feat(rme): run BL2 in root world when FEAT_RME is enabled
This patch enables BL2 to run in root world (EL3) which is
needed as per the security model of RME-enabled systems.
Using the existing BL2_AT_EL3 TF-A build option is not convenient
because that option assumes TF-A BL1 doesn't exist, which is not
the case for RME-enabled systems. For the purposes of RME, we use
a normal BL1 image but we also want to run BL2 in EL3 as normally as
possible, therefore rather than use the special bl2_entrypoint
function in bl2_el3_entrypoint.S, we use a new bl2_entrypoint
function (in bl2_rme_entrypoint.S) which doesn't need reset or
mailbox initialization code seen in the el3_entrypoint_common macro.
The patch also cleans up bl2_el3_entrypoint.S, moving the
bl2_run_next_image function to its own file to avoid duplicating
code.
Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: I99821b4cd550cadcb701f4c0c4dc36da81c7ef55
diff --git a/include/arch/aarch64/el3_common_macros.S b/include/arch/aarch64/el3_common_macros.S
index d496584..7d6a963 100644
--- a/include/arch/aarch64/el3_common_macros.S
+++ b/include/arch/aarch64/el3_common_macros.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2021, Arm Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -88,6 +88,13 @@
*/
orr x0, x0, #(SCR_API_BIT | SCR_APK_BIT)
#endif
+#if ENABLE_RME
+ /*
+ * TODO: Settting the EEL2 bit to allow EL3 access to secure only registers
+ * in context management. This will need to be refactored.
+ */
+ orr x0, x0, #SCR_EEL2_BIT
+#endif
msr scr_el3, x0
/* ---------------------------------------------------------------------
@@ -365,6 +372,7 @@
msr vbar_el3, x0
isb
+#if !(defined(IMAGE_BL2) && ENABLE_RME)
/* ---------------------------------------------------------------------
* It is a cold boot.
* Perform any processor specific actions upon reset e.g. cache, TLB
@@ -372,6 +380,7 @@
* ---------------------------------------------------------------------
*/
bl reset_handler
+#endif
el3_arch_init_common
@@ -414,7 +423,8 @@
* ---------------------------------------------------------------------
*/
.if \_init_c_runtime
-#if defined(IMAGE_BL31) || (defined(IMAGE_BL2) && BL2_AT_EL3 && BL2_INV_DCACHE)
+#if defined(IMAGE_BL31) || (defined(IMAGE_BL2) && \
+ ((BL2_AT_EL3 && BL2_INV_DCACHE) || ENABLE_RME))
/* -------------------------------------------------------------
* Invalidate the RW memory used by the BL31 image. This
* includes the data and NOBITS sections. This is done to