diff mbox series

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

Message ID 20220722015034.809663-4-pcc@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: permit MAP_SHARED mappings with MTE enabled | expand

Commit Message

Peter Collingbourne July 22, 2022, 1:50 a.m. UTC
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(-)

Comments

Marc Zyngier July 22, 2022, 2:16 p.m. UTC | #1
On Fri, 22 Jul 2022 02:50:29 +0100,
Peter Collingbourne <pcc@google.com> wrote:
> 
> 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);

Are PG_arch_2 and PG_arch_3 supposed to share the same user bit in
/proc/kpageflags? This seems odd.

	M.
Peter Collingbourne July 22, 2022, 5:04 p.m. UTC | #2
On Fri, Jul 22, 2022 at 03:16:34PM +0100, Marc Zyngier wrote:
> On Fri, 22 Jul 2022 02:50:29 +0100,
> Peter Collingbourne <pcc@google.com> wrote:
> > 
> > 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);
> 
> Are PG_arch_2 and PG_arch_3 supposed to share the same user bit in
> /proc/kpageflags? This seems odd.

No, that was an oversight, thanks for the catch. I will fix it up like
so in v3.

Peter

diff --git a/fs/proc/page.c b/fs/proc/page.c
index 438b8aa7249d..0129aa3cfb7a 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -220,7 +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);
+	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 eee1877a354e..859f4b0c1b2b 100644
--- 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/tools/vm/page-types.c b/tools/vm/page-types.c
index 381dcc00cb62..364373f5bba0 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -79,6 +79,7 @@
 #define KPF_UNCACHED		39
 #define KPF_SOFTDIRTY		40
 #define KPF_ARCH_2		41
+#define KPF_ARCH_3		42
 
 /* [47-] take some arbitrary free slots for expanding overloaded flags
  * not part of kernel API
@@ -138,6 +139,7 @@ static const char * const page_flag_names[] = {
 	[KPF_UNCACHED]		= "c:uncached",
 	[KPF_SOFTDIRTY]		= "f:softdirty",
 	[KPF_ARCH_2]		= "H:arch_2",
+	[KPF_ARCH_3]		= "H:arch_3",
 
 	[KPF_ANON_EXCLUSIVE]	= "d:anon_exclusive",
 	[KPF_READAHEAD]		= "I:readahead",
diff mbox series

Patch

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)));