1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_TRACE_SEQ_H 3#define _LINUX_TRACE_SEQ_H 4 5#include <linux/seq_buf.h> 6 7#include <asm/page.h> 8 9/* 10 * Trace sequences are used to allow a function to call several other functions 11 * to create a string of data to use. 12 * 13 * Have the trace seq to be 8K which is typically PAGE_SIZE * 2 on 14 * most architectures. The TRACE_SEQ_BUFFER_SIZE (which is 15 * TRACE_SEQ_SIZE minus the other fields of trace_seq), is the 16 * max size the output of a trace event may be. 17 */ 18 19#define TRACE_SEQ_SIZE 8192 20#define TRACE_SEQ_BUFFER_SIZE (TRACE_SEQ_SIZE - \ 21 (sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int))) 22 23struct trace_seq { 24 char buffer[TRACE_SEQ_BUFFER_SIZE]; 25 struct seq_buf seq; 26 size_t readpos; 27 int full; 28}; 29 30static inline void 31trace_seq_init(struct trace_seq *s) 32{ 33 seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE); 34 s->full = 0; 35 s->readpos = 0; 36} 37 38/** 39 * trace_seq_used - amount of actual data written to buffer 40 * @s: trace sequence descriptor 41 * 42 * Returns the amount of data written to the buffer. 43 * 44 * IMPORTANT! 45 * 46 * Use this instead of @s->seq.len if you need to pass the amount 47 * of data from the buffer to another buffer (userspace, or what not). 48 * The @s->seq.len on overflow is bigger than the buffer size and 49 * using it can cause access to undefined memory. 50 */ 51static inline int trace_seq_used(struct trace_seq *s) 52{ 53 return seq_buf_used(&s->seq); 54} 55 56/** 57 * trace_seq_buffer_ptr - return pointer to next location in buffer 58 * @s: trace sequence descriptor 59 * 60 * Returns the pointer to the buffer where the next write to 61 * the buffer will happen. This is useful to save the location 62 * that is about to be written to and then return the result 63 * of that write. 64 */ 65static inline char * 66trace_seq_buffer_ptr(struct trace_seq *s) 67{ 68 return s->buffer + seq_buf_used(&s->seq); 69} 70 71/** 72 * trace_seq_has_overflowed - return true if the trace_seq took too much 73 * @s: trace sequence descriptor 74 * 75 * Returns true if too much data was added to the trace_seq and it is 76 * now full and will not take anymore. 77 */ 78static inline bool trace_seq_has_overflowed(struct trace_seq *s) 79{ 80 return s->full || seq_buf_has_overflowed(&s->seq); 81} 82 83/* 84 * Currently only defined when tracing is enabled. 85 */ 86#ifdef CONFIG_TRACING 87extern __printf(2, 3) 88void trace_seq_printf(struct trace_seq *s, const char *fmt, ...); 89extern __printf(2, 0) 90void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args); 91extern void 92trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary); 93extern int trace_print_seq(struct seq_file *m, struct trace_seq *s); 94extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, 95 int cnt); 96extern void trace_seq_puts(struct trace_seq *s, const char *str); 97extern void trace_seq_putc(struct trace_seq *s, unsigned char c); 98extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len); 99extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, 100 unsigned int len); 101extern int trace_seq_path(struct trace_seq *s, const struct path *path); 102 103extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, 104 int nmaskbits); 105 106extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str, 107 int prefix_type, int rowsize, int groupsize, 108 const void *buf, size_t len, bool ascii); 109char *trace_seq_acquire(struct trace_seq *s, unsigned int len); 110 111#else /* CONFIG_TRACING */ 112static inline __printf(2, 3) 113void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) 114{ 115} 116static inline void 117trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) 118{ 119} 120 121static inline void 122trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, 123 int nmaskbits) 124{ 125} 126 127static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) 128{ 129 return 0; 130} 131static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, 132 int cnt) 133{ 134 return 0; 135} 136static inline void trace_seq_puts(struct trace_seq *s, const char *str) 137{ 138} 139static inline void trace_seq_putc(struct trace_seq *s, unsigned char c) 140{ 141} 142static inline void 143trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) 144{ 145} 146static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, 147 unsigned int len) 148{ 149} 150static inline int trace_seq_path(struct trace_seq *s, const struct path *path) 151{ 152 return 0; 153} 154static inline char *trace_seq_acquire(struct trace_seq *s, unsigned int len) 155{ 156 return NULL; 157} 158#endif /* CONFIG_TRACING */ 159 160#endif /* _LINUX_TRACE_SEQ_H */ 161