s390: Move RO_DATA into "text" PT_LOAD Program Header

In preparation for moving NOTES into RO_DATA, move RO_DATA back into the
"text" PT_LOAD Program Header, as done with other architectures. The
"data" PT_LOAD now starts with the writable data section.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Will Deacon <will@kernel.org>
Cc: x86-ml <x86@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20191029211351.13243-7-keescook@chromium.org

arch/s390/kernel/vmlinux.lds.S

@@ -52,7 +52,7 @@ SECTIONS
 
 	NOTES :text :note
 
-	.dummy : { *(.dummy) } :data
+	.dummy : { *(.dummy) } :text
 
 	RO_DATA_SECTION(PAGE_SIZE)
 
@@ -64,7 +64,7 @@ SECTIONS
 	.data..ro_after_init : {
 		 *(.data..ro_after_init)
 		JUMP_TABLE_DATA
-	}
+	} :data
 	EXCEPTION_TABLE(16)
 	. = ALIGN(PAGE_SIZE);
 	__end_ro_after_init = .;