Commit 8f0f996e authored by Steven Rostedt's avatar Steven Rostedt Committed by Thomas Gleixner
Browse files

ftrace: dont write protect kernel text 



Dynamic ftrace cant work when the kernel has its text write protected.
This patch keeps the kernel from being write protected when
dynamic ftrace is in place.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent a56be3fe

arch/x86/mm/init_32.c

+4 −0
Original line number Diff line number Diff line
@@ -710,6 +710,8 @@ void mark_rodata_ro(void) 
	unsigned long start = PFN_ALIGN(_text);

	unsigned long size = PFN_ALIGN(_etext) - start;



#ifndef CONFIG_DYNAMIC_FTRACE

	/* Dynamic tracing modifies the kernel text section */

	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);

	printk(KERN_INFO "Write protecting the kernel text: %luk\n",

		size >> 10);
@@ -722,6 +724,8 @@ 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 /* CONFIG_DYNAMIC_FTRACE */



	start += size;

	size = (unsigned long)__end_rodata - start;

	set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);

arch/x86/mm/init_64.c

+8 −2
Original line number Diff line number Diff line
@@ -766,6 +766,13 @@ EXPORT_SYMBOL_GPL(rodata_test_data); 
void mark_rodata_ro(void)

{

	unsigned long start = PFN_ALIGN(_stext), end = PFN_ALIGN(__end_rodata);

	unsigned long rodata_start =

		((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;



#ifdef CONFIG_DYNAMIC_FTRACE

	/* Dynamic tracing modifies the kernel text section */

	start = rodata_start;

#endif



	printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",

	       (end - start) >> 10);
@@ -775,8 +782,7 @@ void mark_rodata_ro(void) 
	 * The rodata section (but not the kernel text!) should also be

	 * not-executable.

	 */

	start = ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;

	set_memory_nx(start, (end - start) >> PAGE_SHIFT);

	set_memory_nx(rodata_start, (end - start) >> PAGE_SHIFT);



	rodata_test();