diff -Nur gcc-7.3.0.orig/gcc/config/sh/sh-protos.h gcc-7.3.0/gcc/config/sh/sh-protos.h
--- gcc-7.3.0.orig/gcc/config/sh/sh-protos.h	2017-01-01 13:07:43.000000000 +0100
+++ gcc-7.3.0/gcc/config/sh/sh-protos.h	2018-06-03 02:20:50.000000000 +0200
@@ -35,6 +35,9 @@
   SFUNC_STATIC
 };
 
+#define TARGET_ATOMIC_HARD_CAS \
+  (selected_atomic_model ().type == sh_atomic_model::hard_cas)
+
 #ifdef RTX_CODE
 extern rtx sh_fsca_sf2int (void);
 extern rtx sh_fsca_int2sf (void);
diff -Nur gcc-7.3.0.orig/gcc/config/sh/sh.c gcc-7.3.0/gcc/config/sh/sh.c
--- gcc-7.3.0.orig/gcc/config/sh/sh.c	2017-04-04 00:30:56.000000000 +0200
+++ gcc-7.3.0/gcc/config/sh/sh.c	2018-06-03 02:20:50.000000000 +0200
@@ -662,6 +662,7 @@
   model_names[sh_atomic_model::hard_llcs] = "hard-llcs";
   model_names[sh_atomic_model::soft_tcb] = "soft-tcb";
   model_names[sh_atomic_model::soft_imask] = "soft-imask";
+  model_names[sh_atomic_model::hard_cas] = "hard-cas";
 
   const char* model_cdef_names[sh_atomic_model::num_models];
   model_cdef_names[sh_atomic_model::none] = "NONE";
@@ -669,6 +670,7 @@
   model_cdef_names[sh_atomic_model::hard_llcs] = "HARD_LLCS";
   model_cdef_names[sh_atomic_model::soft_tcb] = "SOFT_TCB";
   model_cdef_names[sh_atomic_model::soft_imask] = "SOFT_IMASK";
+  model_cdef_names[sh_atomic_model::hard_cas] = "HARD_CAS";
 
   sh_atomic_model ret;
   ret.type = sh_atomic_model::none;
@@ -747,6 +749,9 @@
   if (ret.type == sh_atomic_model::soft_imask && TARGET_USERMODE)
     err_ret ("cannot use atomic model %s in user mode", ret.name);
 
+  if (ret.type == sh_atomic_model::hard_cas && !TARGET_SHJ2)
+    err_ret ("atomic model %s is only available J2 targets", ret.name);
+
   return ret;
 
 #undef err_ret
@@ -803,6 +808,8 @@
     sh_cpu = PROCESSOR_SH2E;
   if (TARGET_SH2A)
     sh_cpu = PROCESSOR_SH2A;
+  if (TARGET_SHJ2)
+    sh_cpu = PROCESSOR_SHJ2;
   if (TARGET_SH3)
     sh_cpu = PROCESSOR_SH3;
   if (TARGET_SH3E)
diff -Nur gcc-7.3.0.orig/gcc/config/sh/sh.h gcc-7.3.0/gcc/config/sh/sh.h
--- gcc-7.3.0.orig/gcc/config/sh/sh.h	2017-01-01 13:07:43.000000000 +0100
+++ gcc-7.3.0/gcc/config/sh/sh.h	2018-06-03 02:20:50.000000000 +0200
@@ -83,6 +83,7 @@
 #define SUPPORT_SH4_SINGLE 1
 #define SUPPORT_SH2A 1
 #define SUPPORT_SH2A_SINGLE 1
+#define SUPPORT_SHJ2 1
 #endif
 
 #define TARGET_DIVIDE_CALL_DIV1 (sh_div_strategy == SH_DIV_CALL_DIV1)
@@ -115,6 +116,7 @@
 #define SELECT_SH4A_SINGLE_ONLY  (MASK_SH4A | SELECT_SH4_SINGLE_ONLY)
 #define SELECT_SH4A		 (MASK_SH4A | SELECT_SH4)
 #define SELECT_SH4A_SINGLE	 (MASK_SH4A | SELECT_SH4_SINGLE)
+#define SELECT_SHJ2		 (MASK_SHJ2 | SELECT_SH2)
 
