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The ftrace_preempt_disable/enable functions were to address a recursive race caused by the function tracer. The function tracer traces all functions which makes it easily susceptible to recursion. One area was preempt_enable(). This would call the scheduler and the schedulre would call the function tracer and loop. (So was it thought). The ftrace_preempt_disable/enable was made to protect against recursion inside the scheduler by storing the NEED_RESCHED flag. If it was set before the ftrace_preempt_disable() it would not call schedule on ftrace_preempt_enable(), thinking that if it was set before then it would have already scheduled unless it was already in the scheduler. This worked fine except in the case of SMP, where another task would set the NEED_RESCHED flag for a task on another CPU, and then kick off an IPI to trigger it. This could cause the NEED_RESCHED to be saved at ftrace_preempt_disable() but the IPI to arrive in the the preempt disabled section. The ftrace_preempt_enable() would not call the scheduler because the flag was already set before entring the section. This bug would cause a missed preemption check and cause lower latencies. Investigating further, I found that the recusion caused by the function tracer was not due to schedule(), but due to preempt_schedule(). Now that preempt_schedule is completely annotated with notrace, the recusion no longer is an issue. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
3413 lines
71 KiB
C
3413 lines
71 KiB
C
/*
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* Infrastructure for profiling code inserted by 'gcc -pg'.
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*
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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* Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
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*
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* Originally ported from the -rt patch by:
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* Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
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*
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* Based on code in the latency_tracer, that is:
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*
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* Copyright (C) 2004-2006 Ingo Molnar
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* Copyright (C) 2004 William Lee Irwin III
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*/
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#include <linux/stop_machine.h>
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#include <linux/clocksource.h>
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#include <linux/kallsyms.h>
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#include <linux/seq_file.h>
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#include <linux/suspend.h>
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#include <linux/debugfs.h>
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#include <linux/hardirq.h>
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#include <linux/kthread.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/sysctl.h>
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#include <linux/slab.h>
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#include <linux/ctype.h>
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#include <linux/list.h>
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#include <linux/hash.h>
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#include <linux/rcupdate.h>
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#include <trace/events/sched.h>
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#include <asm/ftrace.h>
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#include <asm/setup.h>
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#include "trace_output.h"
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#include "trace_stat.h"
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#define FTRACE_WARN_ON(cond) \
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do { \
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if (WARN_ON(cond)) \
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ftrace_kill(); \
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} while (0)
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#define FTRACE_WARN_ON_ONCE(cond) \
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do { \
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if (WARN_ON_ONCE(cond)) \
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ftrace_kill(); \
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} while (0)
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/* hash bits for specific function selection */
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#define FTRACE_HASH_BITS 7
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#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
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/* ftrace_enabled is a method to turn ftrace on or off */
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int ftrace_enabled __read_mostly;
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static int last_ftrace_enabled;
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/* Quick disabling of function tracer. */
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int function_trace_stop;
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/* List for set_ftrace_pid's pids. */
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LIST_HEAD(ftrace_pids);
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struct ftrace_pid {
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struct list_head list;
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struct pid *pid;
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};
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/*
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* ftrace_disabled is set when an anomaly is discovered.
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* ftrace_disabled is much stronger than ftrace_enabled.
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*/
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static int ftrace_disabled __read_mostly;
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static DEFINE_MUTEX(ftrace_lock);
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static struct ftrace_ops ftrace_list_end __read_mostly =
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{
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.func = ftrace_stub,
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};
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static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
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ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
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ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
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ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
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/*
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* Traverse the ftrace_list, invoking all entries. The reason that we
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* can use rcu_dereference_raw() is that elements removed from this list
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* are simply leaked, so there is no need to interact with a grace-period
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* mechanism. The rcu_dereference_raw() calls are needed to handle
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* concurrent insertions into the ftrace_list.
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*
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* Silly Alpha and silly pointer-speculation compiler optimizations!
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*/
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static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
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{
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struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
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while (op != &ftrace_list_end) {
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op->func(ip, parent_ip);
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op = rcu_dereference_raw(op->next); /*see above*/
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};
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}
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static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
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{
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if (!test_tsk_trace_trace(current))
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return;
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ftrace_pid_function(ip, parent_ip);
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}
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static void set_ftrace_pid_function(ftrace_func_t func)
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{
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/* do not set ftrace_pid_function to itself! */
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if (func != ftrace_pid_func)
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ftrace_pid_function = func;
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}
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/**
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* clear_ftrace_function - reset the ftrace function
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*
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* This NULLs the ftrace function and in essence stops
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* tracing. There may be lag
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*/
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void clear_ftrace_function(void)
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{
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ftrace_trace_function = ftrace_stub;
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__ftrace_trace_function = ftrace_stub;
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ftrace_pid_function = ftrace_stub;
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}
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#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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/*
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* For those archs that do not test ftrace_trace_stop in their
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* mcount call site, we need to do it from C.
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*/
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static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
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{
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if (function_trace_stop)
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return;
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__ftrace_trace_function(ip, parent_ip);
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}
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#endif
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static int __register_ftrace_function(struct ftrace_ops *ops)
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{
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ops->next = ftrace_list;
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/*
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* We are entering ops into the ftrace_list but another
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* CPU might be walking that list. We need to make sure
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* the ops->next pointer is valid before another CPU sees
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* the ops pointer included into the ftrace_list.
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*/
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rcu_assign_pointer(ftrace_list, ops);
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if (ftrace_enabled) {
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ftrace_func_t func;
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if (ops->next == &ftrace_list_end)
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func = ops->func;
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else
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func = ftrace_list_func;
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if (!list_empty(&ftrace_pids)) {
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set_ftrace_pid_function(func);
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func = ftrace_pid_func;
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}
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/*
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* For one func, simply call it directly.
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* For more than one func, call the chain.
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*/
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#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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ftrace_trace_function = func;
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#else
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__ftrace_trace_function = func;
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ftrace_trace_function = ftrace_test_stop_func;
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#endif
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}
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return 0;
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}
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static int __unregister_ftrace_function(struct ftrace_ops *ops)
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{
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struct ftrace_ops **p;
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/*
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* If we are removing the last function, then simply point
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* to the ftrace_stub.
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*/
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if (ftrace_list == ops && ops->next == &ftrace_list_end) {
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ftrace_trace_function = ftrace_stub;
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ftrace_list = &ftrace_list_end;
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return 0;
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}
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for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
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if (*p == ops)
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break;
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if (*p != ops)
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return -1;
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*p = (*p)->next;
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if (ftrace_enabled) {
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/* If we only have one func left, then call that directly */
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if (ftrace_list->next == &ftrace_list_end) {
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ftrace_func_t func = ftrace_list->func;
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if (!list_empty(&ftrace_pids)) {
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set_ftrace_pid_function(func);
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func = ftrace_pid_func;
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}
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#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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ftrace_trace_function = func;
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#else
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__ftrace_trace_function = func;
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#endif
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}
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}
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return 0;
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}
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static void ftrace_update_pid_func(void)
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{
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ftrace_func_t func;
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if (ftrace_trace_function == ftrace_stub)
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return;
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#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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func = ftrace_trace_function;
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#else
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func = __ftrace_trace_function;
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#endif
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if (!list_empty(&ftrace_pids)) {
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set_ftrace_pid_function(func);
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func = ftrace_pid_func;
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} else {
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if (func == ftrace_pid_func)
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func = ftrace_pid_function;
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}
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#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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ftrace_trace_function = func;
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#else
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__ftrace_trace_function = func;
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#endif
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}
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#ifdef CONFIG_FUNCTION_PROFILER
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struct ftrace_profile {
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struct hlist_node node;
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unsigned long ip;
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unsigned long counter;
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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unsigned long long time;
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unsigned long long time_squared;
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#endif
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};
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struct ftrace_profile_page {
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struct ftrace_profile_page *next;
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unsigned long index;
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struct ftrace_profile records[];
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};
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struct ftrace_profile_stat {
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atomic_t disabled;
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struct hlist_head *hash;
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struct ftrace_profile_page *pages;
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struct ftrace_profile_page *start;
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struct tracer_stat stat;
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};
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#define PROFILE_RECORDS_SIZE \
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(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
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#define PROFILES_PER_PAGE \
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(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
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static int ftrace_profile_bits __read_mostly;
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static int ftrace_profile_enabled __read_mostly;
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/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
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static DEFINE_MUTEX(ftrace_profile_lock);
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static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
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#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
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static void *
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function_stat_next(void *v, int idx)
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{
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struct ftrace_profile *rec = v;
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struct ftrace_profile_page *pg;
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pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
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again:
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if (idx != 0)
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rec++;
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if ((void *)rec >= (void *)&pg->records[pg->index]) {
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pg = pg->next;
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if (!pg)
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return NULL;
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rec = &pg->records[0];
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if (!rec->counter)
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goto again;
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}
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return rec;
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}
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static void *function_stat_start(struct tracer_stat *trace)
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{
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struct ftrace_profile_stat *stat =
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container_of(trace, struct ftrace_profile_stat, stat);
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if (!stat || !stat->start)
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return NULL;
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return function_stat_next(&stat->start->records[0], 0);
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}
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* function graph compares on total time */
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static int function_stat_cmp(void *p1, void *p2)
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{
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struct ftrace_profile *a = p1;
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struct ftrace_profile *b = p2;
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if (a->time < b->time)
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return -1;
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if (a->time > b->time)
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return 1;
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else
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return 0;
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}
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#else
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/* not function graph compares against hits */
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static int function_stat_cmp(void *p1, void *p2)
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{
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struct ftrace_profile *a = p1;
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struct ftrace_profile *b = p2;
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if (a->counter < b->counter)
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return -1;
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if (a->counter > b->counter)
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return 1;
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else
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return 0;
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}
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#endif
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static int function_stat_headers(struct seq_file *m)
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{
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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seq_printf(m, " Function "
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"Hit Time Avg s^2\n"
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" -------- "
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"--- ---- --- ---\n");
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#else
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seq_printf(m, " Function Hit\n"
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" -------- ---\n");
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#endif
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return 0;
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}
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static int function_stat_show(struct seq_file *m, void *v)
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{
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struct ftrace_profile *rec = v;
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char str[KSYM_SYMBOL_LEN];
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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static DEFINE_MUTEX(mutex);
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static struct trace_seq s;
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unsigned long long avg;
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unsigned long long stddev;
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#endif
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kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
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seq_printf(m, " %-30.30s %10lu", str, rec->counter);
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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seq_printf(m, " ");
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avg = rec->time;
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do_div(avg, rec->counter);
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/* Sample standard deviation (s^2) */
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if (rec->counter <= 1)
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stddev = 0;
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else {
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stddev = rec->time_squared - rec->counter * avg * avg;
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/*
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* Divide only 1000 for ns^2 -> us^2 conversion.
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* trace_print_graph_duration will divide 1000 again.
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*/
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do_div(stddev, (rec->counter - 1) * 1000);
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}
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mutex_lock(&mutex);
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trace_seq_init(&s);
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trace_print_graph_duration(rec->time, &s);
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trace_seq_puts(&s, " ");
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trace_print_graph_duration(avg, &s);
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trace_seq_puts(&s, " ");
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trace_print_graph_duration(stddev, &s);
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trace_print_seq(m, &s);
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mutex_unlock(&mutex);
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#endif
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seq_putc(m, '\n');
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return 0;
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}
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static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
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{
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struct ftrace_profile_page *pg;
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pg = stat->pages = stat->start;
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while (pg) {
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memset(pg->records, 0, PROFILE_RECORDS_SIZE);
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pg->index = 0;
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pg = pg->next;
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}
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memset(stat->hash, 0,
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FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
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}
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int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
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{
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struct ftrace_profile_page *pg;
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int functions;
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int pages;
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int i;
|
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|
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/* If we already allocated, do nothing */
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if (stat->pages)
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return 0;
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|
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stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
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if (!stat->pages)
|
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return -ENOMEM;
|
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|
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#ifdef CONFIG_DYNAMIC_FTRACE
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functions = ftrace_update_tot_cnt;
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#else
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/*
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* We do not know the number of functions that exist because
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* dynamic tracing is what counts them. With past experience
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* we have around 20K functions. That should be more than enough.
