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06653d57ff
Implement an emit function for nbcon consoles to output printk messages. It utilizes the lockless printk_get_next_message() and console_prepend_dropped() functions to retrieve/build the output message. The emit function includes the required safety points to check for handover/takeover and calls a new write_atomic callback of the console driver to output the message. It also includes proper handling for updating the nbcon console sequence number. A new nbcon_write_context struct is introduced. This is provided to the write_atomic callback and includes only the information necessary for performing atomic writes. 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/20230916192007.608398-8-john.ogness@linutronix.de
138 lines
4.1 KiB
C
138 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* internal.h - printk internal definitions
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*/
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#include <linux/percpu.h>
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#include <linux/console.h>
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#include "printk_ringbuffer.h"
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#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL)
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void __init printk_sysctl_init(void);
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int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos);
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#else
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#define printk_sysctl_init() do { } while (0)
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#endif
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#define con_printk(lvl, con, fmt, ...) \
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printk(lvl pr_fmt("%s%sconsole [%s%d] " fmt), \
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(con->flags & CON_NBCON) ? "" : "legacy ", \
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(con->flags & CON_BOOT) ? "boot" : "", \
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con->name, con->index, ##__VA_ARGS__)
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#ifdef CONFIG_PRINTK
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#ifdef CONFIG_PRINTK_CALLER
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#define PRINTK_PREFIX_MAX 48
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#else
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#define PRINTK_PREFIX_MAX 32
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#endif
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/*
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* the maximum size of a formatted record (i.e. with prefix added
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* per line and dropped messages or in extended message format)
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*/
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#define PRINTK_MESSAGE_MAX 2048
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/* the maximum size allowed to be reserved for a record */
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#define PRINTKRB_RECORD_MAX 1024
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/* Flags for a single printk record. */
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enum printk_info_flags {
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LOG_NEWLINE = 2, /* text ended with a newline */
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LOG_CONT = 8, /* text is a fragment of a continuation line */
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};
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extern struct printk_ringbuffer *prb;
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__printf(4, 0)
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int vprintk_store(int facility, int level,
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const struct dev_printk_info *dev_info,
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const char *fmt, va_list args);
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__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
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__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
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bool printk_percpu_data_ready(void);
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#define printk_safe_enter_irqsave(flags) \
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do { \
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local_irq_save(flags); \
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__printk_safe_enter(); \
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} while (0)
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#define printk_safe_exit_irqrestore(flags) \
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do { \
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__printk_safe_exit(); \
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local_irq_restore(flags); \
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} while (0)
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void defer_console_output(void);
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u16 printk_parse_prefix(const char *text, int *level,
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enum printk_info_flags *flags);
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u64 nbcon_seq_read(struct console *con);
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void nbcon_seq_force(struct console *con, u64 seq);
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bool nbcon_alloc(struct console *con);
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void nbcon_init(struct console *con);
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void nbcon_free(struct console *con);
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#else
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#define PRINTK_PREFIX_MAX 0
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#define PRINTK_MESSAGE_MAX 0
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#define PRINTKRB_RECORD_MAX 0
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/*
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* In !PRINTK builds we still export console_sem
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* semaphore and some of console functions (console_unlock()/etc.), so
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* printk-safe must preserve the existing local IRQ guarantees.
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*/
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#define printk_safe_enter_irqsave(flags) local_irq_save(flags)
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#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
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static inline bool printk_percpu_data_ready(void) { return false; }
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static inline u64 nbcon_seq_read(struct console *con) { return 0; }
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static inline void nbcon_seq_force(struct console *con, u64 seq) { }
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static inline bool nbcon_alloc(struct console *con) { return false; }
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static inline void nbcon_init(struct console *con) { }
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static inline void nbcon_free(struct console *con) { }
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#endif /* CONFIG_PRINTK */
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extern struct printk_buffers printk_shared_pbufs;
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/**
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* struct printk_buffers - Buffers to read/format/output printk messages.
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* @outbuf: After formatting, contains text to output.
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* @scratchbuf: Used as temporary ringbuffer reading and string-print space.
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*/
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struct printk_buffers {
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char outbuf[PRINTK_MESSAGE_MAX];
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char scratchbuf[PRINTKRB_RECORD_MAX];
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};
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/**
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* struct printk_message - Container for a prepared printk message.
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* @pbufs: printk buffers used to prepare the message.
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* @outbuf_len: The length of prepared text in @pbufs->outbuf to output. This
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* does not count the terminator. A value of 0 means there is
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* nothing to output and this record should be skipped.
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* @seq: The sequence number of the record used for @pbufs->outbuf.
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* @dropped: The number of dropped records from reading @seq.
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*/
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struct printk_message {
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struct printk_buffers *pbufs;
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unsigned int outbuf_len;
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u64 seq;
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unsigned long dropped;
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};
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bool other_cpu_in_panic(void);
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bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
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bool is_extended, bool may_supress);
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#ifdef CONFIG_PRINTK
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void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped);
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#endif
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