1 files changed, 49 insertions, 220 deletions

diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index 03d12e27189f..befa6ceab574 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -11,7 +11,6 @@
 #include <linux/cleanup.h>
 #include <linux/cma.h>
 #include <linux/count_zeros.h>
-#include <linux/debugfs.h>
 #include <linux/kexec.h>
 #include <linux/kexec_handover.h>
 #include <linux/libfdt.h>
@@ -30,6 +29,7 @@
  */
 #include "../mm/internal.h"
 #include "kexec_internal.h"
+#include "kexec_handover_internal.h"
 
 #define KHO_FDT_COMPATIBLE "kho-v1"
 #define PROP_PRESERVED_MEMORY_MAP "preserved-memory-map"
@@ -105,8 +105,6 @@ struct khoser_mem_chunk;
 
 struct kho_serialization {
 	struct page *fdt;
-	struct list_head fdt_list;
-	struct dentry *sub_fdt_dir;
 	struct kho_mem_track track;
 	/* First chunk of serialized preserved memory map */
 	struct khoser_mem_chunk *preserved_mem_map;
@@ -114,20 +112,16 @@ struct kho_serialization {
 
 struct kho_out {
 	struct blocking_notifier_head chain_head;
-
-	struct dentry *dir;
-
 	struct mutex lock; /* protects KHO FDT finalization */
-
 	struct kho_serialization ser;
 	bool finalized;
+	struct kho_debugfs dbg;
 };
 
 static struct kho_out kho_out = {
 	.chain_head = BLOCKING_NOTIFIER_INIT(kho_out.chain_head),
 	.lock = __MUTEX_INITIALIZER(kho_out.lock),
 	.ser = {
-		.fdt_list = LIST_HEAD_INIT(kho_out.ser.fdt_list),
 		.track = {
 			.orders = XARRAY_INIT(kho_out.ser.track.orders, 0),
 		},
@@ -674,37 +668,6 @@ err_disable_kho:
 	kho_enable = false;
 }
 
-struct fdt_debugfs {
-	struct list_head list;
-	struct debugfs_blob_wrapper wrapper;
-	struct dentry *file;
-};
-
-static int kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir,
-			       const char *name, const void *fdt)
-{
-	struct fdt_debugfs *f;
-	struct dentry *file;
-
-	f = kmalloc(sizeof(*f), GFP_KERNEL);
-	if (!f)
-		return -ENOMEM;
-
-	f->wrapper.data = (void *)fdt;
-	f->wrapper.size = fdt_totalsize(fdt);
-
-	file = debugfs_create_blob(name, 0400, dir, &f->wrapper);
-	if (IS_ERR(file)) {
-		kfree(f);
-		return PTR_ERR(file);
-	}
-
-	f->file = file;
-	list_add(&f->list, list);
-
-	return 0;
-}
-
 /**
  * kho_add_subtree - record the physical address of a sub FDT in KHO root tree.
  * @ser: serialization control object passed by KHO notifiers.
@@ -716,7 +679,8 @@ static int kho_debugfs_fdt_add(struct list_head *list, struct dentry *dir,
  * by KHO for the new kernel to retrieve it after kexec.
  *
  * A debugfs blob entry is also created at
- * ``/sys/kernel/debug/kho/out/sub_fdts/@name``.
+ * ``/sys/kernel/debug/kho/out/sub_fdts/@name`` when kernel is configured with
+ * CONFIG_KEXEC_HANDOVER_DEBUGFS
  *
  * Return: 0 on success, error code on failure
  */
@@ -733,7 +697,7 @@ int kho_add_subtree(struct kho_serialization *ser, const char *name, void *fdt)
 	if (err)
 		return err;
 
-	return kho_debugfs_fdt_add(&ser->fdt_list, ser->sub_fdt_dir, name, fdt);
+	return kho_debugfs_fdt_add(&kho_out.dbg, name, fdt, false);
 }
 EXPORT_SYMBOL_GPL(kho_add_subtree);
 
@@ -1065,30 +1029,7 @@ err_free_pages_array:
 }
 EXPORT_SYMBOL_GPL(kho_restore_vmalloc);
 
