arm64: big-endian: set correct endianess on kernel entry

The endianness of memory accesses at EL2 and EL1 are configured by
SCTLR_EL2.EE and SCTLR_EL1.EE respectively. When the kernel is booted,
the state of SCTLR_EL{2,1}.EE is unknown, and thus the kernel must
ensure that they are set before performing any memory accesses.

This patch ensures that SCTLR_EL{2,1} are configured appropriately at
boot for kernels of either endianness.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
[catalin.marinas@arm.com: fix SCTLR_EL1.E0E bit setting in head.S]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 14 insertions, 3 deletions

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 775ecb313ee7..7009387348b7 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -159,12 +159,22 @@ ENTRY(el2_setup)
         mrs     x0, CurrentEL
         cmp     x0, #PSR_MODE_EL2t
         ccmp    x0, #PSR_MODE_EL2h, #0x4, ne
-        b.eq    1f
+        b.ne    1f
+        mrs     x0, sctlr_el2
+CPU_BE( orr     x0, x0, #(1 << 25)      )       // Set the EE bit for EL2
+CPU_LE( bic     x0, x0, #(1 << 25)      )       // Clear the EE bit for EL2
+        msr     sctlr_el2, x0
+        b       2f
+1:      mrs     x0, sctlr_el1
+CPU_BE( orr     x0, x0, #(3 << 24)      )       // Set the EE and E0E bits for EL1
+CPU_LE( bic     x0, x0, #(3 << 24)      )       // Clear the EE and E0E bits for EL1
+        msr     sctlr_el1, x0
         mov     w20, #BOOT_CPU_MODE_EL1         // This cpu booted in EL1
+        isb
         ret
 
         /* Hyp configuration. */
-1:      mov     x0, #(1 << 31)                  // 64-bit EL1
+2:      mov     x0, #(1 << 31)                  // 64-bit EL1
         msr     hcr_el2, x0
 
         /* Generic timers. */
@@ -181,7 +191,8 @@ ENTRY(el2_setup)
 
         /* sctlr_el1 */
         mov     x0, #0x0800                     // Set/clear RES{1,0} bits
-        movk    x0, #0x30d0, lsl #16
+CPU_BE( movk    x0, #0x33d0, lsl #16    )       // Set EE and E0E on BE systems
+CPU_LE( movk    x0, #0x30d0, lsl #16    )       // Clear EE and E0E on LE systems
         msr     sctlr_el1, x0
 
         /* Coprocessor traps. */