![Steven Rostedt](/assets/img/avatar_default.png)
Impact: new ftrace_graph_stop function While developing more features of function graph, I hit a bug that caused the WARN_ON to trigger in the prepare_ftrace_return function. Well, it was hard for me to find out that was happening because the bug would not print, it would just cause a hard lockup or reboot. The reason is that it is not safe to call printk from this function. Looking further, I also found that it calls unregister_ftrace_graph, which grabs a mutex and calls kstop machine. This would definitely lock the box up if it were to trigger. This patch adds a fast and safe ftrace_graph_stop() which will stop the function tracer. Then it is safe to call the WARN ON. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
1779 lines
37 KiB
C
1779 lines
37 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/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/kprobes.h>
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#include <linux/ftrace.h>
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#include <linux/sysctl.h>
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#include <linux/ctype.h>
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#include <linux/list.h>
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#include <asm/ftrace.h>
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#include "trace.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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/* 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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/* ftrace_pid_trace >= 0 will only trace threads with this pid */
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static int ftrace_pid_trace = -1;
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/* Quick disabling of function tracer. */
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int function_trace_stop;
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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_SPINLOCK(ftrace_lock);
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static DEFINE_MUTEX(ftrace_sysctl_lock);
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static DEFINE_MUTEX(ftrace_start_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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static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
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{
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struct ftrace_ops *op = ftrace_list;
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/* in case someone actually ports this to alpha! */
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read_barrier_depends();
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while (op != &ftrace_list_end) {
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/* silly alpha */
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read_barrier_depends();
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op->func(ip, parent_ip);
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op = op->next;
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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 (current->pid != ftrace_pid_trace)
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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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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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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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smp_wmb();
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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 (ftrace_pid_trace >= 0) {
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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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spin_unlock(&ftrace_lock);
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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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int ret = 0;
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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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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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goto out;
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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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ret = -1;
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goto out;
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}
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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 (ftrace_pid_trace >= 0) {
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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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out:
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spin_unlock(&ftrace_lock);
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return ret;
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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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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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if (ftrace_trace_function == ftrace_stub)
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goto out;
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func = ftrace_trace_function;
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if (ftrace_pid_trace >= 0) {
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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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out:
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spin_unlock(&ftrace_lock);
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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#ifndef CONFIG_FTRACE_MCOUNT_RECORD
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# error Dynamic ftrace depends on MCOUNT_RECORD
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#endif
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/*
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* Since MCOUNT_ADDR may point to mcount itself, we do not want
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* to get it confused by reading a reference in the code as we
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* are parsing on objcopy output of text. Use a variable for
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* it instead.
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*/
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static unsigned long mcount_addr = MCOUNT_ADDR;
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enum {
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FTRACE_ENABLE_CALLS = (1 << 0),
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FTRACE_DISABLE_CALLS = (1 << 1),
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FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
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FTRACE_ENABLE_MCOUNT = (1 << 3),
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FTRACE_DISABLE_MCOUNT = (1 << 4),
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FTRACE_START_FUNC_RET = (1 << 5),
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FTRACE_STOP_FUNC_RET = (1 << 6),
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};
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static int ftrace_filtered;
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static LIST_HEAD(ftrace_new_addrs);
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static DEFINE_MUTEX(ftrace_regex_lock);
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struct ftrace_page {
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struct ftrace_page *next;
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unsigned long index;
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struct dyn_ftrace records[];
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};
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#define ENTRIES_PER_PAGE \
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((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
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/* estimate from running different kernels */
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#define NR_TO_INIT 10000
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static struct ftrace_page *ftrace_pages_start;
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static struct ftrace_page *ftrace_pages;
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static struct dyn_ftrace *ftrace_free_records;
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#ifdef CONFIG_KPROBES
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static int frozen_record_count;
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static inline void freeze_record(struct dyn_ftrace *rec)
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{
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if (!(rec->flags & FTRACE_FL_FROZEN)) {
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rec->flags |= FTRACE_FL_FROZEN;
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frozen_record_count++;
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}
