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 | unsigned 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 unsigned 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 | #else /* CONFIG_TRACING */ |
96 | static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) |
97 | { |
98 | } |
99 | static inline void |
100 | trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) |
101 | { |
102 | } |
103 | |
104 | static inline void |
105 | trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, |
106 | int nmaskbits) |
107 | { |
108 | } |
109 | |
110 | static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) |
111 | { |
112 | return 0; |
113 | } |
114 | static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, |
115 | int cnt) |
116 | { |
117 | return 0; |
118 | } |
119 | static inline void trace_seq_puts(struct trace_seq *s, const char *str) |
120 | { |
121 | } |
122 | static inline void trace_seq_putc(struct trace_seq *s, unsigned char c) |
123 | { |
124 | } |
125 | static inline void |
126 | trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) |
127 | { |
128 | } |
129 | static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, |
130 | unsigned int len) |
131 | { |
132 | } |
133 | static inline int trace_seq_path(struct trace_seq *s, const struct path *path) |
134 | { |
135 | return 0; |
136 | } |
137 | #endif /* CONFIG_TRACING */ |
138 | |
139 | #endif /* _LINUX_TRACE_SEQ_H */ |
140 | |