[PATCH 19/57] docs: kdump: convert it to ReST

Mauro Carvalho Chehab
2019-04-16T02:58:22Z

Convert kdump documentation to ReST and add it to the
user faced manual, as the documents are mainly focused on
sysadmins that would be enabling kdump.

Note: the vmcoreinfo.rst has one very long title for
sub-sections. I opted to break this one, in order to make it
easier to display in html.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
Documentation/kdump/kdump.txt | 131 +++++++++++++++++------------
Documentation/kdump/vmcoreinfo.txt | 59 ++++++-------
2 files changed, 104 insertions(+), 86 deletions(-)

diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 51814450a7f8..1da2d7b765f6 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -71,9 +71,8 @@ This is a symlink to the latest version.

The latest kexec-tools git tree is available at:

-git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
-and
-http://www.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
+- git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
+- http://www.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git

There is also a gitweb interface available at
http://www.kernel.org/git/?p=utils/kernel/kexec/kexec-tools.git
@@ -81,25 +80,25 @@ http://www.kernel.org/git/?p=utils/kernel/kexec/kexec-tools.git
More information about kexec-tools can be found at
http://horms.net/projects/kexec/

-3) Unpack the tarball with the tar command, as follows:
+3) Unpack the tarball with the tar command, as follows::

- tar xvpzf kexec-tools.tar.gz
+ tar xvpzf kexec-tools.tar.gz

-4) Change to the kexec-tools directory, as follows:
+4) Change to the kexec-tools directory, as follows::

- cd kexec-tools-VERSION
+ cd kexec-tools-VERSION

-5) Configure the package, as follows:
+5) Configure the package, as follows::

- ./configure
+ ./configure

-6) Compile the package, as follows:
+6) Compile the package, as follows::

- make
+ make

-7) Install the package, as follows:
+7) Install the package, as follows::

- make install
+ make install

Build the system and dump-capture kernels
@@ -126,25 +125,25 @@ dump-capture kernels for enabling kdump support.
System kernel config options
----------------------------

-1) Enable "kexec system call" in "Processor type and features."
+1) Enable "kexec system call" in "Processor type and features."::

- CONFIG_KEXEC=y
+ CONFIG_KEXEC=y

2) Enable "sysfs file system support" in "Filesystem" -> "Pseudo
- filesystems." This is usually enabled by default.
+ filesystems." This is usually enabled by default::

- CONFIG_SYSFS=y
+ CONFIG_SYSFS=y

Note that "sysfs file system support" might not appear in the "Pseudo
filesystems" menu if "Configure standard kernel features (for small
systems)" is not enabled in "General Setup." In this case, check the
- .config file itself to ensure that sysfs is turned on, as follows:
+ .config file itself to ensure that sysfs is turned on, as follows::

- grep 'CONFIG_SYSFS' .config
+ grep 'CONFIG_SYSFS' .config

-3) Enable "Compile the kernel with debug info" in "Kernel hacking."
+3) Enable "Compile the kernel with debug info" in "Kernel hacking."::

- CONFIG_DEBUG_INFO=Y
+ CONFIG_DEBUG_INFO=Y

This causes the kernel to be built with debug symbols. The dump
analysis tools require a vmlinux with debug symbols in order to read
@@ -154,29 +153,32 @@ Dump-capture kernel config options (Arch Independent)
-----------------------------------------------------

1) Enable "kernel crash dumps" support under "Processor type and
- features":
+ features"::

- CONFIG_CRASH_DUMP=y
+ CONFIG_CRASH_DUMP=y

-2) Enable "/proc/vmcore support" under "Filesystems" -> "Pseudo filesystems".
+2) Enable "/proc/vmcore support" under "Filesystems" -> "Pseudo filesystems"::
+
+ CONFIG_PROC_VMCORE=y

- CONFIG_PROC_VMCORE=y
(CONFIG_PROC_VMCORE is set by default when CONFIG_CRASH_DUMP is selected.)

Dump-capture kernel config options (Arch Dependent, i386 and x86_64)
--------------------------------------------------------------------

1) On i386, enable high memory support under "Processor type and
- features":
+ features"::

- CONFIG_HIGHMEM64G=y
- or
- CONFIG_HIGHMEM4G
+ CONFIG_HIGHMEM64G=y
+
+ or::
+
+ CONFIG_HIGHMEM4G

2) On i386 and x86_64, disable symmetric multi-processing support
- under "Processor type and features":
+ under "Processor type and features"::

- CONFIG_SMP=n
+ CONFIG_SMP=n

(If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line
when loading the dump-capture kernel, see section "Load the Dump-capture
@@ -184,9 +186,9 @@ Dump-capture kernel config options (Arch Dependent, i386 and x86_64)

3) If one wants to build and use a relocatable kernel,
Enable "Build a relocatable kernel" support under "Processor type and
- features"
+ features"::

- CONFIG_RELOCATABLE=y
+ CONFIG_RELOCATABLE=y

4) Use a suitable value for "Physical address where the kernel is
loaded" (under "Processor type and features"). This only appears when
@@ -211,13 +213,13 @@ Dump-capture kernel config options (Arch Dependent, i386 and x86_64)
Dump-capture kernel config options (Arch Dependent, ppc64)
----------------------------------------------------------

-1) Enable "Build a kdump crash kernel" support under "Kernel" options:
+1) Enable "Build a kdump crash kernel" support under "Kernel" options::

- CONFIG_CRASH_DUMP=y
+ CONFIG_CRASH_DUMP=y

-2) Enable "Build a relocatable kernel" support
+2) Enable "Build a relocatable kernel" support::

- CONFIG_RELOCATABLE=y
+ CONFIG_RELOCATABLE=y

Make and install the kernel and its modules.

@@ -231,11 +233,13 @@ Dump-capture kernel config options (Arch Dependent, ia64)

The crashkernel region can be automatically placed by the system
kernel at run time. This is done by specifying the base address as 0,
- or omitting it all together.
+ or omitting it all together::

- crashkernel=256M@0
- or
- crashkernel=256M
+ crashkernel=256M@0
+
+ or::
+
+ crashkernel=256M

If the start address is specified, note that the start address of the
kernel will be aligned to 64Mb, so if the start address is not then
@@ -245,9 +249,9 @@ Dump-capture kernel config options (Arch Dependent, arm)
----------------------------------------------------------

- To use a relocatable kernel,
- Enable "AUTO_ZRELADDR" support under "Boot" options:
+ Enable "AUTO_ZRELADDR" support under "Boot" options::

- AUTO_ZRELADDR=y
+ AUTO_ZRELADDR=y

Dump-capture kernel config options (Arch Dependent, arm64)
----------------------------------------------------------
@@ -265,12 +269,12 @@ on the value of System RAM -- that's mostly for distributors that pre-setup
the kernel command line to avoid a unbootable system after some memory has
been removed from the machine.

-The syntax is:
+The syntax is::

crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset]
range=start-[end]

-For example:
+For example::

crashkernel=512M-2G:64M,2G-:128M

@@ -326,35 +330,46 @@ can choose to load the uncompressed vmlinux or compressed bzImage/vmlinuz
of dump-capture kernel. Following is the summary.

For i386 and x86_64:
+
- Use vmlinux if kernel is not relocatable.
- Use bzImage/vmlinuz if kernel is relocatable.
+
For ppc64:
+
- Use vmlinux
+
For ia64:
+
- Use vmlinux or vmlinuz.gz
+
For s390x:
+
- Use image or bzImage
+
For arm:
+
- Use zImage
+
For arm64:
+
- Use vmlinux or Image

If you are using an uncompressed vmlinux image then use following command
-to load dump-capture kernel.
+to load dump-capture kernel::

kexec -p <dump-capture-kernel-vmlinux-image> \
--initrd=<initrd-for-dump-capture-kernel> --args-linux \
--append="root=<root-dev> <arch-specific-options>"

