linux-kernel - Re: [PATCH 24/27] Documentation: x86: convert x86

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Message-ID: <20190427153602.14835973@coco.lan>
Date:   Sat, 27 Apr 2019 15:36:02 -0300
From:   Mauro Carvalho Chehab <mchehab+samsung@...nel.org>
To:     Changbin Du <changbin.du@...il.com>
Cc:     Jonathan Corbet <corbet@....net>, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 24/27] Documentation: x86: convert
 x86_64/5level-paging.txt to reST

Em Fri, 26 Apr 2019 23:31:47 +0800
Changbin Du <changbin.du@...il.com> escreveu:

> This converts the plain text documentation to reStructuredText format and
> add it to Sphinx TOC tree. No essential content change.
> 
> Signed-off-by: Changbin Du <changbin.du@...il.com>

Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@...nel.org>

> ---
>  .../{5level-paging.txt => 5level-paging.rst}     | 16 +++++++++++-----
>  Documentation/x86/x86_64/index.rst               |  1 +
>  2 files changed, 12 insertions(+), 5 deletions(-)
>  rename Documentation/x86/x86_64/{5level-paging.txt => 5level-paging.rst} (91%)
> 
> diff --git a/Documentation/x86/x86_64/5level-paging.txt b/Documentation/x86/x86_64/5level-paging.rst
> similarity index 91%
> rename from Documentation/x86/x86_64/5level-paging.txt
> rename to Documentation/x86/x86_64/5level-paging.rst
> index 2432a5ef86d9..ab88a4514163 100644
> --- a/Documentation/x86/x86_64/5level-paging.txt
> +++ b/Documentation/x86/x86_64/5level-paging.rst
> @@ -1,5 +1,11 @@
> -== Overview ==
> +.. SPDX-License-Identifier: GPL-2.0
>  
> +==============
> +5-level paging
> +==============
> +
> +Overview
> +========
>  Original x86-64 was limited by 4-level paing to 256 TiB of virtual address
>  space and 64 TiB of physical address space. We are already bumping into
>  this limit: some vendors offers servers with 64 TiB of memory today.
> @@ -16,16 +22,17 @@ QEMU 2.9 and later support 5-level paging.
>  Virtual memory layout for 5-level paging is described in
>  Documentation/x86/x86_64/mm.txt
>  
> -== Enabling 5-level paging ==
>  
> +Enabling 5-level paging
> +=======================
>  CONFIG_X86_5LEVEL=y enables the feature.
>  
>  Kernel with CONFIG_X86_5LEVEL=y still able to boot on 4-level hardware.
>  In this case additional page table level -- p4d -- will be folded at
>  runtime.
>  
> -== User-space and large virtual address space ==
> -
> +User-space and large virtual address space
> +==========================================
>  On x86, 5-level paging enables 56-bit userspace virtual address space.
>  Not all user space is ready to handle wide addresses. It's known that
>  at least some JIT compilers use higher bits in pointers to encode their
> @@ -58,4 +65,3 @@ One important case we need to handle here is interaction with MPX.
>  MPX (without MAWA extension) cannot handle addresses above 47-bit, so we
>  need to make sure that MPX cannot be enabled we already have VMA above
>  the boundary and forbid creating such VMAs once MPX is enabled.
> -
> diff --git a/Documentation/x86/x86_64/index.rst b/Documentation/x86/x86_64/index.rst
> index 4b65d29ef459..7b8c82151358 100644
> --- a/Documentation/x86/x86_64/index.rst
> +++ b/Documentation/x86/x86_64/index.rst
> @@ -10,3 +10,4 @@ x86_64 Support
>     boot-options
>     uefi
>     mm
> +   5level-paging



Thanks,
Mauro