diff --git a/gas/ChangeLog b/gas/ChangeLog
index 47e5c32f2b1ac1697e7e4c9f62c3308833bf9d4c..1e2b1567cb058ac0c6bbdf44848577e86e072624 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,8 @@
+2013-11-18  Zhenqiang Chen  <zhenqiang.chen@linaro.org>
+
+	* config/tc-aarch64.c (parse_sys_reg): Support
+	S2_<op1>_<Cn>_<Cm>_<op2>.
+
 2013-11-18  Yufeng Zhang  <yufeng.zhang@arm.com>
 
 	Revert
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index c230b1e1e1b262d5e18e503e8046d0fae131711f..fb0ae33326d5fabecdcd66167bb0df5b96979f61 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -3270,7 +3270,7 @@ parse_barrier (char **str)
    Returns the encoding for the option, or PARSE_FAIL.
 
    If IMPLE_DEFINED_P is non-zero, the function will also try to parse the
-   implementation defined system register name S3_<op1>_<Cn>_<Cm>_<op2>.  */
+   implementation defined system register name S<op0>_<op1>_<Cn>_<Cm>_<op2>.  */
 
 static int
 parse_sys_reg (char **str, struct hash_control *sys_regs, int imple_defined_p)
@@ -3295,7 +3295,7 @@ parse_sys_reg (char **str, struct hash_control *sys_regs, int imple_defined_p)
 	return PARSE_FAIL;
       else
 	{
-	  /* Parse S3_<op1>_<Cn>_<Cm>_<op2>, the implementation defined
+	  /* Parse S<op0>_<op1>_<Cn>_<Cm>_<op2>, the implementation defined
 	     registers.  */
 	  unsigned int op0, op1, cn, cm, op2;
 	  if (sscanf (buf, "s%u_%u_c%u_c%u_%u", &op0, &op1, &cn, &cm, &op2) != 5)
@@ -3303,11 +3303,11 @@ parse_sys_reg (char **str, struct hash_control *sys_regs, int imple_defined_p)
 	  /* The architecture specifies the encoding space for implementation
 	     defined registers as:
 	     op0  op1  CRn   CRm   op2
-	     11   xxx  1x11  xxxx  xxx
+	     1x   xxx  1x11  xxxx  xxx
 	     For convenience GAS accepts a wider encoding space, as follows:
 	     op0  op1  CRn   CRm   op2
-	     11   xxx  xxxx  xxxx  xxx  */
-	  if (op0 != 3 || op1 > 7 || cn > 15 || cm > 15 || op2 > 7)
+	     1x   xxx  xxxx  xxxx  xxx  */
+	  if ((op0 != 2 && op0 != 3) || op1 > 7 || cn > 15 || cm > 15 || op2 > 7)
 	    return PARSE_FAIL;
 	  value = (op0 << 14) | (op1 << 11) | (cn << 7) | (cm << 3) | op2;
 	}
diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index 5f4bdd6e2d08c986ad2d12c6ea0ab5a281cb8050..a5c5071d171822a672256dd1877123680a6792e5 100644
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-11-18  Zhenqiang Chen  <zhenqiang.chen@linaro.org>
+
+	* gas/testsuite/sysreg.s: Add test.
+	* gas/testsuite/sysreg.d: Update.
+
 2013-11-18  Yufeng Zhang  <yufeng.zhang@arm.com>
 
 	Revert
diff --git a/gas/testsuite/gas/aarch64/sysreg.d b/gas/testsuite/gas/aarch64/sysreg.d
index c7cf00efe2b7364cced83912f7d742341fa03765..7795b4dd30ea360249c2162a251014184d9adad4 100644
--- a/gas/testsuite/gas/aarch64/sysreg.d
+++ b/gas/testsuite/gas/aarch64/sysreg.d
@@ -26,3 +26,5 @@ Disassembly of section \.text:
   48:	d538cc00 	mrs	x0, s3_0_c12_c12_0
   4c:	d5384600 	mrs	x0, s3_0_c4_c6_0
   50:	d5184600 	msr	s3_0_c4_c6_0, x0
+  54:	d5310300 	mrs	x0, s2_1_c0_c3_0
+  58:	d5110300 	msr	s2_1_c0_c3_0, x0
diff --git a/gas/testsuite/gas/aarch64/sysreg.s b/gas/testsuite/gas/aarch64/sysreg.s
index 328759446f3d27e062961c8b0a12151a48767e3e..b7e5ff6ca1f64858c8da46dc8591246910491ebd 100644
--- a/gas/testsuite/gas/aarch64/sysreg.s
+++ b/gas/testsuite/gas/aarch64/sysreg.s
@@ -26,3 +26,6 @@
 	mrs x0, s3_0_c12_c12_0
 	mrs x0, s3_0_c4_c6_0
 	msr s3_0_c4_c6_0, x0
+
+	mrs x0, s2_1_c0_c3_0
+	msr s2_1_c0_c3_0, x0