kexec: load-preserve-context option on s390
holzheu at linux.vnet.ibm.com
Tue Oct 4 10:07:06 EDT 2011
On Fri, 2011-09-30 at 12:06 -0400, Vivek Goyal wrote:
> On Thu, Sep 29, 2011 at 03:38:31PM +0200, Michael Holzheu wrote:
> > Hello Vivec,
> Right spelling is "Vivek" and not "Vivec" :-)
I know... and I really wanted to avoid that error. But somehow the "c"
is always coming automatically :-)
> > > Shouldn't kexec system call return error if KEXEC_JUMP is not supported
> > > and user asked for it?
> > I think currently not. I assume that we should check the
> > KEXEC_PRESERVE_CONTEXT flag in the kexec_load system call.
> Shouldn't following existing code take care of this already?
> * Verify we have a legal set of flags
> * This leaves us room for future extensions.
> if ((flags & KEXEC_FLAGS) != (flags & ~KEXEC_ARCH_MASK))
> return -EINVAL;
> In include/linux/kexec.h, we have following.
> /* List of defined/legal kexec flags */
> #ifndef CONFIG_KEXEC_JUMP
> #define KEXEC_FLAGS KEXEC_ON_CRASH
> #define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT)
> Not sure why it is not working.
Hmmm, actually it is working. I somehow must have overlooked that
When I call kexec with --load-preserve-context - while not really
knowing what I am doing here - I get the following:
# kexec -p /boot/vmlinuz --load-preserve-context --mem-min=0x10000
kexec_load failed: Invalid argument
entry = 0x10000 flags = 160002
nr_segments = 2
segment.buf = 0x3fffc989010
segment.bufsz = 330600
segment.mem = 0x10000
segment.memsz = 331000
segment.buf = (nil)
segment.bufsz = 0
segment.mem = 0x341000
segment.memsz = 334be000
Perhaps a better error message could help here. But there are several
possible reasons for getting EINVAL from kexec_load(). So probably we
can't say "--load-preserve-context not supported by current kernel"
every time we get EINVAL from kexec_load().
Not sure what to do here. Perhaps we just leave it as it is.
BTW: Is there any good documentation on KEXEC_PRESERVE_CONTEXT?
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