[Xen-devel] [PATCH v3 2/3] arm: traps: handle unknown exceptions in check_conditional_instr()

[Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>]

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@xxxxxxxx>
Acked-by: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/traps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index c07999b..eae2212 100644
--- 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 */
-- 
2.7.4


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