diff options
author | Mike Marshall <hubcap@omnibond.com> | 2016-03-14 15:39:42 -0400 |
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committer | Mike Marshall <hubcap@omnibond.com> | 2016-03-14 15:39:42 -0400 |
commit | ab6652524aaf834d5dcdb46dd7695813b8d63da5 (patch) | |
tree | bb3876a9b61254be902416f7dbf578deb28e9f22 /Documentation/s390/zfcpdump.txt | |
parent | acfcbaf1925f2dc5c46c61de69d756dec92a2ff8 (diff) | |
parent | b562e44f507e863c6792946e4e1b1449fbbac85d (diff) |
Orangefs: merge to v4.5
Merge tag 'v4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into current
Linux 4.5
Diffstat (limited to 'Documentation/s390/zfcpdump.txt')
-rw-r--r-- | Documentation/s390/zfcpdump.txt | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/Documentation/s390/zfcpdump.txt b/Documentation/s390/zfcpdump.txt index dc929be96016..b064aa59714d 100644 --- a/Documentation/s390/zfcpdump.txt +++ b/Documentation/s390/zfcpdump.txt @@ -15,19 +15,15 @@ the s390-tools package) to make the device bootable. The operator of a Linux system can then trigger a SCSI dump by booting the SCSI disk, where zfcpdump resides on. -The kernel part of zfcpdump is implemented as a debugfs file under "zcore/mem", -which exports memory and registers of the crashed Linux in an s390 -standalone dump format. It can be used in the same way as e.g. /dev/mem. The -dump format defines a 4K header followed by plain uncompressed memory. The -register sets are stored in the prefix pages of the respective CPUs. To build a -dump enabled kernel with the zcore driver, the kernel config option -CONFIG_CRASH_DUMP has to be set. When reading from "zcore/mem", the part of -memory, which has been saved by hardware is read by the driver via the SCLP -hardware interface. The second part is just copied from the non overwritten real -memory. - -Since kernel version 3.12 also the /proc/vmcore file can also be used to access -the dump. +The user space dump tool accesses the memory of the crashed system by means +of the /proc/vmcore interface. This interface exports the crashed system's +memory and registers in ELF core dump format. To access the memory which has +been saved by the hardware SCLP requests will be created at the time the data +is needed by /proc/vmcore. The tail part of the crashed systems memory which +has not been stashed by hardware can just be copied from real memory. + +To build a dump enabled kernel the kernel config option CONFIG_CRASH_DUMP +has to be set. To get a valid zfcpdump kernel configuration use "make zfcpdump_defconfig". |