ftrace: add kernel command line graph function filtering
Add a command line parameter to allow limiting the function graphs that are traced on boot up from the given top-level callers , when ftrace=function_graph is specified. This patch adds the following command line option: ftrace_graph_filter=function-list Where function-list is a comma separated list of functions to filter. [fweisbec@gmail.com: picked the documentation changes from the v2 patch] Signed-off-by: Stefan Assmann <sassmann@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4AD2DEB9.2@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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@ -778,6 +778,13 @@ and is between 256 and 4096 characters. It is defined in the file
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by the set_ftrace_notrace file in the debugfs
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tracing directory.
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ftrace_graph_filter=[function-list]
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[FTRACE] Limit the top level callers functions traced
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by the function graph tracer at boot up.
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function-list is a comma separated list of functions
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that can be changed at run time by the
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set_graph_function file in the debugfs tracing directory.
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gamecon.map[2|3]=
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[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
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support via parallel port (up to 5 devices per port)
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@ -78,6 +78,10 @@ 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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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
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#endif
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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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@ -2248,6 +2252,7 @@ void ftrace_set_notrace(unsigned char *buf, int len, int reset)
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#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
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static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
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static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
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static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
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static int __init set_ftrace_notrace(char *str)
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{
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@ -2263,6 +2268,31 @@ static int __init set_ftrace_filter(char *str)
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}
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__setup("ftrace_filter=", set_ftrace_filter);
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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static int __init set_graph_function(char *str)
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{
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strncpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
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return 1;
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}
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__setup("ftrace_graph_filter=", set_graph_function);
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static void __init set_ftrace_early_graph(char *buf)
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{
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int ret;
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char *func;
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while (buf) {
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func = strsep(&buf, ",");
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/* we allow only one expression at a time */
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ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
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func);
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if (ret)
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printk(KERN_DEBUG "ftrace: function %s not "
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"traceable\n", func);
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}
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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static void __init set_ftrace_early_filter(char *buf, int enable)
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{
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char *func;
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@ -2279,6 +2309,10 @@ static void __init set_ftrace_early_filters(void)
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set_ftrace_early_filter(ftrace_filter_buf, 1);
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if (ftrace_notrace_buf[0])
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set_ftrace_early_filter(ftrace_notrace_buf, 0);
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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if (ftrace_graph_buf[0])
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set_ftrace_early_graph(ftrace_graph_buf);
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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}
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static int
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