s390/nospec: align and size extern thunks

Kernel has full control over how extern thunks generated by
arch/s390/lib/expoline.S look like. Align them to 16 bytes like other
symbols. Also set proper symbols size which is important for tooling.
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/nospec-insn.h

@@ -20,6 +20,7 @@ _LC_BR_R1 = __LC_BR_R1
 	.macro __THUNK_PROLOG_NAME name
 #ifdef CONFIG_EXPOLINE_EXTERN
 	.pushsection .text,"ax",@progbits
+	.align 16,0x07
 #else
 	.pushsection .text.\name,"axG",@progbits,\name,comdat
 #endif
@@ -30,8 +31,11 @@ _LC_BR_R1 = __LC_BR_R1
 	CFI_STARTPROC
 	.endm
 
-	.macro __THUNK_EPILOG
+	.macro __THUNK_EPILOG_NAME name
 	CFI_ENDPROC
+#ifdef CONFIG_EXPOLINE_EXTERN
+	.size \name, .-\name
+#endif
 	.popsection
 	.endm
 
@@ -40,6 +44,10 @@ _LC_BR_R1 = __LC_BR_R1
 	__THUNK_PROLOG_NAME __s390_indirect_jump_r\r1
 	.endm
 
+	.macro __THUNK_EPILOG_BR r1,r2
+	__THUNK_EPILOG_NAME __s390_indirect_jump_r\r1
+	.endm
+
 	.macro __THUNK_BR r1,r2
 	jg	__s390_indirect_jump_r\r1
 	.endm
@@ -52,6 +60,10 @@ _LC_BR_R1 = __LC_BR_R1
 	__THUNK_PROLOG_NAME __s390_indirect_jump_r\r2\()use_r\r1
 	.endm
 
+	.macro __THUNK_EPILOG_BR r1,r2
+	__THUNK_EPILOG_NAME __s390_indirect_jump_r\r2\()use_r\r1
+	.endm
+
 	.macro __THUNK_BR r1,r2
 	jg	__s390_indirect_jump_r\r2\()use_r\r1
 	.endm
@@ -128,7 +140,7 @@ _LC_BR_R1 = __LC_BR_R1
 #endif
 	__DECODE_RR __THUNK_PROLOG_BR,\reg,\ruse
 	__THUNK_EX_BR \reg,\ruse
-	__THUNK_EPILOG
+	__DECODE_RR __THUNK_EPILOG_BR,\reg,\ruse
 	.endm
 
 	.macro BR_EX reg,ruse=%r1