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authorJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-11 10:41:07 +0300
committerJosé Pekkarinen <jose.pekkarinen@nokia.com>2016-04-13 08:17:18 +0300
commite09b41010ba33a20a87472ee821fa407a5b8da36 (patch)
treed10dc367189862e7ca5c592f033dc3726e1df4e3 /kernel/arch/arm/xen/hypercall.S
parentf93b97fd65072de626c074dbe099a1fff05ce060 (diff)
These changes are the raw update to linux-4.4.6-rt14. Kernel sources
are taken from kernel.org, and rt patch from the rt wiki download page. During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen <jose.pekkarinen@nokia.com>
Diffstat (limited to 'kernel/arch/arm/xen/hypercall.S')
-rw-r--r--kernel/arch/arm/xen/hypercall.S15
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/arch/arm/xen/hypercall.S b/kernel/arch/arm/xen/hypercall.S
index f00e08075..10fd99c56 100644
--- a/kernel/arch/arm/xen/hypercall.S
+++ b/kernel/arch/arm/xen/hypercall.S
@@ -98,8 +98,23 @@ ENTRY(privcmd_call)
mov r1, r2
mov r2, r3
ldr r3, [sp, #8]
+ /*
+ * Privcmd calls are issued by the userspace. We need to allow the
+ * kernel to access the userspace memory before issuing the hypercall.
+ */
+ uaccess_enable r4
+
+ /* r4 is loaded now as we use it as scratch register before */
ldr r4, [sp, #4]
__HVC(XEN_IMM)
+
+ /*
+ * Disable userspace access from kernel. This is fine to do it
+ * unconditionally as no set_fs(KERNEL_DS)/set_fs(get_ds()) is
+ * called before.
+ */
+ uaccess_disable r4
+
ldm sp!, {r4}
ret lr
ENDPROC(privcmd_call);