![Steven Rostedt (Red Hat)](/assets/img/avatar_default.png)
Create a "set_ftrace_filter" and "set_ftrace_notrace" files in the instance directories to let users filter of functions to trace for the given instance. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
629 lines
13 KiB
C
629 lines
13 KiB
C
/*
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* ring buffer based function tracer
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*
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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* Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
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*
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* Based on code from 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 Nadia Yvette Chambers
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*/
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#include <linux/ring_buffer.h>
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#include <linux/debugfs.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include "trace.h"
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static void tracing_start_function_trace(struct trace_array *tr);
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static void tracing_stop_function_trace(struct trace_array *tr);
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static void
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function_trace_call(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *op, struct pt_regs *pt_regs);
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static void
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function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *op, struct pt_regs *pt_regs);
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static struct ftrace_ops trace_ops;
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static struct ftrace_ops trace_stack_ops;
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static struct tracer_flags func_flags;
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/* Our option */
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enum {
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TRACE_FUNC_OPT_STACK = 0x1,
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};
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static int allocate_ftrace_ops(struct trace_array *tr)
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{
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struct ftrace_ops *ops;
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ops = kzalloc(sizeof(*ops), GFP_KERNEL);
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if (!ops)
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return -ENOMEM;
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/* Currently only the non stack verision is supported */
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ops->func = function_trace_call;
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ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
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tr->ops = ops;
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ops->private = tr;
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return 0;
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}
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int ftrace_create_function_files(struct trace_array *tr,
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struct dentry *parent)
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{
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int ret;
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/* The top level array uses the "global_ops". */
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if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL)) {
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ret = allocate_ftrace_ops(tr);
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if (ret)
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return ret;
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}
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ftrace_create_filter_files(tr->ops, parent);
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return 0;
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}
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void ftrace_destroy_function_files(struct trace_array *tr)
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{
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ftrace_destroy_filter_files(tr->ops);
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kfree(tr->ops);
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tr->ops = NULL;
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}
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static int function_trace_init(struct trace_array *tr)
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{
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struct ftrace_ops *ops;
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if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
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/* There's only one global tr */
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if (!trace_ops.private) {
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trace_ops.private = tr;
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trace_stack_ops.private = tr;
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}
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if (func_flags.val & TRACE_FUNC_OPT_STACK)
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ops = &trace_stack_ops;
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else
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ops = &trace_ops;
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tr->ops = ops;
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} else if (!tr->ops) {
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/*
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* Instance trace_arrays get their ops allocated
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* at instance creation. Unless it failed
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* the allocation.
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*/
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return -ENOMEM;
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}
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tr->trace_buffer.cpu = get_cpu();
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put_cpu();
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tracing_start_cmdline_record();
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tracing_start_function_trace(tr);
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return 0;
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}
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static void function_trace_reset(struct trace_array *tr)
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{
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tracing_stop_function_trace(tr);
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tracing_stop_cmdline_record();
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}
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static void function_trace_start(struct trace_array *tr)
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{
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tracing_reset_online_cpus(&tr->trace_buffer);
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}
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static void
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function_trace_call(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *op, struct pt_regs *pt_regs)
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{
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struct trace_array *tr = op->private;
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struct trace_array_cpu *data;
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unsigned long flags;
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int bit;
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int cpu;
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int pc;
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if (unlikely(!tr->function_enabled))
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return;
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pc = preempt_count();
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preempt_disable_notrace();
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bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX);
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if (bit < 0)
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goto out;
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cpu = smp_processor_id();
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data = per_cpu_ptr(tr->trace_buffer.data, cpu);
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if (!atomic_read(&data->disabled)) {
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local_save_flags(flags);
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trace_function(tr, ip, parent_ip, flags, pc);
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}
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trace_clear_recursion(bit);
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out:
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preempt_enable_notrace();
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}
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static void
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function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
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struct ftrace_ops *op, struct pt_regs *pt_regs)
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{
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struct trace_array *tr = op->private;
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struct trace_array_cpu *data;
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unsigned long flags;
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long disabled;
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int cpu;
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int pc;
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if (unlikely(!tr->function_enabled))
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return;
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/*
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* Need to use raw, since this must be called before the
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* recursive protection is performed.
