libc: Add Armv8.3-A PAuth and Armv8.5-A BTI compatibility to *.S
The most notable change is in sigsetjmp/siglongjmp. The former
stores LR signed with the current SP into jmp_buf. Calling siglongjmp
reads a signed LR and the corresponding SP from jmp_buf. This way not
only the checksum provides some means of integrity protection but
Pointer Authentication too.
Test: Tested on FVP with BTI enabled.
Change-Id: I9d720239775f8d2829a677901f546c4b14b5cbe5
diff --git a/libc/arch-arm64/bionic/syscall.S b/libc/arch-arm64/bionic/syscall.S
index 8389f98..9e6f68a 100644
--- a/libc/arch-arm64/bionic/syscall.S
+++ b/libc/arch-arm64/bionic/syscall.S
@@ -47,3 +47,5 @@
ret
END(syscall)
+
+NOTE_GNU_PROPERTY()