On Fri, Mar 13, 2026 at 04:32:23PM +0100, Greg Kroah-Hartman wrote:
On Fri, Mar 13, 2026 at 11:09:13AM -0400, Sasha Levin wrote:
Add a debugfs interface to expose kernel API specifications at runtime.
This allows tools and users to query the complete API specifications
through the debugfs filesystem.
The interface provides:
- /sys/kernel/debug/kapi/list - lists all available API specifications
- /sys/kernel/debug/kapi/specs/<name> - detailed info for each API
Each specification file includes:
- Function name, version, and descriptions
- Execution context requirements and flags
- Parameter details with types, flags, and constraints
- Return value specifications and success conditions
- Error codes with descriptions and conditions
- Locking requirements and constraints
- Signal handling specifications
- Examples, notes, and deprecation status
This enables runtime introspection of kernel APIs for documentation
tools, static analyzers, and debugging purposes.
Signed-off-by: Sasha Levin <[email protected]>
---
Documentation/dev-tools/kernel-api-spec.rst | 88 ++--
You are removing stuff from the file you created earlier in this patch
series, is that ok?
Sorry, just a rebasing artifact from shuffling patches around. I'll fix it.
--- /dev/null
+++ b/kernel/api/kapi_debugfs.c
@@ -0,0 +1,503 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel API specification debugfs interface
+ *
+ * This provides a debugfs interface to expose kernel API specifications
+ * at runtime, allowing tools and users to query the complete API specs.
+ */
No copyright line? :)
I'll add one.
And this is, a totally and crazy interface with debugfs, I love it!
Thanks :)
Two minor minor nits:
+static int __init kapi_debugfs_init(void)
+{
+ struct kernel_api_spec *spec;
+ struct dentry *spec_dir;
+
+ /* Create main directory */
+ kapi_debugfs_root = debugfs_create_dir("kapi", NULL);
+
+ /* Create list file */
+ debugfs_create_file("list", 0444, kapi_debugfs_root, NULL,
&kapi_list_fops);
+
+ /* Create specs subdirectory */
+ spec_dir = debugfs_create_dir("specs", kapi_debugfs_root);
+
+ /* Create a file for each API spec */
+ for (spec = __start_kapi_specs; spec < __stop_kapi_specs; spec++) {
+ debugfs_create_file(spec->name, 0444, spec_dir, spec,
&kapi_spec_fops);
+ }
No need for { }
ack
+
+ pr_info("Kernel API debugfs interface initialized\n");
When code is working properly, it should be quiet, no need for this as
initializing this can not fail.
ack
--
Thanks,
Sasha
