diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2023-09-16 21:26:03 +0206 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2023-09-18 17:03:45 +0200 |
| commit | 5634c90fd8553de7cbafecd048d0273690a2e84e (patch) | |
| tree | c5c9c0698e4b3a1d727fb8cc6067169aa89cebff /kernel/printk/internal.h | |
| parent | d818b56f77521ecc5e3eda71dc9b2beb3d6681e3 (diff) | |
printk: nbcon: Add buffer management
In case of hostile takeovers it must be ensured that the previous
owner cannot scribble over the output buffer of the emergency/panic
context. This is achieved by:
- Adding a global output buffer instance for the panic context.
This is the only situation where hostile takeovers can occur and
there is always at most 1 panic context.
- Allocating an output buffer per non-boot console upon console
registration. This buffer is used by the console owner when not
in panic context. (For boot consoles, the existing shared global
legacy output buffer is used instead. Boot console printing will
be synchronized with legacy console printing.)
- Choosing the appropriate buffer is handled in the acquire/release
functions.
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>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230916192007.608398-5-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk/internal.h')
| -rw-r--r-- | kernel/printk/internal.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 7199d60bfc25..f6161cd75d7d 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -13,6 +13,12 @@ int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, #define printk_sysctl_init() do { } while (0) #endif +#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__) + #ifdef CONFIG_PRINTK #ifdef CONFIG_PRINTK_CALLER @@ -63,8 +69,9 @@ void defer_console_output(void); u16 printk_parse_prefix(const char *text, int *level, enum printk_info_flags *flags); +bool nbcon_alloc(struct console *con); void nbcon_init(struct console *con); -void nbcon_cleanup(struct console *con); +void nbcon_free(struct console *con); #else @@ -81,8 +88,9 @@ void nbcon_cleanup(struct console *con); #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) static inline bool printk_percpu_data_ready(void) { return false; } +static inline bool nbcon_alloc(struct console *con) { return false; } static inline void nbcon_init(struct console *con) { } -static inline void nbcon_cleanup(struct console *con) { } +static inline void nbcon_free(struct console *con) { } #endif /* CONFIG_PRINTK */ |