Commit 7e66cbc9 authored Aug 28, 2014 by Konstantin Khlebnikov Committed by Russell King Sep 02, 2014

ARM: 8132/1: LPAE: drop wrong carry flag correction after adding TTBR1_OFFSET



ARM: LPAE: drop wrong carry flag correction after adding TTBR1_OFFSET

In commit 7fb00c2f ("ARM: 8114/1: LPAE:
load upper bits of early TTBR0/TTBR1") part which fixes carrying in adding
TTBR1_OFFSET to TTRR1 was wrong:

        addls   ttbr1, ttbr1, #TTBR1_OFFSET
        adcls   tmp, tmp, #0

addls doesn't update flags, adcls adds carry from cmp above:

        cmp     ttbr1, tmp                    @ PHYS_OFFSET > PAGE_OFFSET?

Condition 'ls' means carry flag is clear or zero flag is set, thus only one
case is affected: when PHYS_OFFSET == PAGE_OFFSET.

It seems safer to remove this fixup. Bug is here for ages and nobody
complained. Let's fix it separately.

Reported-and-Tested-by: Jassi Brar <jassisinghbrar@gmail.com>

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent eba1c718

arch/arm/mm/proc-v7-3level.S

+0 −1

Original line number	Diff line number	Diff line
		@@ -146,7 +146,6 @@ ENDPROC(cpu_v7_set_pte_ext)
		mov \tmp, \ttbr1, lsr #(32 - ARCH_PGD_SHIFT) @ upper bits
		mov \ttbr1, \ttbr1, lsl #ARCH_PGD_SHIFT @ lower bits
		addls \ttbr1, \ttbr1, #TTBR1_OFFSET
		adcls \tmp, \tmp, #0
		mcrr p15, 1, \ttbr1, \tmp, c2 @ load TTBR1
		mov \tmp, \ttbr0, lsr #(32 - ARCH_PGD_SHIFT) @ upper bits
		mov \ttbr0, \ttbr0, lsl #ARCH_PGD_SHIFT @ lower bits