diff options
Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch b/debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch new file mode 100644 index 0000000000..cee70cb44e --- /dev/null +++ b/debian/patches-rt/0103-printk-nbcon-Implement-processing-in-port-lock-wrapp.patch @@ -0,0 +1,244 @@ +From: John Ogness <john.ogness@linutronix.de> +Date: Wed, 13 Sep 2023 08:35:23 +0000 +Subject: [PATCH 103/134] printk: nbcon: Implement processing in port->lock + wrapper +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz + +Currently the port->lock wrappers uart_port_lock(), +uart_port_unlock() (and their variants) only lock/unlock +the spin_lock. + +If the port is an nbcon console, the wrappers must also +acquire/release the console and mark the region as unsafe. This +allows general port->lock synchronization to be synchronized +with the nbcon console ownership. + +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + include/linux/console.h | 2 + + include/linux/printk.h | 13 +++++++ + include/linux/serial_core.h | 18 +++++++++- + kernel/printk/nbcon.c | 77 ++++++++++++++++++++++++++++++++++++++++++++ + 4 files changed, 108 insertions(+), 2 deletions(-) + +--- a/include/linux/console.h ++++ b/include/linux/console.h +@@ -299,6 +299,7 @@ struct nbcon_write_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 ++ * @locked_port: True, if the port lock is locked by nbcon + */ + struct console { + char name[16]; +@@ -325,6 +326,7 @@ struct console { + atomic_t __private nbcon_state; + atomic_long_t __private nbcon_seq; + struct printk_buffers *pbufs; ++ bool locked_port; + }; + + #ifdef CONFIG_LOCKDEP +--- a/include/linux/printk.h ++++ b/include/linux/printk.h +@@ -9,6 +9,8 @@ + #include <linux/ratelimit_types.h> + #include <linux/once_lite.h> + ++struct uart_port; ++ + extern const char linux_banner[]; + extern const char linux_proc_banner[]; + +@@ -195,6 +197,8 @@ void show_regs_print_info(const char *lo + extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold; + extern asmlinkage void dump_stack(void) __cold; + void printk_trigger_flush(void); ++extern void nbcon_acquire(struct uart_port *up); ++extern void nbcon_release(struct uart_port *up); + #else + static inline __printf(1, 0) + int vprintk(const char *s, va_list args) +@@ -274,6 +278,15 @@ static inline void dump_stack(void) + static inline void printk_trigger_flush(void) + { + } ++ ++static inline void nbcon_acquire(struct uart_port *up) ++{ ++} ++ ++static inline void nbcon_release(struct uart_port *up) ++{ ++} ++ + #endif + + #ifdef CONFIG_SMP +--- a/include/linux/serial_core.h ++++ b/include/linux/serial_core.h +@@ -595,6 +595,7 @@ struct uart_port { + static inline void uart_port_lock(struct uart_port *up) + { + spin_lock(&up->lock); ++ nbcon_acquire(up); + } + + /** +@@ -604,6 +605,7 @@ static inline void uart_port_lock(struct + static inline void uart_port_lock_irq(struct uart_port *up) + { + spin_lock_irq(&up->lock); ++ nbcon_acquire(up); + } + + /** +@@ -614,6 +616,7 @@ static inline void uart_port_lock_irq(st + static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) + { + spin_lock_irqsave(&up->lock, *flags); ++ nbcon_acquire(up); + } + + /** +@@ -624,7 +627,11 @@ static inline void uart_port_lock_irqsav + */ + static inline bool uart_port_trylock(struct uart_port *up) + { +- return spin_trylock(&up->lock); ++ if (!spin_trylock(&up->lock)) ++ return false; ++ ++ nbcon_acquire(up); ++ return true; + } + + /** +@@ -636,7 +643,11 @@ static inline bool uart_port_trylock(str + */ + static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags) + { +- return spin_trylock_irqsave(&up->lock, *flags); ++ if (!spin_trylock_irqsave(&up->lock, *flags)) ++ return false; ++ ++ nbcon_acquire(up); ++ return true; + } + + /** +@@ -645,6 +656,7 @@ static inline bool uart_port_trylock_irq + */ + static inline void uart_port_unlock(struct uart_port *up) + { ++ nbcon_release(up); + spin_unlock(&up->lock); + } + +@@ -654,6 +666,7 @@ static inline void uart_port_unlock(stru + */ + static inline void uart_port_unlock_irq(struct uart_port *up) + { ++ nbcon_release(up); + spin_unlock_irq(&up->lock); + } + +@@ -664,6 +677,7 @@ static inline void uart_port_unlock_irq( + */ + static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) + { ++ nbcon_release(up); + spin_unlock_irqrestore(&up->lock, flags); + } + +--- a/kernel/printk/nbcon.c ++++ b/kernel/printk/nbcon.c +@@ -6,6 +6,7 @@ + #include <linux/console.h> + #include <linux/delay.h> + #include <linux/slab.h> ++#include <linux/serial_core.h> + #include "internal.h" + /* + * Printk console printing implementation for consoles which does not depend +@@ -995,3 +996,79 @@ void nbcon_free(struct console *con) + + con->pbufs = NULL; + } ++ ++static inline bool uart_is_nbcon(struct uart_port *up) ++{ ++ int cookie; ++ bool ret; ++ ++ if (!uart_console(up)) ++ return false; ++ ++ cookie = console_srcu_read_lock(); ++ ret = (console_srcu_read_flags(up->cons) & CON_NBCON); ++ console_srcu_read_unlock(cookie); ++ return ret; ++} ++ ++/** ++ * nbcon_acquire - The second half of the port locking wrapper ++ * @up: The uart port whose @lock was locked ++ * ++ * The uart_port_lock() wrappers will first lock the spin_lock @up->lock. ++ * Then this function is called to implement nbcon-specific processing. ++ * ++ * If @up is an nbcon console, this console will be acquired and marked as ++ * unsafe. Otherwise this function does nothing. ++ */ ++void nbcon_acquire(struct uart_port *up) ++{ ++ struct console *con = up->cons; ++ struct nbcon_context ctxt; ++ ++ if (!uart_is_nbcon(up)) ++ return; ++ ++ WARN_ON_ONCE(con->locked_port); ++ ++ do { ++ do { ++ memset(&ctxt, 0, sizeof(ctxt)); ++ ctxt.console = con; ++ ctxt.prio = NBCON_PRIO_NORMAL; ++ } while (!nbcon_context_try_acquire(&ctxt)); ++ ++ } while (!nbcon_context_enter_unsafe(&ctxt)); ++ ++ con->locked_port = true; ++} ++EXPORT_SYMBOL_GPL(nbcon_acquire); ++ ++/** ++ * nbcon_release - The first half of the port unlocking wrapper ++ * @up: The uart port whose @lock is about to be unlocked ++ * ++ * The uart_port_unlock() wrappers will first call this function to implement ++ * nbcon-specific processing. Then afterwards the uart_port_unlock() wrappers ++ * will unlock the spin_lock @up->lock. ++ * ++ * If @up is an nbcon console, the console will be marked as safe and ++ * released. Otherwise this function does nothing. ++ */ ++void nbcon_release(struct uart_port *up) ++{ ++ struct console *con = up->cons; ++ struct nbcon_context ctxt = { ++ .console = con, ++ .prio = NBCON_PRIO_NORMAL, ++ }; ++ ++ if (!con->locked_port) ++ return; ++ ++ if (nbcon_context_exit_unsafe(&ctxt)) ++ nbcon_context_release(&ctxt); ++ ++ con->locked_port = false; ++} ++EXPORT_SYMBOL_GPL(nbcon_release); |