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From: Hari Bathini <hbathini@linux.ibm.com>
To: linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.ibm.com>,
	Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
	Vasant Hegde <hegdevasant@linux.ibm.com>,
	Oliver <oohall@gmail.com>, Nicholas Piggin <npiggin@gmail.com>,
	Daniel Axtens <dja@axtens.net>
Subject: [PATCH v6 04/36] powerpc/fadump: Improve fadump documentation
Date: Wed, 11 Sep 2019 20:17:07 +0530
Message-ID: <156821322070.5656.8194734198500730487.stgit@hbathini.in.ibm.com> (raw)
In-Reply-To: <156821308145.5656.2233728784001623843.stgit@hbathini.in.ibm.com>

The figures depicting FADump's (Firmware-Assisted Dump) memory layout
are missing some finer details like different memory regions and what
they represent. Improve the documentation by updating those details.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---

* No changes in v6.


 Documentation/powerpc/firmware-assisted-dump.rst |   61 ++++++++++++----------
 1 file changed, 33 insertions(+), 28 deletions(-)

diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index 9ca1283..563c021 100644
--- a/Documentation/powerpc/firmware-assisted-dump.rst
+++ b/Documentation/powerpc/firmware-assisted-dump.rst
@@ -76,8 +76,9 @@ as follows:
    there is crash data available from a previous boot. During
    the early boot OS will reserve rest of the memory above
    boot memory size effectively booting with restricted memory
-   size. This will make sure that the second kernel will not
-   touch any of the dump memory area.
+   size. This will make sure that this kernel (also, referred
+   to as second kernel or capture kernel) will not touch any
+   of the dump memory area.
 
 -  User-space tools will read /proc/vmcore to obtain the contents
    of memory, which holds the previous crashed kernel dump in ELF
@@ -128,42 +129,46 @@ space memory except the user pages that were present in CMA region::
 
   o Memory Reservation during first kernel
 
-  Low memory                                         Top of memory
-  0      boot memory size                                       |
-  |           |                |<--Reserved dump area -->|      |
-  V           V                |   Permanent Reservation |      V
-  +-----------+----------/ /---+---+----+-----------+----+------+
-  |           |                |CPU|HPTE|  DUMP     |ELF |      |
-  +-----------+----------/ /---+---+----+-----------+----+------+
-        |                                           ^
-        |                                           |
-        \                                           /
-         -------------------------------------------
-          Boot memory content gets transferred to
-          reserved area by firmware at the time of
-          crash
+  Low memory                                                Top of memory
+  0      boot memory size      |<--Reserved dump area --->|      |
+  |           |                | (Permanent Reservation)  |      |
+  V           V                |                          |      V
+  +-----------+----------/ /---+---+----+--------+---+----+------+
+  |           |                |CPU|HPTE|  DUMP  |HDR|ELF |      |
+  +-----------+----------/ /---+---+----+--------+---+----+------+
+        |                                   ^      ^
+        |                                   |      |
+        \                                   /      |
+         -----------------------------------     FADump Header
+          Boot memory content gets transferred   (meta area)
+          to reserved area by firmware at the
+          time of crash
+
                    Fig. 1
 
+
   o Memory Reservation during second kernel after crash
 
-  Low memory                                        Top of memory
-  0      boot memory size                                       |
-  |           |<------------- Reserved dump area ----------- -->|
-  V           V                                                 V
-  +-----------+----------/ /---+---+----+-----------+----+------+
-  |           |                |CPU|HPTE|  DUMP     |ELF |      |
-  +-----------+----------/ /---+---+----+-----------+----+------+
+  Low memory                                                Top of memory
+  0      boot memory size                                        |
+  |           |<----------- Crash preserved area --------------->|
+  V           V                |<-- Reserved dump area -->|      V
+  +-----------+----------/ /---+---+----+--------+---+----+------+
+  |           |                |CPU|HPTE|  DUMP  |HDR|ELF |      |
+  +-----------+----------/ /---+---+----+--------+---+----+------+
         |                                              |
         V                                              V
    Used by second                                /proc/vmcore
    kernel to boot
                    Fig. 2
 
-Currently the dump will be copied from /proc/vmcore to a
-a new file upon user intervention. The dump data available through
-/proc/vmcore will be in ELF format. Hence the existing kdump
-infrastructure (kdump scripts) to save the dump works fine with
-minor modifications.
+Currently the dump will be copied from /proc/vmcore to a new file upon
+user intervention. The dump data available through /proc/vmcore will be
+in ELF format. Hence the existing kdump infrastructure (kdump scripts)
+to save the dump works fine with minor modifications. KDump scripts on
+major Distro releases have already been modified to work seemlessly (no
+user intervention in saving the dump) when FADump is used, instead of
+KDump, as dump mechanism.
 
