The patch titled
Subject: ARM: do not select ARCH_HAS_KERNEL_FPU_SUPPORT
has been added to the -mm mm-nonmm-unstable branch. Its filename is
arm-implement-arch_has_kernel_fpu_support-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/arm-implement-arch_has_kernel_fpu_support-fix.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Samuel Holland <samuel.holland@xxxxxxxxxx>
Subject: ARM: do not select ARCH_HAS_KERNEL_FPU_SUPPORT
Date: Wed, 8 May 2024 18:37:10 -0700
On 32-bit ARM, conversions between `double` and `long long` require
runtime library support. Since the kernel does not currently provide this
library support, the amdgpu driver fails to build:
ERROR: modpost: "__aeabi_l2d" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!
ERROR: modpost: "__aeabi_d2ulz" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!
As Arnd reports, there are likely no 32-bit ARM platforms which can use
the amdgpu driver anyway, due to lack of features like 64-bit prefetchable
BARs. Since amdgpu is currently the only real user of
ARCH_HAS_KERNEL_FPU_SUPPORT, drop support for this option instead of
bothering to implement the library functions.
Link: https://lkml.kernel.org/r/20240509013727.648600-1-samuel.holland@xxxxxxxxxx
Fixes: 12624fe2d707 ("ARM: implement ARCH_HAS_KERNEL_FPU_SUPPORT")
Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
Reported-by: Thiago Jung Bauermann <thiago.bauermann@xxxxxxxxxx>
Closes: https://lore.kernel.org/lkml/87wmp4oo3y.fsf@xxxxxxxxxx/
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202404042327.jRpt81kP-lkp@xxxxxxxxx/
Suggested-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/Kconfig | 1 -
1 file changed, 1 deletion(-)
--- a/arch/arm/Kconfig~arm-implement-arch_has_kernel_fpu_support-fix
+++ a/arch/arm/Kconfig
@@ -15,7 +15,6 @@ config ARM
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_KCOV
- select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
_
Patches currently in -mm which might be from samuel.holland@xxxxxxxxxx are
x86-fpu-fix-asm-fpu-typesh-include-guard.patch
arch-add-arch_has_kernel_fpu_support.patch
arm-implement-arch_has_kernel_fpu_support.patch
arm-implement-arch_has_kernel_fpu_support-fix.patch
arm-crypto-use-cc_flags_fpu-for-neon-cflags.patch
arm64-implement-arch_has_kernel_fpu_support.patch
arm64-crypto-use-cc_flags_fpu-for-neon-cflags.patch
lib-raid6-use-cc_flags_fpu-for-neon-cflags.patch
loongarch-implement-arch_has_kernel_fpu_support.patch
powerpc-implement-arch_has_kernel_fpu_support.patch
x86-implement-arch_has_kernel_fpu_support.patch
riscv-add-support-for-kernel-mode-fpu.patch
drm-amd-display-use-arch_has_kernel_fpu_support.patch
selftests-fpu-move-fp-code-to-a-separate-translation-unit.patch
selftests-fpu-allow-building-on-other-architectures.patch
