On Fri, Jan 24, 2025 at 07:16:45AM -0800, Breno Leitao wrote:
Add infrastructure to automatically append kernel-generated data (sysdata) to netconsole messages. As the first use case, implement CPU number population, which adds the CPU that sent the message.
This change introduces three distinct data types:
- extradata: The complete set of appended data (sysdata + userdata)
- userdata: User-provided key-value pairs from userspace
- sysdata: Kernel-populated data (e.g. cpu=XX)
The implementation adds a new configfs attribute 'cpu_nr' to control CPU number population per target. When enabled, each message is tagged with its originating CPU. The sysdata is dynamically updated at message time and appended after any existing userdata.
The CPU number is formatted as "cpu=XX" and is added to the extradata buffer, respecting the existing size limits.
Signed-off-by: Breno Leitao leitao@debian.org
Reviewed-by: Simon Horman horms@kernel.org