feat(ras): use FEAT_IESB for error synchronization
For synchronization of errors at exception boundries TF-A uses "esb"
instruction with FEAT_RAS or "dsb" and "isb" otherwise. The problem
with esb instruction is, along with synching errors it might also
consume the error, which is not ideal in all scenarios. On the other
hand we can't use dsb always as its in the hot path.
To solve above mentioned problem the best way is to use FEAT_IESB
feature which provides controls to insert an implicit Error
synchronization event at exception entry and exception return.
Assumption in TF-A is, if RAS Extension is present then FEAT_IESB will
also be present and enabled.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Ie5861eec5da4028a116406bb4d1fea7dac232456
diff --git a/lib/el3_runtime/aarch64/context.S b/lib/el3_runtime/aarch64/context.S
index 894165a..631094f 100644
--- a/lib/el3_runtime/aarch64/context.S
+++ b/lib/el3_runtime/aarch64/context.S
@@ -649,23 +649,9 @@
1:
#endif /* IMAGE_BL31 && DYNAMIC_WORKAROUND_CVE_2018_3639 */
-/*
- * This is a hot path, so we don't want to do some actual FEAT_RAS runtime
- * detection here. The "esb" is a cheaper variant, so using "dsb" in the
- * ENABLE_FEAT_RAS==2 case is not ideal, but won't hurt.
- */
-#if IMAGE_BL31 && ENABLE_FEAT_RAS == 1
- /* ----------------------------------------------------------
- * Issue Error Synchronization Barrier to synchronize SErrors
- * before exiting EL3. We're running with EAs unmasked, so
- * any synchronized errors would be taken immediately;
- * therefore no need to inspect DISR_EL1 register.
- * ----------------------------------------------------------
- */
- esb
-#else
- dsb sy
-#endif /* IMAGE_BL31 && ENABLE_FEAT_RAS */
+#if IMAGE_BL31
+ synchronize_errors
+#endif /* IMAGE_BL31 */
/* ----------------------------------------------------------
* Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET