On 03/14/2014 07:07 PM, Will Deacon wrote:
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.
Please ignore my comment.
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.
Fix it.
-Takahiro AKASHI
Will