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*/
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local_irq_save(flags);
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cpu = raw_smp_processor_id();
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data = per_cpu_ptr(tr->trace_buffer.data, cpu);
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disabled = atomic_inc_return(&data->disabled);
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if (likely(disabled == 1)) {
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pc = preempt_count();
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trace_function(tr, ip, parent_ip, flags, pc);
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/*
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* skip over 5 funcs:
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* __ftrace_trace_stack,
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* __trace_stack,
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* function_stack_trace_call
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* ftrace_list_func
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* ftrace_call
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*/
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__trace_stack(tr, flags, 5, pc);
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}
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atomic_dec(&data->disabled);
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local_irq_restore(flags);
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}
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static struct ftrace_ops trace_ops __read_mostly =
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{
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.func = function_trace_call,
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.flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
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};
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static struct ftrace_ops trace_stack_ops __read_mostly =
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{
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.func = function_stack_trace_call,
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.flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
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};
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static struct tracer_opt func_opts[] = {
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#ifdef CONFIG_STACKTRACE
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{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
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#endif
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{ } /* Always set a last empty entry */
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};
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static struct tracer_flags func_flags = {
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.val = 0, /* By default: all flags disabled */
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.opts = func_opts
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};
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static void tracing_start_function_trace(struct trace_array *tr)
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{
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tr->function_enabled = 0;
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register_ftrace_function(tr->ops);
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tr->function_enabled = 1;
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}
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static void tracing_stop_function_trace(struct trace_array *tr)
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{
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tr->function_enabled = 0;
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unregister_ftrace_function(tr->ops);
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}
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static int
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func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
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{
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switch (bit) {
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case TRACE_FUNC_OPT_STACK:
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/* do nothing if already set */
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if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
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break;
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unregister_ftrace_function(tr->ops);
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if (set) {
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tr->ops = &trace_stack_ops;
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register_ftrace_function(tr->ops);
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} else {
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tr->ops = &trace_ops;
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register_ftrace_function(tr->ops);
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}
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static struct tracer function_trace __tracer_data =
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{
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.name = "function",
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.init = function_trace_init,
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.reset = function_trace_reset,
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.start = function_trace_start,
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.wait_pipe = poll_wait_pipe,
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.flags = &func_flags,
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.set_flag = func_set_flag,
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.allow_instances = true,
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#ifdef CONFIG_FTRACE_SELFTEST
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.selftest = trace_selftest_startup_function,
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#endif
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};
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#ifdef CONFIG_DYNAMIC_FTRACE
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static int update_count(void **data)
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{
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unsigned long *count = (long *)data;
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if (!*count)
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return 0;
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if (*count != -1)
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(*count)--;
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return 1;
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}
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static void
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ftrace_traceon_count(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (tracing_is_on())
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return;
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if (update_count(data))
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tracing_on();
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}
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static void
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ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (!tracing_is_on())
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return;
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if (update_count(data))
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tracing_off();
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}
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static void
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ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (tracing_is_on())
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return;
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tracing_on();
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}
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static void
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ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (!tracing_is_on())
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return;
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tracing_off();
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}
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/*
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* Skip 4:
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* ftrace_stacktrace()
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* function_trace_probe_call()
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* ftrace_ops_list_func()
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* ftrace_call()
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*/
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#define STACK_SKIP 4
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static void
