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authorSteven Rostedt <rostedt@goodmis.org>2008-05-12 21:20:56 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 21:16:22 +0200
commit8f0f996e80b980fba07d11961d96a5fefb60976a (patch)
treee3dadf2ff9d8d6e3253b072e947204706e4475c0 /arch/x86
parenta56be3fe2f65f9f776e727bfd382e35db75911d6 (diff)
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: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/mm/init_32.c4
-rw-r--r--arch/x86/mm/init_64.c10
2 files changed, 12 insertions, 2 deletions
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index ec30d10154b..f96eca21ad8 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -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);
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 32ba13b0f81..41824e776b6 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -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();