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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-26 12:07:21 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-26 12:07:21 -0700
commit602033ed5907a59ce86f709082a35be047743a86 (patch)
tree35c9f4b3d09dd02a9088e8932f963498d5c33d98 /arch/i386/mm
parent07d4e9af109221ab731c5aaf832e89776c64b013 (diff)
Revert most of "x86: Fix alternatives and kprobes to remap write-protected kernel text"
This reverts most of commit 19d36ccdc34f5ed444f8a6af0cbfdb6790eb1177. The way to DEBUG_RODATA interactions with KPROBES and CPU hotplug is to just not mark the text as being write-protected in the first place. Both of those facilities depend on rewriting instructions. Having "helpful" debug facilities that just cause more problem is not being helpful. It just adds complexity and bugs. Not worth it. Reported-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Andi Kleen <ak@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386/mm')
-rw-r--r--arch/i386/mm/init.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index 1b1a1e66d09..4c4809f13cb 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -800,9 +800,17 @@ void mark_rodata_ro(void)
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
- change_page_attr(virt_to_page(start),
- size >> PAGE_SHIFT, PAGE_KERNEL_RX);
- printk("Write protecting the kernel text: %luk\n", size >> 10);
+#ifndef CONFIG_KPROBES
+#ifdef CONFIG_HOTPLUG_CPU
+ /* It must still be possible to apply SMP alternatives. */
+ if (num_possible_cpus() <= 1)
+#endif
+ {
+ change_page_attr(virt_to_page(start),
+ size >> PAGE_SHIFT, PAGE_KERNEL_RX);
+ printk("Write protecting the kernel text: %luk\n", size >> 10);
+ }
+#endif
start += size;
size = (unsigned long)__end_rodata - start;
change_page_attr(virt_to_page(start),