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}
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static inline void unfreeze_record(struct dyn_ftrace *rec)
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{
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if (rec->flags & FTRACE_FL_FROZEN) {
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rec->flags &= ~FTRACE_FL_FROZEN;
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frozen_record_count--;
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}
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}
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static inline int record_frozen(struct dyn_ftrace *rec)
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{
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return rec->flags & FTRACE_FL_FROZEN;
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}
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#else
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# define freeze_record(rec) ({ 0; })
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# define unfreeze_record(rec) ({ 0; })
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# define record_frozen(rec) ({ 0; })
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#endif /* CONFIG_KPROBES */
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static void ftrace_free_rec(struct dyn_ftrace *rec)
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{
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rec->ip = (unsigned long)ftrace_free_records;
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ftrace_free_records = rec;
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rec->flags |= FTRACE_FL_FREE;
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}
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void ftrace_release(void *start, unsigned long size)
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{
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struct dyn_ftrace *rec;
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struct ftrace_page *pg;
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unsigned long s = (unsigned long)start;
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unsigned long e = s + size;
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int i;
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if (ftrace_disabled || !start)
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return;
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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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for (pg = ftrace_pages_start; pg; pg = pg->next) {
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for (i = 0; i < pg->index; i++) {
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rec = &pg->records[i];
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if ((rec->ip >= s) && (rec->ip < e))
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ftrace_free_rec(rec);
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}
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}
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spin_unlock(&ftrace_lock);
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}
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static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
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{
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struct dyn_ftrace *rec;
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/* First check for freed records */
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if (ftrace_free_records) {
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rec = ftrace_free_records;
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if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
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FTRACE_WARN_ON_ONCE(1);
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ftrace_free_records = NULL;
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return NULL;
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}
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ftrace_free_records = (void *)rec->ip;
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memset(rec, 0, sizeof(*rec));
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return rec;
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}
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if (ftrace_pages->index == ENTRIES_PER_PAGE) {
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if (!ftrace_pages->next) {
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/* allocate another page */
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ftrace_pages->next =
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(void *)get_zeroed_page(GFP_KERNEL);
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if (!ftrace_pages->next)
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return NULL;
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}
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ftrace_pages = ftrace_pages->next;
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}
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return &ftrace_pages->records[ftrace_pages->index++];
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}
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static struct dyn_ftrace *
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ftrace_record_ip(unsigned long ip)
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{
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struct dyn_ftrace *rec;
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if (ftrace_disabled)
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return NULL;
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rec = ftrace_alloc_dyn_node(ip);
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if (!rec)
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return NULL;
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rec->ip = ip;
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list_add(&rec->list, &ftrace_new_addrs);
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return rec;
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}
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static void print_ip_ins(const char *fmt, unsigned char *p)
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{
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int i;
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printk(KERN_CONT "%s", fmt);
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for (i = 0; i < MCOUNT_INSN_SIZE; i++)
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printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
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}
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static void ftrace_bug(int failed, unsigned long ip)
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{
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switch (failed) {
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case -EFAULT:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace faulted on modifying ");
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print_ip_sym(ip);
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break;
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case -EINVAL:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace failed to modify ");
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print_ip_sym(ip);
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print_ip_ins(" actual: ", (unsigned char *)ip);
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printk(KERN_CONT "\n");
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break;
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case -EPERM:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace faulted on writing ");
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print_ip_sym(ip);
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break;
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default:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace faulted on unknown error ");
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print_ip_sym(ip);
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}
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}
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static int
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__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
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{
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unsigned long ip, fl;
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unsigned long ftrace_addr;
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ftrace_addr = (unsigned long)ftrace_caller;
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ip = rec->ip;
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/*
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* If this record is not to be traced and
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* it is not enabled then do nothing.
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*
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* If this record is not to be traced and
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* it is enabled then disabled it.
