s390/ftrace: do not assume module_alloc() returns executable memory

The ftrace code assumes at two places that module_alloc() returns
executable memory. While this is currently true, this will be changed
with a subsequent patch to follow other architectures which implement
ARCH_HAS_STRICT_MODULE_RWX.
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/kernel/ftrace.c

@@ -226,7 +226,7 @@ static int __init ftrace_plt_init(void)
 
 	start = ftrace_shared_hotpatch_trampoline(&end);
 	memcpy(ftrace_plt, start, end - start);
-	set_memory_ro((unsigned long)ftrace_plt, 1);
+	set_memory_rox((unsigned long)ftrace_plt, 1);
 	return 0;
 }
 device_initcall(ftrace_plt_init);

arch/s390/kernel/module.c

@@ -509,7 +509,7 @@ static int module_alloc_ftrace_hotpatch_trampolines(struct module *me,
 	start = module_alloc(numpages * PAGE_SIZE);
 	if (!start)
 		return -ENOMEM;
-	set_memory_ro((unsigned long)start, numpages);
+	set_memory_rox((unsigned long)start, numpages);
 	end = start + size;
 
 	me->arch.trampolines_start = (struct ftrace_hotpatch_trampoline *)start;