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* It is highly unlikely we will execute every function in
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* the kernel.
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*/
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functions = 20000;
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#endif
|
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pg = stat->start = stat->pages;
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pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
|
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|
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for (i = 0; i < pages; i++) {
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pg->next = (void *)get_zeroed_page(GFP_KERNEL);
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if (!pg->next)
|
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goto out_free;
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pg = pg->next;
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}
|
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|
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return 0;
|
|
|
|
out_free:
|
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pg = stat->start;
|
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while (pg) {
|
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unsigned long tmp = (unsigned long)pg;
|
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|
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pg = pg->next;
|
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free_page(tmp);
|
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}
|
|
|
|
free_page((unsigned long)stat->pages);
|
|
stat->pages = NULL;
|
|
stat->start = NULL;
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int ftrace_profile_init_cpu(int cpu)
|
|
{
|
|
struct ftrace_profile_stat *stat;
|
|
int size;
|
|
|
|
stat = &per_cpu(ftrace_profile_stats, cpu);
|
|
|
|
if (stat->hash) {
|
|
/* If the profile is already created, simply reset it */
|
|
ftrace_profile_reset(stat);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We are profiling all functions, but usually only a few thousand
|
|
* functions are hit. We'll make a hash of 1024 items.
|
|
*/
|
|
size = FTRACE_PROFILE_HASH_SIZE;
|
|
|
|
stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
|
|
|
|
if (!stat->hash)
|
|
return -ENOMEM;
|
|
|
|
if (!ftrace_profile_bits) {
|
|
size--;
|
|
|
|
for (; size; size >>= 1)
|
|
ftrace_profile_bits++;
|
|
}
|
|
|
|
/* Preallocate the function profiling pages */
|
|
if (ftrace_profile_pages_init(stat) < 0) {
|
|
kfree(stat->hash);
|
|
stat->hash = NULL;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ftrace_profile_init(void)
|
|
{
|
|
int cpu;
|
|
int ret = 0;
|
|
|
|
for_each_online_cpu(cpu) {
|
|
ret = ftrace_profile_init_cpu(cpu);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* interrupts must be disabled */
|
|
static struct ftrace_profile *
|
|
ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
|
|
{
|
|
struct ftrace_profile *rec;
|
|
struct hlist_head *hhd;
|
|
struct hlist_node *n;
|
|
unsigned long key;
|
|
|
|
key = hash_long(ip, ftrace_profile_bits);
|
|
hhd = &stat->hash[key];
|
|
|
|
if (hlist_empty(hhd))
|
|
return NULL;
|
|
|
|
hlist_for_each_entry_rcu(rec, n, hhd, node) {
|
|
if (rec->ip == ip)
|
|
return rec;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static void ftrace_add_profile(struct ftrace_profile_stat *stat,
|
|
struct ftrace_profile *rec)
|
|
{
|
|
unsigned long key;
|
|
|
|
key = hash_long(rec->ip, ftrace_profile_bits);
|
|
hlist_add_head_rcu(&rec->node, &stat->hash[key]);
|
|
}
|
|
|
|
/*
|
|
* The memory is already allocated, this simply finds a new record to use.
|
|
*/
|
|
static struct ftrace_profile *
|
|
ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
|
|
{
|
|
struct ftrace_profile *rec = NULL;
|
|
|
|
/* prevent recursion (from NMIs) */
|
|
if (atomic_inc_return(&stat->disabled) != 1)
|
|
goto out;
|
|
|
|
/*
|
|
* Try to find the function again since an NMI
|
|
* could have added it
|
|
*/
|
|
rec = ftrace_find_profiled_func(stat, ip);
|
|
if (rec)
|
|
goto out;
|
|
|
|
if (stat->pages->index == PROFILES_PER_PAGE) {
|
|
if (!stat->pages->next)
|
|
goto out;
|
|
stat->pages = stat->pages->next;
|
|
}
|
|
|
|
rec = &stat->pages->records[stat->pages->index++];
|
|
rec->ip = ip;
|
|
ftrace_add_profile(stat, rec);
|
|
|
|
out:
|
|
atomic_dec(&stat->disabled);
|
|
|
|
return rec;
|
|
}
|
|
|
|
static void
|
|
function_profile_call(unsigned long ip, unsigned long parent_ip)
|
|
{
|
|
struct ftrace_profile_stat *stat;
|
|
struct ftrace_profile *rec;
|
|
unsigned long flags;
|
|
|
|
if (!ftrace_profile_enabled)
|
|
return;
|
|
|
|
local_irq_save(flags);
|
|
|
|
stat = &__get_cpu_var(ftrace_profile_stats);
|
|
if (!stat->hash || !ftrace_profile_enabled)
|
|
goto out;
|
|
|
|
rec = ftrace_find_profiled_func(stat, ip);
|
|
if (!rec) {
|
|
rec = ftrace_profile_alloc(stat, ip);
|
|
if (!rec)
|
|
goto out;
|
|
}
|
|
|
|
rec->counter++;
|
|
out:
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
static int profile_graph_entry(struct ftrace_graph_ent *trace)
|
|
{
|
|
function_profile_call(trace->func, 0);
|
|
return 1;
|
|
}
|
|
|
|
static void profile_graph_return(struct ftrace_graph_ret *trace)
|
|
{
|
|
struct ftrace_profile_stat *stat;
|
|
unsigned long long calltime;
|
|
struct ftrace_profile *rec;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
stat = &__get_cpu_var(ftrace_profile_stats);
|
|
if (!stat->hash || !ftrace_profile_enabled)
|
|
goto out;
|
|
|
|
/* If the calltime was zero'd ignore it */
|
|
if (!trace->calltime)
|
|
goto out;
|
|
|
|
calltime = trace->rettime - trace->calltime;
|
|
|
|
if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
|
|
int index;
|
|
|
|
index = trace->depth;
|
|
|
|
/* Append this call time to the parent time to subtract */
|
|
if (index)
|
|
current->ret_stack[index - 1].subtime += calltime;
|
|
|
|
if (current->ret_stack[index].subtime < calltime)
|
|
calltime -= current->ret_stack[index].subtime;
|
|
else
|
|
calltime = 0;
|
|
}
|
|
|
|
rec = ftrace_find_profiled_func(stat, trace->func);
|
|
if (rec) {
|
|
rec->time += calltime;
|
|
rec->time_squared += calltime * calltime;
|
|
}
|
|
|
|
out:
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static int register_ftrace_profiler(void)
|
|
{
|
|
return register_ftrace_graph(&profile_graph_return,
|
|
&profile_graph_entry);
|
|
}
|
|
|
|
static void unregister_ftrace_profiler(void)
|
|
{
|
|
unregister_ftrace_graph();
|
|
}
|
|
#else
|
|
static struct ftrace_ops ftrace_profile_ops __read_mostly =
|
|
{
|
|
.func = function_profile_call,
|
|
};
|
|
|
|
static int register_ftrace_profiler(void)
|
|
{
|
|
return register_ftrace_function(&ftrace_profile_ops);
|
|
}
|
|
|
|
static void unregister_ftrace_profiler(void)
|
|
{
|
|
unregister_ftrace_function(&ftrace_profile_ops);
|
|
}
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
|
|
static ssize_t
|
|
ftrace_profile_write(struct file *filp, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
unsigned long val;
|
|
char buf[64]; /* big enough to hold a number */
|
|
int ret;
|
|
|
|
if (cnt >= sizeof(buf))
|
|
return -EINVAL;
|
|
|
|
if (copy_from_user(&buf, ubuf, cnt))
|
|
return -EFAULT;
|
|
|
|
buf[cnt] = 0;
|
|
|
|
ret = strict_strtoul(buf, 10, &val);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
val = !!val;
|
|
|
|
mutex_lock(&ftrace_profile_lock);
|
|
if (ftrace_profile_enabled ^ val) {
|
|
if (val) {
|
|
ret = ftrace_profile_init();
|
|
if (ret < 0) {
|
|
cnt = ret;
|
|
goto out;
|
|
}
|
|
|
|
ret = register_ftrace_profiler();
|
|
if (ret < 0) {
|
|
cnt = ret;
|
|
goto out;
|
|
}
|
|
ftrace_profile_enabled = 1;
|
|
} else {
|
|
ftrace_profile_enabled = 0;
|
|
/*
|
|
* unregister_ftrace_profiler calls stop_machine
|
|
* so this acts like an synchronize_sched.
|
|
*/
|
|
unregister_ftrace_profiler();
|
|
}
|
|
}
|
|
out:
|
|
mutex_unlock(&ftrace_profile_lock);
|
|
|
|
*ppos += cnt;
|
|
|
|
return cnt;
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_profile_read(struct file *filp, char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
char buf[64]; /* big enough to hold a number */
|
|
int r;
|
|
|
|
r = sprintf(buf, "%u\n", ftrace_profile_enabled);
|
|
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
|
|
}
|
|
|
|
static const struct file_operations ftrace_profile_fops = {
|
|
.open = tracing_open_generic,
|
|
.read = ftrace_profile_read,
|
|
.write = ftrace_profile_write,
|
|
};
|
|
|
|
/* used to initialize the real stat files */
|
|
static struct tracer_stat function_stats __initdata = {
|
|
.name = "functions",
|
|
.stat_start = function_stat_start,
|
|
.stat_next = function_stat_next,
|
|
.stat_cmp = function_stat_cmp,
|
|
.stat_headers = function_stat_headers,
|
|
.stat_show = function_stat_show
|
|
};
|
|
|
|
static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
|
|
{
|
|
struct ftrace_profile_stat *stat;
|
|
struct dentry *entry;
|
|
char *name;
|
|
int ret;
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
stat = &per_cpu(ftrace_profile_stats, cpu);
|
|
|
|
/* allocate enough for function name + cpu number */
|
|
name = kmalloc(32, GFP_KERNEL);
|
|
if (!name) {
|
|
/*
|
|
* The files created are permanent, if something happens
|
|
* we still do not free memory.
