diff options
Diffstat (limited to 'debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch')
| -rw-r--r-- | debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch | 186 |
1 files changed, 0 insertions, 186 deletions
diff --git a/debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch b/debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch deleted file mode 100644 index 14933eef67..0000000000 --- a/debian/patches-rt/0108-printk-nbcon-Provide-function-to-flush-using-write_a.patch +++ /dev/null @@ -1,186 +0,0 @@ -From: Thomas Gleixner <tglx@linutronix.de> -Date: Tue, 12 Sep 2023 12:00:08 +0000 -Subject: [PATCH 108/134] printk: nbcon: Provide function to flush using - write_atomic() -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz - -Provide nbcon_atomic_flush_all() to perform flushing of all -registered nbcon consoles using their write_atomic() callback. -Like with legacy consoles, the nbcon consoles are flushed one -record per console. This allows all nbcon consoles to print -lines pseudo-simultaneously, rather than one console waiting -for the full ringbuffer to dump to another console before -printing anything. - -Unlike console_flush_all(), nbcon_atomic_flush_all() will only -flush up through the newest record at the time of the call. -This prevents a CPU from printing unbounded when other CPUs are -adding records. - -Perform nbcon console atomic flushing in -console_flush_on_panic(). This function is not only used in -panic() but also other locations where there may be stored -messages that need to be flushed. - -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> -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - kernel/printk/internal.h | 2 - kernel/printk/nbcon.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++- - kernel/printk/printk.c | 2 - 3 files changed, 102 insertions(+), 2 deletions(-) - ---- a/kernel/printk/internal.h -+++ b/kernel/printk/internal.h -@@ -77,6 +77,7 @@ void nbcon_seq_force(struct console *con - bool nbcon_alloc(struct console *con); - void nbcon_init(struct console *con); - void nbcon_free(struct console *con); -+void nbcon_atomic_flush_all(void); - - /* - * Check if the given console is currently capable and allowed to print -@@ -131,6 +132,7 @@ 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) { } - static inline void nbcon_free(struct console *con) { } -+static inline void nbcon_atomic_flush_all(void) { } - - static inline bool console_is_usable(struct console *con, short flags) { return false; } - ---- a/kernel/printk/nbcon.c -+++ b/kernel/printk/nbcon.c -@@ -539,7 +539,6 @@ static struct printk_buffers panic_nbcon - * in an unsafe state. Otherwise, on success the caller may assume - * the console is not in an unsafe state. - */ --__maybe_unused - static bool nbcon_context_try_acquire(struct nbcon_context *ctxt) - { - unsigned int cpu = smp_processor_id(); -@@ -841,7 +840,6 @@ EXPORT_SYMBOL_GPL(nbcon_exit_unsafe); - * When true is returned, @wctxt->ctxt.backlog indicates whether there are - * still records pending in the ringbuffer, - */ --__maybe_unused - static bool nbcon_emit_next_record(struct nbcon_write_context *wctxt) - { - struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); -@@ -931,6 +929,104 @@ static bool nbcon_emit_next_record(struc - } - - /** -+ * nbcon_atomic_emit_one - Print one record for an nbcon console using the -+ * write_atomic() callback -+ * @wctxt: An initialized write context struct to use -+ * for this context -+ * -+ * Return: False if the given console could not print a record or there -+ * are no more records to print, otherwise true. -+ * -+ * This is an internal helper to handle the locking of the console before -+ * calling nbcon_emit_next_record(). -+ */ -+static bool nbcon_atomic_emit_one(struct nbcon_write_context *wctxt) -+{ -+ struct nbcon_context *ctxt = &ACCESS_PRIVATE(wctxt, ctxt); -+ -+ if (!nbcon_context_try_acquire(ctxt)) -+ return false; -+ -+ /* -+ * nbcon_emit_next_record() returns false when the console was -+ * handed over or taken over. In both cases the context is no -+ * longer valid. -+ */ -+ if (!nbcon_emit_next_record(wctxt)) -+ return false; -+ -+ nbcon_context_release(ctxt); -+ -+ return ctxt->backlog; -+} -+ -+/** -+ * __nbcon_atomic_flush_all - Flush all nbcon consoles using their -+ * write_atomic() callback -+ * @stop_seq: Flush up until this record -+ */ -+static void __nbcon_atomic_flush_all(u64 stop_seq) -+{ -+ struct nbcon_write_context wctxt = { }; -+ struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); -+ struct console *con; -+ bool any_progress; -+ int cookie; -+ -+ do { -+ any_progress = false; -+ -+ cookie = console_srcu_read_lock(); -+ for_each_console_srcu(con) { -+ short flags = console_srcu_read_flags(con); -+ unsigned long irq_flags; -+ -+ if (!(flags & CON_NBCON)) -+ continue; -+ -+ if (!console_is_usable(con, flags)) -+ continue; -+ -+ if (nbcon_seq_read(con) >= stop_seq) -+ continue; -+ -+ memset(ctxt, 0, sizeof(*ctxt)); -+ ctxt->console = con; -+ ctxt->spinwait_max_us = 2000; -+ ctxt->prio = NBCON_PRIO_NORMAL; -+ -+ /* -+ * Atomic flushing does not use console driver -+ * synchronization (i.e. it does not hold the port -+ * lock for uart consoles). Therefore IRQs must be -+ * disabled to avoid being interrupted and then -+ * calling into a driver that will deadlock trying -+ * acquire console ownership. -+ */ -+ local_irq_save(irq_flags); -+ -+ any_progress |= nbcon_atomic_emit_one(&wctxt); -+ -+ local_irq_restore(irq_flags); -+ } -+ console_srcu_read_unlock(cookie); -+ } while (any_progress); -+} -+ -+/** -+ * nbcon_atomic_flush_all - Flush all nbcon consoles using their -+ * write_atomic() callback -+ * -+ * Flush the backlog up through the currently newest record. Any new -+ * records added while flushing will not be flushed. This is to avoid -+ * one CPU printing unbounded because other CPUs continue to add records. -+ */ -+void nbcon_atomic_flush_all(void) -+{ -+ __nbcon_atomic_flush_all(prb_next_reserve_seq(prb)); -+} -+ -+/** - * nbcon_alloc - Allocate buffers needed by the nbcon console - * @con: Console to allocate buffers for - * ---- a/kernel/printk/printk.c -+++ b/kernel/printk/printk.c -@@ -3170,6 +3170,8 @@ void console_flush_on_panic(enum con_flu - console_srcu_read_unlock(cookie); - } - -+ nbcon_atomic_flush_all(); -+ - console_flush_all(false, &next_seq, &handover); - } - |