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![Steven Rostedt](/assets/img/avatar_default.png)
When the fuction graph tracer starts, it needs to make a special stack for each task to save the real return values of the tasks. All running tasks have this stack created, as well as any new tasks. On CPU hot plug, the new idle task will allocate a stack as well when init_idle() is called. The problem is that cpu hotplug does not create a new idle_task. Instead it uses the idle task that existed when the cpu went down. ftrace_graph_init_task() will add a new ret_stack to the task that is given to it. Because a clone will make the task have a stack of its parent it does not check if the task's ret_stack is already NULL or not. When the CPU hotplug code starts a CPU up again, it will allocate a new stack even though one already existed for it. The solution is to treat the idle_task specially. In fact, the function_graph code already does, just not at init_idle(). Instead of using the ftrace_graph_init_task() for the idle task, which that function expects the task to be a clone, have a separate ftrace_graph_init_idle_task(). Also, we will create a per_cpu ret_stack that is used by the idle task. When we call ftrace_graph_init_idle_task() it will check if the idle task's ret_stack is NULL, if it is, then it will assign it the per_cpu ret_stack. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stable Tree <stable@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
535 lines
15 KiB
C
535 lines
15 KiB
C
/*
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* Ftrace header. For implementation details beyond the random comments
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* scattered below, see: Documentation/trace/ftrace-design.txt
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*/
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#ifndef _LINUX_FTRACE_H
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#define _LINUX_FTRACE_H
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#include <linux/trace_clock.h>
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#include <linux/kallsyms.h>
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#include <linux/linkage.h>
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#include <linux/bitops.h>
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#include <linux/module.h>
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#include <linux/ktime.h>
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#include <linux/sched.h>
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <asm/ftrace.h>
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#ifdef CONFIG_FUNCTION_TRACER
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extern int ftrace_enabled;
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extern int
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ftrace_enable_sysctl(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
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struct ftrace_ops {
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ftrace_func_t func;
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struct ftrace_ops *next;
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};
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extern int function_trace_stop;
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/*
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* Type of the current tracing.
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*/
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enum ftrace_tracing_type_t {
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FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
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FTRACE_TYPE_RETURN, /* Hook the return of the function */
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};
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/* Current tracing type, default is FTRACE_TYPE_ENTER */
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extern enum ftrace_tracing_type_t ftrace_tracing_type;
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/**
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* ftrace_stop - stop function tracer.
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*
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* A quick way to stop the function tracer. Note this an on off switch,
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* it is not something that is recursive like preempt_disable.
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* This does not disable the calling of mcount, it only stops the
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* calling of functions from mcount.
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*/
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static inline void ftrace_stop(void)
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{
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function_trace_stop = 1;
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}
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/**
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* ftrace_start - start the function tracer.
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*
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* This function is the inverse of ftrace_stop. This does not enable
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* the function tracing if the function tracer is disabled. This only
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* sets the function tracer flag to continue calling the functions
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* from mcount.
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*/
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static inline void ftrace_start(void)
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{
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function_trace_stop = 0;
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}
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/*
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* The ftrace_ops must be a static and should also
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* be read_mostly. These functions do modify read_mostly variables
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* so use them sparely. Never free an ftrace_op or modify the
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* next pointer after it has been registered. Even after unregistering
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* it, the next pointer may still be used internally.
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*/
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int register_ftrace_function(struct ftrace_ops *ops);
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int unregister_ftrace_function(struct ftrace_ops *ops);
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void clear_ftrace_function(void);
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extern void ftrace_stub(unsigned long a0, unsigned long a1);
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#else /* !CONFIG_FUNCTION_TRACER */
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/*
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* (un)register_ftrace_function must be a macro since the ops parameter
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* must not be evaluated.
