ARM: 7275/1: LPAE: Check the CPU support for the long descriptor format
This patch adds a check for the presence of the LPAE feature during the
CPU initialisation. If not present, it reports an error when
CONFIG_DEBUG_LL is enabled.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 14e277d..6d57911 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -99,6 +99,14 @@
THUMB( it eq ) @ force fixup-able long branch encoding
beq __error_p @ yes, error 'p'
+#ifdef CONFIG_ARM_LPAE
+ mrc p15, 0, r3, c0, c1, 4 @ read ID_MMFR0
+ and r3, r3, #0xf @ extract VMSA support
+ cmp r3, #5 @ long-descriptor translation table format?
+ THUMB( it lo ) @ force fixup-able long branch encoding
+ blo __error_p @ only classic page table format
+#endif
+
#ifndef CONFIG_XIP_KERNEL
adr r3, 2f
ldmia r3, {r4, r8}