[PATCH v8 2/6] kho: rename fdt parameter to blob in kho_add/remove_subtree()

Breno Leitao
2026-03-09T13:42:35Z

Since kho_add_subtree() now accepts arbitrary data blobs (not just
FDTs), rename the parameter from 'fdt' to 'blob' to better reflect
its purpose. Apply the same rename to kho_remove_subtree() for
consistency.

Also rename kho_debugfs_fdt_add() and kho_debugfs_fdt_remove() to
kho_debugfs_blob_add() and kho_debugfs_blob_remove() respectively,
with the same parameter rename from 'fdt' to 'blob'.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
Documentation/admin-guide/mm/kho.rst | 2 +-
include/linux/kexec_handover.h | 8 +++----
kernel/liveupdate/kexec_handover.c | 33 +++++++++++++++--------------
kernel/liveupdate/kexec_handover_debugfs.c | 25 +++++++++++-----------
kernel/liveupdate/kexec_handover_internal.h | 16 +++++++-------
5 files changed, 43 insertions(+), 41 deletions(-)

diff --git a/Documentation/admin-guide/mm/kho.rst b/Documentation/admin-guide/mm/kho.rst
index cb9a20f649206..6a4ddf3440465 100644
--- a/Documentation/admin-guide/mm/kho.rst
+++ b/Documentation/admin-guide/mm/kho.rst
@@ -80,5 +80,5 @@ stabilized.
it finished to interpret their metadata.

``/sys/kernel/debug/kho/in/sub_fdts/``
- Similar to ``kho/out/sub_fdts/``, but contains sub FDT blobs
+ Similar to ``kho/out/sub_fdts/``, but contains sub blobs
of KHO producers passed from the old kernel.
diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h
index abb1d324f42d0..0666cf298c7f4 100644
--- a/include/linux/kexec_handover.h
+++ b/include/linux/kexec_handover.h
@@ -32,8 +32,8 @@ void kho_restore_free(void *mem);
struct folio *kho_restore_folio(phys_addr_t phys);
struct page *kho_restore_pages(phys_addr_t phys, unsigned long nr_pages);
void *kho_restore_vmalloc(const struct kho_vmalloc *preservation);
-int kho_add_subtree(const char *name, void *fdt, size_t size);
-void kho_remove_subtree(void *fdt);
+int kho_add_subtree(const char *name, void *blob, size_t size);
+void kho_remove_subtree(void *blob);
int kho_retrieve_subtree(const char *name, phys_addr_t *phys);

void kho_memory_init(void);
@@ -97,12 +97,12 @@ static inline void *kho_restore_vmalloc(const struct kho_vmalloc *preservation)
return NULL;
}

-static inline int kho_add_subtree(const char *name, void *fdt, size_t size)
+static inline int kho_add_subtree(const char *name, void *blob, size_t size)
{
return -EOPNOTSUPP;
}

-static inline void kho_remove_subtree(void *fdt) { }
+static inline void kho_remove_subtree(void *blob) { }

static inline int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
{
diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
index 55bdc5d2d1929..54fe59fe43acd 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -749,13 +749,13 @@ static void __init kho_reserve_scratch(void)
}

/**
- * kho_add_subtree - record the physical address of a sub FDT in KHO root tree.
+ * kho_add_subtree - record the physical address of a sub blob in KHO root tree.
* @name: name of the sub tree.
- * @fdt: the sub tree blob.
+ * @blob: the sub tree blob.
* @size: size of the blob in bytes.
*
* Creates a new child node named @name in KHO root FDT and records
- * the physical address of @fdt. The pages of @fdt must also be preserved
+ * the physical address of @blob. The pages of @blob must also be preserved
* by KHO for the new kernel to retrieve it after kexec.
*
* A debugfs blob entry is also created at
@@ -764,9 +764,9 @@ static void __init kho_reserve_scratch(void)
*
* Return: 0 on success, error code on failure
*/
-int kho_add_subtree(const char *name, void *fdt, size_t size)
+int kho_add_subtree(const char *name, void *blob, size_t size)
{
- phys_addr_t phys = virt_to_phys(fdt);
+ phys_addr_t phys = virt_to_phys(blob);
void *root_fdt = kho_out.fdt;
int err = -ENOMEM;
int off, fdt_err;
@@ -789,7 +789,8 @@ int kho_add_subtree(const char *name, void *fdt, size_t size)
if (err < 0)
goto out_pack;

- WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, name, fdt, size, false));
+ WARN_ON_ONCE(kho_debugfs_blob_add(&kho_out.dbg, name, blob,
+ size, false));

out_pack:
fdt_pack(root_fdt);
@@ -798,9 +799,9 @@ int kho_add_subtree(const char *name, void *fdt, size_t size)
}
EXPORT_SYMBOL_GPL(kho_add_subtree);

-void kho_remove_subtree(void *fdt)
+void kho_remove_subtree(void *blob)
{
- phys_addr_t target_phys = virt_to_phys(fdt);
+ phys_addr_t target_phys = virt_to_phys(blob);
void *root_fdt = kho_out.fdt;
int off;
int err;
@@ -822,7 +823,7 @@ void kho_remove_subtree(void *fdt)

if ((phys_addr_t)*val == target_phys) {
fdt_del_node(root_fdt, off);
- kho_debugfs_fdt_remove(&kho_out.dbg, fdt);
+ kho_debugfs_blob_remove(&kho_out.dbg, blob);
break;
}
}
@@ -1310,11 +1311,11 @@ bool is_kho_boot(void)
EXPORT_SYMBOL_GPL(is_kho_boot);

/**
- * kho_retrieve_subtree - retrieve a preserved sub FDT by its name.
- * @name: the name of the sub FDT passed to kho_add_subtree().
- * @phys: if found, the physical address of the sub FDT is stored in @phys.
+ * kho_retrieve_subtree - retrieve a preserved sub blob by its name.
+ * @name: the name of the sub blob passed to kho_add_subtree().
+ * @phys: if found, the physical address of the sub blob is stored in @phys.
*
- * Retrieve a preserved sub FDT named @name and store its physical
+ * Retrieve a preserved sub blob named @name and store its physical
* address in @phys.
*
* Return: 0 on success, error code on failure
@@ -1452,9 +1453,9 @@ static __init int kho_init(void)
return 0;
}

- WARN_ON_ONCE(kho_debugfs_fdt_add(&kho_out.dbg, "fdt",
- kho_out.fdt,
- fdt_totalsize(kho_out.fdt), true));
+ WARN_ON_ONCE(kho_debugfs_blob_add(&kho_out.dbg, "fdt",
+ kho_out.fdt,
+ fdt_totalsize(kho_out.fdt), true));

return 0;

diff --git a/kernel/liveupdate/kexec_handover_debugfs.c b/kernel/liveupdate/kexec_handover_debugfs.c
index b5a1e09ca8f14..7a100f2bf3947 100644
--- a/kernel/liveupdate/kexec_handover_debugfs.c
+++ b/kernel/liveupdate/kexec_handover_debugfs.c
@@ -23,8 +23,9 @@ struct fdt_debugfs {
struct dentry *file;
};

-static int __kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir,
- const char *name, const void *fdt, size_t size)
+static int __kho_debugfs_blob_add(struct list_head *list, struct dentry *dir,
+ const char *name, const void *blob,
+ size_t size)
{
struct fdt_debugfs *f;
struct dentry *file;
@@ -33,7 +34,7 @@ static int __kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir,
if (!f)
return -ENOMEM;

- f->wrapper.data = (void *)fdt;
+ f->wrapper.data = (void *)blob;
f->wrapper.size = size;

file = debugfs_create_blob(name, 0400, dir, &f->wrapper);
@@ -48,8 +49,8 @@ static int __kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir,
return 0;
}

