Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751901AbbLCSFY (ORCPT ); Thu, 3 Dec 2015 13:05:24 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:42755 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751109AbbLCSFW (ORCPT ); Thu, 3 Dec 2015 13:05:22 -0500 Message-ID: <5660845E.4030705@codeaurora.org> Date: Thu, 03 Dec 2015 13:05:18 -0500 From: Christopher Covington User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:36.0) Gecko/20100101 Thunderbird/36.0 MIME-Version: 1.0 To: Will Deacon CC: Mark Rutland , Jason Cooper , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , linux-kernel@vger.kernel.org, Jens Axboe , Daniel Borkmann , linux-arm-msm@vger.kernel.org, Andrew Morton , Laurent Dufour , Ingo Molnar , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] arm64: Support VDSO remapping References: <1448455781-26660-1-git-send-email-cov@codeaurora.org> <20151202121918.GA4523@arm.com> In-Reply-To: <20151202121918.GA4523@arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4315 Lines: 120 On 12/02/2015 07:19 AM, Will Deacon wrote: > Hi Christopher, > > On Wed, Nov 25, 2015 at 07:49:29AM -0500, Christopher Covington wrote: >> Some applications such as Checkpoint/Restore In Userspace (CRIU) remap and >> unmap the VDSO. Add support for this to the AArch64 kernel by copying in >> the PowerPC code with slight modifications. >> >> Signed-off-by: Christopher Covington >> --- >> arch/arm64/include/asm/Kbuild | 1 - >> arch/arm64/include/asm/mm-arch-hooks.h | 28 ++++++++++++++++++++++++++++ >> arch/arm64/include/asm/mmu_context.h | 23 ++++++++++++++++++++++- >> 3 files changed, 50 insertions(+), 2 deletions(-) >> create mode 100644 arch/arm64/include/asm/mm-arch-hooks.h >> >> diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild >> index 70fd9ff..b112a39 100644 >> --- a/arch/arm64/include/asm/Kbuild >> +++ b/arch/arm64/include/asm/Kbuild >> @@ -25,7 +25,6 @@ generic-y += kvm_para.h >> generic-y += local.h >> generic-y += local64.h >> generic-y += mcs_spinlock.h >> -generic-y += mm-arch-hooks.h >> generic-y += mman.h >> generic-y += msgbuf.h >> generic-y += msi.h >> diff --git a/arch/arm64/include/asm/mm-arch-hooks.h b/arch/arm64/include/asm/mm-arch-hooks.h >> new file mode 100644 >> index 0000000..e6923fb >> --- /dev/null >> +++ b/arch/arm64/include/asm/mm-arch-hooks.h >> @@ -0,0 +1,28 @@ >> +/* >> + * Architecture specific mm hooks >> + * >> + * Copyright (C) 2015, IBM Corporation >> + * Author: Laurent Dufour >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + */ >> + >> +#ifndef __ASM_MM_ARCH_HOOKS_H >> +#define __ASM_MM_ARCH_HOOKS_H >> + >> +static inline void arch_remap(struct mm_struct *mm, >> + unsigned long old_start, unsigned long old_end, >> + unsigned long new_start, unsigned long new_end) >> +{ >> + /* >> + * mremap() doesn't allow moving multiple vmas so we can limit the >> + * check to old_start == vdso_base. >> + */ >> + if ((void *)old_start == mm->context.vdso) >> + mm->context.vdso = (void *)new_start; >> +} >> +#define arch_remap arch_remap >> + >> +#endif /* __ASM_MM_ARCH_HOOKS_H */ >> diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h >> index 2416578..9fe0773 100644 >> --- a/arch/arm64/include/asm/mmu_context.h >> +++ b/arch/arm64/include/asm/mmu_context.h >> @@ -24,7 +24,6 @@ >> >> #include >> #include >> -#include >> #include >> #include >> >> @@ -147,4 +146,26 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next, >> #define deactivate_mm(tsk,mm) do { } while (0) >> #define activate_mm(prev,next) switch_mm(prev, next, NULL) >> >> +static inline void arch_dup_mmap(struct mm_struct *oldmm, >> + struct mm_struct *mm) >> +{ >> +} >> + >> +static inline void arch_exit_mmap(struct mm_struct *mm) >> +{ >> +} >> + >> +static inline void arch_unmap(struct mm_struct *mm, >> + struct vm_area_struct *vma, >> + unsigned long start, unsigned long end) >> +{ >> + if ((void *)start <= mm->context.vdso && mm->context.vdso < (void *)end) >> + mm->context.vdso = NULL; >> +} >> + >> +static inline void arch_bprm_mm_init(struct mm_struct *mm, >> + struct vm_area_struct *vma) >> +{ >> +} > > This is virtually identical to the PowerPC implementation, afaict. Any > chance we could move this to core code and define some generic vdso > accessors for the mm? I think the same criticism applies to the VDSO code itself, and I'm not sure how easy it is to provide common VDSO remap/unmap without common VDSO code. I guess I'll do some investigating when I have then chance. Thanks, Christopher Covington -- Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/