-/* Handling for debug/kho/out */
-
-static struct dentry *debugfs_root;
-
-static int kho_out_update_debugfs_fdt(void)
-{
-	int err = 0;
-	struct fdt_debugfs *ff, *tmp;
-
-	if (kho_out.finalized) {
-		err = kho_debugfs_fdt_add(&kho_out.ser.fdt_list, kho_out.dir,
-					  "fdt", page_to_virt(kho_out.ser.fdt));
-	} else {
-		list_for_each_entry_safe(ff, tmp, &kho_out.ser.fdt_list, list) {
-			debugfs_remove(ff->file);
-			list_del(&ff->list);
-			kfree(ff);
-		}
-	}
-
-	return err;
-}
-
-static int kho_abort(void)
+static int __kho_abort(void)
 {
 	int err;
 	unsigned long order;
@@ -1121,7 +1062,28 @@ static int kho_abort(void)
 	return err;
 }
 
-static int kho_finalize(void)
+int kho_abort(void)
+{
+	int ret = 0;
+
+	if (!kho_enable)
+		return -EOPNOTSUPP;
+
+	guard(mutex)(&kho_out.lock);
+	if (!kho_out.finalized)
+		return -ENOENT;
+
+	ret = __kho_abort();
+	if (ret)
+		return ret;
+
+	kho_out.finalized = false;
+	kho_debugfs_cleanup(&kho_out.dbg);
+
+	return 0;
+}
+
+static int __kho_finalize(void)
 {
 	int err = 0;
 	u64 *preserved_mem_map;
@@ -1164,118 +1126,46 @@ static int kho_finalize(void)
 abort:
 	if (err) {
 		pr_err("Failed to convert KHO state tree: %d\n", err);
-		kho_abort();
+		__kho_abort();
 	}
 
 	return err;
 }
 
-static int kho_out_finalize_get(void *data, u64 *val)
-{
-	mutex_lock(&kho_out.lock);
-	*val = kho_out.finalized;
-	mutex_unlock(&kho_out.lock);
-
-	return 0;
-}
-
-static int kho_out_finalize_set(void *data, u64 _val)
+int kho_finalize(void)
 {
-	int ret = 0;
-	bool val = !!_val;
-
-	mutex_lock(&kho_out.lock);
+	int ret;
 
-	if (val == kho_out.finalized) {
-		if (kho_out.finalized)
-			ret = -EEXIST;
-		else
-			ret = -ENOENT;
-		goto unlock;
-	}
+	if (!kho_enable)
+		return -EOPNOTSUPP;
 
-	if (val)
-		ret = kho_finalize();
-	else
-		ret = kho_abort();
+	guard(mutex)(&kho_out.lock);
+	if (kho_out.finalized)
+		return -EEXIST;
 
+	ret = __kho_finalize();
 	if (ret)
-		goto unlock;
-
-	kho_out.finalized = val;
-	ret = kho_out_update_debugfs_fdt();
-
-unlock:
-	mutex_unlock(&kho_out.lock);
-	return ret;
-}
-
-DEFINE_DEBUGFS_ATTRIBUTE(fops_kho_out_finalize, kho_out_finalize_get,
-			 kho_out_finalize_set, "%llu\n");
-
-static int scratch_phys_show(struct seq_file *m, void *v)
-{
-	for (int i = 0; i < kho_scratch_cnt; i++)
-		seq_printf(m, "0x%llx\n", kho_scratch[i].addr);
-
-	return 0;
-}
-DEFINE_SHOW_ATTRIBUTE(scratch_phys);
+		return ret;
 
-static int scratch_len_show(struct seq_file *m, void *v)
-{
-	for (int i = 0; i < kho_scratch_cnt; i++)
-		seq_printf(m, "0x%llx\n", kho_scratch[i].size);
+	kho_out.finalized = true;
 
-	return 0;
+	return kho_debugfs_fdt_add(&kho_out.dbg, "fdt",
+				   page_to_virt(kho_out.ser.fdt), true);
 }
-DEFINE_SHOW_ATTRIBUTE(scratch_len);
 
