diff options
| -rw-r--r-- | include/linux/mm.h | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 64a71bf20536..8ba434287387 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1461,16 +1461,28 @@ static inline bool cpupid_match_pid(struct task_struct *task, int cpupid) #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) +/* + * KASAN per-page tags are stored xor'ed with 0xff. This allows to avoid + * setting tags for all pages to native kernel tag value 0xff, as the default + * value 0x00 maps to 0xff. + */ + static inline u8 page_kasan_tag(const struct page *page) { - if (kasan_enabled()) - return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; - return 0xff; + u8 tag = 0xff; + + if (kasan_enabled()) { + tag = (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; + tag ^= 0xff; + } + + return tag; } static inline void page_kasan_tag_set(struct page *page, u8 tag) { if (kasan_enabled()) { + tag ^= 0xff; page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT); page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT; } |