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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-10-28 09:47:58 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2015-11-27 09:24:12 +0100 |
| commit | ffa52d02c50ea31420dc70869c0b6b439e7cb5ef (patch) | |
| tree | b27a59ae8df0162393e67067c476467ac48748c2 /Documentation | |
| parent | bbfed511c262db4d046a35f0389d98645124814f (diff) | |
| download | lwn-ffa52d02c50ea31420dc70869c0b6b439e7cb5ef.tar.gz lwn-ffa52d02c50ea31420dc70869c0b6b439e7cb5ef.zip | |
s390/zcore: remove /sys/kernel/debug/zcore/mem
New versions of the SCSI dumper use the /dev/vmcore interface instead
of zcore mem. Remove the outdated interface.
Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'Documentation')
| -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". |