Lines Matching +full:no +full:- +full:reset +full:- +full:on +full:- +full:init
2 Firmware-Assisted Dump
7 The goal of firmware-assisted dump is to enable the dump of
8 a crashed system, and to do so from a fully-reset system, and
12 - Firmware-Assisted Dump (FADump) infrastructure is intended to replace
14 - Fadump uses the same firmware interfaces and memory reservation model
16 - Unlike phyp dump, FADump exports the memory dump through /proc/vmcore
19 - Unlike phyp dump, userspace tool does not need to refer any sysfs
21 - Unlike phyp dump, FADump allows user to release all the memory reserved
23 - Once enabled through kernel boot parameter, FADump can be
26 service start/stop init scripts.
28 Comparing with kdump or other strategies, firmware-assisted
31 - Unlike kdump, the system has been reset, and loaded
35 - Once the dump is copied out, the memory that held the dump
44 - The first kernel registers the sections of memory with the
49 - When system crashes, the Power firmware will copy the registered
63 refer to Documentation/admin-guide/kdump/kdump.rst. If any
68 - After the low memory (boot memory) area has been saved, the
69 firmware will reset PCI and other hardware state. It will
73 - The freshly booted kernel will notice that there is a new node
74 (rtas/ibm,kernel-dump on pSeries or ibm,opal/dump/mpipl-boot
75 on OPAL platform) in the device tree, indicating that
83 - User-space tools will read /proc/vmcore to obtain the contents
88 - Once the userspace tool is done saving dump, it will echo
91 next firmware-assisted dump registration.
97 Please note that the firmware-assisted dump feature
98 is only available on POWER6 and above systems on pSeries
100 or later firmware versions on PowerNV (OPAL) platform.
102 FADump is supported on PowerNV platform.
104 On OPAL based machines, system first boots into an intermittent
110 option CONFIG_PRESERVE_FA_DUMP has to be enabled on such kernel
113 -- On OPAL based machines (PowerNV), if the kernel is build with
124 -----------------------
127 this feature on that particular machine. If it does, then
136 If there is no waiting dump data, then only the memory required to
145 there is no point in blocking this significant chunk of memory from
157 0 boot memory size |<------ Reserved dump area ----->| |
160 +-----------+-----/ /---+---+----+-----------+-------+----+-----+
162 +-----------+-----/ /---+---+----+-----------+-------+----+-----+
166 -------------------------------- | |
176 second kernel after crash, on platforms that support
187 | |<------------ Crash preserved area ------------>|
188 V V |<--- Reserved dump area --->| |
189 +----+---+--+-----/ /---+---+----+-------+-----+-----+-------+
191 +----+---+--+-----/ /---+---+----+-------+-----+-----+-------+
193 ----- ------------------------------ ---------------
197 \ | ----------------------------
204 +---+
205 |///| -> Regions (CPU, HPTE & Metadata) marked like this in the above
206 +---+ figures are not always present. For example, OPAL platform
208 not supported on pSeries currently.
210 +---+
211 |ELF| -> elfcorehdr, it is created in second kernel after crash.
212 +---+
222 to save the dump works fine with minor modifications. KDump scripts on
223 major Distro releases have already been modified to work seamlessly (no
230 How to enable firmware-assisted dump (FADump):
231 ----------------------------------------------
234 2. Boot into linux kernel with 'fadump=on' kernel cmdline option.
246 2. If firmware-assisted dump fails to reserve memory then it
255 --------------------
257 Firmware-assisted dump feature uses sysfs file system to hold
265 - 0 = FADump is disabled
266 - 1 = FADump is enabled
268 This interface can be used by kdump init scripts to identify if
275 - 0 = FADump is not registered.
276 - 1 = FADump is registered and ready to handle system crash.
279 echo 0 > /sys/kernel/fadump_registered for un-register and stop the
280 FADump. Once the FADump is un-registered, the system crash will not
309 This file is available only on OPAL based machines when FADump is
318 +----------------------------------+--------------------------------+
320 +----------------------------------+--------------------------------+
322 +----------------------------------+--------------------------------+
324 +----------------------------------+--------------------------------+
326 +----------------------------------+--------------------------------+
329 (Assuming debugfs is mounted on /sys/kernel/debug directory.)
336 <region>: [<start>-<end>] <reserved-size> bytes, Dumped: <dump-size>
340 DUMP: Src: <src-addr>, Dest: <dest-addr>, Size: <size>, Dumped: # bytes
346 CPU : [0x0000006ffb0000-0x0000006fff001f] 0x40020 bytes, Dumped: 0x0
347 HPTE: [0x0000006fff0020-0x0000006fff101f] 0x1000 bytes, Dumped: 0x0
348 DUMP: [0x0000006fff1020-0x0000007fff101f] 0x10000000 bytes, Dumped: 0x0
353 CPU : [0x0000006ffb0000-0x0000006fff001f] 0x40020 bytes, Dumped: 0x40020
354 HPTE: [0x0000006fff0020-0x0000006fff101f] 0x1000 bytes, Dumped: 0x1000
355 DUMP: [0x0000006fff1020-0x0000007fff101f] 0x10000000 bytes, Dumped: 0x10000000
356 : [0x00000010000000-0x0000006ffaffff] 0x5ffb0000 bytes, Dumped: 0x5ffb0000
360 Please refer to Documentation/filesystems/debugfs.rst on
365 -----
366 - Need to come up with the better approach to find out more
372 This document is based on the original documentation written for phyp