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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-05 18:39:59 +00:00
a9c4bdd505
there is one dwc3 trace event declare as below,
DECLARE_EVENT_CLASS(dwc3_log_event,
TP_PROTO(u32 event, struct dwc3 *dwc),
TP_ARGS(event, dwc),
TP_STRUCT__entry(
__field(u32, event)
__field(u32, ep0state)
__dynamic_array(char, str, DWC3_MSG_MAX)
),
TP_fast_assign(
__entry->event = event;
__entry->ep0state = dwc->ep0state;
),
TP_printk("event (%08x): %s", __entry->event,
dwc3_decode_event(__get_str(str), DWC3_MSG_MAX,
__entry->event, __entry->ep0state))
);
the problem is when trace function called, it will allocate up to
DWC3_MSG_MAX bytes from trace event buffer, but never fill the buffer
during fast assignment, it only fill the buffer when output function are
called, so this means if output function are not called, the buffer will
never used.
add __get_buf(len) which acquiree buffer from iter->tmp_seq when trace
output function called, it allow user write string to acquired buffer.
the mentioned dwc3 trace event will changed as below,
DECLARE_EVENT_CLASS(dwc3_log_event,
TP_PROTO(u32 event, struct dwc3 *dwc),
TP_ARGS(event, dwc),
TP_STRUCT__entry(
__field(u32, event)
__field(u32, ep0state)
),
TP_fast_assign(
__entry->event = event;
__entry->ep0state = dwc->ep0state;
),
TP_printk("event (%08x): %s", __entry->event,
dwc3_decode_event(__get_buf(DWC3_MSG_MAX), DWC3_MSG_MAX,
__entry->event, __entry->ep0state))
);.
Link: https://lore.kernel.org/linux-trace-kernel/1675065249-23368-1-git-send-email-quic_linyyuan@quicinc.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
149 lines
4.1 KiB
C
149 lines
4.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_TRACE_SEQ_H
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#define _LINUX_TRACE_SEQ_H
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#include <linux/seq_buf.h>
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#include <asm/page.h>
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/*
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* Trace sequences are used to allow a function to call several other functions
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* to create a string of data to use (up to a max of PAGE_SIZE).
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*/
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struct trace_seq {
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char buffer[PAGE_SIZE];
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struct seq_buf seq;
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int full;
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};
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static inline void
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trace_seq_init(struct trace_seq *s)
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{
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seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
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s->full = 0;
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}
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/**
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* trace_seq_used - amount of actual data written to buffer
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* @s: trace sequence descriptor
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*
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* Returns the amount of data written to the buffer.
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*
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* IMPORTANT!
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*
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* Use this instead of @s->seq.len if you need to pass the amount
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* of data from the buffer to another buffer (userspace, or what not).
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* The @s->seq.len on overflow is bigger than the buffer size and
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* using it can cause access to undefined memory.
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*/
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static inline int trace_seq_used(struct trace_seq *s)
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{
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return seq_buf_used(&s->seq);
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}
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/**
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* trace_seq_buffer_ptr - return pointer to next location in buffer
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* @s: trace sequence descriptor
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*
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* Returns the pointer to the buffer where the next write to
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* the buffer will happen. This is useful to save the location
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* that is about to be written to and then return the result
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* of that write.
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*/
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static inline char *
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trace_seq_buffer_ptr(struct trace_seq *s)
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{
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return s->buffer + seq_buf_used(&s->seq);
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}
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/**
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* trace_seq_has_overflowed - return true if the trace_seq took too much
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* @s: trace sequence descriptor
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*
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* Returns true if too much data was added to the trace_seq and it is
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* now full and will not take anymore.
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*/
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static inline bool trace_seq_has_overflowed(struct trace_seq *s)
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{
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return s->full || seq_buf_has_overflowed(&s->seq);
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}
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/*
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* Currently only defined when tracing is enabled.
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*/
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#ifdef CONFIG_TRACING
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extern __printf(2, 3)
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void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
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extern __printf(2, 0)
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void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
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extern void
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trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
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extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
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extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
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int cnt);
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extern void trace_seq_puts(struct trace_seq *s, const char *str);
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extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
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extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
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extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
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unsigned int len);
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extern int trace_seq_path(struct trace_seq *s, const struct path *path);
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extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
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int nmaskbits);
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extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
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int prefix_type, int rowsize, int groupsize,
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const void *buf, size_t len, bool ascii);
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char *trace_seq_acquire(struct trace_seq *s, unsigned int len);
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#else /* CONFIG_TRACING */
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static inline __printf(2, 3)
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void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
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{
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}
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static inline void
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trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
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{
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}
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static inline void
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trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
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int nmaskbits)
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{
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}
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static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
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{
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return 0;
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}
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static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
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int cnt)
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{
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return 0;
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}
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static inline void trace_seq_puts(struct trace_seq *s, const char *str)
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{
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}
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static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
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{
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}
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static inline void
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trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
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{
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}
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static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
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unsigned int len)
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{
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}
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static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
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{
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return 0;
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}
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static inline char *trace_seq_acquire(struct trace_seq *s, unsigned int len)
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{
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return NULL;
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}
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#endif /* CONFIG_TRACING */
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#endif /* _LINUX_TRACE_SEQ_H */
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