 #if SUPPORT_SH1
 #define SUPPORT_SH2 1
@@ -122,6 +124,7 @@
 #if SUPPORT_SH2
 #define SUPPORT_SH3 1
 #define SUPPORT_SH2A_NOFPU 1
+#define SUPPORT_SHJ2 1
 #endif
 #if SUPPORT_SH3
 #define SUPPORT_SH4_NOFPU 1
@@ -154,7 +157,7 @@
 #define MASK_ARCH (MASK_SH1 | MASK_SH2 | MASK_SH3 | MASK_SH_E | MASK_SH4 \
 		   | MASK_HARD_SH2A | MASK_HARD_SH2A_DOUBLE | MASK_SH4A \
 		   | MASK_HARD_SH4 | MASK_FPU_SINGLE \
-		   | MASK_FPU_SINGLE_ONLY)
+		   | MASK_FPU_SINGLE_ONLY | MASK_SHJ2)
 
 /* This defaults us to big-endian.  */
 #ifndef TARGET_ENDIAN_DEFAULT
@@ -229,7 +232,8 @@
 %{m2a-single:--isa=sh2a} \
 %{m2a-single-only:--isa=sh2a} \
 %{m2a-nofpu:--isa=sh2a-nofpu} \
-%{m4al:-dsp}"
+%{m4al:-dsp} \
+%{mj2:-isa=j2}"
 
 #define ASM_SPEC SH_ASM_SPEC
 
@@ -345,6 +349,7 @@
     hard_llcs,
     soft_tcb,
     soft_imask,
+    hard_cas,
 
     num_models
   };
@@ -1568,7 +1573,7 @@
 
 /* Nonzero if the target supports dynamic shift instructions
    like shad and shld.  */
-#define TARGET_DYNSHIFT (TARGET_SH3 || TARGET_SH2A)
+#define TARGET_DYNSHIFT (TARGET_SH3 || TARGET_SH2A || TARGET_SHJ2)
 
 /* The cost of using the dynamic shift insns (shad, shld) are the same
    if they are available.  If they are not available a library function will
@@ -1833,6 +1838,7 @@
   PROCESSOR_SH2,
   PROCESSOR_SH2E,
   PROCESSOR_SH2A,
+  PROCESSOR_SHJ2,
   PROCESSOR_SH3,
   PROCESSOR_SH3E,
   PROCESSOR_SH4,
diff -Nur gcc-7.3.0.orig/gcc/config/sh/sh.opt gcc-7.3.0/gcc/config/sh/sh.opt
--- gcc-7.3.0.orig/gcc/config/sh/sh.opt	2017-01-01 13:07:43.000000000 +0100
+++ gcc-7.3.0/gcc/config/sh/sh.opt	2018-06-03 02:20:50.000000000 +0200
@@ -65,6 +65,10 @@
 Target RejectNegative Condition(SUPPORT_SH2E)
 Generate SH2e code.
 
+mj2
+Target RejectNegative Mask(SHJ2) Condition(SUPPORT_SHJ2)
+Generate J2 code.
+
 m3
 Target RejectNegative Mask(SH3) Condition(SUPPORT_SH3)
 Generate SH3 code.
diff -Nur gcc-7.3.0.orig/gcc/config/sh/sync.md gcc-7.3.0/gcc/config/sh/sync.md
--- gcc-7.3.0.orig/gcc/config/sh/sync.md	2017-01-01 13:07:43.000000000 +0100
+++ gcc-7.3.0/gcc/config/sh/sync.md	2018-06-03 02:20:50.000000000 +0200
@@ -240,6 +240,9 @@
       || (TARGET_SH4A && <MODE>mode == SImode && !TARGET_ATOMIC_STRICT))
     atomic_insn = gen_atomic_compare_and_swap<mode>_hard (old_val, mem,
 							  exp_val, new_val);
+  else if (TARGET_ATOMIC_HARD_CAS && <MODE>mode == SImode)
+    atomic_insn = gen_atomic_compare_and_swap<mode>_cas (old_val, mem,
+							 exp_val, new_val);
   else if (TARGET_ATOMIC_SOFT_GUSA)
     atomic_insn = gen_atomic_compare_and_swap<mode>_soft_gusa (old_val, mem,
 		      exp_val, new_val);
@@ -306,6 +309,57 @@
 }
   [(set_attr "length" "14")])
 
