diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2024-08-20 08:35:57 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2024-08-21 15:03:04 +0200 |
| commit | ecb5e1aa82c86642ec1eaafefd4e317dfba3a238 (patch) | |
| tree | 11696502a9e1e73e338cf81d25989099d9f31f91 /include/linux/console.h | |
| parent | 6690d6b52726bcb2b743466a1833e0b9f049b9d7 (diff) | |
printk: nbcon: Implement emergency sections
In emergency situations (something has gone wrong but the
system continues to operate), usually important information
(such as a backtrace) is generated via printk(). This
information should be pushed out to the consoles ASAP.
Add per-CPU emergency nesting tracking because an emergency
can arise while in an emergency situation.
Add functions to mark the beginning and end of emergency
sections where the urgent messages are generated.
Perform direct console flushing at the emergency priority if
the current CPU is in an emergency state and it is safe to do
so.
Note that the emergency state is not system-wide. While one CPU
is in an emergency state, another CPU may attempt to print
console messages at normal priority.
Also note that printk() already attempts to flush consoles in
the caller context for normal priority. However, follow-up
changes will introduce printing kthreads, in which case the
normal priority printk() calls will offload to the kthreads.
Co-developed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Thomas Gleixner (Intel) <tglx@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240820063001.36405-32-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'include/linux/console.h')
| -rw-r--r-- | include/linux/console.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/console.h b/include/linux/console.h index 3706f944de46..9a13f91b0c43 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -553,10 +553,14 @@ static inline bool console_is_registered(const struct console *con) hlist_for_each_entry(con, &console_list, node) #ifdef CONFIG_PRINTK +extern void nbcon_cpu_emergency_enter(void); +extern void nbcon_cpu_emergency_exit(void); extern bool nbcon_can_proceed(struct nbcon_write_context *wctxt); extern bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt); extern bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt); #else +static inline void nbcon_cpu_emergency_enter(void) { } +static inline void nbcon_cpu_emergency_exit(void) { } static inline bool nbcon_can_proceed(struct nbcon_write_context *wctxt) { return false; } static inline bool nbcon_enter_unsafe(struct nbcon_write_context *wctxt) { return false; } static inline bool nbcon_exit_unsafe(struct nbcon_write_context *wctxt) { return false; } |