PC only needs adjusting by 2, otherwise we rerun the instruction prior
to the hvc as well.
hvc is unpredictable if used within a Thumb IT (conditional execution)
block, so we don't need to worry about rewinding any of that state.
Signed-off-by: Ian Campbell <ian.campb...@citrix.com>
---
Should be backported
---
xen/arch/arm/domain.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index 10f13e4..2d2197e 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -387,10 +387,11 @@ unsigned long hypercall_create_continuation(
else
#endif
{
+ int is_thumb = (regs->cpsr & PSR_THUMB);
regs->r12 = op;
/* Ensure the hypercall trap instruction is re-executed. */
- regs->pc -= 4; /* re-execute 'hvc #XEN_HYPERCALL_TAG' */
+ regs->pc -= is_thumb?2:4; /* re-execute 'hvc #XEN_HYPERCALL_TAG' */
for ( i = 0; *p != '\0'; i++ )
{
--
1.7.10.4
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