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ftrace: dont write protect kernel text

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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: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Steven Rostedt 2008-05-12 21:20:56 +02:00 committed by Thomas Gleixner
parent a56be3fe2f
commit 8f0f996e80
2 changed files with 12 additions and 2 deletions
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4
arch/x86/mm/init_32.c
View File

@ -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);

10
arch/x86/mm/init_64.c
View File

@ -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();