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From: Samuel Holland <samuel.holland@sifive.com>
To: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-arm-kernel@lists.infradead.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
	Christoph Hellwig <hch@lst.de>,
	loongarch@lists.linux.dev, amd-gfx@lists.freedesktop.org,
	Alex Deucher <alexander.deucher@amd.com>
Subject: Re: [PATCH v4 13/15] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT
Date: Wed, 10 Apr 2024 20:11:04 -0500	[thread overview]
Message-ID: <4c8e63d6-ba33-47fe-8150-59eba8babf2d@sifive.com> (raw)
In-Reply-To: <87wmp4ogoe.fsf@linaro.org>

Hi Thiago,

On 2024-04-10 8:02 PM, Thiago Jung Bauermann wrote:
> Samuel Holland <samuel.holland@sifive.com> writes:
>> On 2024-04-10 5:21 PM, Thiago Jung Bauermann wrote:
>>>
>>> Unfortunately this patch causes build failures on arm with allyesconfig
>>> and allmodconfig. Tested with next-20240410.
> 
> <snip>
> 
>> In both cases, the issue is that the toolchain requires runtime support to
>> convert between `unsigned long long` and `double`, even when hardware FP is
>> enabled. There was some past discussion about GCC inlining some of these
>> conversions[1], but that did not get implemented.
> 
> Thank you for the explanation and the bugzilla reference. I added a
> comment there mentioning that the problem came up again with this patch
> series.
> 
>> The short-term fix would be to drop the `select ARCH_HAS_KERNEL_FPU_SUPPORT` for
>> 32-bit arm until we can provide these runtime library functions.
> 
> Does this mean that patch 2 in this series:
> 
> [PATCH v4 02/15] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
> 
> will be dropped?

No, because later patches in the series (3, 6) depend on the definition of
CC_FLAGS_FPU from that patch. I will need to send a fixup patch unless I can
find a GPL-2 compatible implementation of the runtime library functions.

Regards,
Samuel


  reply	other threads:[~2024-04-11  1:11 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-29  7:18 [PATCH v4 00/15] Unified cross-architecture kernel-mode FPU API Samuel Holland
2024-03-29  7:18 ` [PATCH v4 01/15] arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29  7:18 ` [PATCH v4 02/15] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29  7:18 ` [PATCH v4 03/15] ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
2024-03-29  7:18 ` [PATCH v4 04/15] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29  7:18 ` [PATCH v4 05/15] arm64: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
2024-03-29  7:18 ` [PATCH v4 06/15] lib/raid6: " Samuel Holland
2024-03-29  7:18 ` [PATCH v4 07/15] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29  7:18 ` [PATCH v4 08/15] powerpc: " Samuel Holland
2024-03-29  7:18 ` [PATCH v4 09/15] x86/fpu: Fix asm/fpu/types.h include guard Samuel Holland
2024-03-29 17:30   ` Dave Hansen
2024-03-29  7:18 ` [PATCH v4 10/15] x86: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29 17:28   ` Dave Hansen
2024-03-29 18:02     ` Samuel Holland
2024-03-29  7:18 ` [PATCH v4 11/15] riscv: Add support for kernel-mode FPU Samuel Holland
2024-03-29  7:18 ` [PATCH v4 12/15] drm/amd/display: Only use hard-float, not altivec on powerpc Samuel Holland
2024-04-30 17:28   ` Harry Wentland
2024-03-29  7:18 ` [PATCH v4 13/15] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-04-10 22:21   ` Thiago Jung Bauermann
2024-04-10 22:47     ` Samuel Holland
2024-04-11  1:02       ` Thiago Jung Bauermann
2024-04-11  1:11         ` Samuel Holland [this message]
2024-04-11  1:27           ` Thiago Jung Bauermann
2024-04-11  7:15           ` Ard Biesheuvel
2024-04-11  7:31             ` Arnd Bergmann
2024-04-12  1:54               ` Dave Airlie
2024-04-30 17:29   ` Harry Wentland
2024-05-24  4:50   ` Guenter Roeck
2024-05-24 13:17     ` Alex Deucher
2024-05-24 13:18       ` Alex Deucher
2024-05-24 13:43         ` Guenter Roeck
2024-05-24 13:53           ` Guenter Roeck
2024-05-24 18:23         ` Guenter Roeck
2024-03-29  7:18 ` [PATCH v4 14/15] selftests/fpu: Move FP code to a separate translation unit Samuel Holland
2024-03-29  7:18 ` [PATCH v4 15/15] selftests/fpu: Allow building on other architectures Samuel Holland
2024-04-03 12:51 ` [PATCH v4 00/15] Unified cross-architecture kernel-mode FPU API Christian König

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