[022/111] ARM: 6299/1: errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID

[Greg KH <gregkh@suse.de>]

2.6.32-stable review patch.  If anyone has any objections, please let us know.

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

From: Will Deacon <will.deacon@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@ti.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
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@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
@@ -887,6 +887,18 @@ config ARM_ERRATA_460075
 	  ACTLR register. Note that setting specific bits in the ACTLR register
 	  may not be available in non-secure mode.
 
+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
@@ -369,7 +369,11 @@ 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 */
@@ -409,7 +413,11 @@ 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 */