+(define_expand "atomic_compare_and_swapsi_cas"
+  [(set (match_operand:SI 0 "register_operand" "=r")
+	(unspec_volatile:SI
+	  [(match_operand:SI 1 "atomic_mem_operand_0" "=Sra")
+	   (match_operand:SI 2 "register_operand" "r")
+	   (match_operand:SI 3 "register_operand" "r")]
+	  UNSPECV_CMPXCHG_1))]
+  "TARGET_ATOMIC_HARD_CAS"
+{
+  rtx mem = gen_rtx_REG (SImode, 0);
+  emit_move_insn (mem, force_reg (SImode, XEXP (operands[1], 0)));
+  emit_insn (gen_shj2_cas (operands[0], mem, operands[2], operands[3]));
+  DONE;
+})
+
+(define_insn "shj2_cas"
+  [(set (match_operand:SI 0 "register_operand" "=&r")
+  (unspec_volatile:SI
+   [(match_operand:SI 1 "register_operand" "=r")
+   (match_operand:SI 2 "register_operand" "r")
+   (match_operand:SI 3 "register_operand" "0")]
+   UNSPECV_CMPXCHG_1))
+   (set (reg:SI T_REG)
+	(unspec_volatile:SI [(const_int 0)] UNSPECV_CMPXCHG_3))]
+  "TARGET_ATOMIC_HARD_CAS"
+  "cas.l	%2,%0,@%1"
+  [(set_attr "length" "2")]
+)
+
+(define_expand "atomic_compare_and_swapqi_cas"
+  [(set (match_operand:SI 0 "arith_reg_dest" "=&r")
+	(unspec_volatile:SI
+	  [(match_operand:SI 1 "atomic_mem_operand_0" "=Sra")
+	   (match_operand:SI 2 "arith_operand" "rI08")
+	   (match_operand:SI 3 "arith_operand" "rI08")]
+	  UNSPECV_CMPXCHG_1))]
+  "TARGET_ATOMIC_HARD_CAS"
+{FAIL;}
+)
+
+(define_expand "atomic_compare_and_swaphi_cas"
+  [(set (match_operand:SI 0 "arith_reg_dest" "=&r")
+	(unspec_volatile:SI
+	  [(match_operand:SI 1 "atomic_mem_operand_0" "=Sra")
+	   (match_operand:SI 2 "arith_operand" "rI08")
+	   (match_operand:SI 3 "arith_operand" "rI08")]
+	  UNSPECV_CMPXCHG_1))]
+  "TARGET_ATOMIC_HARD_CAS"
+{FAIL;}
+)
+
 ;; The QIHImode llcs patterns modify the address register of the memory
 ;; operand.  In order to express that, we have to open code the memory
 ;; operand.  Initially the insn is expanded like every other atomic insn
diff -Nur gcc-7.3.0.orig/gcc/config/sh/t-sh gcc-7.3.0/gcc/config/sh/t-sh
--- gcc-7.3.0.orig/gcc/config/sh/t-sh	2017-01-01 13:07:43.000000000 +0100
+++ gcc-7.3.0/gcc/config/sh/t-sh	2018-06-03 02:20:50.000000000 +0200
@@ -50,7 +50,8 @@
              m2e,m3e,m4-single-only,m4-100-single-only,m4-200-single-only,m4-300-single-only,m4a-single-only \
              m2a-single,m2a-single-only \
              m4-single,m4-100-single,m4-200-single,m4-300-single,m4a-single \
-             m4,m4-100,m4-200,m4-300,m4a; do \
+             m4,m4-100,m4-200,m4-300,m4a \
+             mj2; do \
     subst= ; \
     for lib in `echo $$abi|tr , ' '` ; do \
       if test "`echo $$multilibs|sed s/$$lib//`" != "$$multilibs"; then \
@@ -63,9 +64,9 @@
 