|
|
*/
|
|
WARN(1,
|
|
"Could not allocate stat file for cpu %d\n",
|
|
cpu);
|
|
return;
|
|
}
|
|
stat->stat = function_stats;
|
|
snprintf(name, 32, "function%d", cpu);
|
|
stat->stat.name = name;
|
|
ret = register_stat_tracer(&stat->stat);
|
|
if (ret) {
|
|
WARN(1,
|
|
"Could not register function stat for cpu %d\n",
|
|
cpu);
|
|
kfree(name);
|
|
return;
|
|
}
|
|
}
|
|
|
|
entry = debugfs_create_file("function_profile_enabled", 0644,
|
|
d_tracer, NULL, &ftrace_profile_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'function_profile_enabled' entry\n");
|
|
}
|
|
|
|
#else /* CONFIG_FUNCTION_PROFILER */
|
|
static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
|
|
{
|
|
}
|
|
#endif /* CONFIG_FUNCTION_PROFILER */
|
|
|
|
static struct pid * const ftrace_swapper_pid = &init_struct_pid;
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
|
|
#ifndef CONFIG_FTRACE_MCOUNT_RECORD
|
|
# error Dynamic ftrace depends on MCOUNT_RECORD
|
|
#endif
|
|
|
|
static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
|
|
|
|
struct ftrace_func_probe {
|
|
struct hlist_node node;
|
|
struct ftrace_probe_ops *ops;
|
|
unsigned long flags;
|
|
unsigned long ip;
|
|
void *data;
|
|
struct rcu_head rcu;
|
|
};
|
|
|
|
enum {
|
|
FTRACE_ENABLE_CALLS = (1 << 0),
|
|
FTRACE_DISABLE_CALLS = (1 << 1),
|
|
FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
|
|
FTRACE_ENABLE_MCOUNT = (1 << 3),
|
|
FTRACE_DISABLE_MCOUNT = (1 << 4),
|
|
FTRACE_START_FUNC_RET = (1 << 5),
|
|
FTRACE_STOP_FUNC_RET = (1 << 6),
|
|
};
|
|
|
|
static int ftrace_filtered;
|
|
|
|
static struct dyn_ftrace *ftrace_new_addrs;
|
|
|
|
static DEFINE_MUTEX(ftrace_regex_lock);
|
|
|
|
struct ftrace_page {
|
|
struct ftrace_page *next;
|
|
int index;
|
|
struct dyn_ftrace records[];
|
|
};
|
|
|
|
#define ENTRIES_PER_PAGE \
|
|
((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
|
|
|
|
/* estimate from running different kernels */
|
|
#define NR_TO_INIT 10000
|
|
|
|
static struct ftrace_page *ftrace_pages_start;
|
|
static struct ftrace_page *ftrace_pages;
|
|
|
|
static struct dyn_ftrace *ftrace_free_records;
|
|
|
|
/*
|
|
* This is a double for. Do not use 'break' to break out of the loop,
|
|
* you must use a goto.
|
|
*/
|
|
#define do_for_each_ftrace_rec(pg, rec) \
|
|
for (pg = ftrace_pages_start; pg; pg = pg->next) { \
|
|
int _____i; \
|
|
for (_____i = 0; _____i < pg->index; _____i++) { \
|
|
rec = &pg->records[_____i];
|
|
|
|
#define while_for_each_ftrace_rec() \
|
|
} \
|
|
}
|
|
|
|
static void ftrace_free_rec(struct dyn_ftrace *rec)
|
|
{
|
|
rec->freelist = ftrace_free_records;
|
|
ftrace_free_records = rec;
|
|
rec->flags |= FTRACE_FL_FREE;
|
|
}
|
|
|
|
static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
|
|
{
|
|
struct dyn_ftrace *rec;
|
|
|
|
/* First check for freed records */
|
|
if (ftrace_free_records) {
|
|
rec = ftrace_free_records;
|
|
|
|
if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
|
|
FTRACE_WARN_ON_ONCE(1);
|
|
ftrace_free_records = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
ftrace_free_records = rec->freelist;
|
|
memset(rec, 0, sizeof(*rec));
|
|
return rec;
|
|
}
|
|
|
|
if (ftrace_pages->index == ENTRIES_PER_PAGE) {
|
|
if (!ftrace_pages->next) {
|
|
/* allocate another page */
|
|
ftrace_pages->next =
|
|
(void *)get_zeroed_page(GFP_KERNEL);
|
|
if (!ftrace_pages->next)
|
|
return NULL;
|
|
}
|
|
ftrace_pages = ftrace_pages->next;
|
|
}
|
|
|
|
return &ftrace_pages->records[ftrace_pages->index++];
|
|
}
|
|
|
|
static struct dyn_ftrace *
|
|
ftrace_record_ip(unsigned long ip)
|
|
{
|
|
struct dyn_ftrace *rec;
|
|
|
|
if (ftrace_disabled)
|
|
return NULL;
|
|
|
|
rec = ftrace_alloc_dyn_node(ip);
|
|
if (!rec)
|
|
return NULL;
|
|
|
|
rec->ip = ip;
|
|
rec->newlist = ftrace_new_addrs;
|
|
ftrace_new_addrs = rec;
|
|
|
|
return rec;
|
|
}
|
|
|
|
static void print_ip_ins(const char *fmt, unsigned char *p)
|
|
{
|
|
int i;
|
|
|
|
printk(KERN_CONT "%s", fmt);
|
|
|
|
for (i = 0; i < MCOUNT_INSN_SIZE; i++)
|
|
printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
|
|
}
|
|
|
|
static void ftrace_bug(int failed, unsigned long ip)
|
|
{
|
|
switch (failed) {
|
|
case -EFAULT:
|
|
FTRACE_WARN_ON_ONCE(1);
|
|
pr_info("ftrace faulted on modifying ");
|
|
print_ip_sym(ip);
|
|
break;
|
|
case -EINVAL:
|
|
FTRACE_WARN_ON_ONCE(1);
|
|
pr_info("ftrace failed to modify ");
|
|
print_ip_sym(ip);
|
|
print_ip_ins(" actual: ", (unsigned char *)ip);
|
|
printk(KERN_CONT "\n");
|
|
break;
|
|
case -EPERM:
|
|
FTRACE_WARN_ON_ONCE(1);
|
|
pr_info("ftrace faulted on writing ");
|
|
print_ip_sym(ip);
|
|
break;
|
|
default:
|
|
FTRACE_WARN_ON_ONCE(1);
|
|
pr_info("ftrace faulted on unknown error ");
|
|
print_ip_sym(ip);
|
|
}
|
|
}
|
|
|
|
|
|
/* Return 1 if the address range is reserved for ftrace */
|
|
int ftrace_text_reserved(void *start, void *end)
|
|
{
|
|
struct dyn_ftrace *rec;
|
|
struct ftrace_page *pg;
|
|
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
if (rec->ip <= (unsigned long)end &&
|
|
rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
|
|
return 1;
|
|
} while_for_each_ftrace_rec();
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int
|
|
__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
|
|
{
|
|
unsigned long ftrace_addr;
|
|
unsigned long flag = 0UL;
|
|
|
|
ftrace_addr = (unsigned long)FTRACE_ADDR;
|
|
|
|
/*
|
|
* If this record is not to be traced or we want to disable it,
|
|
* then disable it.
|
|
*
|
|
* If we want to enable it and filtering is off, then enable it.
|
|
*
|
|
* If we want to enable it and filtering is on, enable it only if
|
|
* it's filtered
|
|
*/
|
|
if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
|
|
if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
|
|
flag = FTRACE_FL_ENABLED;
|
|
}
|
|
|
|
/* If the state of this record hasn't changed, then do nothing */
|
|
if ((rec->flags & FTRACE_FL_ENABLED) == flag)
|
|
return 0;
|
|
|
|
if (flag) {
|
|
rec->flags |= FTRACE_FL_ENABLED;
|
|
return ftrace_make_call(rec, ftrace_addr);
|
|
}
|
|
|
|
rec->flags &= ~FTRACE_FL_ENABLED;
|
|
return ftrace_make_nop(NULL, rec, ftrace_addr);
|
|
}
|
|
|
|
static void ftrace_replace_code(int enable)
|
|
{
|
|
struct dyn_ftrace *rec;
|
|
struct ftrace_page *pg;
|
|
int failed;
|
|
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
/*
|
|
* Skip over free records, records that have
|
|
* failed and not converted.
|
|
*/
|
|
if (rec->flags & FTRACE_FL_FREE ||
|
|
rec->flags & FTRACE_FL_FAILED ||
|
|
!(rec->flags & FTRACE_FL_CONVERTED))
|
|
continue;
|
|
|
|
failed = __ftrace_replace_code(rec, enable);
|
|
if (failed) {
|
|
rec->flags |= FTRACE_FL_FAILED;
|
|
ftrace_bug(failed, rec->ip);
|
|
/* Stop processing */
|
|
return;
|
|
}
|
|
} while_for_each_ftrace_rec();
|
|
}
|
|
|
|
static int
|
|
ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
|
|
{
|
|
unsigned long ip;
|
|
int ret;
|
|
|
|
ip = rec->ip;
|
|
|
|
ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
|
|
if (ret) {
|
|
ftrace_bug(ret, ip);
|
|
rec->flags |= FTRACE_FL_FAILED;
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* archs can override this function if they must do something
|
|
* before the modifying code is performed.
|
|
*/
|
|
int __weak ftrace_arch_code_modify_prepare(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* archs can override this function if they must do something
|
|
* after the modifying code is performed.
|
|
*/
|
|
int __weak ftrace_arch_code_modify_post_process(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static int __ftrace_modify_code(void *data)
|
|
{
|
|
int *command = data;
|
|
|
|
if (*command & FTRACE_ENABLE_CALLS)
|
|
ftrace_replace_code(1);
|
|
else if (*command & FTRACE_DISABLE_CALLS)
|
|
ftrace_replace_code(0);
|
|
|
|
if (*command & FTRACE_UPDATE_TRACE_FUNC)
|
|
ftrace_update_ftrace_func(ftrace_trace_function);
|
|
|
|
if (*command & FTRACE_START_FUNC_RET)
|
|
ftrace_enable_ftrace_graph_caller();
|
|
else if (*command & FTRACE_STOP_FUNC_RET)
|
|
ftrace_disable_ftrace_graph_caller();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void ftrace_run_update_code(int command)
|
|
{
|
|
int ret;
|
|
|
|
ret = ftrace_arch_code_modify_prepare();
|
|
FTRACE_WARN_ON(ret);
|
|
if (ret)
|
|
return;
|
|
|
|
stop_machine(__ftrace_modify_code, &command, NULL);
|
|
|
|
ret = ftrace_arch_code_modify_post_process();
|
|
FTRACE_WARN_ON(ret);
|
|
}
|
|
|
|
static ftrace_func_t saved_ftrace_func;
|
|
static int ftrace_start_up;
|
|
|
|
static void ftrace_startup_enable(int command)
|
|
{
|
|
if (saved_ftrace_func != ftrace_trace_function) {
|
|
saved_ftrace_func = ftrace_trace_function;
|
|
command |= FTRACE_UPDATE_TRACE_FUNC;
|
|
}
|
|
|
|
if (!command || !ftrace_enabled)
|
|
return;
|
|
|
|
ftrace_run_update_code(command);
|
|
}
|
|
|
|
static void ftrace_startup(int command)
|
|
{
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
ftrace_start_up++;
|
|
command |= FTRACE_ENABLE_CALLS;
|
|
|
|
ftrace_startup_enable(command);
|
|
}
|
|
|
|
static void ftrace_shutdown(int command)
|
|
{
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
ftrace_start_up--;
|
|
/*
|
|
* Just warn in case of unbalance, no need to kill ftrace, it's not
|
|
* critical but the ftrace_call callers may be never nopped again after
|
|
* further ftrace uses.
