x86: enhance DEBUG_RODATA support for hotplug and kprobes

Standardize DEBUG_RODATA, removing special cases for hotplug and kprobes.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: pageexec@freemail.hu
Cc: akpm@linux-foundation.org
CC: Andi Kleen <andi@firstfloor.org>
CC: pageexec@freemail.hu
CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/mm/init_32.c

@@ -723,12 +723,6 @@ void mark_rodata_ro(void)
 	unsigned long start = PFN_ALIGN(_text);
 	unsigned long size = PFN_ALIGN(_etext) - start;
 
-#ifndef CONFIG_KPROBES
-#ifdef CONFIG_HOTPLUG_CPU
-	/* It must still be possible to apply SMP alternatives. */
-	if (num_possible_cpus() <= 1)
-#endif
-	{
 	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 	printk(KERN_INFO "Write protecting the kernel text: %luk\n",
 		size >> 10);
@@ -740,8 +734,6 @@ void mark_rodata_ro(void)
 
 	printk(KERN_INFO "Testing CPA: write protecting again\n");
 	set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
-#endif
-	}
 #endif
 	start += size;
 	size = (unsigned long)__end_rodata - start;

arch/x86/mm/init_64.c

@@ -635,24 +635,7 @@ EXPORT_SYMBOL_GPL(rodata_test_data);
 
 void mark_rodata_ro(void)
 {
-	unsigned long start = (unsigned long)_stext, end;
-
-#ifdef CONFIG_HOTPLUG_CPU
-	/* It must still be possible to apply SMP alternatives. */
-	if (num_possible_cpus() > 1)
-		start = (unsigned long)_etext;
-#endif
-
-#ifdef CONFIG_KPROBES
-	start = (unsigned long)__start_rodata;
-#endif
-
-	end = (unsigned long)__end_rodata;
-	start = (start + PAGE_SIZE - 1) & PAGE_MASK;
-	end &= PAGE_MASK;
-	if (end <= start)
-		return;
-
+	unsigned long start = PFN_ALIGN(_stext), end = PFN_ALIGN(__end_rodata);
 
 	printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
 	       (end - start) >> 10);
@@ -675,6 +658,7 @@ void mark_rodata_ro(void)
 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
 #endif
 }
+
 #endif
 
 #ifdef CONFIG_BLK_DEV_INITRD