 # SH1 and SH2A support big endian only.
 ifeq ($(DEFAULT_ENDIAN),ml)
-MULTILIB_EXCEPTIONS = m1 ml/m1 m2a* ml/m2a* $(TM_MULTILIB_EXCEPTIONS_CONFIG)
+MULTILIB_EXCEPTIONS = m1 ml/m1 m2a* ml/m2a* ml/mj2 $(TM_MULTILIB_EXCEPTIONS_CONFIG)
 else
-MULTILIB_EXCEPTIONS = ml/m1 ml/m2a* $(TM_MULTILIB_EXCEPTIONS_CONFIG)
+MULTILIB_EXCEPTIONS = ml/m1 ml/m2a* ml/mj2 $(TM_MULTILIB_EXCEPTIONS_CONFIG)
 endif
 
 MULTILIB_OSDIRNAMES = \
@@ -87,7 +88,8 @@
 	m4a-single-only=!m4a-single-only $(OTHER_ENDIAN)/m4a-single-only=!$(OTHER_ENDIAN)/m4a-single-only \
 	m4a-single=!m4a-single $(OTHER_ENDIAN)/m4a-single=!$(OTHER_ENDIAN)/m4a-single \
 	m4a=!m4a $(OTHER_ENDIAN)/m4a=!$(OTHER_ENDIAN)/m4a \
-	m4al=!m4al $(OTHER_ENDIAN)/m4al=!$(OTHER_ENDIAN)/m4al
+	m4al=!m4al $(OTHER_ENDIAN)/m4al=!$(OTHER_ENDIAN)/m4al \
+	mj2=!j2
 
