[PATCH v3 6/8] newlib: libc: setjmp/longjmp M-profile PACBTI-enablement

["Victor L. Do Nascimento" <victor.donascimento@arm.com>]

Hi all,

This adds function prologue/epilogue to conditionally add BTI landing
pads and/or PAC code generation & authentication instructions depending
on compilation flags.

Regards,
Victor
---
 newlib/libc/machine/arm/setjmp.S | 33 ++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/newlib/libc/machine/arm/setjmp.S b/newlib/libc/machine/arm/setjmp.S
index 21d6ff9e7..4fe53cdf2 100644
--- a/newlib/libc/machine/arm/setjmp.S
+++ b/newlib/libc/machine/arm/setjmp.S
@@ -157,11 +157,15 @@ SYM (.arm_start_of.\name):
 	.globl SYM (\name)
 	TYPE (\name)
 SYM (\name):
+	.fnstart
+	.cfi_startproc
 	PROLOGUE \name
 .endm
 
 .macro FUNC_END name
 	RET
+	.cfi_endproc
+	.fnend
 	SIZE (\name)
 .endm
 	
@@ -173,11 +177,26 @@ SYM (\name):
 
 	/* Save all the callee-preserved registers into the jump buffer.  */
 #ifdef __thumb2__
+#if __ARM_FEATURE_PAC_DEFAULT
+#if __ARM_FEATURE_BTI_DEFAULT
+	pacbti		ip, lr, sp
+#else
+	pac		ip, lr, sp
+#endif /* __ARM_FEATURE_BTI_DEFAULT */
+	.cfi_register 	143, 12
+	mov		a4, ip
+	mov		ip, sp
+	stmea		a1!, { a4, v1-v7, fp, ip, lr }
+#else
+#if __ARM_FEATURE_BTI_DEFAULT
+	bti
+#endif /* __ARM_FEATURE_BTI_DEFAULT */
 	mov		ip, sp
 	stmea		a1!, { v1-v7, fp, ip, lr }
+#endif /* __ARM_FEATURE_PAC_DEFAULT */
 #else
 	stmea		a1!, { v1-v7, fp, ip, sp, lr }
-#endif
+#endif /* __thumb2__ */
 	
 #if 0	/* Simulator does not cope with FP instructions yet.  */
 #ifndef __SOFTFP__
@@ -200,11 +219,17 @@ SYM (\name):
 	
 	/* Restore the registers, retrieving the state when setjmp() was called.  */
 #ifdef __thumb2__
+#if __ARM_FEATURE_PAC_DEFAULT
+	ldmfd		a1!, { a4, v1-v7, fp, ip, lr }
+	mov		sp, ip
+	mov         	ip, a4
+#else
 	ldmfd		a1!, { v1-v7, fp, ip, lr }
 	mov		sp, ip
+#endif /* __ARM_FEATURE_PAC_DEFAULT */
 #else
 	ldmfd		a1!, { v1-v7, fp, ip, sp, lr }
-#endif
+#endif /* __thumb2__ */
 	
 #if 0	/* Simulator does not cope with FP instructions yet.  */
 #ifndef __SOFTFP__
@@ -220,5 +245,9 @@ SYM (\name):
 #endif
 	moveq		a1, #1
 
+#if __ARM_FEATURE_PAC_DEFAULT
+	aut		ip, lr, sp
+#endif
+
 	FUNC_END longjmp
 #endif
-- 
2.36.1