mm: Add PG_arch_2 page flag
For arm64 MTE support it is necessary to be able to mark pages that
contain user space visible tags that will need to be saved/restored e.g.
when swapped out.
To support this add a new arch specific flag (PG_arch_2). This flag is
only available on 64-bit architectures due to the limited number of
spare page flags on the 32-bit ones.
Signed-off-by: Steven Price <steven.price@arm.com>
[catalin.marinas@arm.com: use CONFIG_64BIT for guarding this new flag]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
diff --git a/fs/proc/page.c b/fs/proc/page.c
index f909243..9f1077d 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -217,6 +217,9 @@ u64 stable_page_flags(struct page *page)
u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
+#ifdef CONFIG_64BIT
+ u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
+#endif
return u;
};