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*/
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#define register_ftrace_function(ops) ({ 0; })
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#define unregister_ftrace_function(ops) ({ 0; })
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static inline void clear_ftrace_function(void) { }
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static inline void ftrace_kill(void) { }
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static inline void ftrace_stop(void) { }
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static inline void ftrace_start(void) { }
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#endif /* CONFIG_FUNCTION_TRACER */
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#ifdef CONFIG_STACK_TRACER
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extern int stack_tracer_enabled;
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int
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stack_trace_sysctl(struct ctl_table *table, int write,
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void __user *buffer, size_t *lenp,
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loff_t *ppos);
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#endif
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struct ftrace_func_command {
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struct list_head list;
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char *name;
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int (*func)(char *func, char *cmd,
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char *params, int enable);
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};
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#ifdef CONFIG_DYNAMIC_FTRACE
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int ftrace_arch_code_modify_prepare(void);
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int ftrace_arch_code_modify_post_process(void);
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struct seq_file;
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struct ftrace_probe_ops {
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void (*func)(unsigned long ip,
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unsigned long parent_ip,
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void **data);
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int (*callback)(unsigned long ip, void **data);
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void (*free)(void **data);
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int (*print)(struct seq_file *m,
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unsigned long ip,
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struct ftrace_probe_ops *ops,
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void *data);
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};
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extern int
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register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
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void *data);
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extern void
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unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
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void *data);
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extern void
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unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
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extern void unregister_ftrace_function_probe_all(char *glob);
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extern int ftrace_text_reserved(void *start, void *end);
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enum {
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FTRACE_FL_FREE = (1 << 0),
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FTRACE_FL_FAILED = (1 << 1),
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FTRACE_FL_FILTER = (1 << 2),
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FTRACE_FL_ENABLED = (1 << 3),
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FTRACE_FL_NOTRACE = (1 << 4),
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FTRACE_FL_CONVERTED = (1 << 5),
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};
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struct dyn_ftrace {
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union {
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unsigned long ip; /* address of mcount call-site */
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struct dyn_ftrace *freelist;
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};
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union {
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unsigned long flags;
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struct dyn_ftrace *newlist;
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};
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struct dyn_arch_ftrace arch;
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};
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int ftrace_force_update(void);
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void ftrace_set_filter(unsigned char *buf, int len, int reset);
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int register_ftrace_command(struct ftrace_func_command *cmd);
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int unregister_ftrace_command(struct ftrace_func_command *cmd);
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/* defined in arch */
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extern int ftrace_ip_converted(unsigned long ip);
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extern int ftrace_dyn_arch_init(void *data);
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extern int ftrace_update_ftrace_func(ftrace_func_t func);
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extern void ftrace_caller(void);
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extern void ftrace_call(void);
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extern void mcount_call(void);
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#ifndef FTRACE_ADDR
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#define FTRACE_ADDR ((unsigned long)ftrace_caller)
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#endif
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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extern void ftrace_graph_caller(void);
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extern int ftrace_enable_ftrace_graph_caller(void);
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extern int ftrace_disable_ftrace_graph_caller(void);
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#else
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static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
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static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
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#endif
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/**
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* ftrace_make_nop - convert code into nop
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* @mod: module structure if called by module load initialization
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* @rec: the mcount call site record
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* @addr: the address that the call site should be calling
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*
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* This is a very sensitive operation and great care needs
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* to be taken by the arch. The operation should carefully
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* read the location, check to see if what is read is indeed
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* what we expect it to be, and then on success of the compare,
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* it should write to the location.
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*
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* The code segment at @rec->ip should be a caller to @addr
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*
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* Return must be:
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* 0 on success
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* -EFAULT on error reading the location
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* -EINVAL on a failed compare of the contents
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* -EPERM on error writing to the location
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* Any other value will be considered a failure.
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*/
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extern int ftrace_make_nop(struct module *mod,
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struct dyn_ftrace *rec, unsigned long addr);
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/**
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* ftrace_make_call - convert a nop call site into a call to addr
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* @rec: the mcount call site record
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* @addr: the address that the call site should call
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*
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* This is a very sensitive operation and great care needs
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* to be taken by the arch. The operation should carefully
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* read the location, check to see if what is read is indeed
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* what we expect it to be, and then on success of the compare,
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* it should write to the location.
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*
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* The code segment at @rec->ip should be a nop
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*
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* Return must be:
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* 0 on success
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* -EFAULT on error reading the location
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* -EINVAL on a failed compare of the contents
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* -EPERM on error writing to the location
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* Any other value will be considered a failure.
