forked from Minki/linux
ftrace: add traceon traceoff commands to enable/disable the buffers
This patch adds the new function selection commands traceon and traceoff. traceon sets the function to enable the ring buffers while traceoff disables the ring buffers. You can pass in the number of times you want the command to be executed when the function is hit. It will only execute if the state of the buffers are not already in that state. Example: # echo do_fork:traceon:4 Will enable the ring buffers if they are disabled every time it hits do_fork, up to 4 times. # echo sys_close:traceoff This will disable the ring buffers every time (unlimited) when sys_close is called. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
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@ -9,6 +9,7 @@
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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/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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@ -231,9 +232,143 @@ static struct tracer function_trace __read_mostly =
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#endif
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};
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#ifdef CONFIG_DYNAMIC_FTRACE
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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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long *count = (long *)data;
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if (tracing_is_on())
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return;
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if (!*count)
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return;
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if (*count != -1)
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(*count)--;
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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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long *count = (long *)data;
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if (!tracing_is_on())
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return;
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if (!*count)
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return;
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if (*count != -1)
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(*count)--;
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tracing_off();
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}
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static struct ftrace_hook_ops traceon_hook_ops = {
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.func = ftrace_traceon,
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};
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static struct ftrace_hook_ops traceoff_hook_ops = {
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.func = ftrace_traceoff,
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};
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static int
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ftrace_trace_onoff_unreg(char *glob, char *cmd, char *param)
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{
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struct ftrace_hook_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 = &traceon_hook_ops;
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else
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ops = &traceoff_hook_ops;
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unregister_ftrace_function_hook_func(glob, ops);
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return 0;
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}
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static int
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ftrace_trace_onoff_callback(char *glob, char *cmd, char *param, int enable)
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{
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struct ftrace_hook_ops *ops;
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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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return ftrace_trace_onoff_unreg(glob+1, cmd, param);
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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 = &traceon_hook_ops;
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else
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ops = &traceoff_hook_ops;
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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 = strict_strtoul(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_hook(glob, ops, count);
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return ret;
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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 int __init init_func_cmd_traceon(void)
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{
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int ret;
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ret = register_ftrace_command(&ftrace_traceoff_cmd);
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if (ret)
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return ret;
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ret = register_ftrace_command(&ftrace_traceon_cmd);
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if (ret)
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unregister_ftrace_command(&ftrace_traceoff_cmd);
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return ret;
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}
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#else
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static inline int init_func_cmd_traceon(void)
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{
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return 0;
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}
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#endif /* CONFIG_DYNAMIC_FTRACE */
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static __init int init_function_trace(void)
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{
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init_func_cmd_traceon();
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return register_tracer(&function_trace);
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}
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device_initcall(init_function_trace);
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