[PATCH 8/8] newlib: libc: aeabi_memset M-profile PACBTI-enablement

[Victor Do Nascimento]

Add function prologue/epilogue to conditionally add BTI landing pads
and/or PAC code generation & authentication instructions depending on
compilation flags.
---
 newlib/libc/machine/arm/aeabi_memset-thumb2.S | 45 ++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/newlib/libc/machine/arm/aeabi_memset-thumb2.S b/newlib/libc/machine/arm/aeabi_memset-thumb2.S
index eaca1d8d7..a22d4314a 100644
--- a/newlib/libc/machine/arm/aeabi_memset-thumb2.S
+++ b/newlib/libc/machine/arm/aeabi_memset-thumb2.S
@@ -26,14 +26,42 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include "pacbti.h"
+
 	.thumb
 	.syntax unified
 	.global __aeabi_memset
 	.type	__aeabi_memset, %function
+	.fnstart
+	.cfi_startproc
 	ASM_ALIAS __aeabi_memset4 __aeabi_memset
 	ASM_ALIAS __aeabi_memset8 __aeabi_memset
 __aeabi_memset:
+#if __ARM_FEATURE_PAC_DEFAULT
+#if __ARM_FEATURE_BTI_DEFAULT
+	pacbti	ip, lr, sp
+#else
+	pac	ip, lr, sp
+#endif /* __ARM_FEATURE_BTI_DEFAULT */
+	push	{r4, r5, r6, ip}
+	.save	{r4, r5, r6, ra_auth_code}
+	.cfi_def_cfa_offset 16
+	.cfi_offset 4, -16
+	.cfi_offset 5, -12
+	.cfi_offset 6, -8
+	.cfi_offset 143, -4
+#else
+#if __ARM_FEATURE_BTI_DEFAULT
+	bti
+#endif /* __ARM_FEATURE_BTI_DEFAULT */
 	push	{r4, r5, r6}
+	.save	{r4, r5, r6}
+	.cfi_def_cfa_offset 12
+	.cfi_offset 4, -12
+	.cfi_offset 5, -8
+	.cfi_offset 6, -4
+#endif /* __ARM_FEATURE_PAC_DEFAULT */
+
 	lsls	r4, r0, #30
 	beq	10f
 	subs	r4, r1, #1
@@ -98,10 +126,25 @@ __aeabi_memset:
 	cmp	r3, r4
 	bne	8b
 9:
+#if __ARM_FEATURE_PAC_DEFAULT
+	pop	{r4, r5, r6, ip}
+	.cfi_restore 143
+	.cfi_restore 6
+	.cfi_restore 5
+	.cfi_restore 4
+	.cfi_def_cfa_offset 0
+	aut ip, lr, sp
+#else
 	pop	{r4, r5, r6}
-	bx	lr
+	.cfi_restore 6
+	.cfi_restore 5
+	.cfi_restore 4
+	.cfi_def_cfa_offset 0
+#endif /* __ARM_FEATURE_PAC_DEFAULT */
 10:
 	mov	r4, r1
 	mov	r3, r0
 	b	3b
+	.cfi_endproc
+	.fnend
 	.size __aeabi_memset, . - __aeabi_memset
-- 
2.36.1