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authorJonathan Herman <hermanjl@cs.unc.edu>2013-01-17 16:15:55 -0500
committerJonathan Herman <hermanjl@cs.unc.edu>2013-01-17 16:15:55 -0500
commit8dea78da5cee153b8af9c07a2745f6c55057fe12 (patch)
treea8f4d49d63b1ecc92f2fddceba0655b2472c5bd9 /Documentation/kdump/kdump.txt
parent406089d01562f1e2bf9f089fd7637009ebaad589 (diff)
Patched in Tegra support.
Diffstat (limited to 'Documentation/kdump/kdump.txt')
-rw-r--r--Documentation/kdump/kdump.txt37
1 files changed, 4 insertions, 33 deletions
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 13f1aa09b93..7a9e0b4b290 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
17memory image to a dump file on the local disk, or across the network to 17memory image to a dump file on the local disk, or across the network to
18a remote system. 18a remote system.
19 19
20Kdump and kexec are currently supported on the x86, x86_64, ppc64, ia64, 20Kdump and kexec are currently supported on the x86, x86_64, ppc64 and ia64
21and s390x architectures. 21architectures.
22 22
23When the system kernel boots, it reserves a small section of memory for 23When the system kernel boots, it reserves a small section of memory for
24the dump-capture kernel. This ensures that ongoing Direct Memory Access 24the dump-capture kernel. This ensures that ongoing Direct Memory Access
@@ -34,18 +34,11 @@ Similarly on PPC64 machines first 32KB of physical memory is needed for
34booting regardless of where the kernel is loaded and to support 64K page 34booting regardless of where the kernel is loaded and to support 64K page
35size kexec backs up the first 64KB memory. 35size kexec backs up the first 64KB memory.
36 36
37For s390x, when kdump is triggered, the crashkernel region is exchanged
38with the region [0, crashkernel region size] and then the kdump kernel
39runs in [0, crashkernel region size]. Therefore no relocatable kernel is
40needed for s390x.
41
42All of the necessary information about the system kernel's core image is 37All of the necessary information about the system kernel's core image is
43encoded in the ELF format, and stored in a reserved area of memory 38encoded in the ELF format, and stored in a reserved area of memory
44before a crash. The physical address of the start of the ELF header is 39before a crash. The physical address of the start of the ELF header is
45passed to the dump-capture kernel through the elfcorehdr= boot 40passed to the dump-capture kernel through the elfcorehdr= boot
46parameter. Optionally the size of the ELF header can also be passed 41parameter.
47when using the elfcorehdr=[size[KMG]@]offset[KMG] syntax.
48
49 42
50With the dump-capture kernel, you can access the memory image, or "old 43With the dump-capture kernel, you can access the memory image, or "old
51memory," in two ways: 44memory," in two ways:
@@ -86,7 +79,7 @@ There is also a gitweb interface available at
86http://www.kernel.org/git/?p=utils/kernel/kexec/kexec-tools.git 79http://www.kernel.org/git/?p=utils/kernel/kexec/kexec-tools.git
87 80
88More information about kexec-tools can be found at 81More information about kexec-tools can be found at
89http://horms.net/projects/kexec/ 82http://www.kernel.org/pub/linux/utils/kernel/kexec/README.html
90 83
913) Unpack the tarball with the tar command, as follows: 843) Unpack the tarball with the tar command, as follows:
92 85
@@ -298,10 +291,6 @@ Boot into System Kernel
298 The region may be automatically placed on ia64, see the 291 The region may be automatically placed on ia64, see the
299 dump-capture kernel config option notes above. 292 dump-capture kernel config option notes above.
300 293
301 On s390x, typically use "crashkernel=xxM". The value of xx is dependent
302 on the memory consumption of the kdump system. In general this is not
303 dependent on the memory size of the production system.
304
305Load the Dump-capture Kernel 294Load the Dump-capture Kernel
306============================ 295============================
307 296
@@ -319,8 +308,6 @@ For ppc64:
319 - Use vmlinux 308 - Use vmlinux
320For ia64: 309For ia64:
321 - Use vmlinux or vmlinuz.gz 310 - Use vmlinux or vmlinuz.gz
322For s390x:
323 - Use image or bzImage
324 311
325 312
326If you are using a uncompressed vmlinux image then use following command 313If you are using a uncompressed vmlinux image then use following command
@@ -350,8 +337,6 @@ For i386, x86_64 and ia64:
350For ppc64: 337For ppc64:
351 "1 maxcpus=1 noirqdistrib reset_devices" 338 "1 maxcpus=1 noirqdistrib reset_devices"
352 339
353For s390x:
354 "1 maxcpus=1 cgroup_disable=memory"
355 340
356Notes on loading the dump-capture kernel: 341Notes on loading the dump-capture kernel:
357 342
@@ -377,20 +362,6 @@ Notes on loading the dump-capture kernel:
377 dump. Hence generally it is useful either to build a UP dump-capture 362 dump. Hence generally it is useful either to build a UP dump-capture
378 kernel or specify maxcpus=1 option while loading dump-capture kernel. 363 kernel or specify maxcpus=1 option while loading dump-capture kernel.
379 364
380* For s390x there are two kdump modes: If a ELF header is specified with
381 the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
382 is done on all other architectures. If no elfcorehdr= kernel parameter is
383 specified, the s390x kdump kernel dynamically creates the header. The
384 second mode has the advantage that for CPU and memory hotplug, kdump has
385 not to be reloaded with kexec_load().
386
387* For s390x systems with many attached devices the "cio_ignore" kernel
388 parameter should be used for the kdump kernel in order to prevent allocation
389 of kernel memory for devices that are not relevant for kdump. The same
390 applies to systems that use SCSI/FCP devices. In that case the
391 "allow_lun_scan" zfcp module parameter should be set to zero before
392 setting FCP devices online.
393
394Kernel Panic 365Kernel Panic
395============ 366============
396 367