This is a note to let you know that I've just added the patch titled
ARM: 7384/1: ThumbEE: Disable userspace TEEHBR access for
!CONFIG_ARM_THUMBEE
to the 3.3-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-7384-1-thumbee-disable-userspace-teehbr-access-for-config_arm_thumbee.patch
and it can be found in the queue-3.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 078c04545ba56da21567728a909a496df5ff730d Mon Sep 17 00:00:00 2001
From: Jonathan Austin <[email protected]>
Date: Thu, 12 Apr 2012 17:45:25 +0100
Subject: ARM: 7384/1: ThumbEE: Disable userspace TEEHBR access for
!CONFIG_ARM_THUMBEE
From: Jonathan Austin <[email protected]>
commit 078c04545ba56da21567728a909a496df5ff730d upstream.
Currently when ThumbEE is not enabled (!CONFIG_ARM_THUMBEE) the ThumbEE
register states are not saved/restored at context switch. The default state
of the ThumbEE Ctrl register (TEECR) allows userspace accesses to the
ThumbEE Base Handler register (TEEHBR). This can cause unexpected behaviour
when people use ThumbEE on !CONFIG_ARM_THUMBEE kernels, as well as allowing
covert communication - eg between userspace tasks running inside chroot
jails.
This patch sets up TEECR in order to prevent user-space access to TEEHBR
when !CONFIG_ARM_THUMBEE. In this case, tasks are sent SIGILL if they try to
access TEEHBR.
Reviewed-by: Will Deacon <[email protected]>
Signed-off-by: Jonathan Austin <[email protected]>
Signed-off-by: Russell King <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/arm/mm/proc-v7.S | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -255,6 +255,18 @@ __v7_setup:
mcr p15, 0, r5, c10, c2, 0 @ write PRRR
mcr p15, 0, r6, c10, c2, 1 @ write NMRR
#endif
+#ifndef CONFIG_ARM_THUMBEE
+ mrc p15, 0, r0, c0, c1, 0 @ read ID_PFR0 for ThumbEE
+ and r0, r0, #(0xf << 12) @ ThumbEE enabled field
+ teq r0, #(1 << 12) @ check if ThumbEE is present
+ bne 1f
+ mov r5, #0
+ mcr p14, 6, r5, c1, c0, 0 @ Initialize TEEHBR to 0
+ mrc p14, 6, r0, c0, c0, 0 @ load TEECR
+ orr r0, r0, #1 @ set the 1st bit in order to
+ mcr p14, 6, r0, c0, c0, 0 @ stop userspace TEEHBR access
+1:
+#endif
adr r5, v7_crval
ldmia r5, {r5, r6}
#ifdef CONFIG_CPU_ENDIAN_BE8
Patches currently in stable-queue which might be from [email protected]
are
queue-3.3/arm-7384-1-thumbee-disable-userspace-teehbr-access-for-config_arm_thumbee.patch
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