|
|
*/
|
|
WARN_ON_ONCE(ftrace_start_up < 0);
|
|
|
|
if (!ftrace_start_up)
|
|
command |= FTRACE_DISABLE_CALLS;
|
|
|
|
if (saved_ftrace_func != ftrace_trace_function) {
|
|
saved_ftrace_func = ftrace_trace_function;
|
|
command |= FTRACE_UPDATE_TRACE_FUNC;
|
|
}
|
|
|
|
if (!command || !ftrace_enabled)
|
|
return;
|
|
|
|
ftrace_run_update_code(command);
|
|
}
|
|
|
|
static void ftrace_startup_sysctl(void)
|
|
{
|
|
int command = FTRACE_ENABLE_MCOUNT;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
/* Force update next time */
|
|
saved_ftrace_func = NULL;
|
|
/* ftrace_start_up is true if we want ftrace running */
|
|
if (ftrace_start_up)
|
|
command |= FTRACE_ENABLE_CALLS;
|
|
|
|
ftrace_run_update_code(command);
|
|
}
|
|
|
|
static void ftrace_shutdown_sysctl(void)
|
|
{
|
|
int command = FTRACE_DISABLE_MCOUNT;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
/* ftrace_start_up is true if ftrace is running */
|
|
if (ftrace_start_up)
|
|
command |= FTRACE_DISABLE_CALLS;
|
|
|
|
ftrace_run_update_code(command);
|
|
}
|
|
|
|
static cycle_t ftrace_update_time;
|
|
static unsigned long ftrace_update_cnt;
|
|
unsigned long ftrace_update_tot_cnt;
|
|
|
|
static int ftrace_update_code(struct module *mod)
|
|
{
|
|
struct dyn_ftrace *p;
|
|
cycle_t start, stop;
|
|
|
|
start = ftrace_now(raw_smp_processor_id());
|
|
ftrace_update_cnt = 0;
|
|
|
|
while (ftrace_new_addrs) {
|
|
|
|
/* If something went wrong, bail without enabling anything */
|
|
if (unlikely(ftrace_disabled))
|
|
return -1;
|
|
|
|
p = ftrace_new_addrs;
|
|
ftrace_new_addrs = p->newlist;
|
|
p->flags = 0L;
|
|
|
|
/*
|
|
* Do the initial record convertion from mcount jump
|
|
* to the NOP instructions.
|
|
*/
|
|
if (!ftrace_code_disable(mod, p)) {
|
|
ftrace_free_rec(p);
|
|
continue;
|
|
}
|
|
|
|
p->flags |= FTRACE_FL_CONVERTED;
|
|
ftrace_update_cnt++;
|
|
|
|
/*
|
|
* If the tracing is enabled, go ahead and enable the record.
|
|
*
|
|
* The reason not to enable the record immediatelly is the
|
|
* inherent check of ftrace_make_nop/ftrace_make_call for
|
|
* correct previous instructions. Making first the NOP
|
|
* conversion puts the module to the correct state, thus
|
|
* passing the ftrace_make_call check.
|
|
*/
|
|
if (ftrace_start_up) {
|
|
int failed = __ftrace_replace_code(p, 1);
|
|
if (failed) {
|
|
ftrace_bug(failed, p->ip);
|
|
ftrace_free_rec(p);
|
|
}
|
|
}
|
|
}
|
|
|
|
stop = ftrace_now(raw_smp_processor_id());
|
|
ftrace_update_time = stop - start;
|
|
ftrace_update_tot_cnt += ftrace_update_cnt;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
|
|
{
|
|
struct ftrace_page *pg;
|
|
int cnt;
|
|
int i;
|
|
|
|
/* allocate a few pages */
|
|
ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
|
|
if (!ftrace_pages_start)
|
|
return -1;
|
|
|
|
/*
|
|
* Allocate a few more pages.
|
|
*
|
|
* TODO: have some parser search vmlinux before
|
|
* final linking to find all calls to ftrace.
|
|
* Then we can:
|
|
* a) know how many pages to allocate.
|
|
* and/or
|
|
* b) set up the table then.
|
|
*
|
|
* The dynamic code is still necessary for
|
|
* modules.
|
|
*/
|
|
|
|
pg = ftrace_pages = ftrace_pages_start;
|
|
|
|
cnt = num_to_init / ENTRIES_PER_PAGE;
|
|
pr_info("ftrace: allocating %ld entries in %d pages\n",
|
|
num_to_init, cnt + 1);
|
|
|
|
for (i = 0; i < cnt; i++) {
|
|
pg->next = (void *)get_zeroed_page(GFP_KERNEL);
|
|
|
|
/* If we fail, we'll try later anyway */
|
|
if (!pg->next)
|
|
break;
|
|
|
|
pg = pg->next;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
enum {
|
|
FTRACE_ITER_FILTER = (1 << 0),
|
|
FTRACE_ITER_NOTRACE = (1 << 1),
|
|
FTRACE_ITER_FAILURES = (1 << 2),
|
|
FTRACE_ITER_PRINTALL = (1 << 3),
|
|
FTRACE_ITER_HASH = (1 << 4),
|
|
};
|
|
|
|
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
|
|
|
|
struct ftrace_iterator {
|
|
struct ftrace_page *pg;
|
|
int hidx;
|
|
int idx;
|
|
unsigned flags;
|
|
struct trace_parser parser;
|
|
};
|
|
|
|
static void *
|
|
t_hash_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
struct hlist_node *hnd = v;
|
|
struct hlist_head *hhd;
|
|
|
|
WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
|
|
|
|
(*pos)++;
|
|
|
|
retry:
|
|
if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
|
|
return NULL;
|
|
|
|
hhd = &ftrace_func_hash[iter->hidx];
|
|
|
|
if (hlist_empty(hhd)) {
|
|
iter->hidx++;
|
|
hnd = NULL;
|
|
goto retry;
|
|
}
|
|
|
|
if (!hnd)
|
|
hnd = hhd->first;
|
|
else {
|
|
hnd = hnd->next;
|
|
if (!hnd) {
|
|
iter->hidx++;
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
return hnd;
|
|
}
|
|
|
|
static void *t_hash_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
void *p = NULL;
|
|
loff_t l;
|
|
|
|
if (!(iter->flags & FTRACE_ITER_HASH))
|
|
*pos = 0;
|
|
|
|
iter->flags |= FTRACE_ITER_HASH;
|
|
|
|
iter->hidx = 0;
|
|
for (l = 0; l <= *pos; ) {
|
|
p = t_hash_next(m, p, &l);
|
|
if (!p)
|
|
break;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
static int t_hash_show(struct seq_file *m, void *v)
|
|
{
|
|
struct ftrace_func_probe *rec;
|
|
struct hlist_node *hnd = v;
|
|
|
|
rec = hlist_entry(hnd, struct ftrace_func_probe, node);
|
|
|
|
if (rec->ops->print)
|
|
return rec->ops->print(m, rec->ip, rec->ops, rec->data);
|
|
|
|
seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
|
|
|
|
if (rec->data)
|
|
seq_printf(m, ":%p", rec->data);
|
|
seq_putc(m, '\n');
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void *
|
|
t_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
struct dyn_ftrace *rec = NULL;
|
|
|
|
if (iter->flags & FTRACE_ITER_HASH)
|
|
return t_hash_next(m, v, pos);
|
|
|
|
(*pos)++;
|
|
|
|
if (iter->flags & FTRACE_ITER_PRINTALL)
|
|
return NULL;
|
|
|
|
retry:
|
|
if (iter->idx >= iter->pg->index) {
|
|
if (iter->pg->next) {
|
|
iter->pg = iter->pg->next;
|
|
iter->idx = 0;
|
|
goto retry;
|
|
}
|
|
} else {
|
|
rec = &iter->pg->records[iter->idx++];
|
|
if ((rec->flags & FTRACE_FL_FREE) ||
|
|
|
|
(!(iter->flags & FTRACE_ITER_FAILURES) &&
|
|
(rec->flags & FTRACE_FL_FAILED)) ||
|
|
|
|
((iter->flags & FTRACE_ITER_FAILURES) &&
|
|
!(rec->flags & FTRACE_FL_FAILED)) ||
|
|
|
|
((iter->flags & FTRACE_ITER_FILTER) &&
|
|
!(rec->flags & FTRACE_FL_FILTER)) ||
|
|
|
|
((iter->flags & FTRACE_ITER_NOTRACE) &&
|
|
!(rec->flags & FTRACE_FL_NOTRACE))) {
|
|
rec = NULL;
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
return rec;
|
|
}
|
|
|
|
static void *t_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
void *p = NULL;
|
|
loff_t l;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
/*
|
|
* For set_ftrace_filter reading, if we have the filter
|
|
* off, we can short cut and just print out that all
|
|
* functions are enabled.
|
|
*/
|
|
if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
|
|
if (*pos > 0)
|
|
return t_hash_start(m, pos);
|
|
iter->flags |= FTRACE_ITER_PRINTALL;
|
|
return iter;
|
|
}
|
|
|
|
if (iter->flags & FTRACE_ITER_HASH)
|
|
return t_hash_start(m, pos);
|
|
|
|
iter->pg = ftrace_pages_start;
|
|
iter->idx = 0;
|
|
for (l = 0; l <= *pos; ) {
|
|
p = t_next(m, p, &l);
|
|
if (!p)
|
|
break;
|
|
}
|
|
|
|
if (!p && iter->flags & FTRACE_ITER_FILTER)
|
|
return t_hash_start(m, pos);
|
|
|
|
return p;
|
|
}
|
|
|
|
static void t_stop(struct seq_file *m, void *p)
|
|
{
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static int t_show(struct seq_file *m, void *v)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
struct dyn_ftrace *rec = v;
|
|
|
|
if (iter->flags & FTRACE_ITER_HASH)
|
|
return t_hash_show(m, v);
|
|
|
|
if (iter->flags & FTRACE_ITER_PRINTALL) {
|
|
seq_printf(m, "#### all functions enabled ####\n");
|
|
return 0;
|
|
}
|
|
|
|
if (!rec)
|
|
return 0;
|
|
|
|
seq_printf(m, "%ps\n", (void *)rec->ip);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations show_ftrace_seq_ops = {
|
|
.start = t_start,
|
|
.next = t_next,
|
|
.stop = t_stop,
|
|
.show = t_show,
|
|
};
|
|
|
|
static int
|
|
ftrace_avail_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct ftrace_iterator *iter;
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
|
|
iter->pg = ftrace_pages_start;
|
|
|
|
ret = seq_open(file, &show_ftrace_seq_ops);
|
|
if (!ret) {
|
|
struct seq_file *m = file->private_data;
|
|
|
|
m->private = iter;
|
|
} else {
|
|
kfree(iter);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
ftrace_failures_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret;
|
|
struct seq_file *m;
|
|
struct ftrace_iterator *iter;
|
|
|
|
ret = ftrace_avail_open(inode, file);
|
|
if (!ret) {
|
|
m = (struct seq_file *)file->private_data;
|
|
iter = (struct ftrace_iterator *)m->private;
|
|
iter->flags = FTRACE_ITER_FAILURES;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
static void ftrace_filter_reset(int enable)
|
|
{
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
if (enable)
|
|
ftrace_filtered = 0;
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
rec->flags &= ~type;
|
|
} while_for_each_ftrace_rec();
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static int
|
|
ftrace_regex_open(struct inode *inode, struct file *file, int enable)
|
|
{
|
|
struct ftrace_iterator *iter;
|
|
int ret = 0;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
|
|
if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
|
|
kfree(iter);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if ((file->f_mode & FMODE_WRITE) &&
|
|
(file->f_flags & O_TRUNC))
|
|
ftrace_filter_reset(enable);
|
|
|
|
if (file->f_mode & FMODE_READ) {
|
|
iter->pg = ftrace_pages_start;
|
|
iter->flags = enable ? FTRACE_ITER_FILTER :
|
|
FTRACE_ITER_NOTRACE;
|
|
|
|
ret = seq_open(file, &show_ftrace_seq_ops);
|
|
if (!ret) {
|
|
struct seq_file *m = file->private_data;
|
|
m->private = iter;
|
|
} else {
|
|
trace_parser_put(&iter->parser);
|
|
kfree(iter);
|
|
}
|
|
} else
|
|
file->private_data = iter;
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
ftrace_filter_open(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_open(inode, file, 1);
|
|
}
|
|
|
|
static int
|
|
ftrace_notrace_open(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_open(inode, file, 0);
|
|
}
|
|
|
|
static loff_t
|
|
ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
|
|
{
|
|
loff_t ret;
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
ret = seq_lseek(file, offset, origin);
|
|
else
|
|
file->f_pos = ret = 1;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int ftrace_match(char *str, char *regex, int len, int type)
|
|
{
|
|
int matched = 0;
|
|
int slen;
|
|
|
|
switch (type) {
|
|
case MATCH_FULL:
|
|
if (strcmp(str, regex) == 0)
|
|
matched = 1;
|
|
break;
|
|
case MATCH_FRONT_ONLY:
|
|
if (strncmp(str, regex, len) == 0)
|
|
matched = 1;
|
|
break;
|
|
case MATCH_MIDDLE_ONLY:
|
|
if (strstr(str, regex))
|
|
matched = 1;
|
|
break;
|
|
case MATCH_END_ONLY:
|
|
slen = strlen(str);
|
|
if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
|
|
matched = 1;
|
|
break;
|
|
}
|
|
|
|
return matched;
|
|
}
|
|
|
|
static int
|
|
ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
|
|
{
|
|
char str[KSYM_SYMBOL_LEN];
|
|
|
|
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
|
|
return ftrace_match(str, regex, len, type);
|
|
}
|
|
|
|
static int ftrace_match_records(char *buff, int len, int enable)
|
|
{
|
|
unsigned int search_len;
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
unsigned long flag;
|
|
char *search;
|
|
int type;
|
|
int not;
|
|
int found = 0;
|
|
|
|
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
|
|
type = filter_parse_regex(buff, len, &search, ¬);
|
|
|
|
search_len = strlen(search);
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
|
|
if (ftrace_match_record(rec, search, search_len, type)) {
|
|
if (not)
|
|
rec->flags &= ~flag;
|
|
else
|
|
rec->flags |= flag;
|
|
found = 1;
|
|
}
|
|
/*
|
|
* Only enable filtering if we have a function that
|
|
* is filtered on.
