mm: Add PG_arch_3 page flag

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>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221104011041.290951-5-pcc@google.com

diff --git a/fs/proc/page.c b/fs/proc/page.c
index 882525c..6249c34 100644 (file)
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -221,6 +221,7 @@ u64 stable_page_flags(struct page *page)
        u |= kpf_copy_bit(k, KPF_ARCH,          PG_arch_1);
 #ifdef CONFIG_ARCH_USES_PG_ARCH_X
        u |= kpf_copy_bit(k, KPF_ARCH_2,        PG_arch_2);
+       u |= kpf_copy_bit(k, KPF_ARCH_3,        PG_arch_3);
 #endif
 
        return u;

diff --git a/include/linux/kernel-page-flags.h b/include/linux/kernel-page-flags.h
index eee1877..859f4b0 100644 (file)
--- a/include/linux/kernel-page-flags.h
+++ b/include/linux/kernel-page-flags.h
@@ -18,5 +18,6 @@
 #define KPF_UNCACHED           39
 #define KPF_SOFTDIRTY          40
 #define KPF_ARCH_2             41
+#define KPF_ARCH_3             42
 
 #endif /* LINUX_KERNEL_PAGE_FLAGS_H */

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 5dc7977..c50ce28 100644 (file)
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -134,6 +134,7 @@ enum pageflags {
 #endif
 #ifdef CONFIG_ARCH_USES_PG_ARCH_X
        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 d9f6d35..412b5a4 100644 (file)
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -131,6 +131,7 @@ 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_X(PG_arch_2,           "arch_2"        )               \
+IF_HAVE_PG_ARCH_X(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 76e7b97..dfe72ea 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2446,6 +2446,7 @@ static void __split_huge_page_tail(struct page *head, int tail,
                         (1L << PG_unevictable) |
 #ifdef CONFIG_ARCH_USES_PG_ARCH_X
                         (1L << PG_arch_2) |
+                        (1L << PG_arch_3) |
 #endif
                         (1L << PG_dirty) |
                         LRU_GEN_MASK | LRU_REFS_MASK));