ARM: 8408/1: Fix the secondary_startup function in Big Endian case

Since the commit "b2c3e38a5471 ARM: redo TTBR setup code for LPAE",
the setup code had been reworked. As a result the secondary CPUs
failed to come online in Big Endian.

As explained by Russell, the new code expected the value in r4/r5 to
be the least significant 32bits in r4 and the most significant 32bits
in r5. However, in the secondary code, we load this using ldrd, which
on BE reverses that.

This patch swap r4/r5 after the ldrd. It is done using the xor
instructions in order to not use a temporary register.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
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 bd755d97e459d77ff05cc8a1264f336c58c1b598..29e2991465cb27b579f729deec65e2293a0a04b5 100644 (file)
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -399,6 +399,9 @@ ENTRY(secondary_startup)
        sub     lr, r4, r5                      @ mmu has been enabled
        add     r3, r7, lr
        ldrd    r4, [r3, #0]                    @ get secondary_data.pgdir
+ARM_BE8(eor    r4, r4, r5)                     @ Swap r5 and r4 in BE:
+ARM_BE8(eor    r5, r4, r5)                     @ it can be done in 3 steps
+ARM_BE8(eor    r4, r4, r5)                     @ without using a temp reg.
        ldr     r8, [r3, #8]                    @ get secondary_data.swapper_pg_dir
        badr    lr, __enable_mmu                @ return address
        mov     r13, r12                        @ __secondary_switched address