kernel-fxtec-pro1x/include/linux/ftrace.h
Frederic Weisbecker e7d3737ea1 tracing/function-return-tracer: support for dynamic ftrace on function return tracer
This patch adds the support for dynamic tracing on the function return tracer.
The whole difference with normal dynamic function tracing is that we don't need
to hook on a particular callback. The only pro that we want is to nop or set
dynamically the calls to ftrace_caller (which is ftrace_return_caller here).

Some security checks ensure that we are not trying to launch dynamic tracing for
return tracing while normal function tracing is already running.

An example of trace with getnstimeofday set as a filter:

ktime_get_ts+0x22/0x50 -> getnstimeofday (2283 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1396 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1825 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1426 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1524 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1434 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1502 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1404 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1397 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1051 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1314 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1344 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1163 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1390 ns)
ktime_get_ts+0x22/0x50 -> getnstimeofday (1374 ns)

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-16 07:57:38 +01:00

333 lines
9.9 KiB
C

#ifndef _LINUX_FTRACE_H
#define _LINUX_FTRACE_H
#include <linux/linkage.h>
#include <linux/fs.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/kallsyms.h>
#ifdef CONFIG_FUNCTION_TRACER
extern int ftrace_enabled;
extern int
ftrace_enable_sysctl(struct ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp,
loff_t *ppos);
typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
struct ftrace_ops {
ftrace_func_t func;
struct ftrace_ops *next;
};
extern int function_trace_stop;
/*
* Type of the current tracing.
*/
enum ftrace_tracing_type_t {
FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
FTRACE_TYPE_RETURN, /* Hook the return of the function */
};
/* Current tracing type, default is FTRACE_TYPE_ENTER */
extern enum ftrace_tracing_type_t ftrace_tracing_type;
/**
* ftrace_stop - stop function tracer.
*
* A quick way to stop the function tracer. Note this an on off switch,
* it is not something that is recursive like preempt_disable.
* This does not disable the calling of mcount, it only stops the
* calling of functions from mcount.
*/
static inline void ftrace_stop(void)
{
function_trace_stop = 1;
}
/**
* ftrace_start - start the function tracer.
*
* This function is the inverse of ftrace_stop. This does not enable
* the function tracing if the function tracer is disabled. This only
* sets the function tracer flag to continue calling the functions
* from mcount.
*/
static inline void ftrace_start(void)
{
function_trace_stop = 0;
}
/*
* The ftrace_ops must be a static and should also
* be read_mostly. These functions do modify read_mostly variables
* so use them sparely. Never free an ftrace_op or modify the
* next pointer after it has been registered. Even after unregistering
* it, the next pointer may still be used internally.
*/
int register_ftrace_function(struct ftrace_ops *ops);
int unregister_ftrace_function(struct ftrace_ops *ops);
void clear_ftrace_function(void);
extern void ftrace_stub(unsigned long a0, unsigned long a1);
#else /* !CONFIG_FUNCTION_TRACER */
# define register_ftrace_function(ops) do { } while (0)
# define unregister_ftrace_function(ops) do { } while (0)
# define clear_ftrace_function(ops) do { } while (0)
static inline void ftrace_kill(void) { }
static inline void ftrace_stop(void) { }
static inline void ftrace_start(void) { }
#endif /* CONFIG_FUNCTION_TRACER */
#ifdef CONFIG_DYNAMIC_FTRACE
/* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
#include <asm/ftrace.h>
enum {
FTRACE_FL_FREE = (1 << 0),
FTRACE_FL_FAILED = (1 << 1),
FTRACE_FL_FILTER = (1 << 2),
FTRACE_FL_ENABLED = (1 << 3),
FTRACE_FL_NOTRACE = (1 << 4),
FTRACE_FL_CONVERTED = (1 << 5),
FTRACE_FL_FROZEN = (1 << 6),
};
struct dyn_ftrace {
struct list_head list;
unsigned long ip; /* address of mcount call-site */
unsigned long flags;
struct dyn_arch_ftrace arch;
};
int ftrace_force_update(void);
void ftrace_set_filter(unsigned char *buf, int len, int reset);
/* defined in arch */
extern int ftrace_ip_converted(unsigned long ip);
extern int ftrace_dyn_arch_init(void *data);
extern int ftrace_update_ftrace_func(ftrace_func_t func);
extern void ftrace_caller(void);
extern void ftrace_call(void);
extern void mcount_call(void);
#ifdef CONFIG_FUNCTION_RET_TRACER
extern void ftrace_return_caller(void);
#endif
/**
* ftrace_make_nop - convert code into top
* @mod: module structure if called by module load initialization
* @rec: the mcount call site record
* @addr: the address that the call site should be calling
*
* This is a very sensitive operation and great care needs
* to be taken by the arch. The operation should carefully
* read the location, check to see if what is read is indeed
* what we expect it to be, and then on success of the compare,
* it should write to the location.
*
* The code segment at @rec->ip should be a caller to @addr
*