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ftrace_stacktrace(unsigned long ip, unsigned long parent_ip, void **data)
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{
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trace_dump_stack(STACK_SKIP);
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}
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static void
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ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (!tracing_is_on())
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return;
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if (update_count(data))
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trace_dump_stack(STACK_SKIP);
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}
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static void
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ftrace_dump_probe(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (update_count(data))
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ftrace_dump(DUMP_ALL);
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}
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/* Only dump the current CPU buffer. */
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static void
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ftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip, void **data)
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{
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if (update_count(data))
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ftrace_dump(DUMP_ORIG);
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}
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static int
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ftrace_probe_print(const char *name, struct seq_file *m,
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unsigned long ip, void *data)
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{
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long count = (long)data;
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seq_printf(m, "%ps:%s", (void *)ip, name);
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if (count == -1)
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seq_printf(m, ":unlimited\n");
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else
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seq_printf(m, ":count=%ld\n", count);
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return 0;
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}
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static int
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ftrace_traceon_print(struct seq_file *m, unsigned long ip,
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struct ftrace_probe_ops *ops, void *data)
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{
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return ftrace_probe_print("traceon", m, ip, data);
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}
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static int
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ftrace_traceoff_print(struct seq_file *m, unsigned long ip,
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struct ftrace_probe_ops *ops, void *data)
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{
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return ftrace_probe_print("traceoff", m, ip, data);
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}
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static int
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ftrace_stacktrace_print(struct seq_file *m, unsigned long ip,
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struct ftrace_probe_ops *ops, void *data)
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{
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return ftrace_probe_print("stacktrace", m, ip, data);
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}
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static int
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ftrace_dump_print(struct seq_file *m, unsigned long ip,
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struct ftrace_probe_ops *ops, void *data)
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{
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return ftrace_probe_print("dump", m, ip, data);
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}
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static int
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ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
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struct ftrace_probe_ops *ops, void *data)
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{
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return ftrace_probe_print("cpudump", m, ip, data);
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}
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static struct ftrace_probe_ops traceon_count_probe_ops = {
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.func = ftrace_traceon_count,
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.print = ftrace_traceon_print,
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};
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static struct ftrace_probe_ops traceoff_count_probe_ops = {
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.func = ftrace_traceoff_count,
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.print = ftrace_traceoff_print,
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};
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static struct ftrace_probe_ops stacktrace_count_probe_ops = {
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.func = ftrace_stacktrace_count,
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.print = ftrace_stacktrace_print,
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};
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static struct ftrace_probe_ops dump_probe_ops = {
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.func = ftrace_dump_probe,
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.print = ftrace_dump_print,
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};
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static struct ftrace_probe_ops cpudump_probe_ops = {
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.func = ftrace_cpudump_probe,
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.print = ftrace_cpudump_print,
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};
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static struct ftrace_probe_ops traceon_probe_ops = {
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.func = ftrace_traceon,
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.print = ftrace_traceon_print,
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};
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static struct ftrace_probe_ops traceoff_probe_ops = {
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.func = ftrace_traceoff,
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.print = ftrace_traceoff_print,
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};
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static struct ftrace_probe_ops stacktrace_probe_ops = {
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.func = ftrace_stacktrace,
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.print = ftrace_stacktrace_print,
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};
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static int
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ftrace_trace_probe_callback(struct ftrace_probe_ops *ops,
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struct ftrace_hash *hash, char *glob,
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char *cmd, char *param, int enable)
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{
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void *count = (void *)-1;
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char *number;
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int ret;
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/* hash funcs only work with set_ftrace_filter */
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if (!enable)
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return -EINVAL;
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if (glob[0] == '!') {
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unregister_ftrace_function_probe_func(glob+1, ops);
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return 0;
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}
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if (!param)
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goto out_reg;
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number = strsep(¶m, ":");
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if (!strlen(number))
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goto out_reg;
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/*
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* We use the callback data field (which is a pointer)
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* as our counter.