|
|
*/
|
|
if (enable && (rec->flags & FTRACE_FL_FILTER))
|
|
ftrace_filtered = 1;
|
|
} while_for_each_ftrace_rec();
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
return found;
|
|
}
|
|
|
|
static int
|
|
ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
|
|
char *regex, int len, int type)
|
|
{
|
|
char str[KSYM_SYMBOL_LEN];
|
|
char *modname;
|
|
|
|
kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
|
|
|
|
if (!modname || strcmp(modname, mod))
|
|
return 0;
|
|
|
|
/* blank search means to match all funcs in the mod */
|
|
if (len)
|
|
return ftrace_match(str, regex, len, type);
|
|
else
|
|
return 1;
|
|
}
|
|
|
|
static int ftrace_match_module_records(char *buff, char *mod, int enable)
|
|
{
|
|
unsigned search_len = 0;
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
int type = MATCH_FULL;
|
|
char *search = buff;
|
|
unsigned long flag;
|
|
int not = 0;
|
|
int found = 0;
|
|
|
|
flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
|
|
|
|
/* blank or '*' mean the same */
|
|
if (strcmp(buff, "*") == 0)
|
|
buff[0] = 0;
|
|
|
|
/* handle the case of 'dont filter this module' */
|
|
if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
|
|
buff[0] = 0;
|
|
not = 1;
|
|
}
|
|
|
|
if (strlen(buff)) {
|
|
type = filter_parse_regex(buff, strlen(buff), &search, ¬);
|
|
search_len = strlen(search);
|
|
}
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
|
|
if (ftrace_match_module_record(rec, mod,
|
|
search, search_len, type)) {
|
|
if (not)
|
|
rec->flags &= ~flag;
|
|
else
|
|
rec->flags |= flag;
|
|
found = 1;
|
|
}
|
|
if (enable && (rec->flags & FTRACE_FL_FILTER))
|
|
ftrace_filtered = 1;
|
|
|
|
} while_for_each_ftrace_rec();
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
return found;
|
|
}
|
|
|
|
/*
|
|
* We register the module command as a template to show others how
|
|
* to register the a command as well.
|
|
*/
|
|
|
|
static int
|
|
ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
|
|
{
|
|
char *mod;
|
|
|
|
/*
|
|
* cmd == 'mod' because we only registered this func
|
|
* for the 'mod' ftrace_func_command.
|
|
* But if you register one func with multiple commands,
|
|
* you can tell which command was used by the cmd
|
|
* parameter.
|
|
*/
|
|
|
|
/* we must have a module name */
|
|
if (!param)
|
|
return -EINVAL;
|
|
|
|
mod = strsep(¶m, ":");
|
|
if (!strlen(mod))
|
|
return -EINVAL;
|
|
|
|
if (ftrace_match_module_records(func, mod, enable))
|
|
return 0;
|
|
return -EINVAL;
|
|
}
|
|
|
|
static struct ftrace_func_command ftrace_mod_cmd = {
|
|
.name = "mod",
|
|
.func = ftrace_mod_callback,
|
|
};
|
|
|
|
static int __init ftrace_mod_cmd_init(void)
|
|
{
|
|
return register_ftrace_command(&ftrace_mod_cmd);
|
|
}
|
|
device_initcall(ftrace_mod_cmd_init);
|
|
|
|
static void
|
|
function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
|
|
{
|
|
struct ftrace_func_probe *entry;
|
|
struct hlist_head *hhd;
|
|
struct hlist_node *n;
|
|
unsigned long key;
|
|
|
|
key = hash_long(ip, FTRACE_HASH_BITS);
|
|
|
|
hhd = &ftrace_func_hash[key];
|
|
|
|
if (hlist_empty(hhd))
|
|
return;
|
|
|
|
/*
|
|
* Disable preemption for these calls to prevent a RCU grace
|
|
* period. This syncs the hash iteration and freeing of items
|
|
* on the hash. rcu_read_lock is too dangerous here.
|
|
*/
|
|
preempt_disable_notrace();
|
|
hlist_for_each_entry_rcu(entry, n, hhd, node) {
|
|
if (entry->ip == ip)
|
|
entry->ops->func(ip, parent_ip, &entry->data);
|
|
}
|
|
preempt_enable_notrace();
|
|
}
|
|
|
|
static struct ftrace_ops trace_probe_ops __read_mostly =
|
|
{
|
|
.func = function_trace_probe_call,
|
|
};
|
|
|
|
static int ftrace_probe_registered;
|
|
|
|
static void __enable_ftrace_function_probe(void)
|
|
{
|
|
int i;
|
|
|
|
if (ftrace_probe_registered)
|
|
return;
|
|
|
|
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
|
|
struct hlist_head *hhd = &ftrace_func_hash[i];
|
|
if (hhd->first)
|
|
break;
|
|
}
|
|
/* Nothing registered? */
|
|
if (i == FTRACE_FUNC_HASHSIZE)
|
|
return;
|
|
|
|
__register_ftrace_function(&trace_probe_ops);
|
|
ftrace_startup(0);
|
|
ftrace_probe_registered = 1;
|
|
}
|
|
|
|
static void __disable_ftrace_function_probe(void)
|
|
{
|
|
int i;
|
|
|
|
if (!ftrace_probe_registered)
|
|
return;
|
|
|
|
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
|
|
struct hlist_head *hhd = &ftrace_func_hash[i];
|
|
if (hhd->first)
|
|
return;
|
|
}
|
|
|
|
/* no more funcs left */
|
|
__unregister_ftrace_function(&trace_probe_ops);
|
|
ftrace_shutdown(0);
|
|
ftrace_probe_registered = 0;
|
|
}
|
|
|
|
|
|
static void ftrace_free_entry_rcu(struct rcu_head *rhp)
|
|
{
|
|
struct ftrace_func_probe *entry =
|
|
container_of(rhp, struct ftrace_func_probe, rcu);
|
|
|
|
if (entry->ops->free)
|
|
entry->ops->free(&entry->data);
|
|
kfree(entry);
|
|
}
|
|
|
|
|
|
int
|
|
register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
|
|
void *data)
|
|
{
|
|
struct ftrace_func_probe *entry;
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
int type, len, not;
|
|
unsigned long key;
|
|
int count = 0;
|
|
char *search;
|
|
|
|
type = filter_parse_regex(glob, strlen(glob), &search, ¬);
|
|
len = strlen(search);
|
|
|
|
/* we do not support '!' for function probes */
|
|
if (WARN_ON(not))
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
|
|
if (!ftrace_match_record(rec, search, len, type))
|
|
continue;
|
|
|
|
entry = kmalloc(sizeof(*entry), GFP_KERNEL);
|
|
if (!entry) {
|
|
/* If we did not process any, then return error */
|
|
if (!count)
|
|
count = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
count++;
|
|
|
|
entry->data = data;
|
|
|
|
/*
|
|
* The caller might want to do something special
|
|
* for each function we find. We call the callback
|
|
* to give the caller an opportunity to do so.
