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 | |
23 | struct trace_seq { |
24 | char buffer[TRACE_SEQ_BUFFER_SIZE]; |
25 | struct seq_buf seq; |
26 | size_t readpos; |
27 | int full; |
28 | }; |
29 | |
30 | static inline void |
31 | trace_seq_init(struct trace_seq *s) |
32 | { |
33 | seq_buf_init(s: &s->seq, buf: 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 | */ |
51 | static inline int trace_seq_used(struct trace_seq *s) |
52 | { |
53 | return seq_buf_used(s: &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 | */ |
65 | static inline char * |
66 | trace_seq_buffer_ptr(struct trace_seq *s) |
67 | { |
68 | return s->buffer + seq_buf_used(s: &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 | */ |
78 | static inline bool trace_seq_has_overflowed(struct trace_seq *s) |
79 | { |
80 | return s->full || seq_buf_has_overflowed(s: &s->seq); |
81 | } |
82 | |
83 | /* |
84 | * Currently only defined when tracing is enabled. |
85 | */ |
86 | #ifdef CONFIG_TRACING |
87 | extern __printf(2, 3) |
88 | void trace_seq_printf(struct trace_seq *s, const char *fmt, ...); |
89 | extern __printf(2, 0) |
90 | void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args); |
91 | extern void |
92 | trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary); |
93 | extern int trace_print_seq(struct seq_file *m, struct trace_seq *s); |
94 | extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, |
95 | int cnt); |
96 | extern void trace_seq_puts(struct trace_seq *s, const char *str); |
97 | extern void trace_seq_putc(struct trace_seq *s, unsigned char c); |
98 | extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len); |
99 | extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, |
100 | unsigned int len); |
101 | extern int trace_seq_path(struct trace_seq *s, const struct path *path); |
102 | |
103 | extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, |
104 | int nmaskbits); |
105 | |
106 | extern 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); |
109 | char *trace_seq_acquire(struct trace_seq *s, unsigned int len); |
110 | |
111 | #else /* CONFIG_TRACING */ |
112 | static inline __printf(2, 3) |
113 | void trace_seq_printf(struct trace_seq *s, const char *fmt, ...) |
114 | { |
115 | } |
116 | static inline void |
117 | trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) |
118 | { |
119 | } |
120 | |
121 | static inline void |
122 | trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, |
123 | int nmaskbits) |
124 | { |
125 | } |
126 | |
127 | static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s) |
128 | { |
129 | return 0; |
130 | } |
131 | static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, |
132 | int cnt) |
133 | { |
134 | return 0; |
135 | } |
136 | static inline void trace_seq_puts(struct trace_seq *s, const char *str) |
137 | { |
138 | } |
139 | static inline void trace_seq_putc(struct trace_seq *s, unsigned char c) |
140 | { |
141 | } |
142 | static inline void |
143 | trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) |
144 | { |
145 | } |
146 | static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem, |
147 | unsigned int len) |
148 | { |
149 | } |
150 | static inline int trace_seq_path(struct trace_seq *s, const struct path *path) |
151 | { |
152 | return 0; |
153 | } |
154 | static 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 | |