From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by kanga.kvack.org (Postfix) with ESMTP id 4FC046B0038 for ; Fri, 20 Mar 2015 11:53:39 -0400 (EDT) Received: by wixw10 with SMTP id w10so24653934wix.0 for ; Fri, 20 Mar 2015 08:53:38 -0700 (PDT) Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com. [195.75.94.110]) by mx.google.com with ESMTPS id h6si3781331wix.3.2015.03.20.08.53.37 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 20 Mar 2015 08:53:37 -0700 (PDT) Received: from /spool/local by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 20 Mar 2015 15:53:36 -0000 Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id C53E3219004D for ; Fri, 20 Mar 2015 15:53:22 +0000 (GMT) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2KFrXa38585490 for ; Fri, 20 Mar 2015 15:53:33 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2KFrVst005488 for ; Fri, 20 Mar 2015 09:53:32 -0600 From: Laurent Dufour Subject: [PATCH 0/2] Tracking user space vDSO remaping Date: Fri, 20 Mar 2015 16:53:26 +0100 Message-Id: Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org CRIU is recreating the process memory layout by remapping the checkpointee memory area on top of the current process (criu). This includes remapping the vDSO to the place it has at checkpoint time. However some architectures like powerpc are keeping a reference to the vDSO base address to build the signal return stack frame by calling the vDSO sigreturn service. So once the vDSO has been moved, this reference is no more valid and the signal frame built later are not usable. This patch serie is introducing a new mm hook 'arch_remap' which is called when mremap is done and the mm lock still hold. The next patch is adding the vDSO remap and unmap tracking to the powerpc architecture. Laurent Dufour (2): mm: Introducing arch_remap hook powerpc/mm: Tracking vDSO remap arch/powerpc/include/asm/mmu_context.h | 35 +++++++++++++++++++++++++++++++- arch/s390/include/asm/mmu_context.h | 6 ++++++ arch/um/include/asm/mmu_context.h | 5 +++++ arch/unicore32/include/asm/mmu_context.h | 6 ++++++ arch/x86/include/asm/mmu_context.h | 6 ++++++ include/asm-generic/mm_hooks.h | 6 ++++++ mm/mremap.c | 9 ++++++-- 7 files changed, 70 insertions(+), 3 deletions(-) -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f46.google.com (mail-wg0-f46.google.com [74.125.82.46]) by kanga.kvack.org (Postfix) with ESMTP id 639206B006C for ; Fri, 20 Mar 2015 11:53:41 -0400 (EDT) Received: by wggv3 with SMTP id v3so92929451wgg.1 for ; Fri, 20 Mar 2015 08:53:40 -0700 (PDT) Received: from e06smtp16.uk.ibm.com (e06smtp16.uk.ibm.com. [195.75.94.112]) by mx.google.com with ESMTPS id dk4si3731820wib.95.2015.03.20.08.53.39 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 20 Mar 2015 08:53:39 -0700 (PDT) Received: from /spool/local by e06smtp16.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 20 Mar 2015 15:53:38 -0000 Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 37CA8219005F for ; Fri, 20 Mar 2015 15:53:26 +0000 (GMT) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2KFraXH7668124 for ; Fri, 20 Mar 2015 15:53:36 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2KFrXBC005569 for ; Fri, 20 Mar 2015 09:53:36 -0600 From: Laurent Dufour Subject: [PATCH 1/2] mm: Introducing arch_remap hook Date: Fri, 20 Mar 2015 16:53:27 +0100 Message-Id: <503499aae380db1c4673f146bcba6ad095021257.1426866405.git.ldufour@linux.vnet.ibm.com> In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Some architecture would like to be triggered when a memory area is moved through the mremap system call. This patch is introducing a new arch_remap mm hook which is placed in the path of mremap, and is called before the old area is unmapped (and the arch_unmap hook is called). To no break the build, this patch adds the empty hook definition to the architectures that were not using the generic hook's definition. Signed-off-by: Laurent Dufour --- arch/s390/include/asm/mmu_context.h | 6 ++++++ arch/um/include/asm/mmu_context.h | 5 +++++ arch/unicore32/include/asm/mmu_context.h | 6 ++++++ arch/x86/include/asm/mmu_context.h | 6 ++++++ include/asm-generic/mm_hooks.h | 6 ++++++ mm/mremap.c | 9 +++++++-- 6 files changed, 36 insertions(+), 2 deletions(-) diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h index 8fb3802f8fad..ddd861a490ba 100644 --- a/arch/s390/include/asm/mmu_context.h +++ b/arch/s390/include/asm/mmu_context.h @@ -131,4 +131,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, { } +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) +{ +} + #endif /* __S390_MMU_CONTEXT_H */ diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h index 941527e507f7..f499b017c1f9 100644 --- a/arch/um/include/asm/mmu_context.h +++ b/arch/um/include/asm/mmu_context.h @@ -27,6 +27,11 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, struct vm_area_struct *vma) { } +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) +{ +} /* * end asm-generic/mm_hooks.h functions */ diff --git a/arch/unicore32/include/asm/mmu_context.h b/arch/unicore32/include/asm/mmu_context.h index 1cb5220afaf9..39a0a553172e 100644 --- a/arch/unicore32/include/asm/mmu_context.h +++ b/arch/unicore32/include/asm/mmu_context.h @@ -97,4 +97,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, { } +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) +{ +} + #endif diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 