* Return must be:
* 0 on success
* -EFAULT on error reading the location
* -EINVAL on a failed compare of the contents
* -EPERM on error writing to the location
* Any other value will be considered a failure.
*/
extern int ftrace_make_nop(struct module *mod,
struct dyn_ftrace *rec, unsigned long addr);
/**
* ftrace_make_call - convert a nop call site into a call to addr
* @rec: the mcount call site record
* @addr: the address that the call site should call
*
* This is a very sensitive operation and great care needs
* to be taken by the arch. The operation should carefully
* read the location, check to see if what is read is indeed
* what we expect it to be, and then on success of the compare,
* it should write to the location.
*
* The code segment at @rec->ip should be a nop
*
* Return must be:
* 0 on success
* -EFAULT on error reading the location
* -EINVAL on a failed compare of the contents
* -EPERM on error writing to the location
* Any other value will be considered a failure.
*/
extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
/* May be defined in arch */
extern int ftrace_arch_read_dyn_info(char *buf, int size);
extern int skip_trace(unsigned long ip);
extern void ftrace_release(void *start, unsigned long size);
extern void ftrace_disable_daemon(void);
extern void ftrace_enable_daemon(void);
#else
# define skip_trace(ip) ({ 0; })
# define ftrace_force_update() ({ 0; })
# define ftrace_set_filter(buf, len, reset) do { } while (0)
# define ftrace_disable_daemon() do { } while (0)
# define ftrace_enable_daemon() do { } while (0)
static inline void ftrace_release(void *start, unsigned long size) { }
#endif /* CONFIG_DYNAMIC_FTRACE */
/* totally disable ftrace - can not re-enable after this */
void ftrace_kill(void);
static inline void tracer_disable(void)
{
#ifdef CONFIG_FUNCTION_TRACER
ftrace_enabled = 0;
#endif
}
/*
* Ftrace disable/restore without lock. Some synchronization mechanism
* must be used to prevent ftrace_enabled to be changed between
* disable/restore.
*/
static inline int __ftrace_enabled_save(void)
{
#ifdef CONFIG_FUNCTION_TRACER
int saved_ftrace_enabled = ftrace_enabled;
ftrace_enabled = 0;
return saved_ftrace_enabled;
#else
return 0;
#endif
}
static inline void __ftrace_enabled_restore(int enabled)
{
#ifdef CONFIG_FUNCTION_TRACER
ftrace_enabled = enabled;
#endif
}
#ifdef CONFIG_FRAME_POINTER
/* TODO: need to fix this for ARM */
# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
#else
# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
# define CALLER_ADDR1 0UL
# define CALLER_ADDR2 0UL
# define CALLER_ADDR3 0UL
# define CALLER_ADDR4 0UL
# define CALLER_ADDR5 0UL
# define CALLER_ADDR6 0UL
#endif
#ifdef CONFIG_IRQSOFF_TRACER
extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
#else
# define time_hardirqs_on(a0, a1) do { } while (0)
# define time_hardirqs_off(a0, a1) do { } while (0)
#endif
#ifdef CONFIG_PREEMPT_TRACER
extern void trace_preempt_on(unsigned long a0, unsigned long a1);
extern void trace_preempt_off(unsigned long a0, unsigned long a1);
#else
# define trace_preempt_on(a0, a1) do { } while (0)
# define trace_preempt_off(a0, a1) do { } while (0)
#endif
#ifdef CONFIG_TRACING
extern int ftrace_dump_on_oops;
extern void tracing_start(void);
extern void tracing_stop(void);
extern void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
/**
* ftrace_printk - printf formatting in the ftrace buffer
* @fmt: the printf format for printing
*
* Note: __ftrace_printk is an internal function for ftrace_printk and
* the @ip is passed in via the ftrace_printk macro.
*
* This function allows a kernel developer to debug fast path sections
* that printk is not appropriate for. By scattering in various
* printk like tracing in the code, a developer can quickly see
* where problems are occurring.
*
* This is intended as a debugging tool for the developer only.
* Please refrain from leaving ftrace_printks scattered around in
* your code.
*/
# define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
extern int
__ftrace_printk(unsigned long ip, const char *fmt, ...)
__attribute__ ((format (printf, 2, 3)));
extern void ftrace_dump(void);
#else
static inline void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
static inline int
ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
static inline void tracing_start(void) { }
static inline void tracing_stop(void) { }
static inline int
ftrace_printk(const char *fmt, ...)
{
return 0;
}
static inline void ftrace_dump(void) { }
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
extern void ftrace_init(void);
extern void ftrace_init_module(struct module *mod,
unsigned long *start, unsigned long *end);
#else
static inline void ftrace_init(void) { }
static inline void
ftrace_init_module(struct module *mod,
unsigned long *start, unsigned long *end) { }
#endif
/*
* Structure that defines a return function trace.
*/
struct ftrace_retfunc {
unsigned long ret; /* Return address */
unsigned long func; /* Current function */
unsigned long long calltime;
unsigned long long rettime;
};
#ifdef CONFIG_FUNCTION_RET_TRACER
/* Type of a callback handler of tracing return function */
typedef void (*trace_function_return_t)(struct ftrace_retfunc *);
extern int register_ftrace_return(trace_function_return_t func);
/* The current handler in use */
extern trace_function_return_t ftrace_function_return;
extern void unregister_ftrace_return(void);
#endif
#endif /* _LINUX_FTRACE_H */