 $(out_object_file): gt-sh.h
 gt-sh.h : s-gtype ; @true
diff -Nur gcc-7.3.0.orig/gcc/config.gcc gcc-7.3.0/gcc/config.gcc
--- gcc-7.3.0.orig/gcc/config.gcc	2018-01-08 14:39:11.000000000 +0100
+++ gcc-7.3.0/gcc/config.gcc	2018-06-03 02:20:50.000000000 +0200
@@ -474,7 +474,7 @@
 	extra_headers="s390intrin.h htmintrin.h htmxlintrin.h vecintrin.h"
 	;;
 # Note the 'l'; we need to be able to match e.g. "shle" or "shl".
-sh[123456789lbe]*-*-* | sh-*-*)
+sh[123456789lbej]*-*-* | sh-*-*)
 	cpu_type=sh
 	extra_options="${extra_options} fused-madd.opt"
 	extra_objs="${extra_objs} sh_treg_combine.o sh-mem.o sh_optimize_sett_clrt.o"
@@ -2664,18 +2664,18 @@
 	extra_options="${extra_options} s390/tpf.opt"
 	tmake_file="${tmake_file} s390/t-s390"
 	;;
-sh-*-elf* | sh[12346l]*-*-elf* | \
-  sh-*-linux* | sh[2346lbe]*-*-linux* | \
+sh-*-elf* | sh[12346lj]*-*-elf* | \
+  sh-*-linux* | sh[2346lbej]*-*-linux* | \
   sh-*-netbsdelf* | shl*-*-netbsdelf*)
 	tmake_file="${tmake_file} sh/t-sh sh/t-elf"
 	if test x${with_endian} = x; then
 		case ${target} in
-		sh[1234]*be-*-* | sh[1234]*eb-*-*) with_endian=big ;;
+		sh[j1234]*be-*-* | sh[n1234]*eb-*-*) with_endian=big ;;
 		shbe-*-* | sheb-*-*)		   with_endian=big,little ;;
 		sh[1234]l* | sh[34]*-*-linux*)	   with_endian=little ;;
 		shl* | sh*-*-linux* | \
 		  sh-superh-elf)		   with_endian=little,big ;;
-		sh[1234]*-*-*)			   with_endian=big ;;
+		sh[j1234]*-*-*)			   with_endian=big ;;
 		*)				   with_endian=big,little ;;
 		esac
 	fi
@@ -2742,6 +2742,7 @@
 	sh2a_nofpu*)		sh_cpu_target=sh2a-nofpu ;;
 	sh2a*)			sh_cpu_target=sh2a ;;
 	sh2e*)			sh_cpu_target=sh2e ;;
+	shj2*)			sh_cpu_target=shj2;;
 	sh2*)			sh_cpu_target=sh2 ;;
 	*)			sh_cpu_target=sh1 ;;
 	esac
@@ -2763,7 +2764,7 @@
 	  sh2a-single-only | sh2a-single | sh2a-nofpu | sh2a | \
 	  sh4a-single-only | sh4a-single | sh4a-nofpu | sh4a | sh4al | \
 	  sh4-single-only | sh4-single | sh4-nofpu | sh4 | sh4-300 | \
-	  sh3e | sh3 | sh2e | sh2 | sh1) ;;
+	  sh3e | sh3 | sh2e | sh2 | sh1 | shj2) ;;
 	"")	sh_cpu_default=${sh_cpu_target} ;;
 	*)	echo "with_cpu=$with_cpu not supported"; exit 1 ;;
 	esac
@@ -2772,9 +2773,9 @@
 		case ${target} in
 		sh[1234]*)	sh_multilibs=${sh_cpu_target} ;;
 		sh-superh-*)	sh_multilibs=m4,m4-single,m4-single-only,m4-nofpu ;;
-		sh*-*-linux*)	sh_multilibs=m1,m2,m2a,m3e,m4 ;;
+		sh*-*-linux*)	sh_multilibs=m1,m2,m2a,m3e,m4,mj2 ;;
 		sh*-*-netbsd*)	sh_multilibs=m3,m3e,m4 ;;
-		*) sh_multilibs=m1,m2,m2e,m4,m4-single,m4-single-only,m2a,m2a-single ;;
+		*) sh_multilibs=m1,m2,m2e,m4,m4-single,m4-single-only,m2a,m2a-single,mj2 ;;
 		esac
 		if test x$with_fp = xno; then
 			sh_multilibs="`echo $sh_multilibs|sed -e s/m4/sh4-nofpu/ -e s/,m4-[^,]*//g -e s/,m[23]e// -e s/m2a,m2a-single/m2a-nofpu/ -e s/m5-..m....,//g`"
@@ -2789,7 +2790,8 @@
 		m1 | m2 | m2e | m3 | m3e | \
 		m4 | m4-single | m4-single-only | m4-nofpu | m4-300 |\
 		m4a | m4a-single | m4a-single-only | m4a-nofpu | m4al | \
-		m2a | m2a-single | m2a-single-only | m2a-nofpu)
+		m2a | m2a-single | m2a-single-only | m2a-nofpu | \
+		mj2)
 			# TM_MULTILIB_CONFIG is used by t-sh for the non-endian multilib definition
 			# It is passed to MULTIILIB_OPTIONS verbatim.
 			TM_MULTILIB_CONFIG="${TM_MULTILIB_CONFIG}/${sh_multilib}"
@@ -2806,7 +2808,7 @@
 	done
 	TM_MULTILIB_CONFIG=`echo $TM_MULTILIB_CONFIG | sed 's:^/::'`
 	if test x${enable_incomplete_targets} = xyes ; then
-		tm_defines="$tm_defines SUPPORT_SH1=1 SUPPORT_SH2E=1 SUPPORT_SH4=1 SUPPORT_SH4_SINGLE=1 SUPPORT_SH2A=1 SUPPORT_SH2A_SINGLE=1"
+		tm_defines="$tm_defines SUPPORT_SH1=1 SUPPORT_SH2E=1 SUPPORT_SH4=1 SUPPORT_SH4_SINGLE=1 SUPPORT_SH2A=1 SUPPORT_SH2A_SINGLE=1 SUPPORT_SHJ2=1"
 	fi
 	tm_file="$tm_file ./sysroot-suffix.h"
 	tmake_file="$tmake_file t-sysroot-suffix"
@@ -4380,6 +4382,8 @@
 			;;
 		m4a | m4a-single | m4a-single-only | m4a-nofpu | m4al)
 		        ;;
+		mj2)
+			;;
 		*)
 			echo "Unknown CPU used in --with-cpu=$with_cpu, known values:"  1>&2
 			echo "m1 m2 m2e m3 m3e m4 m4-single m4-single-only m4-nofpu" 1>&2
@@ -4589,7 +4593,7 @@
 		tmake_file="rs6000/t-rs6000 ${tmake_file}"
 		;;
 
-	sh[123456ble]*-*-* | sh-*-*)
+	sh[123456blej]*-*-* | sh-*-*)
 		c_target_objs="${c_target_objs} sh-c.o"
 		cxx_target_objs="${cxx_target_objs} sh-c.o"
 		;;