feat(el3-runtime): modify vector entry paths
Vector entries in EL3 from lower ELs, first check for any pending
async EAs from lower EL before handling the original exception.
This happens when there is an error (EA) in the system which is not
yet signaled to PE while executing at lower EL. During entry into EL3
the errors (EA) are synchronized causing async EA to pend at EL3.
On detecting the pending EA (via ISR_EL1.A) EL3 either reflects it back
to lower EL (KFH) or handles it in EL3 (FFH) based on EA routing model.
In case of Firmware First handling mode (FFH), EL3 handles the pended
EA first before returing back to handle the original exception.
While in case of Kernel First handling mode (KFH), EL3 will return back
to lower EL without handling the original exception. On returing to
lower EL, EA will be pended. In KFH mode there is a risk of back and
forth between EL3 and lower EL if the EA is masked at lower EL or
priority of EA is lower than that of original exception. This is a
limitation in current architecture but can be solved in future if EL3
gets a capability to inject virtual SError.
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I3a2a31de7cf454d9d690b1ef769432a5b24f6c11
diff --git a/include/lib/el3_runtime/aarch64/context.h b/include/lib/el3_runtime/aarch64/context.h
index 470d113..fb28505 100644
--- a/include/lib/el3_runtime/aarch64/context.h
+++ b/include/lib/el3_runtime/aarch64/context.h
@@ -63,7 +63,22 @@
#define CTX_PMCR_EL0 U(0x28)
#define CTX_IS_IN_EL3 U(0x30)
#define CTX_MPAM3_EL3 U(0x38)
-#define CTX_EL3STATE_END U(0x40) /* Align to the next 16 byte boundary */
+/* Constants required in supporting nested exception in EL3 */
+#define CTX_SAVED_ELR_EL3 U(0x40)
+/*
+ * General purpose flag, to save various EL3 states
+ * FFH mode : Used to identify if handling nested exception
+ * KFH mode : Used as counter value
+ */
+#define CTX_NESTED_EA_FLAG U(0x48)
+#if HANDLE_EA_EL3_FIRST_NS
+ #define CTX_SAVED_ESR_EL3 U(0x50)
+ #define CTX_SAVED_SPSR_EL3 U(0x58)
+ #define CTX_SAVED_GPREG_LR U(0x60)
+ #define CTX_EL3STATE_END U(0x70) /* Align to the next 16 byte boundary */
+#else
+ #define CTX_EL3STATE_END U(0x50) /* Align to the next 16 byte boundary */
+#endif
/*******************************************************************************
* Constants that allow assembler code to access members of and the