Lines Matching refs:kernel
22 for dump, with a single operation of echo 1 > /sys/kernel/fadump_release_mem.
23 - Once enabled through kernel boot parameter, FADump can be
24 started/stopped through /sys/kernel/fadump_registered interface (see
32 with a fresh copy of the kernel. In particular,
36 is immediately available to the running kernel. And therefore,
44 - The first kernel registers the sections of memory with the
47 kernel during early boot.
55 that is required for a kernel to boot successfully when
61 boot memory size is not sufficient for second kernel to
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
79 size. This will make sure that this kernel (also, referred
80 to as second kernel or capture kernel) will not touch any
84 of memory, which holds the previous crashed kernel dump in ELF
89 '1' to /sys/kernel/fadump_release_mem to release the reserved
95 # echo 1 > /sys/kernel/fadump_release_mem
105 kernel (referred to as petitboot kernel) before booting into the
106 capture kernel. This kernel would have minimal kernel and/or
107 userspace support to process crash data. Such kernel needs to
108 preserve previously crash'ed kernel's memory for the subsequent
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
116 helpful in debugging OPAL crashes with GDB. The kernel memory
133 /sys/kernel/fadump_release_mem file is created, and the reserved
146 production kernel. Hence, the implementation uses the Linux kernel's
148 configured for kernel. With CMA reservation this memory will be
149 available for applications to use it, while kernel is prevented from
151 kernel memory and most of the user space memory except the user pages
154 o Memory Reservation during first kernel
176 second kernel after crash, on platforms that support
183 o Memory Reservation during second kernel after crash
211 |ELF| -> elfcorehdr, it is created in second kernel after crash.
214 Note: Memory from 0 to the boot memory size is used by second kernel
233 1. Set config option CONFIG_FA_DUMP=y and build kernel.
234 2. Boot into linux kernel with 'fadump=on' kernel cmdline option.
236 Alternatively, user can boot linux kernel with 'fadump=nocma' to
238 3. Optionally, user can also set 'crashkernel=' kernel cmdline
248 option is set at kernel cmdline.
251 'fadump=nocma' kernel parameter can be used to fallback to
260 Here is the list of files under kernel sysfs:
262 /sys/kernel/fadump_enabled
269 FADump is enabled in the kernel and act accordingly.
271 /sys/kernel/fadump_registered
278 To register FADump echo 1 > /sys/kernel/fadump_registered and
279 echo 0 > /sys/kernel/fadump_registered for un-register and stop the
284 /sys/kernel/fadump/mem_reserved
289 /sys/kernel/fadump_release_mem
291 second kernel. This is used to release the reserved memory
295 echo 1 > /sys/kernel/fadump_release_mem
297 After echo 1, the content of the /sys/kernel/debug/powerpc/fadump_region
304 Note: /sys/kernel/fadump_release_opalcore sysfs has moved to
310 active during capture kernel. This is used to release the memory
311 used by the kernel to export /sys/firmware/opal/mpipl/core file. To
321 | /sys/kernel/fadump_enabled | /sys/kernel/fadump/enabled |
323 | /sys/kernel/fadump_registered | /sys/kernel/fadump/registered |
325 | /sys/kernel/fadump_release_mem | /sys/kernel/fadump/release_mem |
329 (Assuming debugfs is mounted on /sys/kernel/debug directory.)
331 /sys/kernel/debug/powerpc/fadump_region
338 and for kernel DUMP region is:
343 Contents when FADump is registered during first kernel::
345 # cat /sys/kernel/debug/powerpc/fadump_region
350 Contents when FADump is active during second kernel::
352 # cat /sys/kernel/debug/powerpc/fadump_region
367 accurate boot memory size that is required for a kernel to