883f6b933fa4..75cb71f4be1e 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -172,4 +172,10 @@ static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma, mpx_notify_unmap(mm, vma, start, end); } +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) +{ +} + #endif /* _ASM_X86_MMU_CONTEXT_H */ diff --git a/include/asm-generic/mm_hooks.h b/include/asm-generic/mm_hooks.h index 866aa461efa5..e507f4783a5b 100644 --- a/include/asm-generic/mm_hooks.h +++ b/include/asm-generic/mm_hooks.h @@ -26,4 +26,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, { } +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) +{ +} + #endif /* _ASM_GENERIC_MM_HOOKS_H */ diff --git a/mm/mremap.c b/mm/mremap.c index 57dadc025c64..6a409ca09425 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -25,6 +25,7 @@ #include #include +#include #include "internal.h" @@ -286,8 +287,12 @@ static unsigned long move_vma(struct vm_area_struct *vma, old_len = new_len; old_addr = new_addr; new_addr = -ENOMEM; - } else if (vma->vm_file && vma->vm_file->f_op->mremap) - vma->vm_file->f_op->mremap(vma->vm_file, new_vma); + } else { + if (vma->vm_file && vma->vm_file->f_op->mremap) + vma->vm_file->f_op->mremap(vma->vm_file, new_vma); + arch_remap(mm, old_addr, old_addr+old_len, + new_addr, new_addr+new_len); + } /* Conceal VM_ACCOUNT so old reservation is not undone */ if (vm_flags & VM_ACCOUNT) { -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f43.google.com (mail-wg0-f43.google.com [74.125.82.43]) by kanga.kvack.org (Postfix) with ESMTP id 697686B006E for ; Fri, 20 Mar 2015 11:53:45 -0400 (EDT) Received: by wgra20 with SMTP id a20so92818088wgr.3 for ; Fri, 20 Mar 2015 08:53:44 -0700 (PDT) Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com. [195.75.94.111]) by mx.google.com with ESMTPS id us7si7574870wjc.151.2015.03.20.08.53.43 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 20 Mar 2015 08:53:44 -0700 (PDT) Received: from /spool/local by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 20 Mar 2015 15:53:42 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 4357417D805A for ; Fri, 20 Mar 2015 15:54:05 +0000 (GMT) Received: from d06av04.portsmouth.uk.ibm.com (d06av04.portsmouth.uk.ibm.com [9.149.37.216]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2KFrdYh3801428 for ; Fri, 20 Mar 2015 15:53:39 GMT Received: from d06av04.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av04.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2KFratt005657 for ; Fri, 20 Mar 2015 09:53:38 -0600 From: Laurent Dufour Subject: [PATCH 2/2] powerpc/mm: Tracking vDSO remap Date: Fri, 20 Mar 2015 16:53:28 +0100 Message-Id: <462eda8901babf0a08b5ef642684ae1c6303bd5b.1426866405.git.ldufour@linux.vnet.ibm.com> In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Some processes (CRIU) are moving the vDSO area using the mremap system call. As a consequence the kernel reference to the vDSO base address is no more valid and the signal return frame built once the vDSO has been moved is not pointing to the new sigreturn address. This patch handles vDSO remapping and unmapping. Signed-off-by: Laurent Dufour --- arch/powerpc/include/asm/mmu_context.h | 35 +++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 73382eba02dc..ce7fc93518ee 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -8,7 +8,6 @@ #include #include #include -#include #include /* @@ -109,5 +108,39 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, #endif } +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 (start <= mm->context.vdso_base && mm->context.vdso_base < end) + mm->context.vdso_base = 0; +} + +static inline void arch_bprm_mm_init(struct mm_struct *mm, + struct vm_area_struct *vma) +{ +} + +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 don't allow moving multiple vma so we can limit the check + * to old_start == vdso_base. + */ + if (old_start == mm->context.vdso_base) + mm->context.vdso_base = new_start; +} + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_MMU_CONTEXT_H */ -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f170.google.com (mail-wi0-f170.google.com [209.85.212.170]) by kanga.kvack.org (Postfix) with ESMTP id 1501F6B0038 for ; Fri, 20 Mar 2015 19:19:49 -0400 (EDT) Received: by wibg7 with SMTP id g7so539432wib.1 for ; Fri, 20 Mar 2015 16:19:48 -0700 (PDT) Received: from radon.swed.at (a.ns.miles-group.at. [95.130.255.143]) by mx.google.com with ESMTPS id hq9si9068479wjb.91.2015.03.20.16.19.46 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Fri, 20 Mar 2015 16:19:47 -0700 (PDT) Message-ID: <550CAB0A.8070402@nod.at> Date: Sat, 21 Mar 2015 00:19:38 +0100 From: Richard Weinberger MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mm: Introducing arch_remap hook References: <503499aae380db1c4673f146bcba6ad095021257.1426866405.git.ldufour@linux.vnet.ibm.com> In-Reply-To: <503499aae380db1c4673f146bcba6ad095021257.1426866405.git.ldufour@linux.vnet.ibm.com> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Am 20.03.2015 um 16:53 schrieb Laurent Dufour: > Some architecture would like to be triggered when a memory area is moved > through the mremap system call. > > This patch is introducing a new arch_remap mm hook which is placed in the > path of mremap, and is called before the old area is unmapped (and the > arch_unmap hook is called). > > To no break the build, this patch adds the