armv8: Support loading 32-bit OS in AArch32 execution state
To support loading a 32-bit OS, the execution state will change from
AArch64 to AArch32 when jumping to kernel.
The architecture information will be got through checking FIT image,
then U-Boot will load 32-bit OS or 64-bit OS automatically.
Signed-off-by: Ebony Zhu <ebony.zhu@nxp.com>
Signed-off-by: Alison Wang <alison.wang@nxp.com>
Signed-off-by: Chenhui Zhao <chenhui.zhao@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S
index 253a39b..bbccf2b 100644
--- a/arch/arm/cpu/armv8/transition.S
+++ b/arch/arm/cpu/armv8/transition.S
@@ -11,13 +11,24 @@
#include <asm/macro.h>
ENTRY(armv8_switch_to_el2)
- switch_el x0, 1f, 0f, 0f
-0: ret
-1: armv8_switch_to_el2_m x0
+ switch_el x5, 1f, 0f, 0f
+0:
+ /*
+ * x3 is kernel entry point or switch_to_el1
+ * if CONFIG_ARMV8_SWITCH_TO_EL1 is defined.
+ * When running in EL2 now, jump to the
+ * address saved in x3.
+ */
+ br x3
+1: armv8_switch_to_el2_m x3, x4, x5
ENDPROC(armv8_switch_to_el2)
ENTRY(armv8_switch_to_el1)
- switch_el x0, 0f, 1f, 0f
-0: ret
-1: armv8_switch_to_el1_m x0, x1
+ switch_el x5, 0f, 1f, 0f
+0:
+ /* x3 is kernel entry point. When running in EL1
+ * now, jump to the address saved in x3.
+ */
+ br x3
+1: armv8_switch_to_el1_m x3, x4, x5
ENDPROC(armv8_switch_to_el1)