From: Stefano Stabellini <sstabellini@kernel.org>
Date: Tue, 13 Dec 2016 19:08:39 +0000 (-0800)
Subject: fix LDRB Thumb2 decoding
X-Git-Tag: 4.9.0-rc1~920
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=9963caae97ad140fa207c3c61a9442b417afc1e9;p=people%2Fandrewcoop%2Fxen.git

fix LDRB Thumb2 decoding

Rt is four bit at offset 12, not three. See see encoding T2 for LDRB
A8.8.70 in ARM DDI 0406C.c

Suggested-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Julien Grall <julien.grall@arm.com>
---

diff --git a/xen/arch/arm/decode.c b/xen/arch/arm/decode.c
index c6f49a5139..514b7a21a5 100644
--- a/xen/arch/arm/decode.c
+++ b/xen/arch/arm/decode.c
@@ -41,7 +41,7 @@ static int decode_thumb2(register_t pc, struct hsr_dabt *dabt, uint16_t hw1)
     if ( raw_copy_from_guest(&hw2, (void *__user)(pc + 2), sizeof (hw2)) )
         return -EFAULT;
 
-    rt = (hw2 >> 12) & 0x7;
+    rt = (hw2 >> 12) & 0xf;
 
     switch ( (hw1 >> 9) & 0xf )
     {