diff options
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/Makefile | 2 | ||||
| -rw-r--r-- | kernel/printk/internal.h | 8 | ||||
| -rw-r--r-- | kernel/printk/nbcon.c | 70 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 13 |
4 files changed, 89 insertions, 4 deletions
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile index f5b388e810b9..39a2b61c7232 100644 --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only obj-y = printk.o -obj-$(CONFIG_PRINTK) += printk_safe.o +obj-$(CONFIG_PRINTK) += printk_safe.o nbcon.o obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o obj-$(CONFIG_PRINTK_INDEX) += index.o diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 7d4979d5c3ce..2ca0ab78802c 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -3,6 +3,7 @@ * internal.h - printk internal definitions */ #include <linux/percpu.h> +#include <linux/console.h> #if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL) void __init printk_sysctl_init(void); @@ -61,6 +62,10 @@ void defer_console_output(void); u16 printk_parse_prefix(const char *text, int *level, enum printk_info_flags *flags); + +void nbcon_init(struct console *con); +void nbcon_cleanup(struct console *con); + #else #define PRINTK_PREFIX_MAX 0 @@ -76,6 +81,9 @@ u16 printk_parse_prefix(const char *text, int *level, #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) static inline bool printk_percpu_data_ready(void) { return false; } +static inline void nbcon_init(struct console *con) { } +static inline void nbcon_cleanup(struct console *con) { } + #endif /* CONFIG_PRINTK */ /** diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c new file mode 100644 index 000000000000..63d24ca62ac5 --- /dev/null +++ b/kernel/printk/nbcon.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2022 Linutronix GmbH, John Ogness +// Copyright (C) 2022 Intel, Thomas Gleixner + +#include <linux/kernel.h> +#include <linux/console.h> +#include "internal.h" +/* + * Printk console printing implementation for consoles which does not depend + * on the legacy style console_lock mechanism. + */ + +/** + * nbcon_state_set - Helper function to set the console state + * @con: Console to update + * @new: The new state to write + * + * Only to be used when the console is not yet or no longer visible in the + * system. Otherwise use nbcon_state_try_cmpxchg(). + */ +static inline void nbcon_state_set(struct console *con, struct nbcon_state *new) +{ + atomic_set(&ACCESS_PRIVATE(con, nbcon_state), new->atom); +} + +/** + * nbcon_state_read - Helper function to read the console state + * @con: Console to read + * @state: The state to store the result + */ +static inline void nbcon_state_read(struct console *con, struct nbcon_state *state) +{ + state->atom = atomic_read(&ACCESS_PRIVATE(con, nbcon_state)); +} + +/** + * nbcon_state_try_cmpxchg() - Helper function for atomic_try_cmpxchg() on console state + * @con: Console to update + * @cur: Old/expected state + * @new: New state + * + * Return: True on success. False on fail and @cur is updated. + */ +static inline bool nbcon_state_try_cmpxchg(struct console *con, struct nbcon_state *cur, + struct nbcon_state *new) +{ + return atomic_try_cmpxchg(&ACCESS_PRIVATE(con, nbcon_state), &cur->atom, new->atom); +} + +/** + * nbcon_init - Initialize the nbcon console specific data + * @con: Console to initialize + */ +void nbcon_init(struct console *con) +{ + struct nbcon_state state = { }; + + nbcon_state_set(con, &state); +} + +/** + * nbcon_cleanup - Cleanup the nbcon console specific data + * @con: Console to cleanup + */ +void nbcon_cleanup(struct console *con) +{ + struct nbcon_state state = { }; + + nbcon_state_set(con, &state); +} diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 7e0b4dd02398..5f372eaceb29 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -3326,9 +3326,10 @@ static void try_enable_default_console(struct console *newcon) newcon->flags |= CON_CONSDEV; } -#define con_printk(lvl, con, fmt, ...) \ - printk(lvl pr_fmt("%sconsole [%s%d] " fmt), \ - (con->flags & CON_BOOT) ? "boot" : "", \ +#define con_printk(lvl, con, fmt, ...) \ + printk(lvl pr_fmt("%s%sconsole [%s%d] " fmt), \ + (con->flags & CON_NBCON) ? "" : "legacy ", \ + (con->flags & CON_BOOT) ? "boot" : "", \ con->name, con->index, ##__VA_ARGS__) static void console_init_seq(struct console *newcon, bool bootcon_registered) @@ -3488,6 +3489,9 @@ void register_console(struct console *newcon) newcon->dropped = 0; console_init_seq(newcon, bootcon_registered); + if (newcon->flags & CON_NBCON) + nbcon_init(newcon); + /* * Put this console in the list - keep the * preferred driver at the head of the list. @@ -3579,6 +3583,9 @@ static int unregister_console_locked(struct console *console) */ synchronize_srcu(&console_srcu); + if (console->flags & CON_NBCON) + nbcon_cleanup(console); + console_sysfs_notify(); if (console->exit) |