[PATCH RFC v3 09/36] kmsan: add KMSAN bits to struct page and struct task_struct

[glider@google.com]

Each struct page now contains pointers to two struct pages holding KMSAN
metadata (shadow and origins) for the original struct page.

Each task_struct contains a struct kmsan_task_state used to track the
metadata of function parameters and return values for that task.

Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-mm@kvack.org
---

Change-Id: Ie329527e558dd60307fb88b2da151f7f4db951ac
---
 include/linux/mm_types.h | 9 +++++++++
 include/linux/sched.h    | 5 +++++
 2 files changed, 14 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 2222fa795284..c87c5416a802 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -216,6 +216,15 @@ struct page {
 					   not kmapped, ie. highmem) */
 #endif /* WANT_PAGE_VIRTUAL */
 
+#ifdef CONFIG_KMSAN
+	/*
+	 * Bits in struct page are scarce, so the LSB in *shadow is used to
+	 * indicate whether the page should be ignored by KMSAN or not.
+	 */
+	struct page *shadow;
+	struct page *origin;
+#endif
+
 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
 	int _last_cpupid;
 #endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 72b20f33c56e..ba705f66f78c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -15,6 +15,7 @@
 #include <linux/sem.h>
 #include <linux/shm.h>
 #include <linux/kcov.h>
+#include <linux/kmsan.h>
 #include <linux/mutex.h>
 #include <linux/plist.h>
 #include <linux/hrtimer.h>
@@ -1173,6 +1174,10 @@ struct task_struct {
 	unsigned int			kasan_depth;
 #endif
 
+#ifdef CONFIG_KMSAN
+	struct kmsan_task_state		kmsan;
+#endif
+
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	/* Index of current stored address in ret_stack: */
 	int				curr_ret_stack;
-- 
2.24.0.432.g9d3f5f5b63-goog