[V3 PATCH] arm64: remove redundant FRAME_POINTER kconfig option and force to select it

[yalin wang]

> On Nov 10, 2015, at 18:37, Catalin Marinas <catalin.marinas at arm.com> wrote:
> 
> On Mon, Nov 09, 2015 at 10:09:55AM -0800, Yang Shi wrote:
>> FRAME_POINTER  is defined in lib/Kconfig.debug, it is unnecessary to redefine
>> it in arch/arm64/Kconfig.debug. Actually, the one defined in arm64 directory
>> is never used.
> 
> That's not true since the arm64 definition seems to take precedence.
> 
>> This adds a dependency on DEBUG_KERNEL for building with frame pointers.
> 
> It doesn't because arm64 selects ARCH_WANT_FRAME_POINTERS.
> 
>> ARM64 depends on frame pointer to get correct stack backtrace and need
>> FRAME_POINTER kconfig option enabled all the time.
>> However, currect implementation makes it could be disabled, so force it
>> to be selected by ARM64.
>> 
>> Signed-off-by: Yang Shi <yang.shi at linaro.org>
> 
> Patch applied but I changed the commit log slightly. Thanks.
i have a question,
why FRAME_POINTER  config must be enabled ?
and i see ARM arch can  disable this config .
if i don’t need stack trace dump and the software release is for 
final product , don’t need debug stack trace log .
is it possible to disable it for performance reason ?

Thanks