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*/
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ret = kstrtoul(number, 0, (unsigned long *)&count);
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if (ret)
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return ret;
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out_reg:
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ret = register_ftrace_function_probe(glob, ops, count);
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return ret < 0 ? ret : 0;
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}
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static int
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ftrace_trace_onoff_callback(struct ftrace_hash *hash,
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char *glob, char *cmd, char *param, int enable)
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{
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struct ftrace_probe_ops *ops;
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/* we register both traceon and traceoff to this callback */
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if (strcmp(cmd, "traceon") == 0)
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ops = param ? &traceon_count_probe_ops : &traceon_probe_ops;
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else
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ops = param ? &traceoff_count_probe_ops : &traceoff_probe_ops;
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return ftrace_trace_probe_callback(ops, hash, glob, cmd,
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param, enable);
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}
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static int
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ftrace_stacktrace_callback(struct ftrace_hash *hash,
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char *glob, char *cmd, char *param, int enable)
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{
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struct ftrace_probe_ops *ops;
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ops = param ? &stacktrace_count_probe_ops : &stacktrace_probe_ops;
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return ftrace_trace_probe_callback(ops, hash, glob, cmd,
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param, enable);
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}
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static int
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ftrace_dump_callback(struct ftrace_hash *hash,
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char *glob, char *cmd, char *param, int enable)
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{
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struct ftrace_probe_ops *ops;
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ops = &dump_probe_ops;
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/* Only dump once. */
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return ftrace_trace_probe_callback(ops, hash, glob, cmd,
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"1", enable);
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}
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static int
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ftrace_cpudump_callback(struct ftrace_hash *hash,
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char *glob, char *cmd, char *param, int enable)
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{
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struct ftrace_probe_ops *ops;
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ops = &cpudump_probe_ops;
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/* Only dump once. */
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return ftrace_trace_probe_callback(ops, hash, glob, cmd,
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"1", enable);
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}
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static struct ftrace_func_command ftrace_traceon_cmd = {
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.name = "traceon",
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.func = ftrace_trace_onoff_callback,
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};
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static struct ftrace_func_command ftrace_traceoff_cmd = {
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.name = "traceoff",
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.func = ftrace_trace_onoff_callback,
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};
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static struct ftrace_func_command ftrace_stacktrace_cmd = {
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.name = "stacktrace",
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.func = ftrace_stacktrace_callback,
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};
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|
|
static struct ftrace_func_command ftrace_dump_cmd = {
|
|
.name = "dump",
|
|
.func = ftrace_dump_callback,
|
|
};
|
|
|
|
static struct ftrace_func_command ftrace_cpudump_cmd = {
|
|
.name = "cpudump",
|
|
.func = ftrace_cpudump_callback,
|
|
};
|
|
|
|
static int __init init_func_cmd_traceon(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = register_ftrace_command(&ftrace_traceoff_cmd);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = register_ftrace_command(&ftrace_traceon_cmd);
|
|
if (ret)
|
|
goto out_free_traceoff;
|
|
|
|
ret = register_ftrace_command(&ftrace_stacktrace_cmd);
|
|
if (ret)
|
|
goto out_free_traceon;
|
|
|
|
ret = register_ftrace_command(&ftrace_dump_cmd);
|
|
if (ret)
|
|
goto out_free_stacktrace;
|
|
|
|
ret = register_ftrace_command(&ftrace_cpudump_cmd);
|
|
if (ret)
|
|
goto out_free_dump;
|
|
|
|
return 0;
|
|
|
|
out_free_dump:
|
|
unregister_ftrace_command(&ftrace_dump_cmd);
|
|
out_free_stacktrace:
|
|
unregister_ftrace_command(&ftrace_stacktrace_cmd);
|
|
out_free_traceon:
|
|
unregister_ftrace_command(&ftrace_traceon_cmd);
|
|
out_free_traceoff:
|
|
unregister_ftrace_command(&ftrace_traceoff_cmd);
|
|
|
|
return ret;
|
|
}
|
|
#else
|
|
static inline int init_func_cmd_traceon(void)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
static __init int init_function_trace(void)
|
|
{
|
|
init_func_cmd_traceon();
|
|
return register_tracer(&function_trace);
|
|
}
|
|
core_initcall(init_function_trace);
|