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authorLinus Torvalds <torvalds@linux-foundation.org>2016-01-13 13:16:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-13 13:16:16 -0800
commitcbd88cd4c07f9361914ab7fd7e21c9227986fe68 (patch)
tree8bc448d73f93f10ebd34ef38c911b06359000ed0 /Documentation
parent928b3f12e5fea9d201bbc029d8d537ba7cc14fe7 (diff)
parentc2ab7282f0fcd11eea4d0ba45d1c65d89428c314 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Martin Schwidefsky: "Among the traditional bug fixes and cleanups are some improvements: - A tool to generated the facility lists, generating the bit fields by hand has been a source of bugs in the past - The spinlock loop is reordered to avoid bursts of hypervisor calls - Add support for the open-for-business interface to the service element - The get_cpu call is added to the vdso - A set of tracepoints is defined for the common I/O layer - The deprecated sclp_cpi module is removed - Update default configuration" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (56 commits) s390/sclp: fix possible control register corruption s390: fix normalization bug in exception table sorting s390/configs: update default configurations s390/vdso: optimize getcpu system call s390: drop smp_mb in vdso_init s390: rename struct _lowcore to struct lowcore s390/mem_detect: use unsigned longs s390/ptrace: get rid of long longs in psw_bits s390/sysinfo: add missing SYSIB 1.2.2 multithreading fields s390: get rid of CONFIG_SCHED_MC and CONFIG_SCHED_BOOK s390/Kconfig: remove pointless 64 bit dependencies s390/dasd: fix failfast for disconnected devices s390/con3270: testing return kzalloc retval s390/hmcdrv: constify hmcdrv_ftp_ops structs s390/cio: add NULL test s390/cio: Change I/O instructions from inline to normal functions s390/cio: Introduce common I/O layer tracepoints s390/cio: Consolidate inline assemblies and related data definitions s390/cio: Fix incorrect xsch opcode specification s390/cio: Remove unused inline assemblies ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/s390/zfcpdump.txt22
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".