|
|
*/
|
|
if (ops->callback) {
|
|
if (ops->callback(rec->ip, &entry->data) < 0) {
|
|
/* caller does not like this func */
|
|
kfree(entry);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
entry->ops = ops;
|
|
entry->ip = rec->ip;
|
|
|
|
key = hash_long(entry->ip, FTRACE_HASH_BITS);
|
|
hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
|
|
|
|
} while_for_each_ftrace_rec();
|
|
__enable_ftrace_function_probe();
|
|
|
|
out_unlock:
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
return count;
|
|
}
|
|
|
|
enum {
|
|
PROBE_TEST_FUNC = 1,
|
|
PROBE_TEST_DATA = 2
|
|
};
|
|
|
|
static void
|
|
__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
|
|
void *data, int flags)
|
|
{
|
|
struct ftrace_func_probe *entry;
|
|
struct hlist_node *n, *tmp;
|
|
char str[KSYM_SYMBOL_LEN];
|
|
int type = MATCH_FULL;
|
|
int i, len = 0;
|
|
char *search;
|
|
|
|
if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
|
|
glob = NULL;
|
|
else if (glob) {
|
|
int not;
|
|
|
|
type = filter_parse_regex(glob, strlen(glob), &search, ¬);
|
|
len = strlen(search);
|
|
|
|
/* we do not support '!' for function probes */
|
|
if (WARN_ON(not))
|
|
return;
|
|
}
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
|
|
struct hlist_head *hhd = &ftrace_func_hash[i];
|
|
|
|
hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
|
|
|
|
/* break up if statements for readability */
|
|
if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
|
|
continue;
|
|
|
|
if ((flags & PROBE_TEST_DATA) && entry->data != data)
|
|
continue;
|
|
|
|
/* do this last, since it is the most expensive */
|
|
if (glob) {
|
|
kallsyms_lookup(entry->ip, NULL, NULL,
|
|
NULL, str);
|
|
if (!ftrace_match(str, glob, len, type))
|
|
continue;
|
|
}
|
|
|
|
hlist_del(&entry->node);
|
|
call_rcu(&entry->rcu, ftrace_free_entry_rcu);
|
|
}
|
|
}
|
|
__disable_ftrace_function_probe();
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
void
|
|
unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
|
|
void *data)
|
|
{
|
|
__unregister_ftrace_function_probe(glob, ops, data,
|
|
PROBE_TEST_FUNC | PROBE_TEST_DATA);
|
|
}
|
|
|
|
void
|
|
unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
|
|
{
|
|
__unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
|
|
}
|
|
|
|
void unregister_ftrace_function_probe_all(char *glob)
|
|
{
|
|
__unregister_ftrace_function_probe(glob, NULL, NULL, 0);
|
|
}
|
|
|
|
static LIST_HEAD(ftrace_commands);
|
|
static DEFINE_MUTEX(ftrace_cmd_mutex);
|
|
|
|
int register_ftrace_command(struct ftrace_func_command *cmd)
|
|
{
|
|
struct ftrace_func_command *p;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&ftrace_cmd_mutex);
|
|
list_for_each_entry(p, &ftrace_commands, list) {
|
|
if (strcmp(cmd->name, p->name) == 0) {
|
|
ret = -EBUSY;
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
list_add(&cmd->list, &ftrace_commands);
|
|
out_unlock:
|
|
mutex_unlock(&ftrace_cmd_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int unregister_ftrace_command(struct ftrace_func_command *cmd)
|
|
{
|
|
struct ftrace_func_command *p, *n;
|
|
int ret = -ENODEV;
|
|
|
|
mutex_lock(&ftrace_cmd_mutex);
|
|
list_for_each_entry_safe(p, n, &ftrace_commands, list) {
|
|
if (strcmp(cmd->name, p->name) == 0) {
|
|
ret = 0;
|
|
list_del_init(&p->list);
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&ftrace_cmd_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int ftrace_process_regex(char *buff, int len, int enable)
|
|
{
|
|
char *func, *command, *next = buff;
|
|
struct ftrace_func_command *p;
|
|
int ret = -EINVAL;
|
|
|
|
func = strsep(&next, ":");
|
|
|
|
if (!next) {
|
|
if (ftrace_match_records(func, len, enable))
|
|
return 0;
|
|
return ret;
|
|
}
|
|
|
|
/* command found */
|
|
|
|
command = strsep(&next, ":");
|
|
|
|
mutex_lock(&ftrace_cmd_mutex);
|
|
list_for_each_entry(p, &ftrace_commands, list) {
|
|
if (strcmp(p->name, command) == 0) {
|
|
ret = p->func(func, command, next, enable);
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&ftrace_cmd_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_regex_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos, int enable)
|
|
{
|
|
struct ftrace_iterator *iter;
|
|
struct trace_parser *parser;
|
|
ssize_t ret, read;
|
|
|
|
if (!cnt)
|
|
return 0;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
|
|
if (file->f_mode & FMODE_READ) {
|
|
struct seq_file *m = file->private_data;
|
|
iter = m->private;
|
|
} else
|
|
iter = file->private_data;
|
|
|
|
parser = &iter->parser;
|
|
read = trace_get_user(parser, ubuf, cnt, ppos);
|
|
|
|
if (read >= 0 && trace_parser_loaded(parser) &&
|
|
!trace_parser_cont(parser)) {
|
|
ret = ftrace_process_regex(parser->buffer,
|
|
parser->idx, enable);
|
|
trace_parser_clear(parser);
|
|
if (ret)
|
|
goto out_unlock;
|
|
}
|
|
|
|
ret = read;
|
|
out_unlock:
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_filter_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_notrace_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
|
|
}
|
|
|
|
static void
|
|
ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
|
|
{
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if (reset)
|
|
ftrace_filter_reset(enable);
|
|
if (buf)
|
|
ftrace_match_records(buf, len, enable);
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
}
|
|
|
|
/**
|
|
* ftrace_set_filter - set a function to filter on in ftrace
|
|
* @buf - the string that holds the function filter text.
|
|
* @len - the length of the string.
|
|
* @reset - non zero to reset all filters before applying this filter.
|
|
*
|
|
* Filters denote which functions should be enabled when tracing is enabled.
|
|
* If @buf is NULL and reset is set, all functions will be enabled for tracing.
|
|
*/
|
|
void ftrace_set_filter(unsigned char *buf, int len, int reset)
|
|
{
|
|
ftrace_set_regex(buf, len, reset, 1);
|
|
}
|
|
|
|
/**
|
|
* ftrace_set_notrace - set a function to not trace in ftrace
|
|
* @buf - the string that holds the function notrace text.
|
|
* @len - the length of the string.
|
|
* @reset - non zero to reset all filters before applying this filter.
|
|
*
|
|
* Notrace Filters denote which functions should not be enabled when tracing
|
|
* is enabled. If @buf is NULL and reset is set, all functions will be enabled
|
|
* for tracing.
|
|
*/
|
|
void ftrace_set_notrace(unsigned char *buf, int len, int reset)
|
|
{
|
|
ftrace_set_regex(buf, len, reset, 0);
|
|
}
|
|
|
|
/*
|
|
* command line interface to allow users to set filters on boot up.
|
|
*/
|
|
#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
|
|
static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
|
|
static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
|
|
|
|
static int __init set_ftrace_notrace(char *str)
|
|
{
|
|
strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
|
|
return 1;
|
|
}
|
|
__setup("ftrace_notrace=", set_ftrace_notrace);
|
|
|
|
static int __init set_ftrace_filter(char *str)
|
|
{
|
|
strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
|
|
return 1;
|
|
}
|
|
__setup("ftrace_filter=", set_ftrace_filter);
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
|
|
static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
|
|
|
|
static int __init set_graph_function(char *str)
|
|
{
|
|
strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
|
|
return 1;
|
|
}
|
|
__setup("ftrace_graph_filter=", set_graph_function);
|
|
|
|
static void __init set_ftrace_early_graph(char *buf)
|
|
{
|
|
int ret;
|
|
char *func;
|
|
|
|
while (buf) {
|
|
func = strsep(&buf, ",");
|
|
/* we allow only one expression at a time */
|
|
ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
|
|
func);
|
|
if (ret)
|
|
printk(KERN_DEBUG "ftrace: function %s not "
|
|
"traceable\n", func);
|
|
}
|
|
}
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
|
|
static void __init set_ftrace_early_filter(char *buf, int enable)
|
|
{
|
|
char *func;
|
|
|
|
while (buf) {
|
|
func = strsep(&buf, ",");
|
|
ftrace_set_regex(func, strlen(func), 0, enable);
|
|
}
|
|
}
|
|
|
|
static void __init set_ftrace_early_filters(void)
|
|
{
|
|
if (ftrace_filter_buf[0])
|
|
set_ftrace_early_filter(ftrace_filter_buf, 1);
|
|
if (ftrace_notrace_buf[0])
|
|
set_ftrace_early_filter(ftrace_notrace_buf, 0);
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
if (ftrace_graph_buf[0])
|
|
set_ftrace_early_graph(ftrace_graph_buf);
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
}
|
|
|
|
static int
|
|
ftrace_regex_release(struct inode *inode, struct file *file, int enable)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
struct ftrace_iterator *iter;
|
|
struct trace_parser *parser;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if (file->f_mode & FMODE_READ) {
|
|
iter = m->private;
|
|
|
|
seq_release(inode, file);
|
|
} else
|
|
iter = file->private_data;
|
|
|
|
parser = &iter->parser;
|
|
if (trace_parser_loaded(parser)) {
|
|
parser->buffer[parser->idx] = 0;
|
|
ftrace_match_records(parser->buffer, parser->idx, enable);
|
|
}
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
if (ftrace_start_up && ftrace_enabled)
|
|
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
trace_parser_put(parser);
|
|
kfree(iter);
|
|
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ftrace_filter_release(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_release(inode, file, 1);
|
|
}
|
|
|
|
static int
|
|
ftrace_notrace_release(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_release(inode, file, 0);
|
|
}
|
|
|
|
static const struct file_operations ftrace_avail_fops = {
|
|
.open = ftrace_avail_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release_private,
|
|
};
|
|
|
|
static const struct file_operations ftrace_failures_fops = {
|
|
.open = ftrace_failures_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release_private,
|
|
};
|
|
|
|
static const struct file_operations ftrace_filter_fops = {
|
|
.open = ftrace_filter_open,
|
|
.read = seq_read,
|
|
.write = ftrace_filter_write,
|
|
.llseek = ftrace_regex_lseek,
|
|
.release = ftrace_filter_release,
|
|
};
|
|
|
|
static const struct file_operations ftrace_notrace_fops = {
|
|
.open = ftrace_notrace_open,
|
|
.read = seq_read,
|
|
.write = ftrace_notrace_write,
|
|
.llseek = ftrace_regex_lseek,
|
|
.release = ftrace_notrace_release,
|
|
};
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
|
|
static DEFINE_MUTEX(graph_lock);
|
|
|
|
int ftrace_graph_count;
|
|
int ftrace_graph_filter_enabled;
|
|
unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
|
|
|
|
static void *
|
|
__g_next(struct seq_file *m, loff_t *pos)
|
|
{
|
|
if (*pos >= ftrace_graph_count)
|
|
return NULL;
|
|
return &ftrace_graph_funcs[*pos];
|
|
}
|
|
|
|
static void *
|
|
g_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
(*pos)++;
|
|
return __g_next(m, pos);
|
|
}
|
|
|
|
static void *g_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
mutex_lock(&graph_lock);
|
|
|
|
/* Nothing, tell g_show to print all functions are enabled */
|
|
if (!ftrace_graph_filter_enabled && !*pos)
|
|
return (void *)1;
|
|
|
|
return __g_next(m, pos);
|
|
}
|
|
|
|
static void g_stop(struct seq_file *m, void *p)
|
|
{
|
|
mutex_unlock(&graph_lock);
|
|
}
|
|
|
|
static int g_show(struct seq_file *m, void *v)
|
|
{
|
|
unsigned long *ptr = v;
|
|
|
|
if (!ptr)
|
|
return 0;
|
|
|
|
if (ptr == (unsigned long *)1) {
|
|
seq_printf(m, "#### all functions enabled ####\n");
|
|
return 0;
|
|
}
|
|
|
|
seq_printf(m, "%ps\n", (void *)*ptr);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations ftrace_graph_seq_ops = {
|
|
.start = g_start,
|
|
.next = g_next,
|
|
.stop = g_stop,
|
|
.show = g_show,
|
|
};
|
|
|
|
static int
|
|
ftrace_graph_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
mutex_lock(&graph_lock);
|
|
if ((file->f_mode & FMODE_WRITE) &&
|
|
(file->f_flags & O_TRUNC)) {
|
|
ftrace_graph_filter_enabled = 0;
|
|
ftrace_graph_count = 0;
|
|
memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
|
|
}
|
|
mutex_unlock(&graph_lock);
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
ret = seq_open(file, &ftrace_graph_seq_ops);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
ftrace_graph_release(struct inode *inode, struct file *file)
|
|
{
|
|
if (file->f_mode & FMODE_READ)
|
|
seq_release(inode, file);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ftrace_set_func(unsigned long *array, int *idx, char *buffer)
|
|
{
|
|
struct dyn_ftrace *rec;
|
|
struct ftrace_page *pg;
|
|
int search_len;
|
|
int fail = 1;
|
|
int type, not;
|
|
char *search;
|
|
bool exists;
|
|
int i;
|
|
|
|
if (ftrace_disabled)
|
|
return -ENODEV;
|
|
|
|
/* decode regex */
|
|
type = filter_parse_regex(buffer, strlen(buffer), &search, ¬);
|
|
if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
|
|
return -EBUSY;
|
|
|
|
search_len = strlen(search);
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
|
|
if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
|
|
continue;
|
|
|
|
if (ftrace_match_record(rec, search, search_len, type)) {
|
|
/* if it is in the array */
|
|
exists = false;
|
|
for (i = 0; i < *idx; i++) {
|
|
if (array[i] == rec->ip) {
|
|
exists = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!not) {
|
|
fail = 0;
|
|
if (!exists) {
|
|
array[(*idx)++] = rec->ip;
|
|
if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
|
|
goto out;
|
|
}
|
|
} else {
|
|
if (exists) {
|
|
array[i] = array[--(*idx)];
|
|
array[*idx] = 0;
|
|
fail = 0;
|
|
}
|
|
}
|
|
}
|
|
} while_for_each_ftrace_rec();
|
|
out:
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
if (fail)
|
|
return -EINVAL;
|
|
|
|
ftrace_graph_filter_enabled = 1;
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_graph_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
struct trace_parser parser;
|
|
ssize_t read, ret;
|
|
|
|
if (!cnt)
|
|
return 0;
|
|
|
|
mutex_lock(&graph_lock);
|
|
|
|
if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
|
|
ret = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
read = trace_get_user(&parser, ubuf, cnt, ppos);
|
|
|
|
if (read >= 0 && trace_parser_loaded((&parser))) {
|
|
parser.buffer[parser.idx] = 0;
|
|
|
|
/* we allow only one expression at a time */
|
|
ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
|
|
parser.buffer);
|
|
if (ret)
|
|
goto out_free;
|
|
}
|
|
|
|
ret = read;
|
|
|
|
out_free:
|
|
trace_parser_put(&parser);
|
|
out_unlock:
|
|
mutex_unlock(&graph_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations ftrace_graph_fops = {
|
|
.open = ftrace_graph_open,
|
|
.read = seq_read,
|
|
.write = ftrace_graph_write,
|
|
.release = ftrace_graph_release,
|
|
};
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
|
|
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
|
|
{
|
|
|
|
trace_create_file("available_filter_functions", 0444,
|
|
d_tracer, NULL, &ftrace_avail_fops);
|
|
|
|
trace_create_file("failures", 0444,
|
|
d_tracer, NULL, &ftrace_failures_fops);
|
|
|
|
trace_create_file("set_ftrace_filter", 0644, d_tracer,
|
|
NULL, &ftrace_filter_fops);
|
|
|
|
trace_create_file("set_ftrace_notrace", 0644, d_tracer,
|
|
NULL, &ftrace_notrace_fops);
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
trace_create_file("set_graph_function", 0444, d_tracer,
|
|
NULL,
|
|
&ftrace_graph_fops);
|
|
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ftrace_process_locs(struct module *mod,
|
|
unsigned long *start,
|
|
unsigned long *end)
|
|
{
|
|
unsigned long *p;
|
|
unsigned long addr;
|
|
unsigned long flags;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
p = start;
|
|
while (p < end) {
|
|
addr = ftrace_call_adjust(*p++);
|
|
/*
|
|
* Some architecture linkers will pad between
|
|
* the different mcount_loc sections of different
|
|
* object files to satisfy alignments.
