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    SubjectRe: [patch v3 3/8] kdump: Add size to elfcorehdr kernel parameter
    Hello Vivek,

    On Wed, 2011-08-17 at 17:05 -0400, Vivek Goyal wrote:
    > On Fri, Aug 12, 2011 at 03:48:52PM +0200, Michael Holzheu wrote:
    > > From: Michael Holzheu <>
    > >
    > > Currently only the address of the pre-allocated ELF header is passed with
    > > the elfcorehdr= kernel parameter. In order to reserve memory for the header
    > > in the 2nd kernel also the size is required. Current kdump architecture
    > > backends use different methods to do that, e.g. x86 uses the memmap= kernel
    > > parameter. On s390 there is no easy way to transfer this information.
    > > Therefore the elfcorehdr kernel parameter is extended to also pass the size.
    > > This now can also be used as standard mechanism by all future kdump
    > > architecture backends.
    > Michael,
    > This version looks much better. A quick question. Who parses this
    > elfcorehdr= parameter in s390 and how do we make sure these headers are not
    > overwritten.

    The parameter is parsed in common code (kernel/crash_dump.c) in
    early_param("elfcorehdr", setup_elfcorehdr), as it is already currently
    the case.

    We use address and size of the ELF core header to reserve the header
    memory in setup.c (see patch #8):

    + if (is_kdump_kernel())
    + reserve_bootmem(elfcorehdr_addr - OLDMEM_BASE,
    + PAGE_ALIGN(elfcorehdr_size), BOOTMEM_DEFAULT);

    Does that answer your question?


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