lkml.org 
[lkml]   [2022]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 2/3] mm: introduce clear_highpage_kasan_tagged
Date
From: Andrey Konovalov <andreyknvl@google.com>

Add a clear_highpage_kasan_tagged() helper that does clear_highpage()
on a page potentially tagged by KASAN.

This helper is used by the following patch.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

---

Changes v1->v2:
- Renamed clear_highpage_tagged() to clear_highpage_kasan_tagged().
- Removed extra empty line in clear_highpage_kasan_tagged().
---
include/linux/highmem.h | 10 ++++++++++
mm/page_alloc.c | 8 ++------
2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 3af34de54330..70b496bbd2d9 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -243,6 +243,16 @@ static inline void clear_highpage(struct page *page)
kunmap_local(kaddr);
}

+static inline void clear_highpage_kasan_tagged(struct page *page)
+{
+ u8 tag;
+
+ tag = page_kasan_tag(page);
+ page_kasan_tag_reset(page);
+ clear_highpage(page);
+ page_kasan_tag_set(page, tag);
+}
+
#ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE

static inline void tag_clear_highpage(struct page *page)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 66ef8c310dce..76a02255f57c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1302,12 +1302,8 @@ static void kernel_init_pages(struct page *page, int numpages)

/* s390's use of memset() could override KASAN redzones. */
kasan_disable_current();
- for (i = 0; i < numpages; i++) {
- u8 tag = page_kasan_tag(page + i);
- page_kasan_tag_reset(page + i);
- clear_highpage(page + i);
- page_kasan_tag_set(page + i, tag);
- }
+ for (i = 0; i < numpages; i++)
+ clear_highpage_kasan_tagged(page + i);
kasan_enable_current();
}

--
2.25.1
\
 
 \ /
  Last update: 2022-06-09 20:20    [W:0.525 / U:0.244 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site