Patch "bus: arm-ccn: Do not attempt to configure XPs for cycle counter" has been added to the 4.4-stable tree

Patch "bus: arm-ccn: Do not attempt to configure XPs for cycle counter" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    bus: arm-ccn: Do not attempt to configure XPs for cycle counter

to the 4.4-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:
     bus-arm-ccn-do-not-attempt-to-configure-xps-for-cycle-counter.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b7c1beb278e8e3dc664ed3df3fc786db126120a9 Mon Sep 17 00:00:00 2001
From: Pawel Moll <pawel.moll@arm.com>
Date: Fri, 5 Aug 2016 15:07:10 +0100
Subject: bus: arm-ccn: Do not attempt to configure XPs for cycle counter

From: Pawel Moll <pawel.moll@arm.com>

commit b7c1beb278e8e3dc664ed3df3fc786db126120a9 upstream.

Fuzzing the CCN perf driver revealed a small but definitely dangerous
mistake in the event setup code. When a cycle counter is requested, the
driver should not reconfigure the events bus at all, otherwise it will
corrupt (in most but the simplest cases) its configuration and may end
up accessing XP array out of its bounds and corrupting control
registers.

Reported-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/bus/arm-ccn.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/bus/arm-ccn.c
+++ b/drivers/bus/arm-ccn.c
@@ -895,6 +895,10 @@ static void arm_ccn_pmu_xp_dt_config(str
 	struct arm_ccn_component *xp;
 	u32 val, dt_cfg;
 
+	/* Nothing to do for cycle counter */
+	if (hw->idx == CCN_IDX_PMU_CYCLE_COUNTER)
+		return;
+
 	if (CCN_CONFIG_TYPE(event->attr.config) == CCN_TYPE_XP)
 		xp = &ccn->xp[CCN_CONFIG_XP(event->attr.config)];
 	else


Patches currently in stable-queue which might be from pawel.moll@arm.com are

queue-4.4/bus-arm-ccn-fix-xp-watchpoint-settings-bitmask.patch
queue-4.4/bus-arm-ccn-do-not-attempt-to-configure-xps-for-cycle-counter.patch
queue-4.4/bus-arm-ccn-fix-pmu-handling-of-mn.patch