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From: Nathan Chancellor <natechancellor@gmail.com>
To: Qian Cai <cai@lca.pw>
Cc: mark.rutland@arm.com, catalin.marinas@arm.com,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
	will@kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64/cache: silence -Woverride-init warnings
Date: Wed, 7 Aug 2019 21:50:27 -0700	[thread overview]
Message-ID: <20190808045027.GA34150@archlinux-threadripper> (raw)
In-Reply-To: <20190808032916.879-1-cai@lca.pw>

On Wed, Aug 07, 2019 at 11:29:16PM -0400, Qian Cai wrote:
> The commit 155433cb365e ("arm64: cache: Remove support for ASID-tagged
> VIVT I-caches") introduced some compiation warnings from GCC (and
> Clang) with -Winitializer-overrides),
> 
> arch/arm64/kernel/cpuinfo.c:38:26: warning: initialized field
> overwritten [-Woverride-init]
> [ICACHE_POLICY_VIPT]  = "VIPT",
>                         ^~~~~~
> arch/arm64/kernel/cpuinfo.c:38:26: note: (near initialization for
> 'icache_policy_str[2]')
> arch/arm64/kernel/cpuinfo.c:39:26: warning: initialized field
> overwritten [-Woverride-init]
> [ICACHE_POLICY_PIPT]  = "PIPT",
>                         ^~~~~~
> arch/arm64/kernel/cpuinfo.c:39:26: note: (near initialization for
> 'icache_policy_str[3]')
> arch/arm64/kernel/cpuinfo.c:40:27: warning: initialized field
> overwritten [-Woverride-init]
> [ICACHE_POLICY_VPIPT]  = "VPIPT",
>                          ^~~~~~~
> arch/arm64/kernel/cpuinfo.c:40:27: note: (near initialization for
> 'icache_policy_str[0]')
> 
> because it initializes icache_policy_str[0 ... 3] twice. Since
> arm64 developers are keen to keep the style of initializing a static
> array with a non-zero pattern first, just disable those warnings for
> both GCC and Clang of this file.
> 
> Fixes: 155433cb365e ("arm64: cache: Remove support for ASID-tagged VIVT I-caches")
> Signed-off-by: Qian Cai <cai@lca.pw>

It's a shame we can't just use one cc-disable-warning statement but
-Woverride-init wasn't added for GCC compatibility until clang 8.0.0
and we don't have an established minimum clang version.

With that said, I applied your patch and I don't see with warning with
W=1 anymore and I see both options get added to the clang command line
with V=1.

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>

Cheers!

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <natechancellor@gmail.com>
To: Qian Cai <cai@lca.pw>
Cc: will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com,
	linux-arm-kernel@lists.infradead.org,
	clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64/cache: silence -Woverride-init warnings
Date: Wed, 7 Aug 2019 21:50:27 -0700	[thread overview]
Message-ID: <20190808045027.GA34150@archlinux-threadripper> (raw)
In-Reply-To: <20190808032916.879-1-cai@lca.pw>

On Wed, Aug 07, 2019 at 11:29:16PM -0400, Qian Cai wrote:
> The commit 155433cb365e ("arm64: cache: Remove support for ASID-tagged
> VIVT I-caches") introduced some compiation warnings from GCC (and
> Clang) with -Winitializer-overrides),
> 
> arch/arm64/kernel/cpuinfo.c:38:26: warning: initialized field
> overwritten [-Woverride-init]
> [ICACHE_POLICY_VIPT]  = "VIPT",
>                         ^~~~~~
> arch/arm64/kernel/cpuinfo.c:38:26: note: (near initialization for
> 'icache_policy_str[2]')
> arch/arm64/kernel/cpuinfo.c:39:26: warning: initialized field
> overwritten [-Woverride-init]
> [ICACHE_POLICY_PIPT]  = "PIPT",
>                         ^~~~~~
> arch/arm64/kernel/cpuinfo.c:39:26: note: (near initialization for
> 'icache_policy_str[3]')
> arch/arm64/kernel/cpuinfo.c:40:27: warning: initialized field
> overwritten [-Woverride-init]
> [ICACHE_POLICY_VPIPT]  = "VPIPT",
>                          ^~~~~~~
> arch/arm64/kernel/cpuinfo.c:40:27: note: (near initialization for
> 'icache_policy_str[0]')
> 
> because it initializes icache_policy_str[0 ... 3] twice. Since
> arm64 developers are keen to keep the style of initializing a static
> array with a non-zero pattern first, just disable those warnings for
> both GCC and Clang of this file.
> 
> Fixes: 155433cb365e ("arm64: cache: Remove support for ASID-tagged VIVT I-caches")
> Signed-off-by: Qian Cai <cai@lca.pw>

It's a shame we can't just use one cc-disable-warning statement but
-Woverride-init wasn't added for GCC compatibility until clang 8.0.0
and we don't have an established minimum clang version.

With that said, I applied your patch and I don't see with warning with
W=1 anymore and I see both options get added to the clang command line
with V=1.

Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>

Cheers!

  reply	other threads:[~2019-08-08  4:50 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-08  3:29 [PATCH] arm64/cache: silence -Woverride-init warnings Qian Cai
2019-08-08  3:29 ` Qian Cai
2019-08-08  4:50 ` Nathan Chancellor [this message]
2019-08-08  4:50   ` Nathan Chancellor
2019-08-08 10:38 ` Mark Rutland
2019-08-08 10:38   ` Mark Rutland
2019-08-08 17:09   ` Nathan Chancellor
2019-08-08 17:09     ` Nathan Chancellor
2019-08-09  8:32     ` Explicitly marking initializer overrides (was "Re: [PATCH] arm64/cache: silence -Woverride-init warnings") Mark Rutland
2019-08-09  8:32       ` Mark Rutland
2019-08-09 11:31       ` Robin Murphy
2019-08-09 11:31         ` Robin Murphy
2019-08-14 17:26       ` Nathan Chancellor
2019-08-14 17:26         ` Nathan Chancellor
2019-08-08 22:18   ` [PATCH] arm64/cache: silence -Woverride-init warnings Qian Cai
2019-08-08 22:18     ` Qian Cai
2019-08-09  8:53     ` Mark Rutland
2019-08-09  8:53       ` Mark Rutland
2019-08-09 22:14       ` Nick Desaulniers
2019-08-09 22:14         ` Nick Desaulniers
2019-08-09  9:04     ` Will Deacon
2019-08-09  9:04       ` Will Deacon

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