1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * internal.h - printk internal definitions 4 */ 5 #include <linux/percpu.h> 6 7 #if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL) 8 void __init printk_sysctl_init(void); 9 int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, 10 void *buffer, size_t *lenp, loff_t *ppos); 11 #else 12 #define printk_sysctl_init() do { } while (0) 13 #endif 14 15 #ifdef CONFIG_PRINTK 16 17 #ifdef CONFIG_PRINTK_CALLER 18 #define PRINTK_PREFIX_MAX 48 19 #else 20 #define PRINTK_PREFIX_MAX 32 21 #endif 22 23 /* 24 * the maximum size of a formatted record (i.e. with prefix added 25 * per line and dropped messages or in extended message format) 26 */ 27 #define PRINTK_MESSAGE_MAX 2048 28 29 /* the maximum size allowed to be reserved for a record */ 30 #define PRINTKRB_RECORD_MAX 1024 31 32 /* Flags for a single printk record. */ 33 enum printk_info_flags { 34 LOG_NEWLINE = 2, /* text ended with a newline */ 35 LOG_CONT = 8, /* text is a fragment of a continuation line */ 36 }; 37 38 __printf(4, 0) 39 int vprintk_store(int facility, int level, 40 const struct dev_printk_info *dev_info, 41 const char *fmt, va_list args); 42 43 __printf(1, 0) int vprintk_default(const char *fmt, va_list args); 44 __printf(1, 0) int vprintk_deferred(const char *fmt, va_list args); 45 46 bool printk_percpu_data_ready(void); 47 48 #define printk_safe_enter_irqsave(flags) \ 49 do { \ 50 local_irq_save(flags); \ 51 __printk_safe_enter(); \ 52 } while (0) 53 54 #define printk_safe_exit_irqrestore(flags) \ 55 do { \ 56 __printk_safe_exit(); \ 57 local_irq_restore(flags); \ 58 } while (0) 59 60 void defer_console_output(void); 61 62 u16 printk_parse_prefix(const char *text, int *level, 63 enum printk_info_flags *flags); 64 #else 65 66 #define PRINTK_PREFIX_MAX 0 67 #define PRINTK_MESSAGE_MAX 0 68 #define PRINTKRB_RECORD_MAX 0 69 70 /* 71 * In !PRINTK builds we still export console_sem 72 * semaphore and some of console functions (console_unlock()/etc.), so 73 * printk-safe must preserve the existing local IRQ guarantees. 74 */ 75 #define printk_safe_enter_irqsave(flags) local_irq_save(flags) 76 #define printk_safe_exit_irqrestore(flags) local_irq_restore(flags) 77 78 static inline bool printk_percpu_data_ready(void) { return false; } 79 #endif /* CONFIG_PRINTK */ 80 81 /** 82 * struct printk_buffers - Buffers to read/format/output printk messages. 83 * @outbuf: After formatting, contains text to output. 84 * @scratchbuf: Used as temporary ringbuffer reading and string-print space. 85 */ 86 struct printk_buffers { 87 char outbuf[PRINTK_MESSAGE_MAX]; 88 char scratchbuf[PRINTKRB_RECORD_MAX]; 89 }; 90 91 /** 92 * struct printk_message - Container for a prepared printk message. 93 * @pbufs: printk buffers used to prepare the message. 94 * @outbuf_len: The length of prepared text in @pbufs->outbuf to output. This 95 * does not count the terminator. A value of 0 means there is 96 * nothing to output and this record should be skipped. 97 * @seq: The sequence number of the record used for @pbufs->outbuf. 98 * @dropped: The number of dropped records from reading @seq. 99 */ 100 struct printk_message { 101 struct printk_buffers *pbufs; 102 unsigned int outbuf_len; 103 u64 seq; 104 unsigned long dropped; 105 }; 106