[ 11/45] ARM: KVM: clear exclusive monitor on all exception returns

From: Greg Kroah-Hartman
Date: Sun Aug 18 2013 - 16:47:43 EST


3.10-stable review patch. If anyone has any objections, please let me know.

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

From: Marc Zyngier <marc.zyngier@xxxxxxx>

commit 22cfbb6d730ca2fda236b507d9fba17bf002736c upstream.

Make sure we clear the exclusive monitor on all exception returns,
which otherwise could lead to lock corruptions.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Jonghwan Choi <jhbird.choi@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
arch/arm/kvm/interrupts.S | 3 +++
1 file changed, 3 insertions(+)

--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -292,6 +292,7 @@ THUMB( orr r2, r2, #PSR_T_BIT )
ldr r2, =BSYM(panic)
msr ELR_hyp, r2
ldr r0, =\panic_str
+ clrex @ Clear exclusive monitor
eret
.endm

@@ -441,6 +442,7 @@ guest_trap:

4: pop {r0, r1} @ Failed translation, return to guest
mcrr p15, 0, r0, r1, c7 @ PAR
+ clrex
pop {r0, r1, r2}
eret

@@ -467,6 +469,7 @@ switch_to_guest_vfp:

pop {r3-r7}
pop {r0-r2}
+ clrex
eret
#endif



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