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*
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*/
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if (rec->flags & FTRACE_FL_NOTRACE) {
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if (rec->flags & FTRACE_FL_ENABLED)
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rec->flags &= ~FTRACE_FL_ENABLED;
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else
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return 0;
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} else if (ftrace_filtered && enable) {
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/*
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* Filtering is on:
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*/
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fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
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/* Record is filtered and enabled, do nothing */
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if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
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return 0;
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/* Record is not filtered and is not enabled do nothing */
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if (!fl)
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return 0;
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/* Record is not filtered but enabled, disable it */
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if (fl == FTRACE_FL_ENABLED)
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rec->flags &= ~FTRACE_FL_ENABLED;
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else
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/* Otherwise record is filtered but not enabled, enable it */
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rec->flags |= FTRACE_FL_ENABLED;
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} else {
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/* Disable or not filtered */
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if (enable) {
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/* if record is enabled, do nothing */
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if (rec->flags & FTRACE_FL_ENABLED)
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return 0;
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rec->flags |= FTRACE_FL_ENABLED;
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} else {
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/* if record is not enabled do nothing */
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if (!(rec->flags & FTRACE_FL_ENABLED))
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return 0;
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rec->flags &= ~FTRACE_FL_ENABLED;
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}
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}
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if (rec->flags & FTRACE_FL_ENABLED)
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return ftrace_make_call(rec, ftrace_addr);
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else
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return ftrace_make_nop(NULL, rec, ftrace_addr);
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}
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|
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static void ftrace_replace_code(int enable)
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{
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int i, failed;
|
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struct dyn_ftrace *rec;
|
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struct ftrace_page *pg;
|
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|
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for (pg = ftrace_pages_start; pg; pg = pg->next) {
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for (i = 0; i < pg->index; i++) {
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rec = &pg->records[i];
