From: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
To: Samuel Holland <samuel.holland@sifive.com>
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 22:27:52 -0300 [thread overview]
Message-ID: <87le5kofhj.fsf@linaro.org> (raw)
In-Reply-To: <4c8e63d6-ba33-47fe-8150-59eba8babf2d@sifive.com> (Samuel Holland's message of "Wed, 10 Apr 2024 20:11:04 -0500")
Hello Samuel,
Samuel Holland <samuel.holland@sifive.com> writes:
> 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.
Ok, thank you for clarifying.
Andrew Pinski just responded on the GCC bugzilla and if I understood his
point correctly, it seems to be a matter of changing function names to
what GCC (or actually the arm EABI) expects...
--
Thiago
next prev parent reply other threads:[~2024-04-11 1:27 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
2024-04-11 1:27 ` Thiago Jung Bauermann [this message]
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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