On Fri, Mar 14, 2014 at 04:45:13AM +0000, AKASHI Takahiro wrote:
On 03/14/2014 02:08 AM, Will Deacon wrote:
On Thu, Mar 13, 2014 at 10:13:47AM +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.
[...]
You seem not to like this statement :-)
Huh? I was just using '[...]' to signify that I'd removed a lot of context (since the code all looked fine there). Otherwise, review emails can get really long.
str x0, [sp, #-16]!mov x0, x29 // parent's fpbl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp);mov x30, x0 // restore the original return addressldr x0, [sp], #16retand an ENDPROC here.
Fix it. But please note that this (return_to_handler) is not a real function. Declaring it as ENDPROC is not very useful.
Then use END(...). The opening macro was the main point, since that avoid the need for an explicit .globl.
Will