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From: "Shi, Yang" <yang.shi@linaro.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	linaro-kernel@lists.linaro.org, Will Deacon <will.deacon@arm.com>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option
Date: Fri, 06 Nov 2015 09:55:54 -0800	[thread overview]
Message-ID: <563CE9AA.8050905@linaro.org> (raw)
In-Reply-To: <20151106175119.GD7637@e104818-lin.cambridge.arm.com>

On 11/6/2015 9:51 AM, Catalin Marinas wrote:
> On Fri, Nov 06, 2015 at 09:39:07AM -0800, Shi, Yang wrote:
>> On 11/6/2015 9:35 AM, Catalin Marinas wrote:
>>> On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote:
>>>> On 11/6/2015 8:25 AM, Will Deacon wrote:
>>>>> However, the patch would allow one to
>>>>> disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc
>>>>> though).
>>>>
>>>> No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the
>>>> patch.
>>>
>>> In which case I suggest that we always select it just as a clearer
>>> statement that the feature cannot be disabled (and you never know what
>>> the compiler people decide to do in the future).
>>
>> Do you mean select FRAME_POINTER in ARCH_WANT_FRAME_POINTERS?
>>
>> Yes, we could, but this may cause other architectures which select
>> ARCH_WANT_FRAME_POINTERS to have FRAME_POINTER selected too.
>
> This would have been the ideal option, something like:
>
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -322,7 +322,7 @@ config ARCH_WANT_FRAME_POINTERS
>   	help
>
>   config FRAME_POINTER
> -	bool "Compile the kernel with frame pointers"
> +	bool "Compile the kernel with frame pointers" if !ARCH_WANT_FRAME_POINTERS
>   	depends on DEBUG_KERNEL && \
>   		(CRIS || M68K || FRV || UML || \
>   		 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
>
> But, as you said, we would need to check the other architectures
> selecting ARCH_WANT_FRAME_POINTERS.

How about:

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1d1521c..709255a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -319,6 +319,7 @@ config DEBUG_SECTION_MISMATCH
  #
  config ARCH_WANT_FRAME_POINTERS
         bool
+       select FRAME_POINTER if ARM64
         help

  config FRAME_POINTER

If other architectures want the same behavior, they could easily append 
to the is statement. If all arches which selects 
ARCH_WANT_FRAME_POINTERS, the if statement could be just removed.

Yang

>
> In the meantime:
>
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -27,6 +27,7 @@ config ARM64
>   	select CPU_PM if (SUSPEND || CPU_IDLE)
>   	select DCACHE_WORD_ACCESS
>   	select EDAC_SUPPORT
> +	select FRAME_POINTER
>   	select GENERIC_ALLOCATOR
>   	select GENERIC_CLOCKEVENTS
>   	select GENERIC_CLOCKEVENTS_BROADCAST
>


WARNING: multiple messages have this Message-ID (diff)
From: yang.shi@linaro.org (Shi, Yang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: remove redundant FRAME_POINTER kconfig option
Date: Fri, 06 Nov 2015 09:55:54 -0800	[thread overview]
Message-ID: <563CE9AA.8050905@linaro.org> (raw)
In-Reply-To: <20151106175119.GD7637@e104818-lin.cambridge.arm.com>

On 11/6/2015 9:51 AM, Catalin Marinas wrote:
> On Fri, Nov 06, 2015 at 09:39:07AM -0800, Shi, Yang wrote:
>> On 11/6/2015 9:35 AM, Catalin Marinas wrote:
>>> On Fri, Nov 06, 2015 at 09:23:38AM -0800, Shi, Yang wrote:
>>>> On 11/6/2015 8:25 AM, Will Deacon wrote:
>>>>> However, the patch would allow one to
>>>>> disable FRAME_POINTERS (not sure it has any effect on the aarch64 gcc
>>>>> though).
>>>>
>>>> No, it doesn't. Actually, FRAME_POINTER could be disabled regardless of the
>>>> patch.
>>>
>>> In which case I suggest that we always select it just as a clearer
>>> statement that the feature cannot be disabled (and you never know what
>>> the compiler people decide to do in the future).
>>
>> Do you mean select FRAME_POINTER in ARCH_WANT_FRAME_POINTERS?
>>
>> Yes, we could, but this may cause other architectures which select
>> ARCH_WANT_FRAME_POINTERS to have FRAME_POINTER selected too.
>
> This would have been the ideal option, something like:
>
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -322,7 +322,7 @@ config ARCH_WANT_FRAME_POINTERS
>   	help
>
>   config FRAME_POINTER
> -	bool "Compile the kernel with frame pointers"
> +	bool "Compile the kernel with frame pointers" if !ARCH_WANT_FRAME_POINTERS
>   	depends on DEBUG_KERNEL && \
>   		(CRIS || M68K || FRV || UML || \
>   		 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
>
> But, as you said, we would need to check the other architectures
> selecting ARCH_WANT_FRAME_POINTERS.

How about:

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1d1521c..709255a 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -319,6 +319,7 @@ config DEBUG_SECTION_MISMATCH
  #
  config ARCH_WANT_FRAME_POINTERS
         bool
+       select FRAME_POINTER if ARM64
         help

  config FRAME_POINTER

If other architectures want the same behavior, they could easily append 
to the is statement. If all arches which selects 
ARCH_WANT_FRAME_POINTERS, the if statement could be just removed.

Yang

>
> In the meantime:
>
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -27,6 +27,7 @@ config ARM64
>   	select CPU_PM if (SUSPEND || CPU_IDLE)
>   	select DCACHE_WORD_ACCESS
>   	select EDAC_SUPPORT
> +	select FRAME_POINTER
>   	select GENERIC_ALLOCATOR
>   	select GENERIC_CLOCKEVENTS
>   	select GENERIC_CLOCKEVENTS_BROADCAST
>

  reply	other threads:[~2015-11-06 17:55 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-04 17:37 [PATCH] arm64: remove redundant FRAME_POINTER kconfig option Yang Shi
2015-11-04 17:37 ` Yang Shi
2015-11-06 12:30 ` Will Deacon
2015-11-06 12:30   ` Will Deacon
2015-11-06 12:50   ` Mark Rutland
2015-11-06 12:50     ` Mark Rutland
2015-11-06 15:42     ` Will Deacon
2015-11-06 15:42       ` Will Deacon
2015-11-06 16:21     ` Catalin Marinas
2015-11-06 16:21       ` Catalin Marinas
2015-11-06 16:25       ` Will Deacon
2015-11-06 16:25         ` Will Deacon
2015-11-06 17:23         ` Shi, Yang
2015-11-06 17:23           ` Shi, Yang
2015-11-06 17:35           ` Catalin Marinas
2015-11-06 17:35             ` Catalin Marinas
2015-11-06 17:39             ` Shi, Yang
2015-11-06 17:39               ` Shi, Yang
2015-11-06 17:51               ` Catalin Marinas
2015-11-06 17:51                 ` Catalin Marinas
2015-11-06 17:55                 ` Shi, Yang [this message]
2015-11-06 17:55                   ` Shi, Yang
2015-11-09 15:58                   ` Catalin Marinas
2015-11-09 15:58                     ` Catalin Marinas
2015-11-06 16:12   ` Catalin Marinas
2015-11-06 16:12     ` Catalin Marinas
2015-11-06 16:19     ` Will Deacon
2015-11-06 16:19       ` Will Deacon

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