[RFC PATCH 2/2] powerpc: Only support DYNAMIC_FTRACE not static
mpe at ellerman.id.au
Mon Mar 19 12:08:10 AEDT 2018
Steven Rostedt <rostedt at goodmis.org> writes:
> On Sat, 17 Mar 2018 00:46:33 +1100
> Michael Ellerman <mpe at ellerman.id.au> wrote:
>> We've had dynamic ftrace support for over 9 years since Steve first
>> wrote it, all the distros use dynamic, and static is basically
>> untested these days, so drop support for static ftrace.
>> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
>> arch/powerpc/Kconfig | 1 +
>> arch/powerpc/include/asm/ftrace.h | 4 +---
>> arch/powerpc/include/asm/module.h | 5 -----
>> arch/powerpc/kernel/trace/ftrace.c | 2 --
>> arch/powerpc/kernel/trace/ftrace_32.S | 20 ------------------
>> arch/powerpc/kernel/trace/ftrace_64.S | 29 --------------------------
>> arch/powerpc/kernel/trace/ftrace_64_mprofile.S | 3 ---
>> arch/powerpc/kernel/trace/ftrace_64_pg.S | 2 --
>> 8 files changed, 2 insertions(+), 64 deletions(-)
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 73ce5dd07642..23a325df784a 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -189,6 +189,7 @@ config PPC
>> select HAVE_DEBUG_STACKOVERFLOW
>> select HAVE_DMA_API_DEBUG
>> select HAVE_DYNAMIC_FTRACE
>> + select HAVE_DYNAMIC_FTRACE_ONLY
> I still think adding:
> select DYNAMIC_FTRACE if FUNCTION_TRACER
> is the better approach.
OK. As I said in my other reply it's a bit fragile, but it does work.
I'll do a version for powerpc using the above approach.
> But I'm all for this patch. I've debated doing the same thing for x86,
> but the only reason I have not, was because it's the only way I test
> the !DYNAMIC_FTRACE code. I've broken the static function tracing
> several times and only find out during my test suite that still tests
> that case. But yeah, it would be nice to just nuke static function
> tracing for all archs. Perhaps after we finish removing unused archs,
> that may be the way to go forward.
Yeah I did look and we still have some arches that support ftrace but
not dynamic ftrace, but there's not many.
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