On 25/06/2015 09:12, Geert Uytterhoeven wrote:
> On Thu, Jun 25, 2015 at 6:08 AM, Linux Kernel Mailing List
> <linux-kernel@vger.kernel.org> wrote:
>> Gitweb:
>> http://git.kernel.org/linus/;a=commit;h=2ae416b142b625c58c9ccb039aa3ef48ad0e9bae
>> Commit: 2ae416b142b625c58c9ccb039aa3ef48ad0e9bae
>> Parent: e81f2d22370f8231cb7f13f454bcc8c0eb4e23f2
>> Refname: refs/heads/master
>> Author: Laurent Dufour <lduf...@linux.vnet.ibm.com>
>> AuthorDate: Wed Jun 24 16:56:16 2015 -0700
>> Committer: Linus Torvalds <torva...@linux-foundation.org>
>> CommitDate: Wed Jun 24 17:49:41 2015 -0700
>>
>> mm: new mm hook framework
>>
>> 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 framework, and a new
>> arch_remap hook 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.
>>
>> This patch (of 3):
>>
>> This patch introduces a new set of header file to manage mm hooks:
>> - per architecture empty header file (arch/x/include/asm/mm-arch-hooks.h)
>> - a generic header (include/linux/mm-arch-hooks.h)
>>
>> The architecture which need to overwrite a hook as to redefine it in its
>> header file, while architecture which doesn't need have nothing to do.
>>
>> The default hooks are defined in the generic header and are used in the
>> case the architecture is not defining it.
>>
>> In a next step, mm hooks defined in include/asm-generic/mm_hooks.h should
>> be moved here.
>>
>> Signed-off-by: Laurent Dufour <lduf...@linux.vnet.ibm.com>
>> Suggested-by: Andrew Morton <a...@linux-foundation.org>
>> Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com>
>> Cc: Hugh Dickins <hu...@google.com>
>> Cc: Rik van Riel <r...@redhat.com>
>> Cc: Mel Gorman <mgor...@suse.de>
>> Cc: Pavel Emelyanov <xe...@parallels.com>
>> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
>> Cc: Paul Mackerras <pau...@samba.org>
>> Cc: Michael Ellerman <m...@ellerman.id.au>
>> Cc: Ingo Molnar <mi...@kernel.org>
>> Signed-off-by: Andrew Morton <a...@linux-foundation.org>
>> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
>> ---
>> arch/alpha/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/arc/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/arm/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/arm64/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/avr32/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/blackfin/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/c6x/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/cris/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/frv/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/hexagon/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/ia64/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/m32r/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/m68k/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/metag/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/microblaze/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/mips/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/mn10300/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/nios2/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/openrisc/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/parisc/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/powerpc/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/s390/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/score/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/sh/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/sparc/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/tile/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/um/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/unicore32/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/x86/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> arch/xtensa/include/asm/mm-arch-hooks.h | 15 +++++++++++++++
>> include/linux/mm-arch-hooks.h | 16 ++++++++++++++++
>
> Touching all arch/ directories without a CC to linux-arch?
I apologizes, this thread initially was only involving arch/powerpc
files, and following multiple advices it came to impact all arch.
>
>> 31 files changed, 466 insertions(+)
>>
>> diff --git a/arch/alpha/include/asm/mm-arch-hooks.h
>> b/arch/alpha/include/asm/mm-arch-hooks.h
>> new file mode 100644
>> index 0000000..b07fd86
>> --- /dev/null
>> +++ b/arch/alpha/include/asm/mm-arch-hooks.h
>> @@ -0,0 +1,15 @@
>> +/*
>> + * Architecture specific mm hooks
>> + *
>> + * Copyright (C) 2015, IBM Corporation
>> + * Author: Laurent Dufour <lduf...@linux.vnet.ibm.com>
>
> Cool, copyright on an empty header!
>
>> + *
>> + * 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_ALPHA_MM_ARCH_HOOKS_H
>> +#define _ASM_ALPHA_MM_ARCH_HOOKS_H
>> +
>> +#endif /* _ASM_ALPHA_MM_ARCH_HOOKS_H */
>
> [...]
>
> IMHO this screams for the generic version in include/asm-generic/,
> and "generic-y += mm-arch-hooks.h" in arch/*/include/asm/Kbuild/.
I do like your proposal which avoid creating too many *empty* files.
Since Andrew suggested the way I did the current patch, I'd appreciate
his feedback too.
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> ge...@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like
> that.
> -- Linus Torvalds
>
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