diff options
| author | AKASHI Takahiro | 2014-04-30 18:54:33 +0900 |
|---|---|---|
| committer | Will Deacon | 2014-05-29 09:08:08 +0100 |
| commit | 819e50e25d0ce8a75f5cba815416a6a8573655c4 (patch) | |
| tree | 006f9d7dc3f97f47709430357651a83ffdc1f86d /arch/arm64/kernel/arm64ksyms.c | |
| parent | af64d2aa872a174772ffc00e2558083f70193acb (diff) | |
arm64: Add ftrace support
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>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/kernel/arm64ksyms.c')
| -rw-r--r-- | arch/arm64/kernel/arm64ksyms.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/kernel/arm64ksyms.c b/arch/arm64/kernel/arm64ksyms.c index 1edc792b4a1f..a85843ddbde8 100644 --- a/arch/arm64/kernel/arm64ksyms.c +++ b/arch/arm64/kernel/arm64ksyms.c @@ -61,3 +61,7 @@ EXPORT_SYMBOL(clear_bit); EXPORT_SYMBOL(test_and_clear_bit); EXPORT_SYMBOL(change_bit); EXPORT_SYMBOL(test_and_change_bit); + +#ifdef CONFIG_FUNCTION_TRACER +EXPORT_SYMBOL(_mcount); +#endif |