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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TRACE_SEQ_H
#define _LINUX_TRACE_SEQ_H
#include <linux/seq_buf.h>
#include <asm/page.h>
/*
* Trace sequences are used to allow a function to call several other functions
* to create a string of data to use.
*
* Have the trace seq to be 8K which is typically PAGE_SIZE * 2 on
* most architectures. The TRACE_SEQ_BUFFER_SIZE (which is
* TRACE_SEQ_SIZE minus the other fields of trace_seq), is the
* max size the output of a trace event may be.
*/
#define TRACE_SEQ_SIZE 8192
#define TRACE_SEQ_BUFFER_SIZE (TRACE_SEQ_SIZE - \
(sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int)))
struct trace_seq {
char buffer[TRACE_SEQ_BUFFER_SIZE];
struct seq_buf seq;
size_t readpos;
int full;
};
static inline void
trace_seq_init(struct trace_seq *s)
{
seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE);
s->full = 0;
s->readpos = 0;
}
/**
* trace_seq_used - amount of actual data written to buffer
* @s: trace sequence descriptor
*
* Returns the amount of data written to the buffer.
*
* IMPORTANT!
*
* Use this instead of @s->seq.len if you need to pass the amount
* of data from the buffer to another buffer (userspace, or what not).
* The @s->seq.len on overflow is bigger than the buffer size and
* using it can cause access to undefined memory.
*/
static inline int trace_seq_used(struct trace_seq *s)
{
return seq_buf_used(&s->seq);
}
/**
* trace_seq_buffer_ptr - return pointer to next location in buffer
* @s: trace sequence descriptor
*
* Returns the pointer to the buffer where the next write to
* the buffer will happen. This is useful to save the location
* that is about to be written to and then return the result
* of that write.
*/
static inline char *
trace_seq_buffer_ptr(struct trace_seq *s)
{
return s->buffer + seq_buf_used(&s->seq);
}
/**
* trace_seq_has_overflowed - return true if the trace_seq took too much
* @s: trace sequence descriptor
*
* Returns true if too much data was added to the trace_seq and it is
* now full and will not take anymore.
*/
static inline bool trace_seq_has_overflowed(struct trace_seq *s)
{
return s->full || seq_buf_has_overflowed(&s->seq);
}
/*
* Currently only defined when tracing is enabled.
*/
#ifdef CONFIG_TRACING
extern __printf(2, 3)
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern __printf(2, 0)
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
extern void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
int cnt);
extern void trace_seq_puts(struct trace_seq *s, const char *str);
extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len);
extern int trace_seq_path(struct trace_seq *s, const struct path *path);
extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits);
extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
int prefix_type, int rowsize, int groupsize,
const void *buf, size_t len, bool ascii);
char *trace_seq_acquire(struct trace_seq *s, unsigned int len);
#else /* CONFIG_TRACING */
static inline __printf(2, 3)
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
}
static inline void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
}
static inline void
trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
int nmaskbits)
{
}
static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
{
return 0;
}
static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
int cnt)
{
return 0;
}
static inline void trace_seq_puts(struct trace_seq *s, const char *str)
{
}
static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
{
}
static inline void
trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
{
}
static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
unsigned int len)
{
}
static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
{
return 0;
}
static inline char *trace_seq_acquire(struct trace_seq *s, unsigned int len)
{
return NULL;
}
#endif /* CONFIG_TRACING */
#endif /* _LINUX_TRACE_SEQ_H */
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