From: "Justin He (Arm Technology China)" <Justin.He@arm.com> To: Catalin Marinas <Catalin.Marinas@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-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-mm@kvack.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" <hejianet@gmail.com>, "Kaly Xin (Arm Technology China)" <Kaly.Xin@arm.com>, nd <nd@arm.com> Subject: RE: [PATCH v8 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64 Date: Tue, 24 Sep 2019 02:17:49 +0000 [thread overview] Message-ID: <DB7PR08MB3082F91F6502337231EDC63FF7840@DB7PR08MB3082.eurprd08.prod.outlook.com> (raw) In-Reply-To: <20190923161824.GD10192@arrakis.emea.arm.com> > -----Original Message----- > From: Catalin Marinas <catalin.marinas@arm.com> > Sent: 2019年9月24日 0:18 > To: Justin He (Arm Technology China) <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 (Arm Technology > China) <Kaly.Xin@arm.com>; nd <nd@arm.com> > Subject: Re: [PATCH v8 2/3] arm64: mm: implement > arch_faults_on_old_pte() on arm64 > > 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 > Ok > > + * 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 > Ok > > + * 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. Okay -- Cheers, Justin (Jia He) > > > +} > > +#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: "Justin He (Arm Technology China)" <Justin.He@arm.com> To: Catalin Marinas <Catalin.Marinas@arm.com> Cc: "Mark Rutland" <Mark.Rutland@arm.com>, "Kaly Xin (Arm Technology China)" <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" <linux-kernel@vger.kernel.org>, "Matthew Wilcox" <willy@infradead.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "Jérôme Glisse" <jglisse@redhat.com>, "James Morse" <James.Morse@arm.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "Punit Agrawal" <punitagrawal@gmail.com>, "hejianet@gmail.com" <hejianet@gmail.com>, "Thomas Gleixner" <tglx@linutronix.de>, nd <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: Tue, 24 Sep 2019 02:17:49 +0000 [thread overview] Message-ID: <DB7PR08MB3082F91F6502337231EDC63FF7840@DB7PR08MB3082.eurprd08.prod.outlook.com> (raw) In-Reply-To: <20190923161824.GD10192@arrakis.emea.arm.com> > -----Original Message----- > From: Catalin Marinas <catalin.marinas@arm.com> > Sent: 2019年9月24日 0:18 > To: Justin He (Arm Technology China) <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 (Arm Technology > China) <Kaly.Xin@arm.com>; nd <nd@arm.com> > Subject: Re: [PATCH v8 2/3] arm64: mm: implement > arch_faults_on_old_pte() on arm64 > > 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 > Ok > > + * 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 > Ok > > + * 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. Okay -- Cheers, Justin (Jia He) > > > +} > > +#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:[~2019-09-24 2:18 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 2019-09-23 16:18 ` Catalin Marinas 2019-09-24 2:17 ` Justin He (Arm Technology China) [this message] 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
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