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2018-12-22tracing: Fix ftrace_graph_get_ret_stack() to use task and not currentSteven Rostedt (VMware)1-2/+2
The function ftrace_graph_get_ret_stack() takes a task struct descriptor but uses current as the task to perform the operations on. In pretty much all cases the task decriptor is the same as current, so this wasn't an issue. But there is a case in the ARM architecture that passes in a task that is not current, and expects a result from that task, and this code breaks it. Fixes: 51584396cff5 ("arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack") Reported-by: James Morse <james.morse@arm.com> Tested-by: James Morse <james.morse@arm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-10fgraph: Add comment to describe ftrace_graph_get_ret_stackSteven Rostedt (VMware)1-0/+11
The ret_stack should not be accessed directly via the curr_ret_stack variable on the task_struct. This is because the ret_stack is going to be converted into a series of longs and not an array of ret_stack structures. The way that a ret_stack should be retrieved is via the ftrace_graph_get_ret_stack structure, but it needs to be documented on how to use it. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-08function_graph: Have profiler use new helper ftrace_graph_get_ret_stack()Steven Rostedt (VMware)1-0/+11
The ret_stack processing is going to change, and that is going to break anything that is accessing the ret_stack directly. One user is the function graph profiler. By using the ftrace_graph_get_ret_stack() helper function, the profiler can access the ret_stack entry without relying on the implementation details of the stack itself. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-08function_graph: Move ftrace_graph_ret_addr() to fgraph.cSteven Rostedt (VMware)1-0/+55
Move the function function_graph_ret_addr() to fgraph.c, as the management of the curr_ret_stack is going to change, and all the accesses to ret_stack needs to be done in fgraph.c. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-08fgraph: Add new fgraph_ops structure to enable function graph hooksSteven Rostedt (VMware)1-5/+4
Currently the registering of function graph is to pass in a entry and return function. We need to have a way to associate those functions together where the entry can determine to run the return hook. Having a structure that contains both functions will facilitate the process of converting the code to be able to do such. This is similar to the way function hooks are enabled (it passes in ftrace_ops). Instead of passing in the functions to use, a single structure is passed in to the registering function. The unregister function is now passed in the fgraph_ops handle. When we allow more than one callback to the function graph hooks, this will let the system know which one to remove. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-08fgraph: Move function graph specific code into fgraph.cSteven Rostedt (VMware)1-1/+359
To make the function graph infrastructure more managable, the code needs to be in its own file (fgraph.c). Move the code that is specific for managing the function graph infrastructure out of ftrace.c and into fgraph.c Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-12-08function_graph: Remove the use of FTRACE_NOTRACE_DEPTHSteven Rostedt (VMware)1-19/+0
The curr_ret_stack is no longer set to a negative value when a function is not to be traced by the function graph tracer. Remove the usage of FTRACE_NOTRACE_DEPTH, as it is no longer needed. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-11-29fgraph: Have set_graph_notrace only affect function_graph tracerSteven Rostedt (VMware)1-21/+0
In order to make the function graph infrastructure more generic, there can not be code specific for the function_graph tracer in the generic code. This includes the set_graph_notrace logic, that stops all graph calls when a function in the set_graph_notrace is hit. By using the trace_recursion mask, we can use a bit in the current task_struct to implement the notrace code, and move the logic out of fgraph.c and into trace_functions_graph.c and keeps it affecting only the tracer and not all call graph callbacks. Acked-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-11-29fgraph: Create a fgraph.c file to store function graph infrastructureSteven Rostedt (VMware)1-0/+232
As the function graph infrastructure can be used by thing other than tracing, moving the code to its own file out of the trace_functions_graph.c code makes more sense. The fgraph.c file will only contain the infrastructure required to hook into functions and their return code. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>