empty hook definition to the > architectures that were not using the generic hook's definition. Just wanted to point out that I like that new hook as UserModeLinux can benefit from it. UML has the concept of stub pages where the UML host process can inject commands to guest processes. Currently we play nasty games in the TLB code to make all this work. arch_unmap() could make this stuff more clear and less error prone. Thanks, //richard -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f172.google.com (mail-wi0-f172.google.com [209.85.212.172]) by kanga.kvack.org (Postfix) with ESMTP id 1E5E86B0072 for ; Mon, 23 Mar 2015 04:52:15 -0400 (EDT) Received: by wixw10 with SMTP id w10so55214373wix.0 for ; Mon, 23 Mar 2015 01:52:14 -0700 (PDT) Received: from mail-we0-x22c.google.com (mail-we0-x22c.google.com. [2a00:1450:400c:c03::22c]) by mx.google.com with ESMTPS id lf5si182004wjb.111.2015.03.23.01.52.13 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 23 Mar 2015 01:52:13 -0700 (PDT) Received: by wegp1 with SMTP id p1so131768666weg.1 for ; Mon, 23 Mar 2015 01:52:12 -0700 (PDT) Date: Mon, 23 Mar 2015 09:52:09 +0100 From: Ingo Molnar Subject: Re: [PATCH 1/2] mm: Introducing arch_remap hook Message-ID: <20150323085209.GA28965@gmail.com> References: <503499aae380db1c4673f146bcba6ad095021257.1426866405.git.ldufour@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <503499aae380db1c4673f146bcba6ad095021257.1426866405.git.ldufour@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org * Laurent Dufour wrote: > Some architecture would like to be triggered when a memory area is moved > through the mremap system call. > > This patch is introducing a new arch_remap mm hook which is placed in the > path of mremap, and is called before the old area is unmapped (and the > arch_unmap hook is called). > > To no break the build, this patch adds the empty hook definition to the > architectures that were not using the generic hook's definition. > > Signed-off-by: Laurent Dufour > --- > arch/s390/include/asm/mmu_context.h | 6 ++++++ > arch/um/include/asm/mmu_context.h | 5 +++++ > arch/unicore32/include/asm/mmu_context.h | 6 ++++++ > arch/x86/include/asm/mmu_context.h | 6 ++++++ > include/asm-generic/mm_hooks.h | 6 ++++++ > mm/mremap.c | 9 +++++++-- > 6 files changed, 36 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h > index 8fb3802f8fad..ddd861a490ba 100644 > --- a/arch/s390/include/asm/mmu_context.h > +++ b/arch/s390/include/asm/mmu_context.h > @@ -131,4 +131,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, > { > } > > +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) > +{ > +} > + > #endif /* __S390_MMU_CONTEXT_H */ > diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h > index 941527e507f7..f499b017c1f9 100644 > --- a/arch/um/include/asm/mmu_context.h > +++ b/arch/um/include/asm/mmu_context.h > @@ -27,6 +27,11 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, > struct vm_area_struct *vma) > { > } > +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) > +{ > +} > /* > * end asm-generic/mm_hooks.h functions > */ > diff --git a/arch/unicore32/include/asm/mmu_context.h b/arch/unicore32/include/asm/mmu_context.h > index 1cb5220afaf9..39a0a553172e 100644 > --- a/arch/unicore32/include/asm/mmu_context.h > +++ b/arch/unicore32/include/asm/mmu_context.h > @@ -97,4 +97,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, > { > } > > +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) > +{ > +} > + > #endif > diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h > index 883f6b933fa4..75cb71f4be1e 100644 > --- a/arch/x86/include/asm/mmu_context.h > +++ b/arch/x86/include/asm/mmu_context.h > @@ -172,4 +172,10 @@ static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma, > mpx_notify_unmap(mm, vma, start, end); > } > > +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) > +{ > +} > + > #endif /* _ASM_X86_MMU_CONTEXT_H */ So instead of spreading these empty prototypes around mmu_context.h files, why not add something like this to the PPC definition: #define __HAVE_ARCH_REMAP and define the empty prototype for everyone else? It's a bit like how the __HAVE_ARCH_PTEP_* namespace works. That should shrink this patch considerably. Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f170.google.com (mail-wi0-f170.google.com [209.85.212.170]) by kanga.kvack.org (Postfix) with ESMTP id 5F10D6B0074 for ; Mon, 23 Mar 2015 05:11:30 -0400 (EDT) Received: by wibg7 with SMTP id g7so41448256wib.1 for ; Mon, 23 Mar 2015 02:11:29 -0700 (PDT) Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com. [195.75.94.110]) by mx.google.com with ESMTPS id h3si10711017wix.93.2015.03.23.02.11.28 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 23 Mar 2015 02:11:28 -0700 (PDT) Received: from /spool/local by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 23 Mar 2015 09:11:27 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 2934717D805F for ; Mon, 23 Mar 2015 09:11:53 +0000 (GMT) Received: from d06av03.portsmouth.uk.ibm.com (d06av03.portsmouth.uk.ibm.com [9.149.37.213]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2N9BQck53805080 for ; Mon, 23 Mar 2015 09:11:26 GMT Received: from d06av03.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av03.