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/*
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* Skip over free records and records that have
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* failed.
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*/
|
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if (rec->flags & FTRACE_FL_FREE ||
|
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rec->flags & FTRACE_FL_FAILED)
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continue;
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|
|
/* ignore updates to this record's mcount site */
|
|
if (get_kprobe((void *)rec->ip)) {
|
|
freeze_record(rec);
|
|
continue;
|
|
} else {
|
|
unfreeze_record(rec);
|
|
}
|
|
|
|
failed = __ftrace_replace_code(rec, enable);
|
|
if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
|
|
rec->flags |= FTRACE_FL_FAILED;
|
|
if ((system_state == SYSTEM_BOOTING) ||
|
|
!core_kernel_text(rec->ip)) {
|
|
ftrace_free_rec(rec);
|
|
} else
|
|
ftrace_bug(failed, rec->ip);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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)
|
|
{
|
|
stop_machine(__ftrace_modify_code, &command, NULL);
|
|
}
|
|
|
|
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;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
ftrace_start_up++;
|
|
command |= FTRACE_ENABLE_CALLS;
|
|
|
|
ftrace_startup_enable(command);
|
|
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static void ftrace_shutdown(int command)
|
|
{
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
ftrace_start_up--;
|
|
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)
|
|
goto out;
|
|
|
|
ftrace_run_update_code(command);
|
|
out:
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static void ftrace_startup_sysctl(void)
|
|
{
|
|
int command = FTRACE_ENABLE_MCOUNT;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
/* 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);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static void ftrace_shutdown_sysctl(void)
|
|
{
|
|
int command = FTRACE_DISABLE_MCOUNT;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
/* ftrace_start_up is true if ftrace is running */
|
|
if (ftrace_start_up)
|
|
command |= FTRACE_DISABLE_CALLS;
|
|
|
|
ftrace_run_update_code(command);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
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, *t;
|
|
cycle_t start, stop;
|
|
|
|
start = ftrace_now(raw_smp_processor_id());
|
|
ftrace_update_cnt = 0;
|
|
|
|
list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
|
|
|
|
/* If something went wrong, bail without enabling anything */
|
|
if (unlikely(ftrace_disabled))
|
|
return -1;
|
|
|
|
list_del_init(&p->list);
|
|
|
|
/* convert record (i.e, patch mcount-call with NOP) */
|
|
if (ftrace_code_disable(mod, p)) {
|
|
p->flags |= FTRACE_FL_CONVERTED;
|
|
ftrace_update_cnt++;
|
|
} else
|
|
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_CONT = (1 << 1),
|
|
FTRACE_ITER_NOTRACE = (1 << 2),
|
|
FTRACE_ITER_FAILURES = (1 << 3),
|
|
};
|
|
|
|
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
|
|
|
|
struct ftrace_iterator {
|
|
struct ftrace_page *pg;
|
|
unsigned idx;
|
|
unsigned flags;
|
|
unsigned char buffer[FTRACE_BUFF_MAX+1];
|
|
unsigned buffer_idx;
|
|
unsigned filtered;
|
|
};
|
|
|
|
static void *
|
|
t_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
struct dyn_ftrace *rec = NULL;
|
|
|
|
(*pos)++;
|
|
|
|
/* should not be called from interrupt context */
|
|
spin_lock(&ftrace_lock);
|
|
retry:
|
|
if (iter->idx >= iter->pg->index) {
|
|
if (iter->pg->next) {
|
|
iter->pg = iter->pg->next;
|
|
iter->idx = 0;
|
|
goto retry;
|
|
} else {
|
|
iter->idx = -1;
|
|
}
|
|
} 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;
|
|
}
|
|
}
|
|
spin_unlock(&ftrace_lock);
|
|
|
|
return rec;
|
|
}
|
|
|
|
static void *t_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
void *p = NULL;
|
|
|
|
if (*pos > 0) {
|
|
if (iter->idx < 0)
|
|
return p;
|
|
(*pos)--;
|
|
iter->idx--;
|
|
}
|
|
|
|
p = t_next(m, p, pos);
