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

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

2019-09-29 Thread Jia He
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 access flag on arm64. Hence implement arch_faults_on_old_pte on