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