aboutsummaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2012-01-09 08:11:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-09 08:11:13 -0800
commit72f318897e50c29b91efd1ed24515a93c138a2ba (patch)
tree7e7ef8138d5afacd1be4655e4458dc4cee432d1e /Documentation
parenta0e86bd4252519321b0d102dc4ed90557aa7bee9 (diff)
parent2fa1d4fce599809e6bd7d95756709a5faef30710 (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (31 commits) [S390] disassembler: mark exception causing instructions [S390] Enable exception traces by default [S390] return address of compat signals [S390] sysctl: get rid of dead declaration [S390] dasd: fix fixpoint divide exception in define_extent [S390] dasd: add sanity check to detect path connection error [S390] qdio: fix kernel panic for zfcp 31-bit [S390] Add s390x description to Documentation/kdump/kdump.txt [S390] Add VMCOREINFO_SYMBOL(high_memory) to vmcoreinfo [S390] dasd: fix expiration handling for recovery requests [S390] outstanding interrupts vs. smp_send_stop [S390] ipc: call generic sys_ipc demultiplexer [S390] zcrypt: Fix error return codes. [S390] zcrypt: Rework length parameter checking. [S390] cleanup trap handling [S390] Remove Kerntypes leftovers [S390] topology: increase poll frequency if change is anticipated [S390] entry[64].S improvements [S390] make arch/s390 subdirectories depend on config option [S390] kvm: move cmf host id constant out of lowcore ... Fix up conflicts in arch/s390/kernel/{smp.c,topology.c} due to the sysdev removal clashing with "topology: get rid of ifdefs" which moved some of that code around.
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/dontdiff1
-rw-r--r--Documentation/kdump/kdump.txt35
-rw-r--r--Documentation/s390/Debugging390.txt34
3 files changed, 32 insertions, 38 deletions
diff --git a/Documentation/dontdiff b/Documentation/dontdiff
index dfa6fc6e4b2..0c083c5c2fa 100644
--- a/Documentation/dontdiff
+++ b/Documentation/dontdiff
@@ -66,7 +66,6 @@ GRTAGS
GSYMS
GTAGS
Image
-Kerntypes
Module.markers
Module.symvers
PENDING
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 7a9e0b4b290..506c7390c2b 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -17,8 +17,8 @@ You can use common commands, such as cp and scp, to copy the
memory image to a dump file on the local disk, or across the network to
a remote system.
-Kdump and kexec are currently supported on the x86, x86_64, ppc64 and ia64
-architectures.
+Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64,
+and s390x architectures.
When the system kernel boots, it reserves a small section of memory for
the dump-capture kernel. This ensures that ongoing Direct Memory Access
@@ -34,11 +34,18 @@ Similarly on PPC64 machines first 32KB of physical memory is needed for
booting regardless of where the kernel is loaded and to support 64K page
size kexec backs up the first 64KB memory.
+For s390x, when kdump is triggered, the crashkernel region is exchanged
+with the region [0, crashkernel region size] and then the kdump kernel
+runs in [0, crashkernel region size]. Therefore no relocatable kernel is
+needed for s390x.
+
All of the necessary information about the system kernel's core image is
encoded in the ELF format, and stored in a reserved area of memory
before a crash. The physical address of the start of the ELF header is
passed to the dump-capture kernel through the elfcorehdr= boot
-parameter.
+parameter. Optionally the size of the ELF header can also be passed
+when using the elfcorehdr=[size[KMG]@]offset[KMG] syntax.
+
With the dump-capture kernel, you can access the memory image, or "old
memory," in two ways:
@@ -291,6 +298,10 @@ Boot into System Kernel
The region may be automatically placed on ia64, see the
dump-capture kernel config option notes above.
+ On s390x, typically use "crashkernel=xxM". The value of xx is dependent
+ on the memory consumption of the kdump system. In general this is not
+ dependent on the memory size of the production system.
+
Load the Dump-capture Kernel
============================
@@ -308,6 +319,8 @@ For ppc64:
- Use vmlinux
For ia64:
- Use vmlinux or vmlinuz.gz
+For s390x:
+ - Use image or bzImage
If you are using a uncompressed vmlinux image then use following command
@@ -337,6 +350,8 @@ For i386, x86_64 and ia64:
For ppc64:
"1 maxcpus=1 noirqdistrib reset_devices"
+For s390x:
+ "1 maxcpus=1 cgroup_disable=memory"
Notes on loading the dump-capture kernel:
@@ -362,6 +377,20 @@ Notes on loading the dump-capture kernel:
dump. Hence generally it is useful either to build a UP dump-capture
kernel or specify maxcpus=1 option while loading dump-capture kernel.
+* For s390x there are two kdump modes: If a ELF header is specified with
+ the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
+ is done on all other architectures. If no elfcorehdr= kernel parameter is
+ specified, the s390x kdump kernel dynamically creates the header. The
+ second mode has the advantage that for CPU and memory hotplug, kdump has
+ not to be reloaded with kexec_load().
+
+* For s390x systems with many attached devices the "cio_ignore" kernel
+ parameter should be used for the kdump kernel in order to prevent allocation
+ of kernel memory for devices that are not relevant for kdump. The same
+ applies to systems that use SCSI/FCP devices. In that case the
+ "allow_lun_scan" zfcp module parameter should be set to zero before
+ setting FCP devices online.
+
Kernel Panic
============
diff --git a/Documentation/s390/Debugging390.txt b/Documentation/s390/Debugging390.txt
index efe998becc5..462321c1aee 100644
--- a/Documentation/s390/Debugging390.txt
+++ b/Documentation/s390/Debugging390.txt
@@ -41,7 +41,6 @@ ldd
Debugging modules
The proc file system
Starting points for debugging scripting languages etc.
-Dumptool & Lcrash
SysRq
References
Special Thanks
@@ -2455,39 +2454,6 @@ jdb <filename> another fully interactive gdb style debugger.
-Dumptool & Lcrash ( lkcd )
-==========================
-Michael Holzheu & others here at IBM have a fairly mature port of
-SGI's lcrash tool which allows one to look at kernel structures in a
-running kernel.
-
-It also complements a tool called dumptool which dumps all the kernel's
-memory pages & registers to either a tape or a disk.
-This can be used by tech support or an ambitious end user do
-post mortem debugging of a machine like gdb core dumps.
-
-Going into how to use this tool in detail will be explained
-in other documentation supplied by IBM with the patches & the
-lcrash homepage http://oss.sgi.com/projects/lkcd/ & the lcrash manpage.
-
-How they work
--------------
-Lcrash is a perfectly normal program,however, it requires 2
-additional files, Kerntypes which is built using a patch to the
-linux kernel sources in the linux root directory & the System.map.
-
-Kerntypes is an objectfile whose sole purpose in life
-is to provide stabs debug info to lcrash, to do this
-Kerntypes is built from kerntypes.c which just includes the most commonly
-referenced header files used when debugging, lcrash can then read the
-.stabs section of this file.
-
-Debugging a live system it uses /dev/mem
-alternatively for post mortem debugging it uses the data
-collected by dumptool.
-
-
-
SysRq
=====
This is now supported by linux for s/390 & z/Architecture.