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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313/* SPDX-License-Identifier: GPL-2.0-or-later *//* * internal.h - printk internal definitions */#include <linux/console.h>#include <linux/types.h>#include <linux/sysctl.h>
#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL)void __init printk_sysctl_init(void);int devkmsg_sysctl_set_loglvl(const struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos);#else#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__)
/* * Identify if legacy printing is forced in a dedicated kthread. If * true, all printing via console lock occurs within a dedicated * legacy printer thread. The only exception is on panic, after the * nbcon consoles have had their chance to print the panic messages * first. */#ifdef CONFIG_PREEMPT_RT# define force_legacy_kthread() (true)#else# define force_legacy_kthread() (false)#endif
#ifdef CONFIG_PRINTK
#ifdef CONFIG_PRINTK_CALLER#define PRINTK_PREFIX_MAX 48#else#define PRINTK_PREFIX_MAX 32#endif
/* * the maximum size of a formatted record (i.e. with prefix added * per line and dropped messages or in extended message format) */#define PRINTK_MESSAGE_MAX 2048
/* the maximum size allowed to be reserved for a record */#define PRINTKRB_RECORD_MAX 1024
/* Flags for a single printk record. */enum printk_info_flags { /* always show on console, ignore console_loglevel */ LOG_FORCE_CON = 1, LOG_NEWLINE = 2, /* text ended with a newline */ LOG_CONT = 8, /* text is a fragment of a continuation line */};
struct printk_ringbuffer;struct dev_printk_info;
extern struct printk_ringbuffer *prb;extern bool printk_kthreads_running;extern bool printk_kthreads_ready;extern bool debug_non_panic_cpus;
__printf(4, 0)int vprintk_store(int facility, int level, const struct dev_printk_info *dev_info, const char *fmt, va_list args);
__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
void __printk_safe_enter(void);void __printk_safe_exit(void);
bool printk_percpu_data_ready(void);
#define printk_safe_enter_irqsave(flags) \ do { \ local_irq_save(flags); \ __printk_safe_enter(); \ } while (0)
#define printk_safe_exit_irqrestore(flags) \ do { \ __printk_safe_exit(); \ local_irq_restore(flags); \ } while (0)
void defer_console_output(void);bool is_printk_legacy_deferred(void);bool is_printk_force_console(void);
u16 printk_parse_prefix(const char *text, int *level, enum printk_info_flags *flags);void console_lock_spinning_enable(void);int console_lock_spinning_disable_and_check(int cookie);
u64 nbcon_seq_read(struct console *con);void nbcon_seq_force(struct console *con, u64 seq);bool nbcon_alloc(struct console *con);void nbcon_free(struct console *con);enum nbcon_prio nbcon_get_default_prio(void);void nbcon_atomic_flush_pending(void);bool nbcon_legacy_emit_next_record(struct console *con, bool *handover, int cookie, bool use_atomic);bool nbcon_kthread_create(struct console *con);void nbcon_kthread_stop(struct console *con);void nbcon_kthreads_wake(void);
/** * nbcon_kthread_wake - Wake up a console printing thread * @con: Console to operate on */static inline void nbcon_kthread_wake(struct console *con){ /* * Guarantee any new records can be seen by tasks preparing to wait * before this context checks if the rcuwait is empty. * * The full memory barrier in rcuwait_wake_up() pairs with the full * memory barrier within set_current_state() of * ___rcuwait_wait_event(), which is called after prepare_to_rcuwait() * adds the waiter but before it has checked the wait condition. * * This pairs with nbcon_kthread_func:A. */ rcuwait_wake_up(&con->rcuwait); /* LMM(nbcon_kthread_wake:A) */}
#else
#define PRINTK_PREFIX_MAX 0#define PRINTK_MESSAGE_MAX 0#define PRINTKRB_RECORD_MAX 0
#define printk_kthreads_running (false)#define printk_kthreads_ready (false)
/* * In !PRINTK builds we still export console_sem * semaphore and some of console functions (console_unlock()/etc.), so * printk-safe must preserve the existing local IRQ guarantees. */#define printk_safe_enter_irqsave(flags) local_irq_save(flags)#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
