Hello Vivek, On Tue, 7 May 2013 12:37:01 -0400 Vivek Goyal <vgoyal at redhat.com> wrote: > On Mon, May 06, 2013 at 03:09:55PM +0200, Michael Holzheu wrote: > > Hello Vivek, > > > > For s390 we want to use /proc/vmcore for our SCSI stand-alone > > dump (zfcpdump). We have support where the first HSA_SIZE bytes are > > saved into a hypervisor owned memory area (HSA) before the kdump > > kernel is booted. When the kdump kernel starts, it is restricted > > to use only HSA_SIZE bytes. > > > > Hi Michael, > > Hatayama is changing /proc/vmcore interface to support mmap(). Can you > please rebase your changes on top of those patches. > > http://thread.gmane.org/gmane.linux.kernel/1477622 Fine, we will do that. > Secondly, I think /proc/vmcore does not have to know whether elf > headers are in old memory or new memory. Given that s390 is taking > a deviation, so it now becomes an arch specific detail. Can't we > just create few arch specific helper functions to retrieve and free > elf headers. > > - arch_get_crash_headers() > - All arch except return elfcorehdr_add except s390. > - arch_read_crash_header_data() > - All arch just call into read_from_oldmem() except s390. We > can provide a generic implementation in /proc/vmcore.c so > all other arch can use that generic implementation. Or > use symbol override trick. > - arch_free_crash_headers() > - All arch do nothing except s390 which can reclaim the memory > for elf headers prepared. Generic code has parsed/copied > the headers by now. > > What do you think? Above 3 calls should solve the problem and allow > arch to handle elf headers differently. And generic implementation > still keeps common logic for processing headers. Ok, we will try that. There might be a problem that our ELF notes content is also in the new kernel memory. But also for that there be a solution. Michael