|
|
* Skip any NULL pointers.
|
|
*/
|
|
if (!addr)
|
|
continue;
|
|
ftrace_record_ip(addr);
|
|
}
|
|
|
|
/* disable interrupts to prevent kstop machine */
|
|
local_irq_save(flags);
|
|
ftrace_update_code(mod);
|
|
local_irq_restore(flags);
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_MODULES
|
|
void ftrace_release_mod(struct module *mod)
|
|
{
|
|
struct dyn_ftrace *rec;
|
|
struct ftrace_page *pg;
|
|
|
|
if (ftrace_disabled)
|
|
return;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
do_for_each_ftrace_rec(pg, rec) {
|
|
if (within_module_core(rec->ip, mod)) {
|
|
/*
|
|
* rec->ip is changed in ftrace_free_rec()
|
|
* It should not between s and e if record was freed.
|
|
*/
|
|
FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
|
|
ftrace_free_rec(rec);
|
|
}
|
|
} while_for_each_ftrace_rec();
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static void ftrace_init_module(struct module *mod,
|
|
unsigned long *start, unsigned long *end)
|
|
{
|
|
if (ftrace_disabled || start == end)
|
|
return;
|
|
ftrace_process_locs(mod, start, end);
|
|
}
|
|
|
|
static int ftrace_module_notify(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct module *mod = data;
|
|
|
|
switch (val) {
|
|
case MODULE_STATE_COMING:
|
|
ftrace_init_module(mod, mod->ftrace_callsites,
|
|
mod->ftrace_callsites +
|
|
mod->num_ftrace_callsites);
|
|
break;
|
|
case MODULE_STATE_GOING:
|
|
ftrace_release_mod(mod);
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#else
|
|
static int ftrace_module_notify(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_MODULES */
|
|
|
|
struct notifier_block ftrace_module_nb = {
|
|
.notifier_call = ftrace_module_notify,
|
|
.priority = 0,
|
|
};
|
|
|
|
extern unsigned long __start_mcount_loc[];
|
|
extern unsigned long __stop_mcount_loc[];
|
|
|
|
void __init ftrace_init(void)
|
|
{
|
|
unsigned long count, addr, flags;
|
|
int ret;
|
|
|
|
/* Keep the ftrace pointer to the stub */
|
|
addr = (unsigned long)ftrace_stub;
|
|
|
|
local_irq_save(flags);
|
|
ftrace_dyn_arch_init(&addr);
|
|
local_irq_restore(flags);
|
|
|
|
/* ftrace_dyn_arch_init places the return code in addr */
|
|
if (addr)
|
|
goto failed;
|
|
|
|
count = __stop_mcount_loc - __start_mcount_loc;
|
|
|
|
ret = ftrace_dyn_table_alloc(count);
|
|
if (ret)
|
|
goto failed;
|
|
|
|
last_ftrace_enabled = ftrace_enabled = 1;
|
|
|
|
ret = ftrace_process_locs(NULL,
|
|
__start_mcount_loc,
|
|
__stop_mcount_loc);
|
|
|
|
ret = register_module_notifier(&ftrace_module_nb);
|
|
if (ret)
|
|
pr_warning("Failed to register trace ftrace module notifier\n");
|
|
|
|
set_ftrace_early_filters();
|
|
|
|
return;
|
|
failed:
|
|
ftrace_disabled = 1;
|
|
}
|
|
|
|
#else
|
|
|
|
static int __init ftrace_nodyn_init(void)
|
|
{
|
|
ftrace_enabled = 1;
|
|
return 0;
|
|
}
|
|
device_initcall(ftrace_nodyn_init);
|
|
|
|
static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
|
|
static inline void ftrace_startup_enable(int command) { }
|
|
/* Keep as macros so we do not need to define the commands */
|
|
# define ftrace_startup(command) do { } while (0)
|
|
# define ftrace_shutdown(command) do { } while (0)
|
|
# define ftrace_startup_sysctl() do { } while (0)
|
|
# define ftrace_shutdown_sysctl() do { } while (0)
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
static void clear_ftrace_swapper(void)
|
|
{
|
|
struct task_struct *p;
|
|
int cpu;
|
|
|
|
get_online_cpus();
|
|
for_each_online_cpu(cpu) {
|
|
p = idle_task(cpu);
|
|
clear_tsk_trace_trace(p);
|
|
}
|
|
put_online_cpus();
|
|
}
|
|
|
|
static void set_ftrace_swapper(void)
|
|
{
|
|
struct task_struct *p;
|
|
int cpu;
|
|
|
|
get_online_cpus();
|
|
for_each_online_cpu(cpu) {
|
|
p = idle_task(cpu);
|
|
set_tsk_trace_trace(p);
|
|
}
|
|
put_online_cpus();
|
|
}
|
|
|
|
static void clear_ftrace_pid(struct pid *pid)
|
|
{
|
|
struct task_struct *p;
|
|
|
|
rcu_read_lock();
|
|
do_each_pid_task(pid, PIDTYPE_PID, p) {
|
|
clear_tsk_trace_trace(p);
|
|
} while_each_pid_task(pid, PIDTYPE_PID, p);
|
|
rcu_read_unlock();
|
|
|
|
put_pid(pid);
|
|
}
|
|
|
|
static void set_ftrace_pid(struct pid *pid)
|
|
{
|
|
struct task_struct *p;
|
|
|
|
rcu_read_lock();
|
|
do_each_pid_task(pid, PIDTYPE_PID, p) {
|
|
set_tsk_trace_trace(p);
|
|
} while_each_pid_task(pid, PIDTYPE_PID, p);
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static void clear_ftrace_pid_task(struct pid *pid)
|
|
{
|
|
if (pid == ftrace_swapper_pid)
|
|
clear_ftrace_swapper();
|
|
else
|
|
clear_ftrace_pid(pid);
|
|
}
|
|
|
|
static void set_ftrace_pid_task(struct pid *pid)
|
|
{
|
|
if (pid == ftrace_swapper_pid)
|
|
set_ftrace_swapper();
|
|
else
|
|
set_ftrace_pid(pid);
|
|
}
|
|
|
|
static int ftrace_pid_add(int p)
|
|
{
|
|
struct pid *pid;
|
|
struct ftrace_pid *fpid;
|
|
int ret = -EINVAL;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
|
|
if (!p)
|
|
pid = ftrace_swapper_pid;
|
|
else
|
|
pid = find_get_pid(p);
|
|
|
|
if (!pid)
|
|
goto out;
|
|
|
|
ret = 0;
|
|
|
|
list_for_each_entry(fpid, &ftrace_pids, list)
|
|
if (fpid->pid == pid)
|
|
goto out_put;
|
|
|
|
ret = -ENOMEM;
|
|
|
|
fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
|
|
if (!fpid)
|
|
goto out_put;
|
|
|
|
list_add(&fpid->list, &ftrace_pids);
|
|
fpid->pid = pid;
|
|
|
|
set_ftrace_pid_task(pid);
|
|
|
|
ftrace_update_pid_func();
|
|
ftrace_startup_enable(0);
|
|
|
|
mutex_unlock(&ftrace_lock);
|
|
return 0;
|
|
|
|
out_put:
|
|
if (pid != ftrace_swapper_pid)
|
|
put_pid(pid);
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_lock);
|
|
return ret;
|
|
}
|
|
|
|
static void ftrace_pid_reset(void)
|
|
{
|
|
struct ftrace_pid *fpid, *safe;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
|
|
struct pid *pid = fpid->pid;
|
|
|
|
clear_ftrace_pid_task(pid);
|
|
|
|
list_del(&fpid->list);
|
|
kfree(fpid);
|
|
}
|
|
|
|
ftrace_update_pid_func();
|
|
ftrace_startup_enable(0);
|
|
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static void *fpid_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
mutex_lock(&ftrace_lock);
|
|
|
|
if (list_empty(&ftrace_pids) && (!*pos))
|
|
return (void *) 1;
|
|
|
|
return seq_list_start(&ftrace_pids, *pos);
|
|
}
|
|
|
|
static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
if (v == (void *)1)
|
|
return NULL;
|
|
|
|
return seq_list_next(v, &ftrace_pids, pos);
|
|
}
|
|
|
|
static void fpid_stop(struct seq_file *m, void *p)
|
|
{
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static int fpid_show(struct seq_file *m, void *v)
|
|
{
|
|
const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
|
|
|
|
if (v == (void *)1) {
|
|
seq_printf(m, "no pid\n");
|
|
return 0;
|
|
}
|
|
|
|
if (fpid->pid == ftrace_swapper_pid)
|
|
seq_printf(m, "swapper tasks\n");
|
|
else
|
|
seq_printf(m, "%u\n", pid_vnr(fpid->pid));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct seq_operations ftrace_pid_sops = {
|
|
.start = fpid_start,
|
|
.next = fpid_next,
|
|
.stop = fpid_stop,
|
|
.show = fpid_show,
|
|
};
|
|
|
|
static int
|
|
ftrace_pid_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret = 0;
|
|
|
|
if ((file->f_mode & FMODE_WRITE) &&
|
|
(file->f_flags & O_TRUNC))
|
|
ftrace_pid_reset();
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
ret = seq_open(file, &ftrace_pid_sops);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_pid_write(struct file *filp, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
char buf[64], *tmp;
|
|
long val;
|
|
int ret;
|
|
|
|
if (cnt >= sizeof(buf))
|
|
return -EINVAL;
|
|
|
|
if (copy_from_user(&buf, ubuf, cnt))
|
|
return -EFAULT;
|
|
|
|
buf[cnt] = 0;
|
|
|
|
/*
|
|
* Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
|
|
* to clean the filter quietly.
