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)
10 void __init printk_sysctl_init(void);
11 int devkmsg_sysctl_set_loglvl(const 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. */
41 enum 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
46 extern struct printk_ringbuffer *prb;
47
48 __printf(4, 0)
49 int 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
56 bool 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
70 void defer_console_output(void);
71
72 u16 printk_parse_prefix(const char *text, int *level,
73 enum printk_info_flags *flags);
74
75 u64 nbcon_seq_read(struct console *con);
76 void nbcon_seq_force(struct console *con, u64 seq);
77 bool nbcon_alloc(struct console *con);
78 void nbcon_init(struct console *con);
79 void 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
95 static inline bool printk_percpu_data_ready(void) { return false; }
96 static inline u64 nbcon_seq_read(struct console *con) { return 0; }
97 static inline void nbcon_seq_force(struct console *con, u64 seq) { }
98 static inline bool nbcon_alloc(struct console *con) { return false; }
99 static inline void nbcon_init(struct console *con) { }
100 static inline void nbcon_free(struct console *con) { }
101
102 #endif /* CONFIG_PRINTK */
103
104 extern 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 */
111 struct 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 */
125 struct printk_message {
126 struct printk_buffers *pbufs;
127 unsigned int outbuf_len;
128 u64 seq;
129 unsigned long dropped;
130 };
131
132 bool other_cpu_in_panic(void);
133 bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
134 bool is_extended, bool may_supress);
135
136 #ifdef CONFIG_PRINTK
137 void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped);
138 #endif
139
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