HWPOISON: add page flags filter

When specified, only poison pages if ((page_flags & mask) == value).

-       corrupt-filter-flags-mask
-       corrupt-filter-flags-value

This allows stress testing of many kinds of pages.

Strictly speaking, the buddy pages requires taking zone lock, to avoid
setting PG_hwpoison on a "was buddy but now allocated to someone" page.
However we can just do nothing because we set PG_locked in the beginning,
this prevents the page allocator from allocating it to someone. (It will
BUG() on the unexpected PG_locked, which is fine for hwpoison testing.)

[AK: Add select PROC_PAGE_MONITOR to satisfy dependency]

CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/mm/internal.h b/mm/internal.h
index 04bbce8b8ba6..b2027c73119b 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -255,3 +255,5 @@ extern int hwpoison_filter(struct page *p);
 
 extern u32 hwpoison_filter_dev_major;
 extern u32 hwpoison_filter_dev_minor;
+extern u64 hwpoison_filter_flags_mask;
+extern u64 hwpoison_filter_flags_value;