Simplify management of SCTLR_EL3 and SCTLR_EL1
This patch reworks the manner in which the M,A, C, SA, I, WXN & EE bits of
SCTLR_EL3 & SCTLR_EL1 are managed. The EE bit is cleared immediately after reset
in EL3. The I, A and SA bits are set next in EL3 and immediately upon entry in
S-EL1. These bits are no longer managed in the blX_arch_setup() functions. They
do not have to be saved and restored either. The M, WXN and optionally the C
bit are set in the enable_mmu_elX() function. This is done during both the warm
and cold boot paths.
Fixes ARM-software/tf-issues#226
Change-Id: Ie894d1a07b8697c116960d858cd138c50bc7a069
diff --git a/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index 1023983..69d2243 100644
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -52,6 +52,15 @@
mov x20, x0
mov x21, x1
#else
+ /* ---------------------------------------------
+ * Set the CPU endianness before doing anything
+ * that might involve memory reads or writes.
+ * ---------------------------------------------
+ */
+ mrs x0, sctlr_el3
+ bic x0, x0, #SCTLR_EE_BIT
+ msr sctlr_el3, x0
+ isb
/* -----------------------------------------------------
* Perform any processor specific actions upon reset
@@ -61,14 +70,15 @@
*/
bl cpu_reset_handler
#endif
-
/* ---------------------------------------------
- * Enable the instruction cache.
+ * Enable the instruction cache, stack pointer
+ * and data access alignment checks
* ---------------------------------------------
*/
- mrs x1, sctlr_el3
- orr x1, x1, #SCTLR_I_BIT
- msr sctlr_el3, x1
+ mov x1, #(SCTLR_I_BIT | SCTLR_A_BIT | SCTLR_SA_BIT)
+ mrs x0, sctlr_el3
+ orr x0, x0, x1
+ msr sctlr_el3, x0
isb
/* ---------------------------------------------