aarch64: Add asm helpers for GCS

The Guarded Control Stack instructions can be present even if the
hardware does not support the extension (runtime checked feature),
so the asm code should be backward compatible with old assemblers.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>

diff --git a/sysdeps/aarch64/sysdep.h b/sysdeps/aarch64/sysdep.h
index 1b317735a4b58b4eed7c48e20b34ca7683568f9c..4df120ad80bbe56541168034f121a182a49081ae 100644 (file)
--- a/sysdeps/aarch64/sysdep.h
+++ b/sysdeps/aarch64/sysdep.h
@@ -74,6 +74,13 @@ strip_pac (void *p)
 #define PACIASP                hint    25
 #define AUTIASP                hint    29
 
+/* Guarded Control Stack support.  */
+#define CHKFEAT_X16    hint    40
+#define MRS_GCSPR(x)   mrs     x, s3_3_c2_c5_1
+#define GCSPOPM(x)     sysl    x, #3, c7, c7, #1
+#define GCSSS1(x)      sys     #3, c7, c7, #2, x
+#define GCSSS2(x)      sysl    x, #3, c7, c7, #3
+
 /* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code.  */
 #define FEATURE_1_AND 0xc0000000
 #define FEATURE_1_BTI 1