(.ident,_s)
 
 #define	__RCSID(_s)			__IDSTRING(rcsid,_s)