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