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1/*
2 * internal.h - printk internal definitions
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 */
17#include <linux/percpu.h>
18
19typedef __printf(1, 0) int (*printk_func_t)(const char *fmt, va_list args);
20
21int __printf(1, 0) vprintk_default(const char *fmt, va_list args);
22
23#ifdef CONFIG_PRINTK_NMI
24
25extern raw_spinlock_t logbuf_lock;
26
27/*
28 * printk() could not take logbuf_lock in NMI context. Instead,
29 * it temporary stores the strings into a per-CPU buffer.
30 * The alternative implementation is chosen transparently
31 * via per-CPU variable.
32 */
33DECLARE_PER_CPU(printk_func_t, printk_func);
34static inline __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
35{
36 return this_cpu_read(printk_func)(fmt, args);
37}
38
39extern atomic_t nmi_message_lost;
40static inline int get_nmi_message_lost(void)
41{
42 return atomic_xchg(&nmi_message_lost, 0);
43}
44
45#else /* CONFIG_PRINTK_NMI */
46
47static inline __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
48{
49 return vprintk_default(fmt, args);
50}
51
52static inline int get_nmi_message_lost(void)
53{
54 return 0;
55}
56
57#endif /* CONFIG_PRINTK_NMI */
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * internal.h - printk internal definitions
4 */
5#include <linux/percpu.h>
6#include <linux/console.h>
7#include "printk_ringbuffer.h"
8
9#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL)
10void __init printk_sysctl_init(void);
11int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write,
12 void *buffer, size_t *lenp, loff_t *ppos);
13#else
14#define printk_sysctl_init() do { } while (0)
15#endif
16
17#define con_printk(lvl, con, fmt, ...) \
18 printk(lvl pr_fmt("%s%sconsole [%s%d] " fmt), \
19 (con->flags & CON_NBCON) ? "" : "legacy ", \
20 (con->flags & CON_BOOT) ? "boot" : "", \
21 con->name, con->index, ##__VA_ARGS__)
22
23#ifdef CONFIG_PRINTK
24
25#ifdef CONFIG_PRINTK_CALLER
26#define PRINTK_PREFIX_MAX 48
27#else
28#define PRINTK_PREFIX_MAX 32
29#endif
30
31/*
32 * the maximum size of a formatted record (i.e. with prefix added
33 * per line and dropped messages or in extended message format)
34 */
35#define PRINTK_MESSAGE_MAX 2048
36
37/* the maximum size allowed to be reserved for a record */
38#define PRINTKRB_RECORD_MAX 1024
39
40/* Flags for a single printk record. */
41enum printk_info_flags {
42 LOG_NEWLINE = 2, /* text ended with a newline */
43 LOG_CONT = 8, /* text is a fragment of a continuation line */
44};
45
46extern struct printk_ringbuffer *prb;
47
48__printf(4, 0)
49int vprintk_store(int facility, int level,
50 const struct dev_printk_info *dev_info,
51 const char *fmt, va_list args);
52
53__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
54__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
55
56bool printk_percpu_data_ready(void);
57
58#define printk_safe_enter_irqsave(flags) \
59 do { \
60 local_irq_save(flags); \
61 __printk_safe_enter(); \
62 } while (0)
63
64#define printk_safe_exit_irqrestore(flags) \
65 do { \
66 __printk_safe_exit(); \
67 local_irq_restore(flags); \
68 } while (0)
69
70void defer_console_output(void);
71
72u16 printk_parse_prefix(const char *text, int *level,
73 enum printk_info_flags *flags);
74
75u64 nbcon_seq_read(struct console *con);
76void nbcon_seq_force(struct console *con, u64 seq);
77bool nbcon_alloc(struct console *con);
78void nbcon_init(struct console *con);
79void nbcon_free(struct console *con);
80
81#else
82
83#define PRINTK_PREFIX_MAX 0
84#define PRINTK_MESSAGE_MAX 0
85#define PRINTKRB_RECORD_MAX 0
86
87/*
88 * In !PRINTK builds we still export console_sem
89 * semaphore and some of console functions (console_unlock()/etc.), so
90 * printk-safe must preserve the existing local IRQ guarantees.
91 */
92#define printk_safe_enter_irqsave(flags) local_irq_save(flags)
93#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
94
95static inline bool printk_percpu_data_ready(void) { return false; }
96static inline u64 nbcon_seq_read(struct console *con) { return 0; }
97static inline void nbcon_seq_force(struct console *con, u64 seq) { }
98static inline bool nbcon_alloc(struct console *con) { return false; }
99static inline void nbcon_init(struct console *con) { }
100static inline void nbcon_free(struct console *con) { }
101
102#endif /* CONFIG_PRINTK */
103
104extern struct printk_buffers printk_shared_pbufs;
105
106/**
107 * struct printk_buffers - Buffers to read/format/output printk messages.
108 * @outbuf: After formatting, contains text to output.
109 * @scratchbuf: Used as temporary ringbuffer reading and string-print space.
110 */
111struct printk_buffers {
112 char outbuf[PRINTK_MESSAGE_MAX];
113 char scratchbuf[PRINTKRB_RECORD_MAX];
114};
115
116/**
117 * struct printk_message - Container for a prepared printk message.
118 * @pbufs: printk buffers used to prepare the message.
119 * @outbuf_len: The length of prepared text in @pbufs->outbuf to output. This
120 * does not count the terminator. A value of 0 means there is
121 * nothing to output and this record should be skipped.
122 * @seq: The sequence number of the record used for @pbufs->outbuf.
123 * @dropped: The number of dropped records from reading @seq.
124 */
125struct printk_message {
126 struct printk_buffers *pbufs;
127 unsigned int outbuf_len;
128 u64 seq;
129 unsigned long dropped;
130};
131
132bool other_cpu_in_panic(void);
133bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
134 bool is_extended, bool may_supress);
135
136#ifdef CONFIG_PRINTK
137void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped);
138#endif