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Subject[ 07/85] ARM: 7489/1: errata: fix workaround for erratum #720789 on UP systems
Date
From: Greg KH <gregkh@linuxfoundation.org>

3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@arm.com>

commit 730a8128cd8978467eb1cf546b11014acb57d433 upstream.

Commit 5a783cbc4836 ("ARM: 7478/1: errata: extend workaround for erratum
#720789") added workarounds for erratum #720789 to the range TLB
invalidation functions with the observation that the erratum only
affects SMP platforms. However, when running an SMP_ON_UP kernel on a
uniprocessor platform we must take care to preserve the ASID as the
workaround is not required.

This patch ensures that we don't set the ASID to 0 when flushing the TLB
on such a system, preserving the original behaviour with the workaround
disabled.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm/mm/tlb-v7.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/arm/mm/tlb-v7.S
+++ b/arch/arm/mm/tlb-v7.S
@@ -38,10 +38,10 @@ ENTRY(v7wbi_flush_user_tlb_range)
dsb
mov r0, r0, lsr #PAGE_SHIFT @ align address
mov r1, r1, lsr #PAGE_SHIFT
-#ifdef CONFIG_ARM_ERRATA_720789
- mov r3, #0
-#else
asid r3, r3 @ mask ASID
+#ifdef CONFIG_ARM_ERRATA_720789
+ ALT_SMP(W(mov) r3, #0 )
+ ALT_UP(W(nop) )
#endif
orr r0, r3, r0, lsl #PAGE_SHIFT @ Create initial MVA
mov r1, r1, lsl #PAGE_SHIFT



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