This is a note to let you know that I've just added the patch titled
ARM: 7752/1: errata: LoUIS bit field in CLIDR register is incorrect
to the 3.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-7752-1-errata-louis-bit-field-in-clidr-register-is-incorrect.patch
and it can be found in the queue-3.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 691557941af4c12bd307ad81a4d9fa9c7743ac28 Mon Sep 17 00:00:00 2001
From: Jon Medhurst <tixy@xxxxxxxxxx>
Date: Fri, 7 Jun 2013 10:35:35 +0100
Subject: ARM: 7752/1: errata: LoUIS bit field in CLIDR register is incorrect
From: Jon Medhurst <tixy@xxxxxxxxxx>
commit 691557941af4c12bd307ad81a4d9fa9c7743ac28 upstream.
On Cortex-A9 before version r1p0, the LoUIS bit field of the CLIDR
register returns zero when it should return one. This leads to cache
maintenance operations which rely on this value to not function as
intended, causing data corruption.
The workaround for this errata is to detect affected CPUs and correct
the LoUIS value read.
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>
Signed-off-by: Jon Medhurst <tixy@xxxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/Kconfig | 10 ++++++++++
arch/arm/mm/cache-v7.S | 8 ++++++++
2 files changed, 18 insertions(+)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1306,6 +1306,16 @@ config PL310_ERRATA_588369
is not correctly implemented in PL310 as clean lines are not
invalidated as a result of these operations.
+config ARM_ERRATA_643719
+ bool "ARM errata: LoUIS bit field in CLIDR register is incorrect"
+ depends on CPU_V7 && SMP
+ help
+ This option enables the workaround for the 643719 Cortex-A9 (prior to
+ r1p0) erratum. On affected cores the LoUIS bit field of the CLIDR
+ register returns zero when it should return one. The workaround
+ corrects this value, ensuring cache maintenance operations which use
+ it behave as intended and avoiding data corruption.
+
config ARM_ERRATA_720789
bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID"
depends on CPU_V7
--- a/arch/arm/mm/cache-v7.S
+++ b/arch/arm/mm/cache-v7.S
@@ -92,6 +92,14 @@ ENTRY(v7_flush_dcache_louis)
mrc p15, 1, r0, c0, c0, 1 @ read clidr, r0 = clidr
ALT_SMP(ands r3, r0, #(7 << 21)) @ extract LoUIS from clidr
ALT_UP(ands r3, r0, #(7 << 27)) @ extract LoUU from clidr
+#ifdef CONFIG_ARM_ERRATA_643719
+ ALT_SMP(mrceq p15, 0, r2, c0, c0, 0) @ read main ID register
+ ALT_UP(moveq pc, lr) @ LoUU is zero, so nothing to do
+ ldreq r1, =0x410fc090 @ ID of ARM Cortex A9 r0p?
+ biceq r2, r2, #0x0000000f @ clear minor revision number
+ teqeq r2, r1 @ test for errata affected core and if so...
+ orreqs r3, #(1 << 21) @ fix LoUIS value (and set flags state to 'ne')
+#endif
ALT_SMP(mov r3, r3, lsr #20) @ r3 = LoUIS * 2
ALT_UP(mov r3, r3, lsr #26) @ r3 = LoUU * 2
moveq pc, lr @ return if level == 0
Patches currently in stable-queue which might be from tixy@xxxxxxxxxx are
queue-3.9/arm-7752-1-errata-louis-bit-field-in-clidr-register-is-incorrect.patch
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