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2N9BMHJ011313 for ; Mon, 23 Mar 2015 03:11:25 -0600 Message-ID: <550FD8B6.305@linux.vnet.ibm.com> Date: Mon, 23 Mar 2015 10:11:18 +0100 From: Laurent Dufour MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mm: Introducing arch_remap hook References: <503499aae380db1c4673f146bcba6ad095021257.1426866405.git.ldufour@linux.vnet.ibm.com> <20150323085209.GA28965@gmail.com> In-Reply-To: <20150323085209.GA28965@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org On 23/03/2015 09:52, Ingo Molnar wrote: > > * Laurent Dufour wrote: > >> Some architecture would like to be triggered when a memory area is moved >> through the mremap system call. >> >> This patch is introducing a new arch_remap mm hook which is placed in the >> path of mremap, and is called before the old area is unmapped (and the >> arch_unmap hook is called). >> >> To no break the build, this patch adds the empty hook definition to the >> architectures that were not using the generic hook's definition. >> >> Signed-off-by: Laurent Dufour >> --- >> arch/s390/include/asm/mmu_context.h | 6 ++++++ >> arch/um/include/asm/mmu_context.h | 5 +++++ >> arch/unicore32/include/asm/mmu_context.h | 6 ++++++ >> arch/x86/include/asm/mmu_context.h | 6 ++++++ >> include/asm-generic/mm_hooks.h | 6 ++++++ >> mm/mremap.c | 9 +++++++-- >> 6 files changed, 36 insertions(+), 2 deletions(-) >> >> diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h >> index 8fb3802f8fad..ddd861a490ba 100644 >> --- a/arch/s390/include/asm/mmu_context.h >> +++ b/arch/s390/include/asm/mmu_context.h >> @@ -131,4 +131,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, >> { >> } >> >> +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) >> +{ >> +} >> + >> #endif /* __S390_MMU_CONTEXT_H */ >> diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h >> index 941527e507f7..f499b017c1f9 100644 >> --- a/arch/um/include/asm/mmu_context.h >> +++ b/arch/um/include/asm/mmu_context.h >> @@ -27,6 +27,11 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, >> struct vm_area_struct *vma) >> { >> } >> +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) >> +{ >> +} >> /* >> * end asm-generic/mm_hooks.h functions >> */ >> diff --git a/arch/unicore32/include/asm/mmu_context.h b/arch/unicore32/include/asm/mmu_context.h >> index 1cb5220afaf9..39a0a553172e 100644 >> --- a/arch/unicore32/include/asm/mmu_context.h >> +++ b/arch/unicore32/include/asm/mmu_context.h >> @@ -97,4 +97,10 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm, >> { >> } >> >> +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) >> +{ >> +} >> + >> #endif >> diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h >> index 883f6b933fa4..75cb71f4be1e 100644 >> --- a/arch/x86/include/asm/mmu_context.h >> +++ b/arch/x86/include/asm/mmu_context.h >> @@ -172,4 +172,10 @@ static inline void arch_unmap(struct mm_struct *mm, struct vm_area_struct *vma, >> mpx_notify_unmap(mm, vma, start, end); >> } >> >> +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) >> +{ >> +} >> + >> #endif /* _ASM_X86_MMU_CONTEXT_H */ > > So instead of spreading these empty prototypes around mmu_context.h > files, why not add something like this to the PPC definition: > > #define __HAVE_ARCH_REMAP > > and define the empty prototype for everyone else? It's a bit like how > the __HAVE_ARCH_PTEP_* namespace works. > > That should shrink this patch considerably. My idea was to mimic the MMU hook's definition. This new hook is in the continuity of what have been done for arch_dup_mmap, arch_exit_mmap, arch_unmap and arch_bprm_mm_init. Do you think that there is a need to make this one in another way ? Thanks, Laurent. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f43.google.com (mail-wg0-f43.google.com [74.125.82.43]) by kanga.kvack.org (Postfix) with ESMTP id 4A2C16B006C for ; Wed, 25 Mar 2015 07:06:47 -0400 (EDT) Received: by wgbcc7 with SMTP id cc7so23038138wgb.0 for ; Wed, 25 Mar 2015 04:06:46 -0700 (PDT) Received: from e06smtp12.uk.ibm.com (e06smtp12.uk.ibm.com. [195.75.94.108]) by mx.google.com with ESMTPS id u15si3740453wjr.155.2015.03.25.04.06.44 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 04:06:44 -0700 (PDT) Received: from /spool/local by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 11:06:43 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 4176D1B08069 for ; Wed, 25 Mar 2015 11:07:08 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PB6gDg11993440 for ; Wed, 25 Mar 2015 11:06:42 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PB6deN021500 for ; Wed, 25 Mar 2015 05:06:41 -0600 From: Laurent Dufour Subject: [PATCH v2 0/2] Tracking user space vDSO remaping Date: Wed, 25 Mar 2015 12:06:34 +0100 Message-Id: In-Reply-To: <20150323085209.GA28965@gmail.com> References: <20150323085209.GA28965@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org CRIU is recreating the process memory layout by remapping the checkpointee memory area on top of the current process (criu). This includes remapping the vDSO to the place it has at checkpoint time. However some architectures like powerpc are keeping a reference to the vDSO base address to build the signal return stack frame by calling the vDSO sigreturn service. So once the vDSO has been moved, this reference is no more valid and the signal frame built later are not usable. This patch serie is introducing a new mm hook 'arch_remap' which is called when mremap is done and the mm lock still hold. The next patch is adding the vDSO remap