If you are using a compressed bzImage/vmlinuz, then use following command
-to load dump-capture kernel.
+to load dump-capture kernel::

kexec -p <dump-capture-kernel-bzImage> \
--initrd=<initrd-for-dump-capture-kernel> \
--append="root=<root-dev> <arch-specific-options>"

If you are using a compressed zImage, then use following command
-to load dump-capture kernel.
+to load dump-capture kernel::

kexec --type zImage -p <dump-capture-kernel-bzImage> \
--initrd=<initrd-for-dump-capture-kernel> \
@@ -362,7 +377,7 @@ to load dump-capture kernel.
--append="root=<root-dev> <arch-specific-options>"

If you are using an uncompressed Image, then use following command
-to load dump-capture kernel.
+to load dump-capture kernel::

kexec -p <dump-capture-kernel-Image> \
--initrd=<initrd-for-dump-capture-kernel> \
@@ -376,18 +391,23 @@ Following are the arch specific command line options to be used while
loading dump-capture kernel.

For i386, x86_64 and ia64:
+
"1 irqpoll maxcpus=1 reset_devices"

For ppc64:
+
"1 maxcpus=1 noirqdistrib reset_devices"

For s390x:
+
"1 maxcpus=1 cgroup_disable=memory"

For arm:
+
"1 maxcpus=1 reset_devices"

For arm64:
+
"1 maxcpus=1 reset_devices"

Notes on loading the dump-capture kernel:
@@ -464,7 +484,7 @@ Write Out the Dump File
=======================

After the dump-capture kernel is booted, write out the dump file with
-the following command:
+the following command::

cp /proc/vmcore <dump-file>

@@ -476,7 +496,7 @@ Before analyzing the dump image, you should reboot into a stable kernel.

You can do limited analysis using GDB on the dump file copied out of
/proc/vmcore. Use the debug vmlinux built with -g and run the following
-command:
+command::

gdb vmlinux <dump-file>

@@ -504,6 +524,11 @@ to achieve the same behaviour.
Contact
=======

-Vivek Goyal (vgoyal@redhat.com)
-Maneesh Soni (maneesh@in.ibm.com)
+- Vivek Goyal (vgoyal@redhat.com)
+- Maneesh Soni (maneesh@in.ibm.com)

+GDB macros
+==========
+
+.. include:: gdbmacros.txt
+ :literal:
diff --git a/Documentation/kdump/vmcoreinfo.txt b/Documentation/kdump/vmcoreinfo.txt
index bb94a4bd597a..007a6b86e0ee 100644
--- a/Documentation/kdump/vmcoreinfo.txt
+++ b/Documentation/kdump/vmcoreinfo.txt
@@ -1,8 +1,7 @@
-================================================================
- VMCOREINFO
-================================================================
+==========
+VMCOREINFO
+==========

-===========
What is it?
===========

@@ -12,7 +11,6 @@ values, field offsets, etc. These data are packed into an ELF note
section and used by user-space tools like crash and makedumpfile to
analyze a kernel's memory layout.

-================
Common variables
================

@@ -49,7 +47,7 @@ in a system, one bit position per node number. Used to keep track of
which nodes are in the system and online.

swapper_pg_dir
--------------
+--------------

The global page directory pointer of the kernel. Used to translate
virtual to physical addresses.
@@ -132,16 +130,14 @@ nodemask_t
The size of a nodemask_t type. Used to compute the number of online
nodes.

-(page, flags|_refcount|mapping|lru|_mapcount|private|compound_dtor|
- compound_order|compound_head)
--------------------------------------------------------------------
+(page, flags|_refcount|mapping|lru|_mapcount|private|compound_dtor|compound_order|compound_head)
+-------------------------------------------------------------------------------------------------

User-space tools compute their values based on the offset of these
variables. The variables are used when excluding unnecessary pages.