static inline bool printk_percpu_data_ready(void) { return false; }static inline void defer_console_output(void) { }static inline bool is_printk_legacy_deferred(void) { return false; }static inline u64 nbcon_seq_read(struct console *con) { return 0; }static inline void nbcon_seq_force(struct console *con, u64 seq) { }static inline bool nbcon_alloc(struct console *con) { return false; }static inline void nbcon_free(struct console *con) { }static inline enum nbcon_prio nbcon_get_default_prio(void) { return NBCON_PRIO_NONE; }static inline void nbcon_atomic_flush_pending(void) { }static inline bool nbcon_legacy_emit_next_record(struct console *con, bool *handover, int cookie, bool use_atomic) { return false; }static inline void nbcon_kthread_wake(struct console *con) { }static inline void nbcon_kthreads_wake(void) { }
#endif /* CONFIG_PRINTK */
extern bool have_boot_console;extern bool have_nbcon_console;extern bool have_legacy_console;extern bool legacy_allow_panic_sync;
/** * struct console_flush_type - Define available console flush methods * @nbcon_atomic: Flush directly using nbcon_atomic() callback * @nbcon_offload: Offload flush to printer thread * @legacy_direct: Call the legacy loop in this context * @legacy_offload: Offload the legacy loop into IRQ or legacy thread * * Note that the legacy loop also flushes the nbcon consoles. */struct console_flush_type { bool nbcon_atomic; bool nbcon_offload; bool legacy_direct; bool legacy_offload;};
extern bool console_irqwork_blocked;
/* * Identify which console flushing methods should be used in the context of * the caller. */static inline void printk_get_console_flush_type(struct console_flush_type *ft){ memset(ft, 0, sizeof(*ft));
switch (nbcon_get_default_prio()) { case NBCON_PRIO_NORMAL: if (have_nbcon_console && !have_boot_console) { if (printk_kthreads_running && !console_irqwork_blocked) ft->nbcon_offload = true; else ft->nbcon_atomic = true; }
/* Legacy consoles are flushed directly when possible. */ if (have_legacy_console || have_boot_console) { if (!is_printk_legacy_deferred()) ft->legacy_direct = true; else if (!console_irqwork_blocked) ft->legacy_offload = true; } break;
case NBCON_PRIO_EMERGENCY: if (have_nbcon_console && !have_boot_console) ft->nbcon_atomic = true;
/* Legacy consoles are flushed directly when possible. */ if (have_legacy_console || have_boot_console) { if (!is_printk_legacy_deferred()) ft->legacy_direct = true; else if (!console_irqwork_blocked) ft->legacy_offload = true; } break;
case NBCON_PRIO_PANIC: /* * In panic, the nbcon consoles will directly print. But * only allowed if there are no boot consoles. */ if (have_nbcon_console && !have_boot_console) ft->nbcon_atomic = true;
if (have_legacy_console || have_boot_console) { /* * This is the same decision as NBCON_PRIO_NORMAL * except that offloading never occurs in panic. * * Note that console_flush_on_panic() will flush * legacy consoles anyway, even if unsafe. */ if (!is_printk_legacy_deferred()) ft->legacy_direct = true;
/* * In panic, if nbcon atomic printing occurs, * the legacy consoles must remain silent until * explicitly allowed. */ if (ft->nbcon_atomic && !legacy_allow_panic_sync) ft->legacy_direct = false; } break;
default: WARN_ON_ONCE(1); break; }}
extern struct printk_buffers printk_shared_pbufs;
/** * struct printk_buffers - Buffers to read/format/output printk messages. * @outbuf: After formatting, contains text to output. * @scratchbuf: Used as temporary ringbuffer reading and string-print space. */struct printk_buffers { char outbuf[PRINTK_MESSAGE_MAX]; char scratchbuf[PRINTKRB_RECORD_MAX];};
/** * struct printk_message - Container for a prepared printk message. * @pbufs: printk buffers used to prepare the message. * @outbuf_len: The length of prepared text in @pbufs->outbuf to output. This * does not count the terminator. A value of 0 means there is * nothing to output and this record should be skipped. * @seq: The sequence number of the record used for @pbufs->outbuf. * @dropped: The number of dropped records from reading @seq. * @cpu: CPU on which the message was generated. * @pid: PID of the task that generated the message * @comm: Name of the task that generated the message. */struct printk_message { struct printk_buffers *pbufs; unsigned int outbuf_len; u64 seq; unsigned long dropped;#ifdef CONFIG_PRINTK_EXECUTION_CTX int cpu; pid_t pid; char comm[TASK_COMM_LEN];#endif};
bool printk_get_next_message(struct printk_message *pmsg, u64 seq, bool is_extended, bool may_supress);
#ifdef CONFIG_PRINTKvoid console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped);void console_prepend_replay(struct printk_message *pmsg);#endif
#ifdef CONFIG_SMPbool is_printk_cpu_sync_owner(void);#elsestatic inline bool is_printk_cpu_sync_owner(void) { return false; }#endif