fix(el3-runtime): set unset pstate bits to default
During a transition to a higher EL some of the PSTATE bits are not set
by hardware, this means that their state may be leaked from lower ELs.
This patch sets those bits to a default value upon entry to EL3.
This patch was tested using a debugger to check the PSTATE values
are correctly set. As well as adding a test in the next patch to
ensure the PSTATE in lower ELs is still maintained after this change.
Change-Id: Ie546acbca7b9aa3c86bd68185edded91b2a64ae5
Signed-off-by: Daniel Boulby <daniel.boulby@arm.com>
diff --git a/bl31/aarch64/ea_delegate.S b/bl31/aarch64/ea_delegate.S
index 03820bd..fa6ede8 100644
--- a/bl31/aarch64/ea_delegate.S
+++ b/bl31/aarch64/ea_delegate.S
@@ -92,6 +92,7 @@
* Save general purpose and ARMv8.3-PAuth registers (if enabled).
* If Secure Cycle Counter is not disabled in MDCR_EL3 when
* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
+ * Also set the PSTATE to a known state.
*/
bl prepare_el3_entry
@@ -139,6 +140,7 @@
* Save general purpose and ARMv8.3-PAuth registers (if enabled).
* If Secure Cycle Counter is not disabled in MDCR_EL3 when
* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
+ * Also set the PSTATE to a known state.
*/
bl prepare_el3_entry