|
|
|
|
return p;
|
|
}
|
|
|
|
static void t_stop(struct seq_file *m, void *p)
|
|
{
|
|
}
|
|
|
|
static int t_show(struct seq_file *m, void *v)
|
|
{
|
|
struct dyn_ftrace *rec = v;
|
|
char str[KSYM_SYMBOL_LEN];
|
|
|
|
if (!rec)
|
|
return 0;
|
|
|
|
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
|
|
|
|
seq_printf(m, "%s\n", str);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static 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;
|
|
}
|
|
|
|
int ftrace_avail_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
struct ftrace_iterator *iter = m->private;
|
|
|
|
seq_release(inode, file);
|
|
kfree(iter);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
unsigned i;
|
|
|
|
/* should not be called from interrupt context */
|
|
spin_lock(&ftrace_lock);
|
|
if (enable)
|
|
ftrace_filtered = 0;
|
|
pg = ftrace_pages_start;
|
|
while (pg) {
|
|
for (i = 0; i < pg->index; i++) {
|
|
rec = &pg->records[i];
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
rec->flags &= ~type;
|
|
}
|
|
pg = pg->next;
|
|
}
|
|
spin_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;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if ((file->f_mode & FMODE_WRITE) &&
|
|
!(file->f_flags & O_APPEND))
|
|
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
|
|
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 ssize_t
|
|
ftrace_regex_read(struct file *file, char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
if (file->f_mode & FMODE_READ)
|
|
return seq_read(file, ubuf, cnt, ppos);
|
|
else
|
|
return -EPERM;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
enum {
|
|
MATCH_FULL,
|
|
MATCH_FRONT_ONLY,
|
|
MATCH_MIDDLE_ONLY,
|
|
MATCH_END_ONLY,
|
|
};
|
|
|
|
static void
|
|
ftrace_match(unsigned char *buff, int len, int enable)
|
|
{
|
|
char str[KSYM_SYMBOL_LEN];
|
|
char *search = NULL;
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
int type = MATCH_FULL;
|
|
unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
|
|
unsigned i, match = 0, search_len = 0;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
if (buff[i] == '*') {
|
|
if (!i) {
|
|
search = buff + i + 1;
|
|
type = MATCH_END_ONLY;
|
|
search_len = len - (i + 1);
|
|
} else {
|
|
if (type == MATCH_END_ONLY) {
|
|
type = MATCH_MIDDLE_ONLY;
|
|
} else {
|
|
match = i;
|
|
type = MATCH_FRONT_ONLY;
|
|
}
|
|
buff[i] = 0;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* should not be called from interrupt context */
|
|
spin_lock(&ftrace_lock);
|
|
if (enable)
|
|
ftrace_filtered = 1;
|
|
pg = ftrace_pages_start;
|
|
while (pg) {
|
|
for (i = 0; i < pg->index; i++) {
|
|
int matched = 0;
|
|
char *ptr;
|
|
|
|
rec = &pg->records[i];
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
|
|
switch (type) {
|
|
case MATCH_FULL:
|
|
if (strcmp(str, buff) == 0)
|
|
matched = 1;
|
|
break;
|
|
case MATCH_FRONT_ONLY:
|
|
if (memcmp(str, buff, match) == 0)
|
|
matched = 1;
|
|
break;
|
|
case MATCH_MIDDLE_ONLY:
|
|
if (strstr(str, search))
|
|
matched = 1;
|
|
break;
|
|
case MATCH_END_ONLY:
|
|
ptr = strstr(str, search);
|
|
if (ptr && (ptr[search_len] == 0))
|
|
matched = 1;
|
|
break;
|
|
}
|
|
if (matched)
|
|
rec->flags |= flag;
|
|
}
|
|
pg = pg->next;
|
|
}
|
|
spin_unlock(&ftrace_lock);
|
|
}
|
|
|
|
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;
|
|
char ch;
|
|
size_t read = 0;
|
|
ssize_t ret;
|
|
|
|
if (!cnt || cnt < 0)
|
|
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;
|
|
|
|
if (!*ppos) {
|
|
iter->flags &= ~FTRACE_ITER_CONT;
|
|
iter->buffer_idx = 0;
|
|
}
|
|
|
|
ret = get_user(ch, ubuf++);
|
|
if (ret)
|
|
goto out;
|
|
read++;
|
|
cnt--;
|
|
|
|
if (!(iter->flags & ~FTRACE_ITER_CONT)) {
|
|
/* skip white space */
|
|
while (cnt && isspace(ch)) {
|
|
ret = get_user(ch, ubuf++);
|
|
if (ret)
|
|
goto out;
|
|
read++;
|
|
cnt--;
|
|
}
|
|
|
|
if (isspace(ch)) {
|
|
file->f_pos += read;
|
|
ret = read;
|
|
goto out;
|
|
}
|
|
|
|
iter->buffer_idx = 0;
|
|
}
|
|
|
|
while (cnt && !isspace(ch)) {
|
|
if (iter->buffer_idx < FTRACE_BUFF_MAX)
|
|
iter->buffer[iter->buffer_idx++] = ch;
|
|
