[patch 2/2] x86 - Enhance DEBUG_RODATA support for hotplug and kprobes

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

[-- Attachment #1: x86-enhance-debug-rodata-support-for-hotplug-and-kprobes.patch --]
[-- Type: text/plain, Size: 3211 bytes --]

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: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: H. Peter Anvin <hpa@zytor.com>
CC: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/mm/init_32.c |   24 ++++++++----------------
 arch/x86/mm/init_64.c |   20 +++-----------------
 2 files changed, 11 insertions(+), 33 deletions(-)

Index: linux-2.6-lttng/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86/mm/init_32.c	2008-02-02 15:33:24.000000000 -0500
+++ linux-2.6-lttng/arch/x86/mm/init_32.c	2008-02-02 15:33:34.000000000 -0500
@@ -740,25 +740,17 @@ 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);
+	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
+	printk(KERN_INFO "Write protecting the kernel text: %luk\n",
+		size >> 10);
 
 #ifdef CONFIG_CPA_DEBUG
-		printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
-			start, start+size);
-		set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
+	printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
+		start, start+size);
+	set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
 
-		printk(KERN_INFO "Testing CPA: write protecting again\n");
-		set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
-#endif
-	}
+	printk(KERN_INFO "Testing CPA: write protecting again\n");
+	set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
 #endif
 	start += size;
 	size = (unsigned long)__end_rodata - start;
Index: linux-2.6-lttng/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86/mm/init_64.c	2008-02-02 15:33:39.000000000 -0500
+++ linux-2.6-lttng/arch/x86/mm/init_64.c	2008-02-02 15:33:59.000000000 -0500
@@ -618,23 +618,8 @@ 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);
 
 	set_memory_ro(start, (end - start) >> PAGE_SHIFT);
 
@@ -651,6 +636,7 @@ void mark_rodata_ro(void)
 	set_memory_ro(start, (end-start) >> PAGE_SHIFT);
 #endif
 }
+
 #endif
 
 #ifdef CONFIG_BLK_DEV_INITRD

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68