[ARM] 3541/2: workaround for PXA27x erratum E7
Patch from Nicolas Pitre
According to the Intel PXA27x Processor Family Specification
Update document (doc.nr. 280071-009) erratum E7, some care must be taken
to locate the disabling and re-enabling of the MMU to the beginning of a
cache line to avoid problems in some circumstances.
Credits to Simon Vogl <simon.vogl@researchstudios.at> for bringing this
up.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 23016f6..9b42b88 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -448,8 +448,11 @@
mov r1, #-1
mcr p15, 0, r3, c2, c0, 0 @ load page table pointer
mcr p15, 0, r1, c3, c0, 0 @ load domain access control
- mcr p15, 0, r0, c1, c0, 0 @ load control register
- mov pc, lr
+ b 1f
+ .align 5 @ cache line aligned
+1: mcr p15, 0, r0, c1, c0, 0 @ load control register
+ mrc p15, 0, r0, c1, c0, 0 @ and read it back to
+ sub pc, lr, r0, lsr #32 @ properly flush pipeline
/*
* All code following this line is relocatable. It is relocated by