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Subject: Re: [RFC PATCH] MIPS: Kconfig: Select ARCH_WANT_FRAME_POINTERS
To:     Sergei Shtylyov <sergei.shtylyov@gmail.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>
References: <1605502980-31946-1-git-send-email-yangtiezhu@loongson.cn>
 <62ea9838-70ce-ca73-7dae-e94620956ab5@gmail.com>
Cc:     linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        Xuefeng Li <lixuefeng@loongson.cn>
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <aa8b9e92-8851-60d2-32d1-cec99be1af57@loongson.cn>
Date:   Mon, 16 Nov 2020 17:47:50 +0800
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On 11/16/2020 05:08 PM, Sergei Shtylyov wrote:
> Hello!
>
> On 16.11.2020 8:03, Tiezhu Yang wrote:
>
>> Select ARCH_WANT_FRAME_POINTERS to fix the following build error under
>> CONFIG_DEBUG_ATOMIC_SLEEP:
>>
>>    CC      arch/mips/kernel/signal.o
>> {standard input}: Assembler messages:
>> {standard input}:1775: Error: Unable to parse register name $fp
>> scripts/Makefile.build:283: recipe for target 
>> 'arch/mips/kernel/signal.o' failed
>> make[2]: *** [arch/mips/kernel/signal.o] Error 1
>> scripts/Makefile.build:500: recipe for target 'arch/mips/kernel' failed
>> make[1]: *** [arch/mips/kernel] Error 2
>> Makefile:1799: recipe for target 'arch/mips' failed
>> make: *** [arch/mips] Error 2
>>
>> I think it is useful to get debugging information as described in the
>> following texts:
>>
>> lib/Kconfig.debug
>> config FRAME_POINTER
>>          bool "Compile the kernel with frame pointers"
>>          ...
>>          default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
>>          help
>>            If you say Y here the resulting kernel image will be slightly
>>            larger and slower, but it gives very useful debugging 
>> information
>>            in case of kernel bugs. (precise oopses/stacktraces/warnings)
>>
>> Documentation/dev-tools/kgdb.rst
>> This option inserts code to into the compiled executable which saves
>
>    So to or into? :-)

Hi Sergei,

Thanks for pointing that out，this may be a typo which should be "into".
I will update the commit message to correct it.

Thanks,
Tiezhu

>
>> the frame information in registers or on the stack at different points
>> which allows a debugger such as gdb to more accurately construct stack
>> back traces while debugging the kernel.
>>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> [...]
>
> MBR, Sergei