On Sat, Mar 15, 2014 at 05:45:50AM +0000, AKASHI Takahiro wrote:
This patch implements arm64 specific part to support function tracers, such as function (CONFIG_FUNCTION_TRACER), function_graph (CONFIG_FUNCTION_GRAPH_TRACER) and function profiler (CONFIG_FUNCTION_PROFILER).
With 'function' tracer, all the functions in the kernel are traced with timestamps in ${sysfs}/tracing/trace. If function_graph tracer is specified, call graph is generated.
The kernel must be compiled with -pg option so that _mcount() is inserted at the beginning of functions. This function is called on every function's entry as long as tracing is enabled. In addition, function_graph tracer also needs to be able to probe function's exit. ftrace_graph_caller() & return_to_handler do this by faking link register's value to intercept function's return path.
More details on architecture specific requirements are described in Documentation/trace/ftrace-design.txt.
Reviewed-by: Ganapatrao Kulkarni ganapatrao.kulkarni@cavium.com Signed-off-by: AKASHI Takahiro takahiro.akashi@linaro.org
I'm still slightly suspicious about the alignment of your ASCII art, but:
Acked-by: Will Deacon will.deacon@arm.com
Will