forked from Minki/linux
dd0e545f06
This patch adds a feature that can help kernel developers debug their
code using ftrace.
int ftrace_printk(const char *fmt, ...);
This records into the ftrace buffer using printf formatting. The entry
size in the buffers are still a fixed length. A new type has been added
that allows for more entries to be used for a single recording.
The start of the print is still the same as the other entries.
It returns the number of characters written to the ftrace buffer.
For example:
Having a module with the following code:
static int __init ftrace_print_test(void)
{
ftrace_printk("jiffies are %ld\n", jiffies);
return 0;
}
Gives me:
insmod-5441 3...1 7569us : ftrace_print_test: jiffies are 4296626666
for the latency_trace file and:
insmod-5441 [03] 1959.370498: ftrace_print_test jiffies are 4296626666
for the trace file.
Note: Only the infrastructure should go into the kernel. It is to help
facilitate debugging for other kernel developers. Calls to ftrace_printk
is not intended to be left in the kernel, and should be frowned upon just
like scattering printks around in the code.
But having this easily at your fingertips helps the debugging go faster
and bugs be solved quicker.
Maybe later on, we can hook this with markers and have their printf format
be sucked into ftrace output.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
362 lines
9.0 KiB
C
362 lines
9.0 KiB
C
#ifndef _LINUX_KERNEL_TRACE_H
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#define _LINUX_KERNEL_TRACE_H
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#include <linux/fs.h>
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#include <asm/atomic.h>
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#include <linux/sched.h>
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#include <linux/clocksource.h>
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#include <linux/mmiotrace.h>
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enum trace_type {
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__TRACE_FIRST_TYPE = 0,
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TRACE_FN,
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TRACE_CTX,
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TRACE_WAKE,
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TRACE_CONT,
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TRACE_STACK,
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TRACE_PRINT,
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TRACE_SPECIAL,
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TRACE_MMIO_RW,
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TRACE_MMIO_MAP,
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__TRACE_LAST_TYPE
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};
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/*
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* Function trace entry - function address and parent function addres:
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*/
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struct ftrace_entry {
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unsigned long ip;
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unsigned long parent_ip;
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};
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/*
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* Context switch trace entry - which task (and prio) we switched from/to:
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*/
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struct ctx_switch_entry {
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unsigned int prev_pid;
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unsigned char prev_prio;
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unsigned char prev_state;
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unsigned int next_pid;
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unsigned char next_prio;
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unsigned char next_state;
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};
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/*
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* Special (free-form) trace entry:
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*/
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struct special_entry {
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unsigned long arg1;
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unsigned long arg2;
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unsigned long arg3;
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};
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/*
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* Stack-trace entry:
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*/
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#define FTRACE_STACK_ENTRIES 8
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struct stack_entry {
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unsigned long caller[FTRACE_STACK_ENTRIES];
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};
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/*
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* ftrace_printk entry:
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*/
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struct print_entry {
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unsigned long ip;
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char buf[];
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};
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/*
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* The trace field - the most basic unit of tracing. This is what
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* is printed in the end as a single line in the trace output, such as:
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*
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* bash-15816 [01] 235.197585: idle_cpu <- irq_enter
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*/
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struct trace_field {
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char cpu;
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char flags;
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char preempt_count;
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int pid;
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cycle_t t;
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union {
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struct ftrace_entry fn;
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struct ctx_switch_entry ctx;
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struct special_entry special;
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struct stack_entry stack;
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struct print_entry print;
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struct mmiotrace_rw mmiorw;
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struct mmiotrace_map mmiomap;
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};
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};
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struct trace_field_cont {
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char buf[sizeof(struct trace_field)];
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};
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struct trace_entry {
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char type;
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union {
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struct trace_field field;
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struct trace_field_cont cont;
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};
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};
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#define TRACE_ENTRY_SIZE sizeof(struct trace_entry)
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/*
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* The CPU trace array - it consists of thousands of trace entries
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* plus some other descriptor data: (for example which task started
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* the trace, etc.)
