linux-kernel - [PATCH 1/2] iommu/omap: Fix disabling of MMU upon a fault

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 28 Jul 2017 15:49:13 -0500
From:   Josue Albarran <j-albarran@...com>
To:     Joerg Roedel <joro@...tes.org>
CC:     <iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
        Suman Anna <s-anna@...com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        <linux-omap@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH 1/2] iommu/omap: Fix disabling of MMU upon a fault

From: Fernando Guzman Lugo <fernando.lugo@...com>

The IOMMU framework lets its client users be notified on a
MMU fault and allows them to either handle the interrupt by
dynamic reloading of an appropriate TLB/PTE for the offending
fault address or to completely restart/recovery the device
and its IOMMU.

The OMAP remoteproc driver performs the latter option, and
does so after unwinding the previous mappings. The OMAP IOMMU
fault handler however disables the MMU and cuts off the clock
upon a MMU fault at present, resulting in an interconnect abort
during any subsequent operation that touches the MMU registers.

So, disable the IP-level fault interrupts instead of disabling
the MMU, to allow continued MMU register operations as well as
to avoid getting interrupted again.

Signed-off-by: Fernando Guzman Lugo <fernando.lugo@...com>
[s-anna@...com: add commit description]
Signed-off-by: Suman Anna <s-anna@...com>
Signed-off-by: Josue Albarran <j-albarran@...com>
---
 drivers/iommu/omap-iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 641e035cf866..10c9de8de45d 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -786,7 +786,7 @@ static irqreturn_t iommu_fault_handler(int irq, void *data)
 	if (!report_iommu_fault(domain, obj->dev, da, 0))
 		return IRQ_HANDLED;

-	iommu_disable(obj);
+	iommu_write_reg(obj, 0, MMU_IRQENABLE);

 	iopgd = iopgd_offset(obj, da);

-- 
2.7.4