-int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
- const void *fdt, size_t size, bool root)
+int kho_debugfs_blob_add(struct kho_debugfs *dbg, const char *name,
+ const void *blob, size_t size, bool root)
{
struct dentry *dir;

@@ -58,15 +59,15 @@ int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
else
dir = dbg->sub_fdt_dir;

- return __kho_debugfs_fdt_add(&dbg->fdt_list, dir, name, fdt, size);
+ return __kho_debugfs_blob_add(&dbg->fdt_list, dir, name, blob, size);
}

-void kho_debugfs_fdt_remove(struct kho_debugfs *dbg, void *fdt)
+void kho_debugfs_blob_remove(struct kho_debugfs *dbg, void *blob)
{
struct fdt_debugfs *ff;

list_for_each_entry(ff, &dbg->fdt_list, list) {
- if (ff->wrapper.data == fdt) {
+ if (ff->wrapper.data == blob) {
debugfs_remove(ff->file);
list_del(&ff->list);
kfree(ff);
@@ -112,8 +113,8 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt)
goto err_rmdir;
}

- err = __kho_debugfs_fdt_add(&dbg->fdt_list, dir, "fdt", fdt,
- fdt_totalsize(fdt));
+ err = __kho_debugfs_blob_add(&dbg->fdt_list, dir, "fdt", fdt,
+ fdt_totalsize(fdt));
if (err)
goto err_rmdir;

@@ -132,8 +133,8 @@ __init void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt)
continue;
}
sub_fdt = phys_to_virt(*fdt_phys);
- err = __kho_debugfs_fdt_add(&dbg->fdt_list, sub_fdt_dir, name,
- sub_fdt, fdt_totalsize(sub_fdt));
+ err = __kho_debugfs_blob_add(&dbg->fdt_list, sub_fdt_dir, name,
+ sub_fdt, fdt_totalsize(sub_fdt));
if (err) {
pr_warn("failed to add fdt %s to debugfs: %pe\n", name,
ERR_PTR(err));
diff --git a/kernel/liveupdate/kexec_handover_internal.h b/kernel/liveupdate/kexec_handover_internal.h
index 2a28cb8db9b0a..0399ff1077750 100644
--- a/kernel/liveupdate/kexec_handover_internal.h
+++ b/kernel/liveupdate/kexec_handover_internal.h
@@ -26,19 +26,19 @@ extern unsigned int kho_scratch_cnt;
int kho_debugfs_init(void);
void kho_in_debugfs_init(struct kho_debugfs *dbg, const void *fdt);
int kho_out_debugfs_init(struct kho_debugfs *dbg);
-int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
- const void *fdt, size_t size, bool root);
-void kho_debugfs_fdt_remove(struct kho_debugfs *dbg, void *fdt);
+int kho_debugfs_blob_add(struct kho_debugfs *dbg, const char *name,
+ const void *blob, size_t size, bool root);
+void kho_debugfs_blob_remove(struct kho_debugfs *dbg, void *blob);
#else
static inline int kho_debugfs_init(void) { return 0; }
static inline void kho_in_debugfs_init(struct kho_debugfs *dbg,
const void *fdt) { }
static inline int kho_out_debugfs_init(struct kho_debugfs *dbg) { return 0; }
-static inline int kho_debugfs_fdt_add(struct kho_debugfs *dbg, const char *name,
- const void *fdt, size_t size,
- bool root) { return 0; }
-static inline void kho_debugfs_fdt_remove(struct kho_debugfs *dbg,
- void *fdt) { }
+static inline int kho_debugfs_blob_add(struct kho_debugfs *dbg,
+ const char *name, const void *blob,
+ size_t size, bool root) { return 0; }
+static inline void kho_debugfs_blob_remove(struct kho_debugfs *dbg,
+ void *blob) { }
#endif /* CONFIG_KEXEC_HANDOVER_DEBUGFS */

#ifdef CONFIG_KEXEC_HANDOVER_DEBUG

--
2.47.3