Merging debian version 6.9.7-1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/debian/patches-rt/0005-printk-nbcon-Add-detailed-doc-for-write_atomic.patch b/debian/patches-rt/0005-printk-nbcon-Add-detailed-doc-for-write_atomic.patch
new file mode 100644
index 0000000000..7d6a606df3
--- /dev/null
+++ b/debian/patches-rt/0005-printk-nbcon-Add-detailed-doc-for-write_atomic.patch
@@ -0,0 +1,72 @@
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 7 Feb 2024 18:38:14 +0000
+Subject: [PATCH 05/46] printk: nbcon: Add detailed doc for write_atomic()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.9/older/patches-6.9-rt5.tar.xz
+
+The write_atomic() callback has special requirements and is
+allowed to use special helper functions. Provide detailed
+documentation of the callback so that a developer has a
+chance of implementing it correctly.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/console.h |   33 +++++++++++++++++++++++++++++----
+ 1 file changed, 29 insertions(+), 4 deletions(-)
+
+--- a/include/linux/console.h
++++ b/include/linux/console.h
+@@ -303,7 +303,7 @@ struct nbcon_write_context {
+ /**
+  * struct console - The console descriptor structure
+  * @name:		The name of the console driver
+- * @write:		Write callback to output messages (Optional)
++ * @write:		Legacy write callback to output messages (Optional)
+  * @read:		Read callback for console input (Optional)
+  * @device:		The underlying TTY device driver (Optional)
+  * @unblank:		Callback to unblank the console (Optional)
+@@ -320,7 +320,6 @@ struct nbcon_write_context {
+  * @data:		Driver private data
+  * @node:		hlist node for the console list
+  *
+- * @write_atomic:	Write callback for atomic context
+  * @nbcon_state:	State for nbcon consoles
+  * @nbcon_seq:		Sequence number of the next record for nbcon to print
+  * @pbufs:		Pointer to nbcon private buffer
+@@ -345,8 +344,34 @@ struct console {
+ 	struct hlist_node	node;
+ 
+ 	/* nbcon console specific members */
+-	void			(*write_atomic)(struct console *con,
+-						struct nbcon_write_context *wctxt);
++
++	/**
++	 * @write_atomic:
++	 *
++	 * NBCON callback to write out text in any context.
++	 *
++	 * This callback is called with the console already acquired. However,
++	 * a higher priority context is allowed to take it over by default.
++	 *
++	 * The callback must call nbcon_enter_unsafe() and nbcon_exit_unsafe()
++	 * around any code where the takeover is not safe, for example, when
++	 * manipulating the serial port registers.
++	 *
++	 * nbcon_enter_unsafe() will fail if the context has lost the console
++	 * ownership in the meantime. In this case, the callback is no longer
++	 * allowed to go forward. It must back out immediately and carefully.
++	 * The buffer content is also no longer trusted since it no longer
++	 * belongs to the context.
++	 *
++	 * The callback should allow the takeover whenever it is safe. It
++	 * increases the chance to see messages when the system is in trouble.
++	 *
++	 * The callback can be called from any context (including NMI).
++	 * Therefore it must avoid usage of any locking and instead rely
++	 * on the console ownership for synchronization.
++	 */
++	void (*write_atomic)(struct console *con, struct nbcon_write_context *wctxt);
++
+ 	atomic_t		__private nbcon_state;
+ 	atomic_long_t		__private nbcon_seq;
+ 	struct printk_buffers	*pbufs;