Re: [PATCH v10 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64

2019-10-08 Thread Marc Zyngier
n > > Marinas ; Mark Rutland > > ; James Morse ; > > Matthew Wilcox ; Kirill A. Shutemov > > ; linux-arm-ker...@lists.infradead.org; > > linux-kernel@vger.kernel.org; linux...@kvack.org; Punit Agrawal > > ; Thomas Gleixner ; > > Andrew Morton ; hejia...@gm

RE: [PATCH v10 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64

2019-10-07 Thread Justin He (Arm Technology China)
inux-kernel@vger.kernel.org; linux...@kvack.org; Punit Agrawal > ; Thomas Gleixner ; > Andrew Morton ; hejia...@gmail.com; Kaly > Xin (Arm Technology China) ; nd > Subject: RE: [PATCH v10 2/3] arm64: mm: implement > arch_faults_on_old_pte() on arm64 > > Hi Will and Marc > &g

RE: [PATCH v10 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64

2019-10-07 Thread Justin He (Arm Technology China)
ists.infradead.org; > linux-kernel@vger.kernel.org; linux...@kvack.org; Punit Agrawal > ; Thomas Gleixner ; > Andrew Morton ; hejia...@gmail.com; Kaly > Xin (Arm Technology China) > Subject: Re: [PATCH v10 2/3] arm64: mm: implement > arch_faults_on_old_pte() on arm64 > > On

Re: [PATCH v10 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64

2019-10-01 Thread Marc Zyngier
On Tue, 1 Oct 2019 13:50:32 +0100 Will Deacon wrote: > On Mon, Sep 30, 2019 at 09:57:39AM +0800, Jia He wrote: > > On arm64 without hardware Access Flag, copying fromuser will fail because > > the pte is old and cannot be marked young. So we always end up with zeroed > > page after fork() + CoW

Re: [PATCH v10 2/3] arm64: mm: implement arch_faults_on_old_pte() on arm64

2019-10-01 Thread Will Deacon
On Mon, Sep 30, 2019 at 09:57:39AM +0800, Jia He wrote: > On arm64 without hardware Access Flag, copying fromuser will fail because > 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 > hardware-managed