Lines Matching +full:boot +full:- +full:enabled
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
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
47 kernel during early boot.
49 - When system crashes, the Power firmware will copy the registered
50 low memory regions (boot memory) from source to destination area.
54 The term 'boot memory' means size of the low memory chunk
55 that is required for a kernel to boot successfully when
56 booted with restricted memory. By default, the boot memory
58 Alternatively, user can also specify boot memory size
59 through boot parameter 'crashkernel=' which will override
61 boot memory size is not sufficient for second kernel to
62 boot successfully. For syntax of crashkernel= parameter,
63 refer to Documentation/admin-guide/kdump/kdump.rst. If any
66 for boot memory dump preservation in case of a crash.
68 - After the low memory (boot memory) area has been saved, the
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
76 there is crash data available from a previous boot. During
77 the early boot OS will reserve rest of the memory above
78 boot memory size effectively booting with restricted memory
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
109 capture kernel boot to process this crash data. Kernel config
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 -----------------------
126 During boot, a check is made to see if firmware supports
129 then everything but boot memory size of RAM is reserved during
130 early boot (See Fig. 2). This area is released once we finish
137 hold CPU state, HPTE region, boot memory dump, and FADump header is
138 usually reserved at an offset greater than boot memory size (see Fig. 1).
140 reserved, so that it can act as a receptacle for a copy of the boot
157 0 boot memory size |<------ Reserved dump area ----->| |
160 +-----------+-----/ /---+---+----+-----------+-------+----+-----+
162 +-----------+-----/ /---+---+----+-----------+-------+----+-----+
166 -------------------------------- | |
167 Boot memory content gets transferred | |
186 0 boot memory size |
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
210 +---+
211 |ELF| -> elfcorehdr, it is created in second kernel after crash.
212 +---+
214 Note: Memory from 0 to the boot memory size is used by second kernel
230 How to enable firmware-assisted dump (FADump):
231 ----------------------------------------------
234 2. Boot into linux kernel with 'fadump=on' kernel cmdline option.
236 Alternatively, user can boot linux kernel with 'fadump=nocma' to
239 to specify size of the memory to reserve for boot memory dump
245 for boot memory dump preservation.
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
269 FADump is enabled in the kernel and act accordingly.
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
318 +----------------------------------+--------------------------------+
320 +----------------------------------+--------------------------------+
321 | /sys/kernel/fadump_enabled | /sys/kernel/fadump/enabled |
322 +----------------------------------+--------------------------------+
324 +----------------------------------+--------------------------------+
326 +----------------------------------+--------------------------------+
333 enabled otherwise this file is empty. The output format
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
365 -----
366 - Need to come up with the better approach to find out more
367 accurate boot memory size that is required for a kernel to
368 boot successfully when booted with restricted memory.