1 files changed, 71 insertions, 0 deletions
diff --git a/debian/patches-rt/0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch b/debian/patches-rt/0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch
new file mode 100644
index 000000000..2ed6d52b5
--- /dev/null
+++ b/debian/patches-rt/0087-printk-Use-prb_first_seq-as-base-for-32bit-seq-macro.patch
@@ -0,0 +1,71 @@
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 22 Nov 2023 16:13:37 +0000
+Subject: [PATCH 087/134] printk: Use prb_first_seq() as base for 32bit seq
+ macros
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz
+
+Note: This change only applies to 32bit architectures. On 64bit
+      architectures the macros are NOPs.
+
+Currently prb_next_seq() is used as the base for the 32bit seq
+macros __u64seq_to_ulseq() and __ulseq_to_u64seq(). However, in
+a follow-up commit, prb_next_seq() will need to make use of the
+32bit seq macros.
+
+Use prb_first_seq() as the base for the 32bit seq macros instead
+because it is guaranteed to return 64bit sequence numbers without
+relying on any 32bit seq macros.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk_ringbuffer.c |    2 +-
+ kernel/printk/printk_ringbuffer.h |    8 ++++----
+ 2 files changed, 5 insertions(+), 5 deletions(-)
+
+--- a/kernel/printk/printk_ringbuffer.c
++++ b/kernel/printk/printk_ringbuffer.c
+@@ -1832,7 +1832,7 @@ static int prb_read(struct printk_ringbu
+ }
+ 
+ /* Get the sequence number of the tail descriptor. */
+-static u64 prb_first_seq(struct printk_ringbuffer *rb)
++u64 prb_first_seq(struct printk_ringbuffer *rb)
+ {
+ 	struct prb_desc_ring *desc_ring = &rb->desc_ring;
+ 	enum desc_state d_state;
+--- a/kernel/printk/printk_ringbuffer.h
++++ b/kernel/printk/printk_ringbuffer.h
+@@ -378,6 +378,7 @@ bool prb_read_valid(struct printk_ringbu
+ bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq,
+ 			 struct printk_info *info, unsigned int *line_count);
+ 
++u64 prb_first_seq(struct printk_ringbuffer *rb);
+ u64 prb_first_valid_seq(struct printk_ringbuffer *rb);
+ u64 prb_next_seq(struct printk_ringbuffer *rb);
+ 
+@@ -392,12 +393,12 @@ u64 prb_next_seq(struct printk_ringbuffe
+ 
+ static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq)
+ {
++	u64 rb_first_seq = prb_first_seq(rb);
+ 	u64 seq;
+-	u64 rb_next_seq;
+ 
+ 	/*
+ 	 * The provided sequence is only the lower 32 bits of the ringbuffer
+-	 * sequence. It needs to be expanded to 64bit. Get the next sequence
++	 * sequence. It needs to be expanded to 64bit. Get the first sequence
+ 	 * number from the ringbuffer and fold it.
+ 	 *
+ 	 * Having a 32bit representation in the console is sufficient.
+@@ -406,8 +407,7 @@ static inline u64 __ulseq_to_u64seq(stru
+ 	 *
+ 	 * Also the access to the ring buffer is always safe.
+ 	 */
+-	rb_next_seq = prb_next_seq(rb);
+-	seq = rb_next_seq - (s32)((u32)rb_next_seq - ulseq);
++	seq = rb_first_seq - (s32)((u32)rb_first_seq - ulseq);
+ 
+ 	return seq;
+ }