From: Peter Collingbourne <pcc@google.com>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, Cornelia Huck <cohuck@redhat.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Evgenii Stepanov <eugenis@google.com>,
kvm@vger.kernel.org, Steven Price <steven.price@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>
Subject: Re: [PATCH v2 3/7] mm: Add PG_arch_3 page flag
Date: Fri, 22 Jul 2022 10:04:59 -0700 [thread overview]
Message-ID: <YtrYu54WBHJa4YMP@google.com> (raw)
In-Reply-To: <87leslxmf1.wl-maz@kernel.org>
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",
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next prev parent reply other threads:[~2022-07-22 17:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-22 1:50 [PATCH v2 0/7] KVM: arm64: permit MAP_SHARED mappings with MTE enabled Peter Collingbourne
2022-07-22 1:50 ` [PATCH v2 1/7] arm64: mte: Fix/clarify the PG_mte_tagged semantics Peter Collingbourne
2022-07-23 1:53 ` kernel test robot
2022-07-24 1:54 ` kernel test robot
2022-07-22 1:50 ` [PATCH v2 2/7] KVM: arm64: Simplify the sanitise_mte_tags() logic Peter Collingbourne
2022-07-22 1:50 ` [PATCH v2 3/7] mm: Add PG_arch_3 page flag Peter Collingbourne
2022-07-22 14:16 ` Marc Zyngier
2022-07-22 17:04 ` Peter Collingbourne [this message]
2022-07-22 1:50 ` [PATCH v2 4/7] arm64: mte: Lock a page for MTE tag initialisation Peter Collingbourne
2022-07-22 1:50 ` [PATCH v2 5/7] KVM: arm64: unify the tests for VMAs in memslots when MTE is enabled Peter Collingbourne
2022-07-22 1:50 ` [PATCH v2 6/7] KVM: arm64: permit all VM_MTE_ALLOWED mappings with MTE enabled Peter Collingbourne
2022-07-22 1:50 ` [PATCH v2 7/7] Documentation: document the ABI changes for KVM_CAP_ARM_MTE Peter Collingbourne
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