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