and unmap tracking to the powerpc architecture. Changes in v2: -------------- - Following the Ingo Molnar's advice, enabling the call to arch_remap through the __HAVE_ARCH_REMAP macro. This reduces considerably the first patch. Laurent Dufour (2): mm: Introducing arch_remap hook powerpc/mm: Tracking vDSO remap arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- mm/mremap.c | 11 +++++++++-- 2 files changed, 44 insertions(+), 3 deletions(-) -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by kanga.kvack.org (Postfix) with ESMTP id 295006B006C for ; Wed, 25 Mar 2015 07:06:52 -0400 (EDT) Received: by wixw10 with SMTP id w10so33151482wix.0 for ; Wed, 25 Mar 2015 04:06:51 -0700 (PDT) Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com. [195.75.94.111]) by mx.google.com with ESMTPS id je4si22027957wic.42.2015.03.25.04.06.50 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 04:06:50 -0700 (PDT) Received: from /spool/local by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 11:06:49 -0000 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 901751B08076 for ; Wed, 25 Mar 2015 11:07:12 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PB6kGU3801448 for ; Wed, 25 Mar 2015 11:06:46 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PB6hww021664 for ; Wed, 25 Mar 2015 05:06:46 -0600 From: Laurent Dufour Subject: [PATCH v2 1/2] mm: Introducing arch_remap hook Date: Wed, 25 Mar 2015 12:06:35 +0100 Message-Id: In-Reply-To: References: In-Reply-To: References: <20150323085209.GA28965@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Some architecture would like to be triggered when a memory area is moved through the mremap system call. This patch is introducing a new arch_remap mm hook which is placed in the path of mremap, and is called before the old area is unmapped (and the arch_unmap hook is called). The architectures which need to call this hook should define __HAVE_ARCH_REMAP in their asm/mmu_context.h and provide the arch_remap service with the following prototype: void arch_remap(struct mm_struct *mm, unsigned long old_start, unsigned long old_end, unsigned long new_start, unsigned long new_end); Signed-off-by: Laurent Dufour --- mm/mremap.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index 57dadc025c64..bafc234db45c 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -25,6 +25,7 @@ #include #include +#include #include "internal.h" @@ -286,8 +287,14 @@ static unsigned long move_vma(struct vm_area_struct *vma, old_len = new_len; old_addr = new_addr; new_addr = -ENOMEM; - } else if (vma->vm_file && vma->vm_file->f_op->mremap) - vma->vm_file->f_op->mremap(vma->vm_file, new_vma); + } else { + if (vma->vm_file && vma->vm_file->f_op->mremap) + vma->vm_file->f_op->mremap(vma->vm_file, new_vma); +#ifdef __HAVE_ARCH_REMAP + arch_remap(mm, old_addr, old_addr+old_len, + new_addr, new_addr+new_len); +#endif + } /* Conceal VM_ACCOUNT so old reservation is not undone */ if (vm_flags & VM_ACCOUNT) { -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f171.google.com (mail-wi0-f171.google.com [209.85.212.171]) by kanga.kvack.org (Postfix) with ESMTP id C581A6B006E for ; Wed, 25 Mar 2015 07:06:53 -0400 (EDT) Received: by wixw10 with SMTP id w10so33152601wix.0 for ; Wed, 25 Mar 2015 04:06:53 -0700 (PDT) Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com. [195.75.94.111]) by mx.google.com with ESMTPS id k3si3754322wjr.135.2015.03.25.04.06.52 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 04:06:52 -0700 (PDT) Received: from /spool/local by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 11:06:51 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id DAC7D1B08070 for ; Wed, 25 Mar 2015 11:07:14 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PB6m5I8585672 for ; Wed, 25 Mar 2015 11:06:48 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PB6kI6021809 for ; Wed, 25 Mar 2015 05:06:48 -0600 From: Laurent Dufour Subject: [PATCH v2 2/2] powerpc/mm: Tracking vDSO remap Date: Wed, 25 Mar 2015 12:06:36 +0100 Message-Id: <25152b76585716dc635945c3455ab9b49e645f6d.1427280806.git.ldufour@linux.vnet.ibm.com> In-Reply-To: References: In-Reply-To: References: <20150323085209.GA28965@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Some processes (CRIU) are moving the vDSO area using the mremap system call. As a consequence the kernel reference to the vDSO base address is no more valid and the signal return frame built once the vDSO has been moved is not pointing to the new sigreturn address. This patch handles vDSO remapping and unmapping. Signed-off-by: Laurent Dufour --- arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 73382eba02dc..be5dca3f7826 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -8,7 +8,6 @@ #include #include #include -#include #include /* @@ -109,5 +108,40 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, #endif } +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 (start <= mm->context.vdso_base && mm->context.vdso_base < end) + mm->context.vdso_base = 0; +} + +static inline void arch_bprm_mm_init(struct mm_struct *mm, + struct vm_area_struct *vma) +{ +} + +#define __HAVE_ARCH_REMAP +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 don't allow moving multiple vma so we can limit the check + * to old_start == vdso_base. + */ + if (old_start == mm->context.vdso_base) + mm->context.vdso_base = new_start; +} + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_MMU_CONTEXT_H */ -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f51.google.com (mail-wg0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 0B9F36B0038 for ; Wed, 25 Mar 2015 08:11:26 -0400 (EDT) Received: by wgdm6 with SMTP id m6so24965326wgd.2 for ; Wed, 25 Mar 2015 05:11:25 -0700 (PDT) Received: from mail-wi0-x232.google.com (mail-wi0-x232.google.com. [2a00:1450:400c:c05::232]) by mx.google.com with ESMTPS id fx9si4793584wib.15.2015.03.25.05.11.23 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Mar 2015 05:11:24 -0700 (PDT) Received: by wibg7 with SMTP id g7so72886075wib.1 for ; Wed, 25 Mar 2015 05:11:23 -0700 (PDT) Date: Wed, 25 Mar 2015 13:11:19 +0100 From: Ingo Molnar Subject: Re: [PATCH v2 2/2] powerpc/mm: Tracking vDSO remap Message-ID: <20150325121118.GA2542@gmail.com> References: <20150323085209.GA28965@gmail.com> <25152b76585716dc635945c3455ab9b49e645f6d.1427280806.git.ldufour@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <25152b76585716dc635945c3455ab9b49e645f6d.1427280806.git.ldufour@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org * Laurent Dufour wrote: > Some processes (CRIU) are moving the vDSO area using the mremap system > call. As a consequence the kernel reference to the vDSO base address is > no more valid and the signal return frame built once the vDSO has been > moved is not pointing to the new sigreturn address. > > This patch handles vDSO remapping and unmapping. > > Signed-off-by: Laurent Dufour > --- > arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- > 1 file changed, 35 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h > index 73382eba02dc..be5dca3f7826 100644 > --- a/arch/powerpc/include/asm/mmu_context.h > +++ b/arch/powerpc/include/asm/mmu_context.h > @@ -8,7 +8,6 @@ > #include > #include > #include > -#include > #include > > /* > @@ -109,5 +108,40 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, > #endif > } > > +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 (start <= mm->context.vdso_base && mm->context.vdso_base < end) > + mm->context.vdso_base = 0; > +} > + > +static inline void arch_bprm_mm_init(struct mm_struct *mm, > + struct vm_area_struct *vma) > +{ > +} > + > +#define __HAVE_ARCH_REMAP > +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 don't allow moving multiple vma so we can limit the check > + * to old_start == vdso_base. s/mremap don't allow moving multiple vma mremap() doesn't allow moving multiple vmas right? Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f43.google.com (mail-wg0-f43.google.com [74.125.82.43]) by kanga.kvack.org (Postfix) with ESMTP id 5A02D6B0038 for ; Wed, 25 Mar 2015 09:25:28 -0400 (EDT) Received: by wgs2 with SMTP id 2so27394591wgs.1 for ; Wed, 25 Mar 2015 06:25:27 -0700 (PDT) Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com. [195.75.94.109]) by mx.google.com with ESMTPS id bi1si22077015wib.106.2015.03.25.06.25.26 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 06:25:26 -0700 (PDT) Received: from /spool/local by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 13:25:25 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 5BB851B0805F for ; Wed, 25 Mar 2015 13:25:47 +0000 (GMT) Received: from d06av12.portsmouth.uk.ibm.com (d06av12.portsmouth.uk.ibm.com [9.149.37.247]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PDPLKt65601784 for ; Wed, 25 Mar 2015 13:25:21 GMT Received: from d06av12.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av12.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PDPI7B004627 for ; Wed, 25 Mar 2015 07:25:20 -0600 Message-ID: <5512B73C.5050509@linux.vnet.ibm.com> Date: Wed, 25 Mar 2015 14:25:16 +0100 From: Laurent Dufour MIME-Version: 1.0 Subject: Re: [PATCH v2 2/2] powerpc/mm: Tracking vDSO remap References: <20150323085209.GA28965@gmail.com> <25152b76585716dc635945c3455ab9b49e645f6d.1427280806.git.ldufour@linux.vnet.ibm.com> <20150325121118.GA2542@gmail.com> In-Reply-To: <20150325121118.GA2542@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Ingo Molnar Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org On 25/03/2015 13:11, Ingo Molnar wrote: > > * Laurent Dufour wrote: > >> Some processes (CRIU) are moving the vDSO area using the mremap system >> call. As a consequence the kernel reference to the vDSO base address is >> no more valid and the signal return frame built once the vDSO has been >> moved is not pointing to the new sigreturn address. >> >> This patch handles vDSO remapping and unmapping. >> >> Signed-off-by: Laurent Dufour >> --- >> arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- >> 1 file changed, 35 insertions(+), 1 deletion(-) >> >> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h >> index 73382eba02dc..be5dca3f7826 100644 >> --- a/arch/powerpc/include/asm/mmu_context.h >> +++ b/arch/powerpc/include/asm/mmu_context.h >> @@ -8,7 +8,6 @@ >> #include >> #include >> #include >> -#include >> #include >> >> /* >> @@ -109,5 +108,40 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, >> #endif >> } >> >> +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 (start <= mm->context.vdso_base && mm->context.vdso_base < end) >> + mm->context.vdso_base = 0; >> +} >> + >> +static inline void arch_bprm_mm_init(struct mm_struct *mm, >> + struct vm_area_struct *vma) >> +{ >> +} >> + >> +#define __HAVE_ARCH_REMAP >> +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 don't allow moving multiple vma so we can limit the check >> + * to old_start == vdso_base. > > s/mremap don't allow moving multiple vma > mremap() doesn't allow moving multiple vmas > > right? Sure you're right. I'll provide a v3 fixing that comment. Thanks, Laurent. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f180.google.com (mail-wi0-f180.google.com [209.85.212.180]) by kanga.kvack.org (Postfix) with ESMTP id 0F4FB6B0038 for ; Wed, 25 Mar 2015 09:54:03 -0400 (EDT) Received: by wibgn9 with SMTP id gn9so39900909wib.1 for ; Wed, 25 Mar 2015 06:54:02 -0700 (PDT) Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com. [195.75.94.107]) by mx.google.com with ESMTPS id n9si5168507wie.84.2015.03.25.06.54.01 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 06:54:01 -0700 (PDT) Received: from /spool/local by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 13:54:00 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 18B422190046 for ; Wed, 25 Mar 2015 13:53:47 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PDrw092687466 for ; Wed, 25 Mar 2015 13:53:58 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PDrtN1002858 for ; Wed, 25 Mar 2015 07:53:57 -0600 From: Laurent Dufour Subject: [PATCH v3 0/2] Tracking user space vDSO remaping Date: Wed, 25 Mar 2015 14:53:50 +0100 Message-Id: In-Reply-To: <20150325121118.GA2542@gmail.com> References: <20150325121118.GA2542@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org CRIU is recreating the process memory layout by remapping the checkpointee memory area on top of the current process (criu). This includes remapping the vDSO to the place it has at checkpoint time. However some architectures like powerpc are keeping a reference to the vDSO base address to build the signal return stack frame by calling the vDSO sigreturn service. So once the vDSO has been moved, this reference is no more valid and the signal frame built later are not usable. This patch serie is introducing a new mm hook 'arch_remap' which is called when mremap is done and the mm lock still hold. The next patch is adding the vDSO remap and unmap tracking to the powerpc architecture. Changes in v3: -------------- - Fixed grammatical error in a comment of the second patch. Thanks again, Ingo. Changes in v2: -------------- - Following the Ingo Molnar's advice, enabling the call to arch_remap through the __HAVE_ARCH_REMAP macro. This reduces considerably the first patch. Laurent Dufour (2): mm: Introducing arch_remap hook powerpc/mm: Tracking vDSO remap arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- mm/mremap.c | 11 +++++++++-- 2 files changed, 44 insertions(+), 3 deletions(-) -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by kanga.kvack.org (Postfix) with ESMTP id E81706B006C for ; Wed, 25 Mar 2015 09:54:06 -0400 (EDT) Received: by wixw10 with SMTP id w10so75100922wix.0 for ; Wed, 25 Mar 2015 06:54:06 -0700 (PDT) Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com. [195.75.94.107]) by mx.google.com with ESMTPS id gp8si22754156wib.20.2015.03.25.06.54.04 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 06:54:05 -0700 (PDT) Received: from /spool/local by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 13:54:04 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 5BE781B08072 for ; Wed, 25 Mar 2015 13:54:28 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PDs2EV11731262 for ; Wed, 25 Mar 2015 13:54:02 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PDrwGd002997 for ; Wed, 25 Mar 2015 07:54:01 -0600 From: Laurent Dufour Subject: [PATCH v3 1/2] mm: Introducing arch_remap hook Date: Wed, 25 Mar 2015 14:53:51 +0100 Message-Id: In-Reply-To: References: In-Reply-To: References: <20150325121118.GA2542@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Some architecture would like to be triggered when a memory area is moved through the mremap system call. This patch is introducing a new arch_remap mm hook which is placed in the path of mremap, and is called before the old area is unmapped (and the arch_unmap hook is called). The architectures which need to call this hook should define __HAVE_ARCH_REMAP in their asm/mmu_context.h and provide the arch_remap service with the following prototype: void arch_remap(struct mm_struct *mm, unsigned long old_start, unsigned long old_end, unsigned long new_start, unsigned long new_end); Signed-off-by: Laurent Dufour --- mm/mremap.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index 57dadc025c64..bafc234db45c 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -25,6 +25,7 @@ #include #include +#include #include "internal.h" @@ -286,8 +287,14 @@ static unsigned long move_vma(struct vm_area_struct *vma, old_len = new_len; old_addr = new_addr; new_addr = -ENOMEM; - } else if (vma->vm_file && vma->vm_file->f_op->mremap) - vma->vm_file->f_op->mremap(vma->vm_file, new_vma); + } else { + if (vma->vm_file && vma->vm_file->f_op->mremap) + vma->vm_file->f_op->mremap(vma->vm_file, new_vma); +#ifdef __HAVE_ARCH_REMAP + arch_remap(mm, old_addr, old_addr+old_len, + new_addr, new_addr+new_len); +#endif + } /* Conceal VM_ACCOUNT so old reservation is not undone */ if (vm_flags & VM_ACCOUNT) { -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) by kanga.kvack.org (Postfix) with ESMTP id 109C46B006E for ; Wed, 25 Mar 2015 09:54:10 -0400 (EDT) Received: by wixw10 with SMTP id w10so75102134wix.0 for ; Wed, 25 Mar 2015 06:54:09 -0700 (PDT) Received: from e06smtp11.uk.ibm.com (e06smtp11.uk.ibm.com. [195.75.94.107]) by mx.google.com with ESMTPS id gt6si5219807wib.23.2015.03.25.06.54.08 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 25 Mar 2015 06:54:08 -0700 (PDT) Received: from /spool/local by e06smtp11.