else {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
ret = get_user(ch, ubuf++);
|
|
if (ret)
|
|
goto out;
|
|
read++;
|
|
cnt--;
|
|
}
|
|
|
|
if (isspace(ch)) {
|
|
iter->filtered++;
|
|
iter->buffer[iter->buffer_idx] = 0;
|
|
ftrace_match(iter->buffer, iter->buffer_idx, enable);
|
|
iter->buffer_idx = 0;
|
|
} else
|
|
iter->flags |= FTRACE_ITER_CONT;
|
|
|
|
|
|
file->f_pos += read;
|
|
|
|
ret = read;
|
|
out:
|
|
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(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);
|
|
}
|
|
|
|
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;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if (file->f_mode & FMODE_READ) {
|
|
iter = m->private;
|
|
|
|
seq_release(inode, file);
|
|
} else
|
|
iter = file->private_data;
|
|
|
|
if (iter->buffer_idx) {
|
|
iter->filtered++;
|
|
iter->buffer[iter->buffer_idx] = 0;
|
|
ftrace_match(iter->buffer, iter->buffer_idx, enable);
|
|
}
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
mutex_lock(&ftrace_start_lock);
|
|
if (ftrace_start_up && ftrace_enabled)
|
|
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
|
|
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 struct file_operations ftrace_avail_fops = {
|
|
.open = ftrace_avail_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = ftrace_avail_release,
|
|
};
|
|
|
|
static struct file_operations ftrace_failures_fops = {
|
|
.open = ftrace_failures_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = ftrace_avail_release,
|
|
};
|
|
|
|
static struct file_operations ftrace_filter_fops = {
|
|
.open = ftrace_filter_open,
|
|
.read = ftrace_regex_read,
|
|
.write = ftrace_filter_write,
|
|
.llseek = ftrace_regex_lseek,
|
|
.release = ftrace_filter_release,
|
|
};
|
|
|
|
static struct file_operations ftrace_notrace_fops = {
|
|
.open = ftrace_notrace_open,
|
|
.read = ftrace_regex_read,
|
|
.write = ftrace_notrace_write,
|
|
.llseek = ftrace_regex_lseek,
|
|
.release = ftrace_notrace_release,
|
|
};
|
|
|
|
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
|
|
{
|
|
struct dentry *entry;
|
|
|
|
entry = debugfs_create_file("available_filter_functions", 0444,
|
|
d_tracer, NULL, &ftrace_avail_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'available_filter_functions' entry\n");
|
|
|
|
entry = debugfs_create_file("failures", 0444,
|
|
d_tracer, NULL, &ftrace_failures_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs 'failures' entry\n");
|
|
|
|
entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
|
|
NULL, &ftrace_filter_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'set_ftrace_filter' entry\n");
|
|
|
|
entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
|
|
NULL, &ftrace_notrace_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'set_ftrace_notrace' entry\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ftrace_convert_nops(struct module *mod,
|
|
unsigned long *start,
|
|
unsigned long *end)
|
|
{
|
|
unsigned long *p;
|
|
unsigned long addr;
|
|
unsigned long flags;
|
|
|
|
mutex_lock(&ftrace_start_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_start_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void ftrace_init_module(struct module *mod,
|
|
unsigned long *start, unsigned long *end)
|
|
{
|
|
if (ftrace_disabled || start == end)
|
|
return;
|
|
ftrace_convert_nops(mod, start, end);
|
|
}
|
|
|
|
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_convert_nops(NULL,
|
|
__start_mcount_loc,
|
|
__stop_mcount_loc);
|
|
|
|
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 ssize_t
|
|
ftrace_pid_read(struct file *file, char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
char buf[64];
|
|
int r;
|
|
|
|
if (ftrace_pid_trace >= 0)
|
|
r = sprintf(buf, "%u\n", ftrace_pid_trace);
|
|
else
|
|
r = sprintf(buf, "no pid\n");
|
|
|
|
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_pid_write(struct file *filp, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
char buf[64];
|
|
long val;
|
|
int ret;
|
|
|
|
if (cnt >= sizeof(buf))
|
|
return -EINVAL;
|
|
|
|
if (copy_from_user(&buf, ubuf, cnt))
|
|
return -EFAULT;
|
|
|
|
buf[cnt] = 0;
