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From: Greg KH on 11 Aug 2010 20:20
2.6.35-stable review patch. If anyone has any objections, please let us know.

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

From: Will Deacon <will.deacon(a)arm.com>

commit cdf357f1e13a08a11261edacb3083746f65c1ed9 upstream.

On versions of the Cortex-A9 prior to r2p0, performing TLB invalidations by
ASID match can result in the incorrect ASID being broadcast to other CPUs.
As a consequence of this, the targetted TLB entries are not invalidated
across the system.

This workaround changes the TLB flushing routines to invalidate entries
regardless of the ASID.

Tested-by: Rob Clark <rob(a)ti.com>
Acked-by: Catalin Marinas <catalin.marinas(a)arm.com>
Signed-off-by: Will Deacon <will.deacon(a)arm.com>
Signed-off-by: Russell King <rmk+kernel(a)arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

---
arch/arm/Kconfig | 12 ++++++++++++
arch/arm/include/asm/tlbflush.h | 8 ++++++++
2 files changed, 20 insertions(+)

--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1027,6 +1027,18 @@ config PL310_ERRATA_588369
is not correctly implemented in PL310 as clean lines are not
invalidated as a result of these operations. Note that this errata
uses Texas Instrument's secure monitor api.
+
+config ARM_ERRATA_720789
+ bool "ARM errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID"
+ depends on CPU_V7 && SMP
+ help
+ This option enables the workaround for the 720789 Cortex-A9 (prior to
+ r2p0) erratum. A faulty ASID can be sent to the other CPUs for the
+ broadcasted CP15 TLB maintenance operations TLBIASIDIS and TLBIMVAIS.
+ As a consequence of this erratum, some TLB entries which should be
+ invalidated are not, resulting in an incoherency in the system page
+ tables. The workaround changes the TLB flushing routines to invalidate
+ entries regardless of the ASID.
endmenu

source "arch/arm/common/Kconfig"
--- a/arch/arm/include/asm/tlbflush.h
+++ b/arch/arm/include/asm/tlbflush.h
@@ -378,7 +378,11 @@ static inline void local_flush_tlb_mm(st
if (tlb_flag(TLB_V6_I_ASID))
asm("mcr p15, 0, %0, c8, c5, 2" : : "r" (asid) : "cc");
if (tlb_flag(TLB_V7_UIS_ASID))
+#ifdef CONFIG_ARM_ERRATA_720789
+ asm("mcr p15, 0, %0, c8, c3, 0" : : "r" (zero) : "cc");
+#else
asm("mcr p15, 0, %0, c8, c3, 2" : : "r" (asid) : "cc");
+#endif

if (tlb_flag(TLB_BTB)) {
/* flush the branch target cache */
@@ -424,7 +428,11 @@ local_flush_tlb_page(struct vm_area_stru
if (tlb_flag(TLB_V6_I_PAGE))
asm("mcr p15, 0, %0, c8, c5, 1" : : "r" (uaddr) : "cc");
if (tlb_flag(TLB_V7_UIS_PAGE))
+#ifdef CONFIG_ARM_ERRATA_720789
+ asm("mcr p15, 0, %0, c8, c3, 3" : : "r" (uaddr & PAGE_MASK) : "cc");
+#else
asm("mcr p15, 0, %0, c8, c3, 1" : : "r" (uaddr) : "cc");
+#endif

if (tlb_flag(TLB_BTB)) {
/* flush the branch target cache */


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