 The tools to examine the dump will be same as the ones
 used for kdump.


  parent reply index

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-11 14:45 [PATCH v6 00/36] Add FADump support on PowerNV platform Hari Bathini
2019-09-11 14:46 ` [PATCH v6 01/36] powerpc/fadump: move internal macros/definitions to a new header Hari Bathini
2019-09-19 10:25   ` Michael Ellerman
2019-09-11 14:46 ` [PATCH v6 02/36] powerpc/fadump: add helper functions Hari Bathini
2019-09-11 14:46 ` [PATCH v6 03/36] powerpc/fadump: declare helper functions in internal header file Hari Bathini
2019-09-11 14:47 ` Hari Bathini [this message]
2019-09-11 14:47 ` [PATCH v6 05/36] powerpc/fadump: use helper functions to reserve/release cpu notes buffer Hari Bathini
2019-09-11 14:48 ` [PATCH v6 06/36] pseries/fadump: move rtas specific definitions to platform code Hari Bathini
2019-09-11 14:48 ` [PATCH v6 07/36] pseries/fadump: introduce callbacks for platform specific operations Hari Bathini
2019-09-11 14:48 ` [PATCH v6 08/36] pseries/fadump: define RTAS register/un-register callback functions Hari Bathini
2019-09-11 14:49 ` [PATCH v6 09/36] pseries/fadump: add source info while displaying region contents Hari Bathini
2019-09-11 14:49 ` [PATCH v6 10/36] powerpc/fadump: release all the memory above boot memory size Hari Bathini
2019-09-11 14:49 ` [PATCH v6 11/36] pseries/fadump: move out platform specific support from generic code Hari Bathini
2019-09-11 14:49 ` [PATCH v6 12/36] powerpc/fadump: use FADump instead of fadump for how it is pronounced Hari Bathini
2019-09-11 14:50 ` [PATCH v6 13/36] opal: add MPIPL interface definitions Hari Bathini
2019-09-11 14:50 ` [PATCH v6 14/36] powernv/fadump: add fadump support on powernv Hari Bathini
2019-09-11 14:50 ` [PATCH v6 15/36] powerpc/fadump: improve fadump_reserve_mem() Hari Bathini
2019-09-11 14:50 ` [PATCH v6 16/36] powernv/fadump: register kernel metadata address with opal Hari Bathini
2019-09-11 14:51 ` [PATCH v6 17/36] powernv/fadump: reset metadata address during clean up Hari Bathini
2019-09-11 14:51 ` [PATCH v6 18/36] powernv/fadump: define OPAL register/un-register callback functions Hari Bathini
2019-09-11 14:51 ` [PATCH v6 19/36] powernv/fadump: support copying multiple kernel boot memory regions Hari Bathini
2019-09-11 14:51 ` [PATCH v6 20/36] powernv/fadump: process the crashdump by exporting it as /proc/vmcore Hari Bathini
2019-09-11 14:52 ` [PATCH v6 21/36] powernv/fadump: Warn before processing partial crashdump Hari Bathini
2019-09-11 14:53 ` [PATCH v6 22/36] powernv/fadump: handle invalidation of crashdump and re-registraion Hari Bathini
2019-09-11 14:53 ` [PATCH v6 23/36] powerpc/fadump: Update documentation about OPAL platform support Hari Bathini
2019-09-11 14:54 ` [PATCH v6 24/36] powerpc/fadump: make use of memblock's bottom up allocation mode Hari Bathini
2019-09-11 14:54 ` [PATCH v6 25/36] powernv/fadump: process architected register state data provided by firmware Hari Bathini
2019-09-11 14:55 ` [PATCH v6 26/36] powerpc/fadump: make crash memory ranges array allocation generic Hari Bathini
2019-09-11 14:55 ` [PATCH v6 27/36] powerpc/fadump: consider reserved ranges while releasing memory Hari Bathini
2019-09-11 14:55 ` [PATCH v6 28/36] powerpc/fadump: improve how crashed kernel's memory is reserved Hari Bathini
2019-09-11 14:56 ` [PATCH v6 29/36] powernv/fadump: add support to preserve crash data on FADUMP disabled kernel Hari Bathini
2019-09-11 14:56 ` [PATCH v6 30/36] powerpc/fadump: update documentation about CONFIG_PRESERVE_FA_DUMP Hari Bathini
2019-09-11 14:56 ` [PATCH v6 31/36] powernv/opalcore: export /sys/firmware/opal/core for analysing opal crashes Hari Bathini
2019-09-11 14:56 ` [PATCH v6 32/36] powernv/opalcore: provide an option to invalidate /sys/firmware/opal/core file Hari Bathini
2019-09-11 14:56 ` [PATCH v6 33/36] powerpc/fadump: consider f/w load area Hari Bathini
2019-09-11 14:57 ` [PATCH v6 34/36] powernv/fadump: update documentation about option to release opalcore Hari Bathini
2019-09-11 14:57 ` [PATCH v6 35/36] powerpc/fadump: remove RMA_START and RMA_END macros Hari Bathini
2019-09-11 14:57 ` [PATCH v6 36/36] powernv/fadump: support holes in kernel boot memory area Hari Bathini

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