[PATCH] kexec: crash: don't save swapper_pg_dir for !CONFIG_MMU configurations

[Simon Horman]

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.

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);
 
-- 
1.7.4.1