-(pglist_data, node_zones|nr_zones|node_mem_map|node_start_pfn|node_
- spanned_pages|node_id)
--------------------------------------------------------------------
+(pglist_data, node_zones|nr_zones|node_mem_map|node_start_pfn|node_spanned_pages|node_id)
+-----------------------------------------------------------------------------------------

On NUMA machines, each NUMA node has a pg_data_t to describe its memory
layout. On UMA machines there is a single pglist_data which describes the
@@ -245,21 +241,25 @@ NR_FREE_PAGES
On linux-2.6.21 or later, the number of free pages is in
vm_stat[NR_FREE_PAGES]. Used to get the number of free pages.

-PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision
-|PG_head_mask|PAGE_BUDDY_MAPCOUNT_VALUE(~PG_buddy)
-|PAGE_OFFLINE_MAPCOUNT_VALUE(~PG_offline)
------------------------------------------------------------------
+PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision|PG_head_mask
+------------------------------------------------------------------------------

Page attributes. These flags are used to filter various unnecessary for
dumping pages.

+PAGE_BUDDY_MAPCOUNT_VALUE(~PG_buddy)|PAGE_OFFLINE_MAPCOUNT_VALUE(~PG_offline)
+-----------------------------------------------------------------------------
+
+More page attributes. These flags are used to filter various unnecessary for
+dumping pages.
+
+
HUGETLB_PAGE_DTOR
-----------------

The HUGETLB_PAGE_DTOR flag denotes hugetlbfs pages. Makedumpfile
excludes these pages.

-======
x86_64
======

@@ -318,12 +318,12 @@ address.
Currently, sme_mask stores the value of the C-bit position. If needed,
additional SME-relevant info can be placed in that variable.

-For example:
-[ misc ][ enc bit ][ other misc SME info ]
-0000_0000_0000_0000_1000_0000_0000_0000_0000_0000_..._0000
-63 59 55 51 47 43 39 35 31 27 ... 3
+For example::
+
+ [ misc ][ enc bit ][ other misc SME info ]
+ 0000_0000_0000_0000_1000_0000_0000_0000_0000_0000_..._0000
+ 63 59 55 51 47 43 39 35 31 27 ... 3

-======
x86_32
======

@@ -335,7 +335,6 @@ of a higher page table lookup overhead, and also consumes more page
table space per process. Used to check whether PAE was enabled in the
crash kernel when converting virtual addresses to physical addresses.

-====
ia64
====

@@ -366,7 +365,6 @@ PGTABLE_3|PGTABLE_4
User-space tools need to know whether the crash kernel was in 3-level or
4-level paging mode. Used to distinguish the page table.

-=====
ARM64
=====

@@ -395,9 +393,8 @@ KERNELOFFSET
The kernel randomization offset. Used to compute the page offset. If
KASLR is disabled, this value is zero.

-====
arm
-====
+===

ARM_LPAE
--------
@@ -405,12 +402,11 @@ ARM_LPAE
It indicates whether the crash kernel supports large physical address
extensions. Used to translate virtual to physical addresses.

-====
s390
====

lowcore_ptr
-----------
+-----------

An array with a pointer to the lowcore of every CPU. Used to print the
psw and all registers information.
@@ -425,7 +421,6 @@ Used to get the vmalloc_start address from the high_memory symbol.

The maximum number of CPUs.

-=======
powerpc
=======

@@ -460,9 +455,8 @@ Page size definitions, i.e. 4k, 64k, or 16M.

Used to make vtop translations.

-vmemmap_backing|(vmemmap_backing, list)|(vmemmap_backing, phys)|
-(vmemmap_backing, virt_addr)
-----------------------------------------------------------------
+vmemmap_backing|(vmemmap_backing, list)|(vmemmap_backing, phys)|(vmemmap_backing, virt_addr)
+--------------------------------------------------------------------------------------------

The vmemmap virtual address space management does not have a traditional
page table to track which virtual struct pages are backed by a physical
@@ -480,7 +474,6 @@ member.

Used in vtop translations.

-==
sh
==

--
2.20.1