1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* internal.h - printk internal definitions
*/
#include <linux/percpu.h>
#include <linux/console.h>
#include "printk_ringbuffer.h"
#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL)
void __init printk_sysctl_init(void);
int devkmsg_sysctl_set_loglvl(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__)
#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 {
LOG_NEWLINE = 2, /* text ended with a newline */
LOG_CONT = 8, /* text is a fragment of a continuation line */
};
extern struct printk_ringbuffer *prb;
extern bool printk_threads_enabled;
extern bool have_legacy_console;
extern bool have_boot_console;
/*
* Specifies if the console lock/unlock dance is needed for console
* printing. If @have_boot_console is true, the nbcon consoles will
* be printed serially along with the legacy consoles because nbcon
* consoles cannot print simultaneously with boot consoles.
*/
#define printing_via_unlock (have_legacy_console || have_boot_console)
__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);
__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
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);
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_init(struct console *con);
void nbcon_free(struct console *con);
enum nbcon_prio nbcon_get_default_prio(void);
void nbcon_atomic_flush_all(void);
bool nbcon_atomic_emit_next_record(struct console *con, bool *handover, int cookie);
void nbcon_kthread_create(struct console *con);
void nbcon_wake_threads(void);
void nbcon_legacy_kthread_create(void);
/*
* Check if the given console is currently capable and allowed to print
* records. Note that this function does not consider the current context,
* which can also play a role in deciding if @con can be used to print
* records.
*/
static inline bool console_is_usable(struct console *con, short flags, bool use_atomic)
{
if (!(flags & CON_ENABLED))
return false;
if ((flags & CON_SUSPENDED))
return false;
if (flags & CON_NBCON) {
if (use_atomic) {
if (!con->write_atomic)
return false;
} else {
if (!con->write_thread || !con->kthread)
return false;
}
} else {
if (!con->write)
return false;
}
/*
* Console drivers may assume that per-cpu resources have been
* allocated. So unless they're explicitly marked as being able to
* cope (CON_ANYTIME) don't call them until this CPU is officially up.
*/
if (!cpu_online(raw_smp_processor_id()) && !(flags & CON_ANYTIME))
return false;
return true;
}
/**
* nbcon_kthread_wake - Wake up a printk 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
static inline void nbcon_kthread_wake(struct console *con) { }
static inline void nbcon_kthread_create(struct console *con) { }
#define printk_threads_enabled (false)
#define printing_via_unlock (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 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_init(struct console *con) { }
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_all(void) { }
static inline bool nbcon_atomic_emit_next_record(struct console *con, bool *handover,
int cookie) { return false; }
static inline bool console_is_usable(struct console *con, short flags,
bool use_atomic) { return false; }
#endif /* CONFIG_PRINTK */
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.
*/
struct printk_message {
struct printk_buffers *pbufs;
unsigned int outbuf_len;
u64 seq;
unsigned long dropped;
};
bool other_cpu_in_panic(void);
bool this_cpu_in_panic(void);
bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
bool is_extended, bool may_supress);
#ifdef CONFIG_PRINTK
void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped);
#endif
|