|
|
*/
|
|
tmp = strstrip(buf);
|
|
if (strlen(tmp) == 0)
|
|
return 1;
|
|
|
|
ret = strict_strtol(tmp, 10, &val);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
ret = ftrace_pid_add(val);
|
|
|
|
return ret ? ret : cnt;
|
|
}
|
|
|
|
static int
|
|
ftrace_pid_release(struct inode *inode, struct file *file)
|
|
{
|
|
if (file->f_mode & FMODE_READ)
|
|
seq_release(inode, file);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations ftrace_pid_fops = {
|
|
.open = ftrace_pid_open,
|
|
.write = ftrace_pid_write,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = ftrace_pid_release,
|
|
};
|
|
|
|
static __init int ftrace_init_debugfs(void)
|
|
{
|
|
struct dentry *d_tracer;
|
|
|
|
d_tracer = tracing_init_dentry();
|
|
if (!d_tracer)
|
|
return 0;
|
|
|
|
ftrace_init_dyn_debugfs(d_tracer);
|
|
|
|
trace_create_file("set_ftrace_pid", 0644, d_tracer,
|
|
NULL, &ftrace_pid_fops);
|
|
|
|
ftrace_profile_debugfs(d_tracer);
|
|
|
|
return 0;
|
|
}
|
|
fs_initcall(ftrace_init_debugfs);
|
|
|
|
/**
|
|
* ftrace_kill - kill ftrace
|
|
*
|
|
* This function should be used by panic code. It stops ftrace
|
|
* but in a not so nice way. If you need to simply kill ftrace
|
|
* from a non-atomic section, use ftrace_kill.
|
|
*/
|
|
void ftrace_kill(void)
|
|
{
|
|
ftrace_disabled = 1;
|
|
ftrace_enabled = 0;
|
|
clear_ftrace_function();
|
|
}
|
|
|
|
/**
|
|
* register_ftrace_function - register a function for profiling
|
|
* @ops - ops structure that holds the function for profiling.
|
|
*
|
|
* Register a function to be called by all functions in the
|
|
* kernel.
|
|
*
|
|
* Note: @ops->func and all the functions it calls must be labeled
|
|
* with "notrace", otherwise it will go into a
|
|
* recursive loop.
|
|
*/
|
|
int register_ftrace_function(struct ftrace_ops *ops)
|
|
{
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -1;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
|
|
ret = __register_ftrace_function(ops);
|
|
ftrace_startup(0);
|
|
|
|
mutex_unlock(&ftrace_lock);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* unregister_ftrace_function - unregister a function for profiling.
|
|
* @ops - ops structure that holds the function to unregister
|
|
*
|
|
* Unregister a function that was added to be called by ftrace profiling.
|
|
*/
|
|
int unregister_ftrace_function(struct ftrace_ops *ops)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
ret = __unregister_ftrace_function(ops);
|
|
ftrace_shutdown(0);
|
|
mutex_unlock(&ftrace_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
ftrace_enable_sysctl(struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *lenp,
|
|
loff_t *ppos)
|
|
{
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
|
|
ret = proc_dointvec(table, write, buffer, lenp, ppos);
|
|
|
|
if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
|
|
goto out;
|
|
|
|
last_ftrace_enabled = !!ftrace_enabled;
|
|
|
|
if (ftrace_enabled) {
|
|
|
|
ftrace_startup_sysctl();
|
|
|
|
/* we are starting ftrace again */
|
|
if (ftrace_list != &ftrace_list_end) {
|
|
if (ftrace_list->next == &ftrace_list_end)
|
|
ftrace_trace_function = ftrace_list->func;
|
|
else
|
|
ftrace_trace_function = ftrace_list_func;
|
|
}
|
|
|
|
} else {
|
|
/* stopping ftrace calls (just send to ftrace_stub) */
|
|
ftrace_trace_function = ftrace_stub;
|
|
|
|
ftrace_shutdown_sysctl();
|
|
}
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_lock);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
|
|
static int ftrace_graph_active;
|
|
static struct notifier_block ftrace_suspend_notifier;
|
|
|
|
int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/* The callbacks that hook a function */
|
|
trace_func_graph_ret_t ftrace_graph_return =
|
|
(trace_func_graph_ret_t)ftrace_stub;
|
|
trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
|
|
|
|
/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
|
|
static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
|
|
{
|
|
int i;
|
|
int ret = 0;
|
|
unsigned long flags;
|
|
int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
|
|
struct task_struct *g, *t;
|
|
|
|
for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
|
|
ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
|
|
* sizeof(struct ftrace_ret_stack),
|
|
GFP_KERNEL);
|
|
if (!ret_stack_list[i]) {
|
|
start = 0;
|
|
end = i;
|
|
ret = -ENOMEM;
|
|
goto free;
|
|
}
|
|
}
|
|
|
|
read_lock_irqsave(&tasklist_lock, flags);
|
|
do_each_thread(g, t) {
|
|
if (start == end) {
|
|
ret = -EAGAIN;
|
|
goto unlock;
|
|
}
|
|
|
|
if (t->ret_stack == NULL) {
|
|
atomic_set(&t->tracing_graph_pause, 0);
|
|
atomic_set(&t->trace_overrun, 0);
|
|
t->curr_ret_stack = -1;
|
|
/* Make sure the tasks see the -1 first: */
|
|
smp_wmb();
|
|
t->ret_stack = ret_stack_list[start++];
|
|
}
|
|
} while_each_thread(g, t);
|
|
|
|
unlock:
|
|
read_unlock_irqrestore(&tasklist_lock, flags);
|
|
free:
|
|
for (i = start; i < end; i++)
|
|
kfree(ret_stack_list[i]);
|
|
return ret;
|
|
}
|
|
|
|
static void
|
|
ftrace_graph_probe_sched_switch(void *ignore,
|
|
struct task_struct *prev, struct task_struct *next)
|
|
{
|
|
unsigned long long timestamp;
|
|
int index;
|
|
|
|
/*
|
|
* Does the user want to count the time a function was asleep.
|
|
* If so, do not update the time stamps.
|
|
*/
|
|
if (trace_flags & TRACE_ITER_SLEEP_TIME)
|
|
return;
|
|
|
|
timestamp = trace_clock_local();
|
|
|
|
prev->ftrace_timestamp = timestamp;
|
|
|
|
/* only process tasks that we timestamped */
|
|
if (!next->ftrace_timestamp)
|
|
return;
|
|
|
|
/*
|
|
* Update all the counters in next to make up for the
|
|
* time next was sleeping.
|
|
*/
|
|
timestamp -= next->ftrace_timestamp;
|
|
|
|
for (index = next->curr_ret_stack; index >= 0; index--)
|
|
next->ret_stack[index].calltime += timestamp;
|
|
}
|
|
|
|
/* Allocate a return stack for each task */
|
|
static int start_graph_tracing(void)
|
|
{
|
|
struct ftrace_ret_stack **ret_stack_list;
|
|
int ret, cpu;
|
|
|
|
ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
|
|
sizeof(struct ftrace_ret_stack *),
|
|
GFP_KERNEL);
|
|
|
|
if (!ret_stack_list)
|
|
return -ENOMEM;
|
|
|
|
/* The cpu_boot init_task->ret_stack will never be freed */
|
|
for_each_online_cpu(cpu) {
|
|
if (!idle_task(cpu)->ret_stack)
|
|
ftrace_graph_init_task(idle_task(cpu));
|
|
}
|
|
|
|
do {
|
|
ret = alloc_retstack_tasklist(ret_stack_list);
|
|
} while (ret == -EAGAIN);
|
|
|
|
if (!ret) {
|
|
ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
|
|
if (ret)
|
|
pr_info("ftrace_graph: Couldn't activate tracepoint"
|
|
" probe to kernel_sched_switch\n");
|
|
}
|
|
|
|
kfree(ret_stack_list);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Hibernation protection.
|
|
* The state of the current task is too much unstable during
|
|
* suspend/restore to disk. We want to protect against that.
|
|
*/
|
|
static int
|
|
ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
|
|
void *unused)
|
|
{
|
|
switch (state) {
|
|
case PM_HIBERNATION_PREPARE:
|
|
pause_graph_tracing();
|
|
break;
|
|
|
|
case PM_POST_HIBERNATION:
|
|
unpause_graph_tracing();
|
|
break;
|
|
}
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
int register_ftrace_graph(trace_func_graph_ret_t retfunc,
|
|
trace_func_graph_ent_t entryfunc)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&ftrace_lock);
|
|
|
|
/* we currently allow only one tracer registered at a time */
|
|
if (ftrace_graph_active) {
|
|
ret = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
|
|
register_pm_notifier(&ftrace_suspend_notifier);
|
|
|
|
ftrace_graph_active++;
|
|
ret = start_graph_tracing();
|
|
if (ret) {
|
|
ftrace_graph_active--;
|
|
goto out;
|
|
}
|
|
|
|
ftrace_graph_return = retfunc;
|
|
ftrace_graph_entry = entryfunc;
|
|
|
|
ftrace_startup(FTRACE_START_FUNC_RET);
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_lock);
|
|
return ret;
|
|
}
|
|
|
|
void unregister_ftrace_graph(void)
|
|
{
|
|
mutex_lock(&ftrace_lock);
|
|
|
|
if (unlikely(!ftrace_graph_active))
|
|
goto out;
|
|
|
|
ftrace_graph_active--;
|
|
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
|
|
ftrace_graph_entry = ftrace_graph_entry_stub;
|
|
ftrace_shutdown(FTRACE_STOP_FUNC_RET);
|
|
unregister_pm_notifier(&ftrace_suspend_notifier);
|
|
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_lock);
|
|
}
|
|
|
|
/* Allocate a return stack for newly created task */
|
|
void ftrace_graph_init_task(struct task_struct *t)
|
|
{
|
|
/* Make sure we do not use the parent ret_stack */
|
|
t->ret_stack = NULL;
|
|
t->curr_ret_stack = -1;
|
|
|
|
if (ftrace_graph_active) {
|
|
struct ftrace_ret_stack *ret_stack;
|
|
|
|
ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
|
|
* sizeof(struct ftrace_ret_stack),
|
|
GFP_KERNEL);
|
|
if (!ret_stack)
|
|
return;
|
|
atomic_set(&t->tracing_graph_pause, 0);
|
|
atomic_set(&t->trace_overrun, 0);
|
|
t->ftrace_timestamp = 0;
|
|
/* make curr_ret_stack visable before we add the ret_stack */
|
|
smp_wmb();
|
|
t->ret_stack = ret_stack;
|
|
}
|
|
}
|
|
|
|
void ftrace_graph_exit_task(struct task_struct *t)
|
|
{
|
|
struct ftrace_ret_stack *ret_stack = t->ret_stack;
|
|
|
|
t->ret_stack = NULL;
|
|
/* NULL must become visible to IRQs before we free it: */
|
|
barrier();
|
|
|
|
kfree(ret_stack);
|
|
}
|
|
|
|
void ftrace_graph_stop(void)
|
|
{
|
|
ftrace_stop();
|
|
}
|
|
#endif
|