Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030218AbXAKINV (ORCPT ); Thu, 11 Jan 2007 03:13:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030219AbXAKINU (ORCPT ); Thu, 11 Jan 2007 03:13:20 -0500 Received: from koto.vergenet.net ([210.128.90.7]:50241 "EHLO koto.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030218AbXAKINT (ORCPT ); Thu, 11 Jan 2007 03:13:19 -0500 Date: Thu, 11 Jan 2007 17:13:04 +0900 From: Horms To: Vivek Goyal Cc: Mohan Kumar M , linux kernel mailing list , Fastboot mailing list , Morton Andrew Morton Subject: Re: [PATCH] Kdump documentation update for 2.6.20 Message-ID: <20070111081303.GC20508@verge.net.au> References: <20070108075803.GB7889@in.ibm.com> <20070109011846.GB7479@verge.net.au> <20070109144708.GA6924@in.ibm.com> <20070110053705.GA4051@in.ibm.com> <20070110091515.GI8061@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070110091515.GI8061@in.ibm.com> User-Agent: mutt-ng/devel-r804 (Debian) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 14235 Lines: 370 On Wed, Jan 10, 2007 at 02:45:15PM +0530, Vivek Goyal wrote: > On Wed, Jan 10, 2007 at 11:07:05AM +0530, Mohan Kumar M wrote: > > On Tue, Jan 09, 2007 at 08:17:08PM +0530, Vivek Goyal wrote: > > > > > > Mohan, Can you please check the correctness of ppc64 specific details. > > > > > > > Vivek, > > > > My inputs. > > > > Thanks Mohan. I have updated the document as per your feedback. > > Please find attached the latest patch. > > Thanks > Vivek > > > o Kdump documentation update. > - Update details for using relocatable kernel. > - Start using kexec-tools-testing release as it is latest and old > kexec-tools can't load relocatable bzImage file. > - Also add kdump on ia64 specific details. > > Signed-off-by: Vivek Goyal This seems like a great improvement on the existing document. Lets get this in the tree and make any further changes from there. I'll send a patch to add the ia64 details shortly. Signed-off-by: Simon Horman > --- > > Documentation/kdump/kdump.txt | 224 ++++++++++++++++++++++++++++-------------- > 1 file changed, 152 insertions(+), 72 deletions(-) > > diff -puN Documentation/kdump/kdump.txt~kdump-documentation-update Documentation/kdump/kdump.txt > --- linux-2.6.20-rc2-mm1-reloc/Documentation/kdump/kdump.txt~kdump-documentation-update 2007-01-08 12:32:55.000000000 +0530 > +++ linux-2.6.20-rc2-mm1-reloc-root/Documentation/kdump/kdump.txt 2007-01-10 14:38:58.000000000 +0530 > @@ -17,7 +17,7 @@ You can use common Linux commands, such > 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, and ppc64 > +Kdump and kexec are currently supported on the x86, x86_64, ppc64 and IA64 > architectures. > > When the system kernel boots, it reserves a small section of memory for > @@ -54,59 +54,64 @@ memory," in two ways: > Setup and Installation > ====================== > > -Install kexec-tools and the Kdump patch > ---------------------------------------- > +Install kexec-tools > +------------------- > > 1) Login as the root user. > > 2) Download the kexec-tools user-space package from the following URL: > > - http://www.xmission.com/~ebiederm/files/kexec/kexec-tools-1.101.tar.gz > +http://www.kernel.org/pub/linux/kernel/people/horms/kexec-tools/kexec-tools-testing-20061214.tar.gz > > -3) Unpack the tarball with the tar command, as follows: > - > - tar xvpzf kexec-tools-1.101.tar.gz > - > -4) Download the latest consolidated Kdump patch from the following URL: > - > - http://lse.sourceforge.net/kdump/ > +Note: Latest kexec-tools-testing git tree is available at > > - (This location is being used until all the user-space Kdump patches > - are integrated with the kexec-tools package.) > +git://git.kernel.org/pub/scm/linux/kernel/git/horms/kexec-tools-testing.git > +or > +http://www.kernel.org/git/?p=linux/kernel/git/horms/kexec-tools-testing.git;a=summary > > -5) Change to the kexec-tools-1.101 directory, as follows: > +3) Unpack the tarball with the tar command, as follows: > > - cd kexec-tools-1.101 > + tar xvpzf kexec-tools-testing-20061214.tar.gz > > -6) Apply the consolidated patch to the kexec-tools-1.101 source tree > - with the patch command, as follows. (Modify the path to the downloaded > - patch as necessary.) > +4) Change to the kexec-tools-1.101 directory, as follows: > > - patch -p1 < /path-to-kdump-patch/kexec-tools-1.101-kdump.patch > + cd kexec-tools-testing-20061214 > > -7) Configure the package, as follows: > +5) Configure the package, as follows: > > ./configure > > -8) Compile the package, as follows: > +6) Compile the package, as follows: > > make > > -9) Install the package, as follows: > +7) Install the package, as follows: > > make install > > > -Download and