refactor(aarch64): refactor usage of elx_panic

Currently we call el3_panic for panics from EL3 and elx_panic for
panics from lower ELs.

When we boot into a rich OS environment and interact with BL31 using
SMC/ABI calls and we can also decide to handle any lower EL panics in
EL3. Panic can occur in lower EL from rich OS or during SMC/ABI calls
after context switch to EL3.

But after booting into any rich OS we may land in panic either from
rich OS or while servicing any SMC call, here the logic to use
el3_panic or elx_panic is flawed as spsr_el3[3:0] is always EL3h
and end up in elx_panic even if panic occurred from EL3 during
SMC handling.

We try to decouple the elx_panic usage for its intended purpose,
introduce lower_el_panic which would call elx_panic, currently
lower_el_panic is called from default platform_ea_handle which
would be called due to panic from any of the lower ELs.

Also remove the weak linkage for elx_panic and rename it to
report_elx_panic which could be used with lower_el_panic.

Change-Id: I268bca89c01c60520d127ef6c7ba851460edc747
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/plat/common/aarch64/plat_common.c b/plat/common/aarch64/plat_common.c
index 3495323e3..042916a7d 100644
--- a/plat/common/aarch64/plat_common.c
+++ b/plat/common/aarch64/plat_common.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2023, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2023, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -94,5 +94,8 @@ void plat_default_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *co
 		read_mpidr_el1(), get_el_str(level));
 	ERROR("exception reason=%u syndrome=0x%" PRIx64 "\n", ea_reason, syndrome);
 
-	panic();
+	/* We reached here due to a panic from a lower EL and assuming this is the default
+	 * platform registered handler that we could call on a lower EL panic.
+	 */
+	lower_el_panic();
 }