[PATCH] kexec-tools: s390: Do not create ELF header by default

[Simon Horman]

On Fri, Dec 09, 2011 at 02:42:19PM +0100, Michael Holzheu wrote:
> Hello Simon,
> 
> From: Michael Holzheu <holzheu at linux.vnet.ibm.com>
> 
> For s390 we have two modes for kdump:
> 
> For the first mode, as on all other architectures, the kexec tool creates
> the ELF header and the 2nd kernel processes it for /proc/vmcore setup.
> 
> This mode has the disadvantage that for memory and CPU hotplug the kdump
> kernel has to be reloaded by the kexec tool. For s390 this is a real problem
> because we have a cpuplugd daemon that sets CPUs online and offline
> according to the current workload. So CPU online/offline events occur very
> often.
> 
> For the second mode on s390, the ELF header is created by the kdump kernel.
> This is done automatically when the kernel is booted in kdump mode
> and no "elfcorehdr" kernel parameter is specified. On s390 the kdump kernel
> can get all necessary information to build the ELF header. We can get
> the memory map, all CPU registers, and vmcoreinfo 
> 
> With this patch a compile switch WITH_ELF_HEADER is introduced. When the
> macro is defined, kexec will create the ELF header and add the "elfcorehdr"
> kernel parameter. If it is not specified (default), no header is created.
> 
> For s390 we want to have the 2nd mode as default because it has only
> advantages for us.

Thanks Michael,

applied.