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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2017-07-10 15:50:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-10 16:32:33 -0700
commit458f7920f9b1e6c313944d498c440f8599b8a136 (patch)
treecf0b95059db4f4eda086e8c82b5b12646c2444d3 /mm/kasan
parentcf8e0fedf0784ef4bc1889380b09eda295e3d109 (diff)
downloadlwn-458f7920f9b1e6c313944d498c440f8599b8a136.tar.gz
lwn-458f7920f9b1e6c313944d498c440f8599b8a136.zip
mm/kasan/kasan_init.c: use kasan_zero_pud for p4d table
There is missing optimization in zero_p4d_populate() that can save some memory when mapping zero shadow. Implement it like as others. Link: http://lkml.kernel.org/r/1494829255-23946-1-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan')
-rw-r--r--mm/kasan/kasan_init.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c
index b96a5f773d88..554e4c0f23a2 100644
--- a/mm/kasan/kasan_init.c
+++ b/mm/kasan/kasan_init.c
@@ -118,6 +118,18 @@ static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr,
do {
next = p4d_addr_end(addr, end);
+ if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
+ pud_t *pud;
+ pmd_t *pmd;
+
+ p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud));
+ pud = pud_offset(p4d, addr);
+ pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
+ pmd = pmd_offset(pud, addr);
+ pmd_populate_kernel(&init_mm, pmd,
+ lm_alias(kasan_zero_pte));
+ continue;
+ }
if (p4d_none(*p4d)) {
p4d_populate(&init_mm, p4d,