fix(el3_runtime): allow SErrors when executing in EL3
SCR_EL3.EA is set to 1 in BL31 initialization and is cleared before
entering to lower ELs(except for RAS FFH case "HANDLE_EA_EL3_FIRST_NS").
The cleared value persist even during run time when execution comes
back to EL3.
When SCR_EL3.EA is 0 and execution state is EL3, Async EAs(delivered
as SErrors) are implicitly masked and hence any Async EA by EL3 will
remain pending and will trap at the exception level EA is targeted
to and unmasked when entering lower EL.
This causes unexpected EA at lower EL. This is a very rare
to get SError in EL3 until unless there is any programming error.
This patch sets SCR_EL3.EA to 1 when entering EL3 from lower EL.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ibb593369edb034f670fd85ee79adc9829b900a83
diff --git a/lib/el3_runtime/aarch64/context.S b/lib/el3_runtime/aarch64/context.S
index b126b9c..60501f6 100644
--- a/lib/el3_runtime/aarch64/context.S
+++ b/lib/el3_runtime/aarch64/context.S
@@ -788,6 +788,15 @@
#endif /* CTX_INCLUDE_FPREGS */
/*
+ * Set SCR_EL3.EA bit to enable SErrors at EL3
+ */
+ .macro enable_serror_at_el3
+ mrs x8, scr_el3
+ orr x8, x8, #SCR_EA_BIT
+ msr scr_el3, x8
+ .endm
+
+ /*
* Set the PSTATE bits not set when the exception was taken as
* described in the AArch64.TakeException() pseudocode function
* in ARM DDI 0487F.c page J1-7635 to a default value.
@@ -917,6 +926,7 @@
*/
func prepare_el3_entry
save_gp_pmcr_pauth_regs
+ enable_serror_at_el3
/*
* Set the PSTATE bits not described in the Aarch64.TakeException
* pseudocode to their default values.