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Mar 2015 13:54:07 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 4004E17D8056 for ; Wed, 25 Mar 2015 13:54:33 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t2PDs5h166650168 for ; Wed, 25 Mar 2015 13:54:05 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t2PDs2Gk003182 for ; Wed, 25 Mar 2015 07:54:05 -0600 From: Laurent Dufour Subject: [PATCH v3 2/2] powerpc/mm: Tracking vDSO remap Date: Wed, 25 Mar 2015 14:53:52 +0100 Message-Id: In-Reply-To: References: In-Reply-To: References: <20150325121118.GA2542@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: cov@codeaurora.org, criu@openvz.org Some processes (CRIU) are moving the vDSO area using the mremap system call. As a consequence the kernel reference to the vDSO base address is no more valid and the signal return frame built once the vDSO has been moved is not pointing to the new sigreturn address. This patch handles vDSO remapping and unmapping. Signed-off-by: Laurent Dufour --- arch/powerpc/include/asm/mmu_context.h | 36 +++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 73382eba02dc..7d315c1898d4 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -8,7 +8,6 @@ #include #include #include -#include #include /* @@ -109,5 +108,40 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, #endif } +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 (start <= mm->context.vdso_base && mm->context.vdso_base < end) + mm->context.vdso_base = 0; +} + +static inline void arch_bprm_mm_init(struct mm_struct *mm, + struct vm_area_struct *vma) +{ +} + +#define __HAVE_ARCH_REMAP +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 (old_start == mm->context.vdso_base) + mm->context.vdso_base = new_start; +} + #endif /* __KERNEL__ */ #endif /* __ASM_POWERPC_MMU_CONTEXT_H */ -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f51.google.com (mail-wg0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 924906B0032 for ; Wed, 25 Mar 2015 14:33:23 -0400 (EDT) Received: by wgra20 with SMTP id a20so37648658wgr.3 for ; Wed, 25 Mar 2015 11:33:23 -0700 (PDT) Received: from mail-wg0-x234.google.com (mail-wg0-x234.google.com. [2a00:1450:400c:c00::234]) by mx.google.com with ESMTPS id ey12si6417211wid.87.2015.03.25.11.33.21 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Mar 2015 11:33:21 -0700 (PDT) Received: by wgdm6 with SMTP id m6so37930987wgd.2 for ; Wed, 25 Mar 2015 11:33:21 -0700 (PDT) Date: Wed, 25 Mar 2015 19:33:16 +0100 From: Ingo Molnar Subject: Re: [PATCH v3 2/2] powerpc/mm: Tracking vDSO remap Message-ID: <20150325183316.GA9090@gmail.com> References: <20150325121118.GA2542@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jeff Dike , Richard Weinberger , Guan Xuetao , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, user-mode-linux-user@lists.sourceforge.net, linux-arch@vger.kernel.org, linux-mm@kvack.org, cov@codeaurora.org, criu@openvz.org * Laurent Dufour wrote: > +static inline void arch_unmap(struct mm_struct *mm, > + struct vm_area_struct *vma, > + unsigned long start, unsigned long end) > +{ > + if (start <= mm->context.vdso_base && mm->context.vdso_base < end) > + mm->context.vdso_base = 0; > +} So AFAICS PowerPC can have multi-page vDSOs, right? So what happens if I munmap() the middle or end of the vDSO? The above condition only seems to cover unmaps that affect the first page. I think 'affects any page' ought to be the right condition? (But I know nothing about PowerPC so I might be wrong.) > +#define __HAVE_ARCH_REMAP > +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 (old_start == mm->context.vdso_base) > + mm->context.vdso_base = new_start; > +} mremap() doesn't allow moving multiple vmas, but it allows the movement of multi-page vmas and it also allows partial mremap()s, where it will split up a vma. In particular, what happens if an mremap() is done with old_start == vdso_base, but a shorter end than the end of the vDSO? (i.e. a partial mremap() with fewer pages than the vDSO size) Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f176.google.com (mail-wi0-f176.google.com [209.85.212.176]) by kanga.kvack.org (Postfix) with ESMTP id A03156B0032 for ; Wed, 25 Mar 2015 14:36:53 -0400 (EDT) Received: by wibg7 with SMTP id g7so120384612wib.1 for ; Wed, 25 Mar 2015 11:36:53 -0700 (PDT) Received: from mail-wi0-x232.google.com (mail-wi0-x232.google.com. [2a00:1450:400c:c05::232]) by mx.google.com with ESMTPS id p8si5757906wjx.82.2015.03.25.11.36.51 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Mar 2015 11:36:52 -0700 (PDT) Received: by wixw10 with SMTP id w10so81036556wix.0 for ; Wed, 25 Mar 2015 11:36:51 -0700 (PDT) Date: Wed, 25 Mar 2015 19:36:47 +0100 From: Ingo Molnar Subject: Re: [PATCH v3 2/2] powerpc/mm: Tracking vDSO remap Message-ID: <20150325183647.GA9331@gmail.com> References: <20150325121118.GA2542@gmail.com> <20150325183316.GA9090@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150325183316.GA9090@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Laurent Dufour Cc: Benjamin Herrenschmidt