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*/
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extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
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/* May be defined in arch */
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extern int ftrace_arch_read_dyn_info(char *buf, int size);
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extern int skip_trace(unsigned long ip);
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extern void ftrace_disable_daemon(void);
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extern void ftrace_enable_daemon(void);
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#else
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static inline int skip_trace(unsigned long ip) { return 0; }
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static inline int ftrace_force_update(void) { return 0; }
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static inline void ftrace_set_filter(unsigned char *buf, int len, int reset)
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{
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}
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static inline void ftrace_disable_daemon(void) { }
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static inline void ftrace_enable_daemon(void) { }
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static inline void ftrace_release_mod(struct module *mod) {}
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static inline int register_ftrace_command(struct ftrace_func_command *cmd)
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{
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return -EINVAL;
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}
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static inline int unregister_ftrace_command(char *cmd_name)
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{
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return -EINVAL;
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}
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static inline int ftrace_text_reserved(void *start, void *end)
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{
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return 0;
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}
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#endif /* CONFIG_DYNAMIC_FTRACE */
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/* totally disable ftrace - can not re-enable after this */
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void ftrace_kill(void);
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static inline void tracer_disable(void)
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{
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#ifdef CONFIG_FUNCTION_TRACER
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ftrace_enabled = 0;
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#endif
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}
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/*
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* Ftrace disable/restore without lock. Some synchronization mechanism
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* must be used to prevent ftrace_enabled to be changed between
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* disable/restore.
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*/
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static inline int __ftrace_enabled_save(void)
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{
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#ifdef CONFIG_FUNCTION_TRACER
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int saved_ftrace_enabled = ftrace_enabled;
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ftrace_enabled = 0;
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return saved_ftrace_enabled;
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#else
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return 0;
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#endif
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}
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static inline void __ftrace_enabled_restore(int enabled)
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{
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#ifdef CONFIG_FUNCTION_TRACER
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ftrace_enabled = enabled;
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#endif
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}
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#ifndef HAVE_ARCH_CALLER_ADDR
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# ifdef CONFIG_FRAME_POINTER
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
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# define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
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# define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
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# define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
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# define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
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# define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
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# else
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# define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
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# define CALLER_ADDR1 0UL
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# define CALLER_ADDR2 0UL
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# define CALLER_ADDR3 0UL
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# define CALLER_ADDR4 0UL
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# define CALLER_ADDR5 0UL
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# define CALLER_ADDR6 0UL
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# endif
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#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
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#ifdef CONFIG_IRQSOFF_TRACER
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extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
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extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
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#else
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static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
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static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
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#endif
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#ifdef CONFIG_PREEMPT_TRACER
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extern void trace_preempt_on(unsigned long a0, unsigned long a1);
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extern void trace_preempt_off(unsigned long a0, unsigned long a1);
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#else
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static inline void trace_preempt_on(unsigned long a0, unsigned long a1) { }
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static inline void trace_preempt_off(unsigned long a0, unsigned long a1) { }
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#endif
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#ifdef CONFIG_FTRACE_MCOUNT_RECORD
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extern void ftrace_init(void);
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#else
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static inline void ftrace_init(void) { }
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#endif
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/*
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* Structure that defines an entry function trace.
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*/
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struct ftrace_graph_ent {
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unsigned long func; /* Current function */
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int depth;
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};
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/*
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* Structure that defines a return function trace.
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*/
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struct ftrace_graph_ret {
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unsigned long func; /* Current function */
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unsigned long long calltime;
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unsigned long long rettime;
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/* Number of functions that overran the depth limit for current task */
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unsigned long overrun;
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int depth;
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};
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/* Type of the callback handlers for tracing function graph*/
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typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
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typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* for init task */
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#define INIT_FTRACE_GRAPH .ret_stack = NULL,
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/*
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* Stack of return addresses for functions
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* of a thread.
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* Used in struct thread_info
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*/
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struct ftrace_ret_stack {
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unsigned long ret;
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unsigned long func;
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unsigned long long calltime;
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unsigned long long subtime;
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unsigned long fp;
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};
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/*
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* Primary handler of a function return.
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* It relays on ftrace_return_to_handler.
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* Defined in entry_32/64.S
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*/
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extern void return_to_handler(void);
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extern int
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ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
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unsigned long frame_pointer);
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/*
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* Sometimes we don't want to trace a function with the function
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* graph tracer but we want them to keep traced by the usual function
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* tracer if the function graph tracer is not configured.
