[PATCH v2 3/7] mm: Add PG_arch_3 page flag

Peter Collingbourne
2022-07-22T01:51:07Z

As with PG_arch_2, this flag is only allowed on 64-bit architectures due
to the shortage of bits available. It will be used by the arm64 MTE code
in subsequent patches.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Steven Price <steven.price@arm.com>
[catalin.marinas@arm.com: added flag preserving in __split_huge_page_tail()]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
fs/proc/page.c | 1 +
include/linux/page-flags.h | 1 +
include/trace/events/mmflags.h | 7 ++++---
mm/huge_memory.c | 1 +
4 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/proc/page.c b/fs/proc/page.c
index a2873a617ae8..438b8aa7249d 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -220,6 +220,7 @@ u64 stable_page_flags(struct page *page)
u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
#ifdef CONFIG_64BIT
u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_2);
+ u |= kpf_copy_bit(k, KPF_ARCH_2, PG_arch_3);
#endif

return u;
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 465ff35a8c00..ad01a3abf6c8 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -134,6 +134,7 @@ enum pageflags {
#endif
#ifdef CONFIG_64BIT
PG_arch_2,
+ PG_arch_3,
#endif
#ifdef CONFIG_KASAN_HW_TAGS
PG_skip_kasan_poison,
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 11524cda4a95..704380179986 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -91,9 +91,9 @@
#endif

#ifdef CONFIG_64BIT
-#define IF_HAVE_PG_ARCH_2(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_ARCH_2_3(flag,string) ,{1UL << flag, string}
#else
-#define IF_HAVE_PG_ARCH_2(flag,string)
+#define IF_HAVE_PG_ARCH_2_3(flag,string)
#endif

#ifdef CONFIG_KASAN_HW_TAGS
@@ -129,7 +129,8 @@ IF_HAVE_PG_UNCACHED(PG_uncached, "uncached" ) \
IF_HAVE_PG_HWPOISON(PG_hwpoison, "hwpoison" ) \
IF_HAVE_PG_IDLE(PG_young, "young" ) \
IF_HAVE_PG_IDLE(PG_idle, "idle" ) \
-IF_HAVE_PG_ARCH_2(PG_arch_2, "arch_2" ) \
+IF_HAVE_PG_ARCH_2_3(PG_arch_2, "arch_2" ) \
+IF_HAVE_PG_ARCH_2_3(PG_arch_3, "arch_3" ) \
IF_HAVE_PG_SKIP_KASAN_POISON(PG_skip_kasan_poison, "skip_kasan_poison")

#define show_page_flags(flags) \
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8320874901f1..d6e8789e9ebb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2399,6 +2399,7 @@ static void __split_huge_page_tail(struct page *head, int tail,
(1L << PG_unevictable) |
#ifdef CONFIG_64BIT
(1L << PG_arch_2) |
+ (1L << PG_arch_3) |
#endif
(1L << PG_dirty)));

--
2.37.1.359.gd136c6c3e2-goog