From: Catalin Marinas <catalin.marinas@arm.com> To: Jia He <justin.he@arm.com> Cc: "Will Deacon" <will@kernel.org>, "Mark Rutland" <mark.rutland@arm.com>, "James Morse" <james.morse@arm.com>, "Marc Zyngier" <maz@kernel.org>, "Matthew Wilcox" <willy@infradead.org>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Suzuki Poulose" <Suzuki.Poulose@arm.com>, "Punit Agrawal" <punitagrawal@gmail.com>, "Anshuman Khandual" <anshuman.khandual@arm.com>, "Alex Van Brunt" <avanbrunt@nvidia.com>, "Robin Murphy" <robin.murphy@arm.com>, "Thomas Gleixner" <tglx@linutronix.de>, "Andrew Morton" <akpm@linux-foundation.org>, "Jérôme Glisse" <jglisse@redhat.com>, "Ralph Campbell" <rcampbell@nvidia.com>, hejianet@gmail.com, "Kaly Xin" <Kaly.Xin@arm.com>, nd@arm.com Subject: Re: [PATCH v8 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64 Date: Mon, 23 Sep 2019 17:18:25 +0100 [thread overview] Message-ID: <20190923161824.GD10192@arrakis.emea.arm.com> (raw) In-Reply-To: <20190921135054.142360-3-justin.he@arm.com> On Sat, Sep 21, 2019 at 09:50:53PM +0800, Jia He wrote: > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index e09760ece844..4a9939615e41 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -868,6 +868,18 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, > #define phys_to_ttbr(addr) (addr) > #endif > > +/* > + * On arm64 without hardware Access Flag, copying fromuser will fail because ^^^^^^^^ from user > + * the pte is old and cannot be marked young. So we always end up with zeroed > + * page after fork() + CoW for pfn mappings. we don't always have a ^^ We > + * hardware-managed access flag on arm64. > + */ > +static inline bool arch_faults_on_old_pte(void) > +{ > + return !cpu_has_hw_af(); I saw an early incarnation of your patch having a WARN_ON(preemptible()). I think we need this back just in case this function will be used elsewhere in the future. > +} > +#define arch_faults_on_old_pte arch_faults_on_old_pte Otherwise, Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com> To: Jia He <justin.he@arm.com> Cc: "Mark Rutland" <mark.rutland@arm.com>, "Kaly Xin" <Kaly.Xin@arm.com>, "Ralph Campbell" <rcampbell@nvidia.com>, "Andrew Morton" <akpm@linux-foundation.org>, "Suzuki Poulose" <Suzuki.Poulose@arm.com>, "Marc Zyngier" <maz@kernel.org>, "Anshuman Khandual" <anshuman.khandual@arm.com>, linux-kernel@vger.kernel.org, "Matthew Wilcox" <willy@infradead.org>, linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>, "James Morse" <james.morse@arm.com>, linux-arm-kernel@lists.infradead.org, "Punit Agrawal" <punitagrawal@gmail.com>, hejianet@gmail.com, "Thomas Gleixner" <tglx@linutronix.de>, nd@arm.com, "Will Deacon" <will@kernel.org>, "Alex Van Brunt" <avanbrunt@nvidia.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, "Robin Murphy" <robin.murphy@arm.com> Subject: Re: [PATCH v8 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64 Date: Mon, 23 Sep 2019 17:18:25 +0100 [thread overview] Message-ID: <20190923161824.GD10192@arrakis.emea.arm.com> (raw) In-Reply-To: <20190921135054.142360-3-justin.he@arm.com> On Sat, Sep 21, 2019 at 09:50:53PM +0800, Jia He wrote: > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index e09760ece844..4a9939615e41 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -868,6 +868,18 @@ static inline void update_mmu_cache(struct vm_area_struct *vma, > #define phys_to_ttbr(addr) (addr) > #endif > > +/* > + * On arm64 without hardware Access Flag, copying fromuser will fail because ^^^^^^^^ from user > + * the pte is old and cannot be marked young. So we always end up with zeroed > + * page after fork() + CoW for pfn mappings. we don't always have a ^^ We > + * hardware-managed access flag on arm64. > + */ > +static inline bool arch_faults_on_old_pte(void) > +{ > + return !cpu_has_hw_af(); I saw an early incarnation of your patch having a WARN_ON(preemptible()). I think we need this back just in case this function will be used elsewhere in the future. > +} > +#define arch_faults_on_old_pte arch_faults_on_old_pte Otherwise, Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-09-23 16:18 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-09-21 13:50 [PATCH v8 0/3] fix double page fault on arm64 Jia He 2019-09-21 13:50 ` Jia He 2019-09-21 13:50 ` [PATCH v8 1/3] arm64: cpufeature: introduce helper cpu_has_hw_af() Jia He 2019-09-21 13:50 ` Jia He 2019-09-23 16:07 ` Catalin Marinas 2019-09-23 16:07 ` Catalin Marinas 2019-09-24 1:50 ` Justin He (Arm Technology China) 2019-09-24 1:50 ` Justin He (Arm Technology China) 2019-09-21 13:50 ` [PATCH v8 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64 Jia He 2019-09-21 13:50 ` Jia He 2019-09-23 16:18 ` Catalin Marinas [this message] 2019-09-23 16:18 ` Catalin Marinas 2019-09-24 2:17 ` Justin He (Arm Technology China) 2019-09-24 2:17 ` Justin He (Arm Technology China) 2019-09-21 13:50 ` [PATCH v8 3/3] mm: fix double page fault on arm64 if PTE_AF is cleared Jia He 2019-09-21 13:50 ` Jia He 2019-09-21 15:31 ` Matthew Wilcox 2019-09-21 15:31 ` Matthew Wilcox 2019-09-23 8:28 ` Kirill A. Shutemov 2019-09-23 8:28 ` Kirill A. Shutemov 2019-09-23 17:04 ` Catalin Marinas 2019-09-23 17:04 ` Catalin Marinas 2019-09-24 6:43 ` Justin He (Arm Technology China) 2019-09-24 6:43 ` Justin He (Arm Technology China) 2019-09-24 10:33 ` Catalin Marinas 2019-09-24 10:33 ` Catalin Marinas 2019-09-24 11:59 ` Kirill A. Shutemov 2019-09-24 11:59 ` Kirill A. Shutemov 2019-09-24 15:29 ` Jia He 2019-09-24 15:29 ` Jia He 2019-09-24 16:35 ` Catalin Marinas 2019-09-24 16:35 ` Catalin Marinas
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20190923161824.GD10192@arrakis.emea.arm.com \ --to=catalin.marinas@arm.com \ --cc=Kaly.Xin@arm.com \ --cc=Suzuki.Poulose@arm.com \ --cc=akpm@linux-foundation.org \ --cc=anshuman.khandual@arm.com \ --cc=avanbrunt@nvidia.com \ --cc=hejianet@gmail.com \ --cc=james.morse@arm.com \ --cc=jglisse@redhat.com \ --cc=justin.he@arm.com \ --cc=kirill.shutemov@linux.intel.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=mark.rutland@arm.com \ --cc=maz@kernel.org \ --cc=nd@arm.com \ --cc=punitagrawal@gmail.com \ --cc=rcampbell@nvidia.com \ --cc=robin.murphy@arm.com \ --cc=tglx@linutronix.de \ --cc=will@kernel.org \ --cc=willy@infradead.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.