-static __init int kho_out_debugfs_init(void)
+bool kho_finalized(void)
 {
-	struct dentry *dir, *f, *sub_fdt_dir;
-
-	dir = debugfs_create_dir("out", debugfs_root);
-	if (IS_ERR(dir))
-		return -ENOMEM;
-
-	sub_fdt_dir = debugfs_create_dir("sub_fdts", dir);
-	if (IS_ERR(sub_fdt_dir))
-		goto err_rmdir;
-
-	f = debugfs_create_file("scratch_phys", 0400, dir, NULL,
-				&scratch_phys_fops);
-	if (IS_ERR(f))
-		goto err_rmdir;
-
-	f = debugfs_create_file("scratch_len", 0400, dir, NULL,
-				&scratch_len_fops);
-	if (IS_ERR(f))
-		goto err_rmdir;
-
-	f = debugfs_create_file("finalize", 0600, dir, NULL,
-				&fops_kho_out_finalize);
-	if (IS_ERR(f))
-		goto err_rmdir;
-
-	kho_out.dir = dir;
-	kho_out.ser.sub_fdt_dir = sub_fdt_dir;
-	return 0;
-
-err_rmdir:
-	debugfs_remove_recursive(dir);
-	return -ENOENT;
+	guard(mutex)(&kho_out.lock);
+	return kho_out.finalized;
 }
 
 struct kho_in {
-	struct dentry *dir;
 	phys_addr_t fdt_phys;
 	phys_addr_t scratch_phys;
-	struct list_head fdt_list;
+	struct kho_debugfs dbg;
 };
 
 static struct kho_in kho_in = {
-	.fdt_list = LIST_HEAD_INIT(kho_in.fdt_list),
 };
 
 static const void *kho_get_fdt(void)
@@ -1339,56 +1229,6 @@ int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
 }
 EXPORT_SYMBOL_GPL(kho_retrieve_subtree);
 
-/* Handling for debugfs/kho/in */
-
-static __init int kho_in_debugfs_init(const void *fdt)
-{
-	struct dentry *sub_fdt_dir;
-	int err, child;
-
-	kho_in.dir = debugfs_create_dir("in", debugfs_root);
-	if (IS_ERR(kho_in.dir))
-		return PTR_ERR(kho_in.dir);
-
-	sub_fdt_dir = debugfs_create_dir("sub_fdts", kho_in.dir);
-	if (IS_ERR(sub_fdt_dir)) {
-		err = PTR_ERR(sub_fdt_dir);
-		goto err_rmdir;
-	}
-
-	err = kho_debugfs_fdt_add(&kho_in.fdt_list, kho_in.dir, "fdt", fdt);
-	if (err)
-		goto err_rmdir;
-
-	fdt_for_each_subnode(child, fdt, 0) {
-		int len = 0;
-		const char *name = fdt_get_name(fdt, child, NULL);
-		const u64 *fdt_phys;
-
-		fdt_phys = fdt_getprop(fdt, child, "fdt", &len);
-		if (!fdt_phys)
-			continue;
-		if (len != sizeof(*fdt_phys)) {
-			pr_warn("node `%s`'s prop `fdt` has invalid length: %d\n",
-				name, len);
-			continue;
-		}
-		err = kho_debugfs_fdt_add(&kho_in.fdt_list, sub_fdt_dir, name,
-					  phys_to_virt(*fdt_phys));
-		if (err) {
-			pr_warn("failed to add fdt `%s` to debugfs: %d\n", name,
-				err);
-			continue;
-		}
-	}
-
-	return 0;
-
-err_rmdir:
-	debugfs_remove_recursive(kho_in.dir);
-	return err;
-}
-
 static __init int kho_init(void)
 {
 	int err = 0;
@@ -1403,27 +1243,16 @@ static __init int kho_init(void)
 		goto err_free_scratch;
 	}
 
-	debugfs_root = debugfs_create_dir("kho", NULL);
-	if (IS_ERR(debugfs_root)) {
-		err = -ENOENT;
+	err = kho_debugfs_init();
+	if (err)
 		goto err_free_fdt;
-	}
 
-	err = kho_out_debugfs_init();
+	err = kho_out_debugfs_init(&kho_out.dbg);
 	if (err)
 		goto err_free_fdt;
 
 	if (fdt) {
-		err = kho_in_debugfs_init(fdt);
-		/*
-		 * Failure to create /sys/kernel/debug/kho/in does not prevent
-		 * reviving state from KHO and setting up KHO for the next
-		 * kexec.
-		 */
-		if (err)
-			pr_err("failed exposing handover FDT in debugfs: %d\n",
-			       err);
-
+		kho_in_debugfs_init(&kho_in.dbg, fdt);
 		return 0;
 	}