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*/
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struct trace_array_cpu {
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struct list_head trace_pages;
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atomic_t disabled;
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raw_spinlock_t lock;
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struct lock_class_key lock_key;
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/* these fields get copied into max-trace: */
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unsigned trace_head_idx;
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unsigned trace_tail_idx;
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void *trace_head; /* producer */
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void *trace_tail; /* consumer */
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unsigned long trace_idx;
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unsigned long overrun;
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unsigned long saved_latency;
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unsigned long critical_start;
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unsigned long critical_end;
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unsigned long critical_sequence;
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unsigned long nice;
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unsigned long policy;
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unsigned long rt_priority;
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cycle_t preempt_timestamp;
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pid_t pid;
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uid_t uid;
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char comm[TASK_COMM_LEN];
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};
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struct trace_iterator;
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/*
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* The trace array - an array of per-CPU trace arrays. This is the
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* highest level data structure that individual tracers deal with.
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* They have on/off state as well:
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*/
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struct trace_array {
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unsigned long entries;
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long ctrl;
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int cpu;
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cycle_t time_start;
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struct task_struct *waiter;
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struct trace_array_cpu *data[NR_CPUS];
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};
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/*
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* A specific tracer, represented by methods that operate on a trace array:
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*/
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struct tracer {
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const char *name;
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void (*init)(struct trace_array *tr);
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void (*reset)(struct trace_array *tr);
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void (*open)(struct trace_iterator *iter);
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void (*pipe_open)(struct trace_iterator *iter);
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void (*close)(struct trace_iterator *iter);
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void (*start)(struct trace_iterator *iter);
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void (*stop)(struct trace_iterator *iter);
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ssize_t (*read)(struct trace_iterator *iter,
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struct file *filp, char __user *ubuf,
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size_t cnt, loff_t *ppos);
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void (*ctrl_update)(struct trace_array *tr);
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#ifdef CONFIG_FTRACE_STARTUP_TEST
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int (*selftest)(struct tracer *trace,
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struct trace_array *tr);
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#endif
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int (*print_line)(struct trace_iterator *iter);
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struct tracer *next;
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int print_max;
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};
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struct trace_seq {
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unsigned char buffer[PAGE_SIZE];
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unsigned int len;
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unsigned int readpos;
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};
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/*
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* Trace iterator - used by printout routines who present trace
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* results to users and which routines might sleep, etc:
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*/
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struct trace_iterator {
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struct trace_array *tr;
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struct tracer *trace;
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void *private;
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long last_overrun[NR_CPUS];
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long overrun[NR_CPUS];
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/* The below is zeroed out in pipe_read */
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struct trace_seq seq;
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struct trace_entry *ent;
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int cpu;
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struct trace_entry *prev_ent;
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int prev_cpu;
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unsigned long iter_flags;
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loff_t pos;
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unsigned long next_idx[NR_CPUS];
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struct list_head *next_page[NR_CPUS];
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unsigned next_page_idx[NR_CPUS];
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long idx;
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};
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void tracing_reset(struct trace_array_cpu *data);
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int tracing_open_generic(struct inode *inode, struct file *filp);
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struct dentry *tracing_init_dentry(void);
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void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
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void ftrace(struct trace_array *tr,
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struct trace_array_cpu *data,
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unsigned long ip,
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unsigned long parent_ip,
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unsigned long flags);
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void tracing_sched_switch_trace(struct trace_array *tr,
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struct trace_array_cpu *data,
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struct task_struct *prev,
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struct task_struct *next,
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unsigned long flags);
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void tracing_record_cmdline(struct task_struct *tsk);
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void tracing_sched_wakeup_trace(struct trace_array *tr,
