From: John Ogness <john.ogness@linutronix.de>
Date: Thu, 14 Dec 2023 14:38:42 +0000
Subject: [PATCH 17/46] printk: nbcon: Add helper to assign priority based on
 CPU state

Add a helper function to use the current state of the CPU to
determine which priority to assign to the printing context.

The EMERGENCY priority handling is added in a follow-up commit.
It will use a per-CPU variable.

Note: nbcon_driver_try_acquire(), which is used by console
      drivers to acquire the nbcon console for non-printing
      activities, will always use NORMAL priority.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/printk/internal.h |    2 ++
 kernel/printk/nbcon.c    |   16 ++++++++++++++++
 2 files changed, 18 insertions(+)

@ kernel/printk/internal.h:87 @ void nbcon_seq_force(struct console *con
 bool nbcon_alloc(struct console *con);
 void nbcon_init(struct console *con, u64 init_seq);
 void nbcon_free(struct console *con);
+enum nbcon_prio nbcon_get_default_prio(void);
 
 /*
  * Check if the given console is currently capable and allowed to print
@ kernel/printk/internal.h:142 @ static inline void nbcon_seq_force(struc
 static inline bool nbcon_alloc(struct console *con) { return false; }
 static inline void nbcon_init(struct console *con, u64 init_seq) { }
 static inline void nbcon_free(struct console *con) { }
+static inline enum nbcon_prio nbcon_get_default_prio(void) { return NBCON_PRIO_NONE; }
 
 static inline bool console_is_usable(struct console *con, short flags) { return false; }
 
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@ kernel/printk/internal.h:941 @ static bool nbcon_emit_next_record(struc
 }
 
 /**
+ * nbcon_get_default_prio - The appropriate nbcon priority to use for nbcon
+ *				printing on the current CPU
+ *
+ * Context:	Any context which could not be migrated to another CPU.
+ * Return:	The nbcon_prio to use for acquiring an nbcon console in this
+ *		context for printing.
+ */
+enum nbcon_prio nbcon_get_default_prio(void)
+{
+	if (this_cpu_in_panic())
+		return NBCON_PRIO_PANIC;
+
+	return NBCON_PRIO_NORMAL;
+}
+
+/**
  * nbcon_alloc - Allocate buffers needed by the nbcon console
  * @con:	Console to allocate buffers for
  *