Commit 998ef5d8 authored Aug 06, 2015 by Gregory CLEMENT Committed by Russell King Aug 07, 2015

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



Since the commit "b2c3e38a 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>

parent 3473f265

arch/arm/kernel/head.S

+3 −0

Original line number	Diff line number	Diff line
		@@ -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

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