6 files changed, 43 insertions, 1 deletions
diff --git a/sysdeps/aarch64/crti.S b/sysdeps/aarch64/crti.S
index 1728eac37a..c346bcad72 100644
--- a/sysdeps/aarch64/crti.S
+++ b/sysdeps/aarch64/crti.S
@@ -75,6 +75,7 @@ call_weak_fn:
 	.hidden	_init
 	.type	_init, %function
 _init:
+	BTI_C
 	stp	x29, x30, [sp, -16]!
 	mov	x29, sp
 #if PREINIT_FUNCTION_WEAK
@@ -89,5 +90,6 @@ _init:
 	.hidden	_fini
 	.type	_fini, %function
 _fini:
+	BTI_C
 	stp	x29, x30, [sp, -16]!
 	mov	x29, sp
diff --git a/sysdeps/aarch64/crtn.S b/sysdeps/aarch64/crtn.S
index c3e97cc449..0c1ef112c2 100644
--- a/sysdeps/aarch64/crtn.S
+++ b/sysdeps/aarch64/crtn.S
@@ -37,6 +37,8 @@
 /* crtn.S puts function epilogues in the .init and .fini sections
    corresponding to the prologues in crti.S. */
 
+#include <sysdep.h>
+
 	.section .init,"ax",%progbits
 	ldp	x29, x30, [sp], 16
 	RET
diff --git a/sysdeps/aarch64/dl-tlsdesc.S b/sysdeps/aarch64/dl-tlsdesc.S
index 557ad1d505..9d96c8632a 100644
--- a/sysdeps/aarch64/dl-tlsdesc.S
+++ b/sysdeps/aarch64/dl-tlsdesc.S
@@ -74,6 +74,7 @@
 	cfi_startproc
 	.align 2
 _dl_tlsdesc_return:
+	BTI_C
 	DELOUSE (0)
 	ldr	PTR_REG (0), [x0, #PTR_SIZE]
 	RET
@@ -95,6 +96,7 @@ _dl_tlsdesc_return:
 	cfi_startproc
 	.align  2
 _dl_tlsdesc_undefweak:
+	BTI_C
 	str	x1, [sp, #-16]!
 	cfi_adjust_cfa_offset (16)
 	DELOUSE (0)
@@ -142,6 +144,7 @@ _dl_tlsdesc_undefweak:
 	cfi_startproc
 	.align 2
 _dl_tlsdesc_dynamic:
+	BTI_C
 	DELOUSE (0)
 
 	/* Save just enough registers to support fast path, if we fall
diff --git a/sysdeps/aarch64/dl-trampoline.S b/sysdeps/aarch64/dl-trampoline.S
index 94e965c096..2cbfa81434 100644
--- a/sysdeps/aarch64/dl-trampoline.S
+++ b/sysdeps/aarch64/dl-trampoline.S
@@ -35,6 +35,7 @@
 	cfi_startproc
 	.align 2
 _dl_runtime_resolve:
+	BTI_C
 	/* AArch64 we get called with:
 	   ip0		&PLTGOT[2]
 	   ip1		temp(dl resolver entry point)
@@ -126,6 +127,7 @@ _dl_runtime_resolve:
 	cfi_startproc
 	.align 2
 _dl_runtime_profile:
+	BTI_C
 	/* AArch64 we get called with:
 	   ip0		&PLTGOT[2]
 	   ip1		temp(dl resolver entry point)
diff --git a/sysdeps/aarch64/start.S b/sysdeps/aarch64/start.S
index d96cf57e2d..75393e1c18 100644
--- a/sysdeps/aarch64/start.S
+++ b/sysdeps/aarch64/start.S
@@ -46,6 +46,7 @@
 	.globl _start
 	.type _start,#function
 _start:
+	BTI_C
 	/* Create an initial frame with 0 LR and FP */
 	mov	x29, #0
 	mov	x30, #0
diff --git a/sysdeps/aarch64/sysdep.h b/sysdeps/aarch64/sysdep.h
index 604c489170..4664329d3a 100644
--- a/sysdeps/aarch64/sysdep.h
+++ b/sysdeps/aarch64/sysdep.h
@@ -41,12 +41,42 @@
 
 #define ASM_SIZE_DIRECTIVE(name) .size name,.-name
 
+/* Branch Target Identitication support.  */
+#define BTI_C		hint	34
+#define BTI_J		hint	36
+
+/* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code.  */
+#define FEATURE_1_AND 0xc0000000
+#define FEATURE_1_BTI 1
+#define FEATURE_1_PAC 2
+
+/* Add a NT_GNU_PROPERTY_TYPE_0 note.  */
+#define GNU_PROPERTY(type, value)	\
+  .section .note.gnu.property, "a";	\
+  .p2align 3;				\
+  .word 4;				\
+  .word 16;				\
+  .word 5;				\
+  .asciz "GNU";				\
+  .word type;				\
+  .word 4;				\
+  .word value;				\
+  .word 0;				\
+  .text
+
+/* Add GNU property note with the supported features to all asm code
+   where sysdep.h is included.  */
+#if HAVE_AARCH64_BTI
+GNU_PROPERTY (FEATURE_1_AND, FEATURE_1_BTI)
+#endif
+
 /* Define an entry point visible from C.  */
 #define ENTRY(name)						\
   .globl C_SYMBOL_NAME(name);					\
   .type C_SYMBOL_NAME(name),%function;				\
   .align 4;							\
   C_LABEL(name)							\
+  BTI_C;							\
   cfi_startproc;						\
   CALL_MCOUNT
 
@@ -56,6 +86,7 @@
   .type C_SYMBOL_NAME(name),%function;				\
   .p2align align;						\
   C_LABEL(name)							\
+  BTI_C;							\
   cfi_startproc;						\
   CALL_MCOUNT
 
@@ -68,10 +99,11 @@
   .globl C_SYMBOL_NAME(name);					\
   .type C_SYMBOL_NAME(name),%function;				\
   .p2align align;						\
-  .rep padding;							\
+  .rep padding - 1; /* -1 for bti c.  */			\
   nop;								\
   .endr;							\
   C_LABEL(name)							\
+  BTI_C;							\
   cfi_startproc;						\
   CALL_MCOUNT