AArch64: Enable lower ELs to use pointer authentication
Pointer authentication is an Armv8.3 feature that introduces
instructions that can be used to authenticate and verify pointers.
Pointer authentication instructions are allowed to be accessed from all
ELs but only when EL3 explicitly allows for it; otherwise, their usage
will trap to EL3. Since EL3 doesn't have trap handling in place, this
patch unconditionally disables all related traps to EL3 to avoid
potential misconfiguration leading to an unhandled EL3 exception.
Fixes ARM-software/tf-issues#629
Change-Id: I9bd2efe0dc714196f503713b721ffbf05672c14d
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/docs/firmware-design.rst b/docs/firmware-design.rst
index 7cc7485..051b92b 100644
--- a/docs/firmware-design.rst
+++ b/docs/firmware-design.rst
@@ -2532,6 +2532,12 @@
translation table entries for a given stage of translation for a particular
translation regime.
+Armv8.3-A
+~~~~~~~~~
+
+- Pointer Authentication features of Armv8.3-A are unconditionally enabled so
+ that lower ELs are allowed to use them without causing a trap to EL3.
+
Armv7-A
~~~~~~~