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Diffstat (limited to 'Documentation/kdump/kdump.txt')
| -rw-r--r-- | Documentation/kdump/kdump.txt | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt index 07330681834..2fedc081b4c 100644 --- a/Documentation/kdump/kdump.txt +++ b/Documentation/kdump/kdump.txt @@ -30,6 +30,10 @@ On x86 machines, the first 640 KB of physical memory is needed to boot, regardless of where the kernel loads. Therefore, kexec backs up this region just before rebooting into the dump-capture kernel. +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. + 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 @@ -224,7 +228,7 @@ Dump-capture kernel config options (Arch Dependent, x86_64) Dump-capture kernel config options (Arch Dependent, ppc64) ---------------------------------------------------------- -- 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) @@ -251,8 +255,8 @@ Dump-capture kernel config options (Arch Dependent, ia64) 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. +1) 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 @@ -311,10 +315,10 @@ Following are the arch specific command line options to be used while loading dump-capture kernel. For i386, x86_64 and ia64: - "init 1 irqpoll maxcpus=1" + "1 irqpoll maxcpus=1" For ppc64: - "init 1 maxcpus=1 noirqdistrib" + "1 maxcpus=1 noirqdistrib" Notes on loading the dump-capture kernel: @@ -332,8 +336,8 @@ Notes on loading the dump-capture kernel: * You must specify <root-dev> in the format corresponding to the root device name in the output of mount command. -* "init 1" boots the dump-capture kernel into single-user mode without - networking. If you want networking, use "init 3." +* Boot parameter "1" boots the dump-capture kernel into single-user + mode without networking. If you want networking, use "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 @@ -356,10 +360,11 @@ 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 and the system will boot into the dump-capture kernel. +On powererpc 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", -"echo c > /proc/sysrq-trigger or write a module to force the panic. +"echo c > /proc/sysrq-trigger" or write a module to force the panic. Write Out the Dump File ======================= @@ -410,12 +415,9 @@ format. Crash is available on Dave Anderson's site at the following URL: To Do ===== -1) Provide a kernel pages filtering mechanism, so core file size is not - extreme on systems with huge memory banks. - -2) Relocatable kernel can help in maintaining multiple kernels for - crash_dump, and the same kernel as the system kernel can be used to - capture the dump. +1) Provide relocatable kernels for all architectures to help in maintaining + multiple kernels for crash_dump, and the same kernel as the system kernel + can be used to capture the dump. Contact |