On Mon, Feb 27, 2012 at 03:56:43PM -0800, Andrew Morton wrote: > On Tue, 28 Feb 2012 08:52:35 +0900 > Simon Horman <horms at verge.net.au> wrote: > > > On Mon, Feb 27, 2012 at 07:30:54PM +0000, Will Deacon wrote: > > > On Mon, Feb 27, 2012 at 12:37:30AM +0000, Simon Horman wrote: > > > > On Sun, Feb 26, 2012 at 10:58:42PM +0000, Will Deacon wrote: > > > > > On Sat, Feb 25, 2012 at 02:37:49AM +0000, Simon Horman wrote: > > > > > > > > > > > might this cover cases where swapper_pg_dir is interesting? > > > > > > > > > > The only case where it's interesting is when you have CONFIG_MMU enabled - > > > > > otherwise it's always NULL. If it's #defined as NULL, the current code will > > > > > fail at build time so simply omitting it from the dump seems like the best > > > > > bet to me (the alternative being to add a NULL entry explicitly, but I don't > > > > > see what the gains us). > > > > > > > > Hi Will, > > > > > > > > thanks for the clarification. FWIW I am happy with your patch. > > > > > > > > Reviewed-by: Simon Horman <horms at verge.net.au> > > > > > > Cheers, Simon. What's the usual path for generic kexec code getting into > > > mainline? Do I need to get this queued somewhere? > > > > I think that Andrew Morton often picks up these kind of patches. > > I'll take anything, if I have any chance of vaguely understanding it ;) > > > Andrew, can you pick this up if its reposted with you CCed? > > For reference the patch is as follows: > > > > > > From: Will Deacon <will.deacon at arm.com> > > > > kexec: crash: don't save swapper_pg_dir for !CONFIG_MMU configurations > > > > nommu platforms don't have very interesting swapper_pg_dir pointers and > > usually just #define them to NULL, meaning that we can't include them in > > the vmcoreinfo on the kexec crash path. > > > > This patch only saves the swapper_pg_dir if we have an MMU. > > > > Signed-off-by: Will Deacon <will.deacon at arm.com> > > Reviewed-by: Simon Horman <horms at verge.net.au> > > > > --- > > kernel/kexec.c | 2 ++ > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > diff --git a/kernel/kexec.c b/kernel/kexec.c > > index 7b08867..cb5d13c 100644 > > --- a/kernel/kexec.c > > +++ b/kernel/kexec.c > > @@ -1462,7 +1462,9 @@ static int __init crash_save_vmcoreinfo_init(void) > > > > VMCOREINFO_SYMBOL(init_uts_ns); > > VMCOREINFO_SYMBOL(node_online_map); > > +#ifdef CONFIG_MMU > > VMCOREINFO_SYMBOL(swapper_pg_dir); > > +#endif > > VMCOREINFO_SYMBOL(_stext); > > VMCOREINFO_SYMBOL(vmlist); > > Well, what might be the effects of this patch? nommu crashfiles will > no longer have the swapper_pg_dir string? What are the chances that > someone's (badly written!) downstream tool will crash and burn if this > is absent? My understanding is that up until this patch creating a dump for nonmmu platform wouldn't work.
