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 <[email protected]>
[[email protected]: use CONFIG_64BIT for guarding this new flag]
Signed-off-by: Catalin Marinas <[email protected]>
Cc: Andrew Morton <[email protected]>
diff --git a/include/linux/kernel-page-flags.h b/include/linux/kernel-page-flags.h
index abd20ef9..eee1877 100644
--- a/include/linux/kernel-page-flags.h
+++ b/include/linux/kernel-page-flags.h
@@ -17,5 +17,6 @@
#define KPF_ARCH 38
#define KPF_UNCACHED 39
#define KPF_SOFTDIRTY 40
+#define KPF_ARCH_2 41
#endif /* LINUX_KERNEL_PAGE_FLAGS_H */
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 6be1aa5..276140c 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -136,6 +136,9 @@ enum pageflags {
PG_young,
PG_idle,
#endif
+#ifdef CONFIG_64BIT
+ PG_arch_2,
+#endif
__NR_PAGEFLAGS,
/* Filesystems */