|
|
|
|
ret = strict_strtol(buf, 10, &val);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
if (ret < 0) {
|
|
/* disable pid tracing */
|
|
if (ftrace_pid_trace < 0)
|
|
goto out;
|
|
ftrace_pid_trace = -1;
|
|
|
|
} else {
|
|
|
|
if (ftrace_pid_trace == val)
|
|
goto out;
|
|
|
|
ftrace_pid_trace = val;
|
|
}
|
|
|
|
/* update the function call */
|
|
ftrace_update_pid_func();
|
|
ftrace_startup_enable(0);
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_start_lock);
|
|
|
|
return cnt;
|
|
}
|
|
|
|
static struct file_operations ftrace_pid_fops = {
|
|
.read = ftrace_pid_read,
|
|
.write = ftrace_pid_write,
|
|
};
|
|
|
|
static __init int ftrace_init_debugfs(void)
|
|
{
|
|
struct dentry *d_tracer;
|
|
struct dentry *entry;
|
|
|
|
d_tracer = tracing_init_dentry();
|
|
if (!d_tracer)
|
|
return 0;
|
|
|
|
ftrace_init_dyn_debugfs(d_tracer);
|
|
|
|
entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
|
|
NULL, &ftrace_pid_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'set_ftrace_pid' entry\n");
|
|
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_sysctl_lock);
|
|
|
|
ret = __register_ftrace_function(ops);
|
|
ftrace_startup(0);
|
|
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* unregister_ftrace_function - unresgister 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_sysctl_lock);
|
|
ret = __unregister_ftrace_function(ops);
|
|
ftrace_shutdown(0);
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
ftrace_enable_sysctl(struct ctl_table *table, int write,
|
|
struct file *file, void __user *buffer, size_t *lenp,
|
|
loff_t *ppos)
|
|
{
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
|
|
ret = proc_dointvec(table, write, file, 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_sysctl_lock);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
|
|
static atomic_t ftrace_graph_active;
|
|
|
|
/* 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 =
|
|
(trace_func_graph_ent_t)ftrace_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) {
|
|
t->curr_ret_stack = -1;
|
|
/* Make sure IRQs see the -1 first: */
|
|
barrier();
|
|
t->ret_stack = ret_stack_list[start++];
|
|
atomic_set(&t->trace_overrun, 0);
|
|
}
|
|
} 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;
|
|
}
|
|
|
|
/* Allocate a return stack for each task */
|
|
static int start_graph_tracing(void)
|
|
{
|
|
struct ftrace_ret_stack **ret_stack_list;
|
|
int ret;
|
|
|
|
ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
|
|
sizeof(struct ftrace_ret_stack *),
|
|
GFP_KERNEL);
|
|
|
|
if (!ret_stack_list)
|
|
return -ENOMEM;
|
|
|
|
do {
|
|
ret = alloc_retstack_tasklist(ret_stack_list);
|
|
} while (ret == -EAGAIN);
|
|
|
|
kfree(ret_stack_list);
|
|
return ret;
|
|
}
|
|
|
|
int register_ftrace_graph(trace_func_graph_ret_t retfunc,
|
|
trace_func_graph_ent_t entryfunc)
|
|
{
|
|
int ret = 0;
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
|
|
atomic_inc(&ftrace_graph_active);
|
|
ret = start_graph_tracing();
|
|
if (ret) {
|
|
atomic_dec(&ftrace_graph_active);
|
|
goto out;
|
|
}
|
|
|
|
ftrace_graph_return = retfunc;
|
|
ftrace_graph_entry = entryfunc;
|
|
|
|
ftrace_startup(FTRACE_START_FUNC_RET);
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
return ret;
|
|
}
|
|
|
|
void unregister_ftrace_graph(void)
|
|
{
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
|
|
atomic_dec(&ftrace_graph_active);
|
|
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
|
|
ftrace_graph_entry = (trace_func_graph_ent_t)ftrace_stub;
|
|
ftrace_shutdown(FTRACE_STOP_FUNC_RET);
|
|
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
}
|
|
|
|
/* Allocate a return stack for newly created task */
|
|
void ftrace_graph_init_task(struct task_struct *t)
|
|
{
|
|
if (atomic_read(&ftrace_graph_active)) {
|
|
t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
|
|
* sizeof(struct ftrace_ret_stack),
|
|
GFP_KERNEL);
|
|
if (!t->ret_stack)
|
|
return;
|
|
t->curr_ret_stack = -1;
|
|
atomic_set(&t->trace_overrun, 0);
|
|
} else
|
|
t->ret_stack = NULL;
|
|
}
|
|
|
|
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
|
|
|