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struct trace_array_cpu *data,
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struct task_struct *wakee,
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struct task_struct *cur,
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unsigned long flags);
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void trace_special(struct trace_array *tr,
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struct trace_array_cpu *data,
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unsigned long arg1,
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unsigned long arg2,
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unsigned long arg3);
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void trace_function(struct trace_array *tr,
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struct trace_array_cpu *data,
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unsigned long ip,
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unsigned long parent_ip,
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unsigned long flags);
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void tracing_start_cmdline_record(void);
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void tracing_stop_cmdline_record(void);
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int register_tracer(struct tracer *type);
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void unregister_tracer(struct tracer *type);
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extern unsigned long nsecs_to_usecs(unsigned long nsecs);
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extern unsigned long tracing_max_latency;
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extern unsigned long tracing_thresh;
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void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
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void update_max_tr_single(struct trace_array *tr,
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struct task_struct *tsk, int cpu);
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extern cycle_t ftrace_now(int cpu);
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#ifdef CONFIG_FTRACE
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void tracing_start_function_trace(void);
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void tracing_stop_function_trace(void);
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#else
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# define tracing_start_function_trace() do { } while (0)
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# define tracing_stop_function_trace() do { } while (0)
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#endif
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#ifdef CONFIG_CONTEXT_SWITCH_TRACER
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typedef void
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(*tracer_switch_func_t)(void *private,
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void *__rq,
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struct task_struct *prev,
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struct task_struct *next);
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struct tracer_switch_ops {
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tracer_switch_func_t func;
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void *private;
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struct tracer_switch_ops *next;
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};
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#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
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#ifdef CONFIG_DYNAMIC_FTRACE
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extern unsigned long ftrace_update_tot_cnt;
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#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
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extern int DYN_FTRACE_TEST_NAME(void);
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#endif
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#ifdef CONFIG_MMIOTRACE
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extern void __trace_mmiotrace_rw(struct trace_array *tr,
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struct trace_array_cpu *data,
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struct mmiotrace_rw *rw);
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extern void __trace_mmiotrace_map(struct trace_array *tr,
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struct trace_array_cpu *data,
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struct mmiotrace_map *map);
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#endif
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#ifdef CONFIG_FTRACE_STARTUP_TEST
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#ifdef CONFIG_FTRACE
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extern int trace_selftest_startup_function(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#ifdef CONFIG_IRQSOFF_TRACER
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extern int trace_selftest_startup_irqsoff(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#ifdef CONFIG_PREEMPT_TRACER
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extern int trace_selftest_startup_preemptoff(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
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extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#ifdef CONFIG_SCHED_TRACER
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extern int trace_selftest_startup_wakeup(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#ifdef CONFIG_CONTEXT_SWITCH_TRACER
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extern int trace_selftest_startup_sched_switch(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#ifdef CONFIG_SYSPROF_TRACER
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extern int trace_selftest_startup_sysprof(struct tracer *trace,
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struct trace_array *tr);
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#endif
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#endif /* CONFIG_FTRACE_STARTUP_TEST */
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extern void *head_page(struct trace_array_cpu *data);
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extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
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extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
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size_t cnt);
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extern long ns2usecs(cycle_t nsec);
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extern unsigned long trace_flags;
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/*
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* trace_iterator_flags is an enumeration that defines bit
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* positions into trace_flags that controls the output.
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*
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* NOTE: These bits must match the trace_options array in
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* trace.c.
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*/
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enum trace_iterator_flags {
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TRACE_ITER_PRINT_PARENT = 0x01,
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TRACE_ITER_SYM_OFFSET = 0x02,
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TRACE_ITER_SYM_ADDR = 0x04,
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TRACE_ITER_VERBOSE = 0x08,
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TRACE_ITER_RAW = 0x10,
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TRACE_ITER_HEX = 0x20,
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TRACE_ITER_BIN = 0x40,
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TRACE_ITER_BLOCK = 0x80,
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TRACE_ITER_STACKTRACE = 0x100,
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TRACE_ITER_SCHED_TREE = 0x200,
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};
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#endif /* _LINUX_KERNEL_TRACE_H */
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