Re: [PATCH v7 4/6] kho: fix kho_in_debugfs_init() to handle non-FDT blobs

[Breno Leitao <leitao@debian.org>]

On Mon, Mar 09, 2026 at 10:22:50AM +0200, Mike Rapoport wrote:
> On Fri, Mar 06, 2026 at 04:39:23AM -0800, Breno Leitao wrote:
> > kho_in_debugfs_init() has two problems when displaying incoming
> > sub-blobs in debugfs:
> > 
> > 1. It uses the hardcoded property name "fdt" instead of
> >    KHO_FDT_SUB_TREE_PROP_NAME ("preserved-data"), so it never finds
> >    subtrees stored by the current kho_add_subtree().
> > 
> > 2. It calls fdt_totalsize() to determine blob sizes, which assumes
> >    all blobs are FDTs. This breaks for non-FDT blobs like struct
> >    kho_kexec_metadata.
> > 
> > Fix both issues by using KHO_FDT_SUB_TREE_PROP_NAME to find subtrees
> > and reading the "blob-size" property from the FDT (persisted by
> > kho_add_subtree()) instead of calling fdt_totalsize().
> > 
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> >  kernel/liveupdate/kexec_handover_debugfs.c | 38 ++++++++++++++++++++----------
> >  1 file changed, 26 insertions(+), 12 deletions(-)
> > 
> > diff --git a/kernel/liveupdate/kexec_handover_debugfs.c b/kernel/liveupdate/kexec_handover_debugfs.c
> > index 7a100f2bf3947..fc2baa8b104fd 100644
> > --- a/kernel/liveupdate/kexec_handover_debugfs.c
> > +++ b/kernel/liveupdate/kexec_handover_debugfs.c
> > @@ -13,6 +13,7 @@
> >  #include <linux/io.h>
> >  #include <linux/libfdt.h>
> >  #include <linux/mm.h>
> > +#include <linux/kho/abi/kexec_handover.h>
> >  #include "kexec_handover_internal.h"
> >  
> >  static struct dentry *debugfs_root;
> > @@ -121,23 +122,36 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt)
> >  	fdt_for_each_subnode(child, fdt, 0) {
> >  		int len = 0;
> >  		const char *name = fdt_get_name(fdt, child, NULL);
> > -		const u64 *fdt_phys;
> > -		void *sub_fdt;
> > -
> > -		fdt_phys = fdt_getprop(fdt, child, "fdt", &len);
> > -		if (!fdt_phys)
> > +		const u64 *blob_phys;
> > +		const u64 *blob_size;
> > +		void *blob;
> > +		size_t size;
> 
> Do we really need two size variables? Can't we just have u64 *size and pass
> *size to __kho_debugfs_blob_add()?

We definitely can. let me respin with the other changes as well.

Thanks for the review,
--breno