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*/
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#define __notrace_funcgraph notrace
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/*
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* We want to which function is an entrypoint of a hardirq.
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* That will help us to put a signal on output.
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*/
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#define __irq_entry __attribute__((__section__(".irqentry.text")))
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/* Limits of hardirq entrypoints */
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extern char __irqentry_text_start[];
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extern char __irqentry_text_end[];
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#define FTRACE_RETFUNC_DEPTH 50
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#define FTRACE_RETSTACK_ALLOC_SIZE 32
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extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
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trace_func_graph_ent_t entryfunc);
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extern void ftrace_graph_stop(void);
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/* The current handlers in use */
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extern trace_func_graph_ret_t ftrace_graph_return;
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extern trace_func_graph_ent_t ftrace_graph_entry;
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extern void unregister_ftrace_graph(void);
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extern void ftrace_graph_init_task(struct task_struct *t);
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extern void ftrace_graph_exit_task(struct task_struct *t);
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extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
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static inline int task_curr_ret_stack(struct task_struct *t)
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{
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return t->curr_ret_stack;
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}
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static inline void pause_graph_tracing(void)
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{
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atomic_inc(¤t->tracing_graph_pause);
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}
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static inline void unpause_graph_tracing(void)
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{
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atomic_dec(¤t->tracing_graph_pause);
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}
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#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
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#define __notrace_funcgraph
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#define __irq_entry
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#define INIT_FTRACE_GRAPH
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static inline void ftrace_graph_init_task(struct task_struct *t) { }
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static inline void ftrace_graph_exit_task(struct task_struct *t) { }
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static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
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static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
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trace_func_graph_ent_t entryfunc)
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{
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return -1;
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}
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static inline void unregister_ftrace_graph(void) { }
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static inline int task_curr_ret_stack(struct task_struct *tsk)
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{
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return -1;
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}
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static inline void pause_graph_tracing(void) { }
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static inline void unpause_graph_tracing(void) { }
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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#ifdef CONFIG_TRACING
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/* flags for current->trace */
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enum {
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TSK_TRACE_FL_TRACE_BIT = 0,
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TSK_TRACE_FL_GRAPH_BIT = 1,
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};
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enum {
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TSK_TRACE_FL_TRACE = 1 << TSK_TRACE_FL_TRACE_BIT,
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TSK_TRACE_FL_GRAPH = 1 << TSK_TRACE_FL_GRAPH_BIT,
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};
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static inline void set_tsk_trace_trace(struct task_struct *tsk)
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{
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set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
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|
}
|
|
|
|
static inline void clear_tsk_trace_trace(struct task_struct *tsk)
|
|
{
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|
clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
|
|
}
|
|
|
|
static inline int test_tsk_trace_trace(struct task_struct *tsk)
|
|
{
|
|
return tsk->trace & TSK_TRACE_FL_TRACE;
|
|
}
|
|
|
|
static inline void set_tsk_trace_graph(struct task_struct *tsk)
|
|
{
|
|
set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
|
|
}
|
|
|
|
static inline void clear_tsk_trace_graph(struct task_struct *tsk)
|
|
{
|
|
clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
|
|
}
|
|
|
|
static inline int test_tsk_trace_graph(struct task_struct *tsk)
|
|
{
|
|
return tsk->trace & TSK_TRACE_FL_GRAPH;
|
|
}
|
|
|
|
enum ftrace_dump_mode;
|
|
|
|
extern enum ftrace_dump_mode ftrace_dump_on_oops;
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
#define INIT_TRACE_RECURSION .trace_recursion = 0,
|
|
#endif
|
|
|
|
#endif /* CONFIG_TRACING */
|
|
|
|
#ifndef INIT_TRACE_RECURSION
|
|
#define INIT_TRACE_RECURSION
|
|
#endif
|
|
|
|
#ifdef CONFIG_FTRACE_SYSCALLS
|
|
|
|
unsigned long arch_syscall_addr(int nr);
|
|
|
|
#endif /* CONFIG_FTRACE_SYSCALLS */
|
|
|
|
#endif /* _LINUX_FTRACE_H */
|