build the system and dump-capture kernels > ------------------------------------------------------- > +Build the system and dump-capture kernels > +----------------------------------------- > +There are two possible methods of using Kdump. > + > +1) Build a separate custom dump-capture kernel for capturing the > + kernel core dump. > + > +2) Or use the system kernel binary itself as dump-capture kernel and there is > + no need to build a separate dump-capture kernel. This is possible > + only with the architecutres which support a relocatable kernel. As > + of today i386 and ia64 architectures support relocatable kernel. > + > +Building a relocatable kernel is advantageous from the point of view that > +one does not have to build a second kernel for capturing the dump. But > +at the same time one might want to build a custom dump capture kernel > +suitable to his needs. > > -Download the mainline (vanilla) kernel source code (2.6.13-rc1 or newer) > -from http://www.kernel.org. Two kernels must be built: a system kernel > -and a dump-capture kernel. Use the following steps to configure these > -kernels with the necessary kexec and Kdump features: > +Following are the configuration setting required for system and > +dump-capture kernels for enabling kdump support. > > -System kernel > -------------- > +System kernel config options > +---------------------------- > > 1) Enable "kexec system call" in "Processor type and features." > > @@ -132,88 +137,160 @@ System kernel > analysis tools require a vmlinux with debug symbols in order to read > and analyze a dump file. > > -4) Make and install the kernel and its modules. Update the boot loader > - (such as grub, yaboot, or lilo) configuration files as necessary. > +Dump-capture kernel config options (Arch Independent) > +----------------------------------------------------- > > -5) Boot the system kernel with the boot parameter "crashkernel=Y@X", > - where Y specifies how much memory to reserve for the dump-capture kernel > - and X specifies the beginning of this reserved memory. For example, > - "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory > - starting at physical address 0x01000000 for the dump-capture kernel. > - > - On x86 and x86_64, use "crashkernel=64M@16M". > - > - On ppc64, use "crashkernel=128M@32M". > +1) Enable "kernel crash dumps" support under "Processor type and > + features": > > + CONFIG_CRASH_DUMP=y > > -The dump-capture kernel > ------------------------ > +2) Enable "/proc/vmcore support" under "Filesystems" -> "Pseudo filesystems". > > -1) Under "General setup," append "-kdump" to the current string in > - "Local version." > + CONFIG_PROC_VMCORE=y > + (CONFIG_PROC_VMCORE is set by default when CONFIG_CRASH_DUMP is selected.) > > -2) On x86, enable high memory support under "Processor type and > +Dump-capture kernel config options (Arch Dependent, i386) > +-------------------------------------------------------- > +1) On x86, enable high memory support under "Processor type and > features": > > CONFIG_HIGHMEM64G=y > or > CONFIG_HIGHMEM4G > > -3) On x86 and x86_64, disable symmetric multi-processing support > +2) On x86 and x86_64, disable symmetric multi-processing support > under "Processor type and features": > > CONFIG_SMP=n > + > (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line > when loading the dump-capture kernel, see section "Load the Dump-capture > Kernel".) > > -4) On ppc64, disable NUMA support and enable EMBEDDED support: > +3) If one wants to build and use a relocatable kernel, > + Enable "Build a relocatable kernel" support under "Processor type and > + features" > > - CONFIG_NUMA=n > - CONFIG_EMBEDDED=y > - CONFIG_EEH=N for the dump-capture kernel > + CONFIG_RELOCATABLE=y > > -5) Enable "kernel crash dumps" support under "Processor type and > - features": > +4) Use a suitable value for "Physical address where the kernel is > + loaded" (under "Processor type and features"). This only appears when > + "kernel crash dumps" is enabled. A suitable value depends upon > + whether kernel is relocatable or not. > > - CONFIG_CRASH_DUMP=y > + If you are using a relocatable kernel use CONFIG_PHYSICAL_START=0x100000 > + This will compile the kernel for physical address 1MB, but given the fact > + kernel is relocatable, it can be run from any physical address hence > + kexec boot loader will load it in memory region reserved for dump-capture > + kernel. > + > + Otherwise it should be the start of memory region reserved for > + second kernel using boot parameter "crashkernel=Y@X". Here X is > + start of memory region reserved for dump-capture kernel. > + Generally X is 16MB (0x1000000). So you can set > + CONFIG_PHYSICAL_START=0x1000000 > + > +5) Make and install the kernel and its modules. DO NOT add this kernel > + to the boot loader configuration files. > + > +Dump-capture kernel config options (Arch Dependent, x86_64) > +---------------------------------------------------------- > +1) On x86 and x86_64, disable symmetric multi-processing support > + under "Processor type and features": > + > + CONFIG_SMP=n > > -6) Use a suitable value for "Physical address where the kernel is > + (If CONFIG_SMP=y, then specify maxcpus=1 on the kernel command line > + when loading the dump-capture kernel, see section "Load the Dump-capture > + Kernel".) > + > +2) Use a suitable value for "Physical address where the kernel is > loaded" (under "Processor type and features"). This only appears when > "kernel crash dumps" is enabled. By default this value is 0x1000000 > (16MB). It should be the same as X in the "crashkernel=Y@X" boot > - parameter discussed above. > + parameter. > > - On x86 and x86_64, use "CONFIG_PHYSICAL_START=0x1000000". > + For x86_64, normally "CONFIG_PHYSICAL_START=0x1000000". > > - On ppc64 the value is automatically set at 32MB when > - CONFIG_CRASH_DUMP is set. > +3) Make and install the kernel and its modules. DO NOT add this kernel > + to the boot loader configuration files. > > -6) Optionally enable "/proc/vmcore support" under "Filesystems" -> > - "Pseudo filesystems". > +Dump-capture kernel config options (Arch Dependent, ppc64) > +---------------------------------------------------------- > > - CONFIG_PROC_VMCORE=y > - (CONFIG_PROC_VMCORE is set by default when CONFIG_CRASH_DUMP is selected.) > - > -7) Make and install the kernel and its modules. DO NOT add this kernel > +- Make and install the kernel and its modules. DO NOT add this kernel > to the boot loader configuration files. > > +Dump-capture kernel config options (Arch Dependent, ia64) > +---------------------------------------------------------- > +(To be filled) > + > + > +Boot into System Kernel > +======================= > + > +1) Make and install the kernel and its modules. Update the boot loader > + (such as grub, yaboot, or lilo) configuration files as necessary. > + > +2) Boot the system kernel with the boot parameter "crashkernel=Y@X", > + where Y specifies how much memory to reserve for the dump-capture kernel > + and X specifies the beginning of this reserved memory. For example, > + "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory > + starting at physical address 0x01000000 (16MB) for the dump-capture kernel. > + > + On x86 and x86_64, use "crashkernel=64M@16M". > + > + On ppc64, use "crashkernel=128M@32M". > > Load the Dump-capture Kernel > ============================ > > -After booting to the system kernel, load the dump-capture kernel using > -the following command: > +After booting to the system kernel, dump-capture kernel needs to be > +loaded. > + > +Based on the architecture and type of image (relocatable or not), one > +can choose to load the uncompressed vmlinux or compressed bzImage/vmlinuz > +of dump-capture kernel. Following is the summary. > + > +For i386: > + - Use vmlinux if kernel is not relocatable. > + - Use bzImage/vmlinuz if kernel is relocatable. > +For x86_64: > + - Use vmlinux > +For ppc64: > + - Use vmlinux > +For ia64: > + (To be filled) > + > +If you are using a uncompressed vmlinux image then use following command > +to load dump-capture kernel. > > - kexec -p \ > + kexec -p \ > --initrd= --args-linux \ > - --append="root= init 1 irqpoll" > + --append="root= " > > +If you are using a compressed bzImage/vmlinuz, then use following command > +to load dump-capture kernel. > > -Notes on loading the dump-capture kernel: > + kexec -p \ > + --initrd= \ > + --append="root= " > + > +Following are the arch specific command line options to be used while > +loading dump-capture kernel. > + > +For i386 and x86_64: > + "init 1 irqpoll maxcpus=1" > + > +For ppc64: > + "init 1 maxcpus=1 noirqdistrib" > > -* must be a vmlinux image (that is, an > - uncompressed ELF image). bzImage does not work at this time. > +For IA64 > + (To be filled) > + > + > +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 > @@ -231,6 +308,9 @@ Notes on loading the dump-capture kernel > * "init 1" boots the dump-capture kernel into single-user mode without > networking. If you want networking, use "init 3." > > +* We generally don' have to bring up a SMP kernel just to capture the > + dump. Hence generally it is useful either to build a UP dump-capture > + kernel or specify maxcpus=1 option while loading dump-capture kernel. > > Kernel Panic > ============ > _ -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/