Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[pandora-kernel.git] / Documentation / kdump / kdump.txt

diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 68aa165..d0ac72c 100644 (file)
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -13,7 +13,7 @@ dump of the system kernel's memory needs to be taken (for example, when
 the system panics). The system kernel's memory image is preserved across
 the reboot and is accessible to the dump-capture kernel.
 
-You can use common Linux commands, such as cp and scp, to copy the
+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.
 
@@ -69,7 +69,7 @@ http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/kexec-tools-test
 
 This is a symlink to the latest version, which at the time of writing is
 20061214, the only release of kexec-tools-testing so far. As other versions
-are made released, the older onese will remain available at
+are released, the older ones will remain available at
 http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/
 
 Note: Latest kexec-tools-testing git tree is available at
@@ -231,6 +231,32 @@ Dump-capture kernel config options (Arch Dependent, ia64)
   any space below the alignment point will be wasted.
 
 
+Extended crashkernel syntax
+===========================
+
+While the "crashkernel=size[@offset]" syntax is sufficient for most
+configurations, sometimes it's handy to have the reserved memory dependent
+on the value of System RAM -- that's mostly for distributors that pre-setup
+the kernel command line to avoid a unbootable system after some memory has
+been removed from the machine.
+
+The syntax is:
+
+    crashkernel=<range1>:<size1>[,<range2>:<size2>,...][@offset]
+    range=start-[end]
+
+For example:
+
+    crashkernel=512M-2G:64M,2G-:128M
+
+This would mean:
+
+    1) if the RAM is smaller than 512M, then don't reserve anything
+       (this is the "rescue" case)
+    2) if the RAM size is between 512M and 2G, then reserve 64M
+    3) if the RAM size is larger than 2G, then reserve 128M
+
+
 Boot into System Kernel
 =======================
 
@@ -292,20 +318,22 @@ Following are the arch specific command line options to be used while
 loading dump-capture kernel.
 
 For i386, x86_64 and ia64:
-       "1 irqpoll maxcpus=1"
+       "1 irqpoll maxcpus=1 reset_devices"
 
 For ppc64:
-       "1 maxcpus=1 noirqdistrib"
+       "1 maxcpus=1 noirqdistrib reset_devices"
 
 
 Notes on loading the dump-capture kernel:
 
 * By default, the ELF headers are stored in ELF64 format to support
-  systems with more than 4GB memory. The --elf32-core-headers option can
-  be used to force the generation of ELF32 headers. This is necessary
-  because GDB currently cannot open vmcore files with ELF64 headers on
-  32-bit systems. ELF32 headers can be used on non-PAE systems (that is,
-  less than 4GB of memory).
+  systems with more than 4GB memory. On i386, kexec automatically checks if
+  the physical RAM size exceeds the 4 GB limit and if not, uses ELF32.
+  So, on non-PAE systems, ELF32 is always used.
+
+  The --elf32-core-headers option can be used to force the generation of ELF32
+  headers. This is necessary because GDB currently cannot open vmcore files
+  with ELF64 headers on 32-bit systems.
 
 * The "irqpoll" boot parameter reduces driver initialization failures
   due to shared interrupts in the dump-capture kernel.
@@ -337,7 +365,7 @@ If die() is called, and it happens to be a thread with pid 0 or 1, or die()
 is called inside interrupt context or die() is called and panic_on_oops is set,
 the system will boot into the dump-capture kernel.
 
-On powererpc systems when a soft-reset is generated, die() is called by all cpus
+On powerpc systems when a soft-reset is generated, die() is called by all cpus
 and the system will boot into the dump-capture kernel.
 
 For testing purposes, you can trigger a crash by using "ALT-SysRq-c",
@@ -403,9 +431,3 @@ Contact
 Vivek Goyal (vgoyal@in.ibm.com)
 Maneesh Soni (maneesh@in.ibm.com)
 
-
-Trademark
-=========
-
-Linux is a trademark of Linus Torvalds in the United States, other
-countries, or both.