arm: traps: handle unknown exceptions in check_conditional_instr()

According to ARM architecture reference manual (ARM DDI 0487B.a page D7-2259,
ARM DDI 0406C.c page B3-1426), exception with unknown reason (HSR.EC == 0)
has no valid bits in HSR (apart from HSR.EC), so we can't check if that was
caused by conditional instruction. We need to assume that it is unconditional.

Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Acked-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index c07999b518490af7f010adba47b456cbda27a8cc..eae221272cdf0291c1fc280e95b07d4452714789 100644 (file)
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1717,7 +1717,7 @@ static int check_conditional_instr(struct cpu_user_regs *regs,
     int cond;
 
     /* Unconditional Exception classes */
-    if ( hsr.ec >= 0x10 )
+    if ( hsr.ec == HSR_EC_UNKNOWN || hsr.ec >= 0x10 )
         return 1;
 
     /* Check for valid condition in hsr */