feat(gcs): support guarded control stack
Arm v9.4 introduces support for Guarded Control Stack, providing
mitigations against some forms of RPO attacks and an efficient mechanism
for obtaining the current call stack without requiring a full stack
unwind. Enable access to this feature for EL2 and below, context
switching the newly added EL2 registers as appropriate.
Change the FVP platform to default to handling this as a dynamic option
so the right decision can be made by the code at runtime.
Signed-off-by: Mark Brown <broonie@kernel.org>
Change-Id: I691aa7c22e3547bb3abe98d96993baf18c5f0e7b
diff --git a/include/lib/el3_runtime/aarch64/context.h b/include/lib/el3_runtime/aarch64/context.h
index a8e6d8a..dd2b836 100644
--- a/include/lib/el3_runtime/aarch64/context.h
+++ b/include/lib/el3_runtime/aarch64/context.h
@@ -234,9 +234,11 @@
#define CTX_PIRE0_EL2 U(0x1e8)
#define CTX_PIR_EL2 U(0x1f0)
#define CTX_S2PIR_EL2 U(0x1f8)
+#define CTX_GCSCR_EL2 U(0x200)
+#define CTX_GCSPR_EL2 U(0x208)
/* Align to the next 16 byte boundary */
-#define CTX_EL2_SYSREGS_END U(0x200)
+#define CTX_EL2_SYSREGS_END U(0x210)
#endif /* CTX_INCLUDE_EL2_REGS */