| Message ID | 20240509013727.648600-1-samuel.holland@sifive.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | ARM: Do not select ARCH_HAS_KERNEL_FPU_SUPPORT | expand |
On Thu, 9 May 2024 at 03:37, Samuel Holland <samuel.holland@sifive.com> wrote: > > 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. > > Fixes: 12624fe2d707 ("ARM: implement ARCH_HAS_KERNEL_FPU_SUPPORT") This commit is not in mainline yet. Could we just drop the original patch instead? > Reported-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> > Closes: https://lore.kernel.org/lkml/87wmp4oo3y.fsf@linaro.org/ > Reported-by: kernel test robot <lkp@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202404042327.jRpt81kP-lkp@intel.com/ > Suggested-by: Ard Biesheuvel <ardb@kernel.org> > Signed-off-by: Samuel Holland <samuel.holland@sifive.com> > --- > > arch/arm/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index b1751c2cab87..b14aed3a17ab 100644 > --- a/arch/arm/Kconfig > +++ b/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 > -- > 2.44.0 >
Hello Ard, On 2024-05-09 2:39 AM, Ard Biesheuvel wrote: > On Thu, 9 May 2024 at 03:37, Samuel Holland <samuel.holland@sifive.com> wrote: >> >> 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. >> >> Fixes: 12624fe2d707 ("ARM: implement ARCH_HAS_KERNEL_FPU_SUPPORT") > > This commit is not in mainline yet. Could we just drop the original > patch instead? No, like I mentioned in the original thread, later patches in the series (for example bbce5cac4f5a ("lib/raid6: use CC_FLAGS_FPU for NEON CFLAGS")) depend on CC_FLAGS_FPU being defined for both arm and arm64. arm can't select ARCH_HAS_KERNEL_FPU_SUPPORT because the contract of that option is not fully implemented, but in my opinion it doesn't hurt to keep the part that is implemented. Regards, Samuel >> Reported-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> >> Closes: https://lore.kernel.org/lkml/87wmp4oo3y.fsf@linaro.org/ >> Reported-by: kernel test robot <lkp@intel.com> >> Closes: https://lore.kernel.org/oe-kbuild-all/202404042327.jRpt81kP-lkp@intel.com/ >> Suggested-by: Ard Biesheuvel <ardb@kernel.org> >> Signed-off-by: Samuel Holland <samuel.holland@sifive.com> >> --- >> >> arch/arm/Kconfig | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig >> index b1751c2cab87..b14aed3a17ab 100644 >> --- a/arch/arm/Kconfig >> +++ b/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 >> -- >> 2.44.0 >>
On Wed, 15 May 2024 at 00:48, Samuel Holland <samuel.holland@sifive.com> wrote: > > Hello Ard, > > On 2024-05-09 2:39 AM, Ard Biesheuvel wrote: > > On Thu, 9 May 2024 at 03:37, Samuel Holland <samuel.holland@sifive.com> wrote: > >> > >> 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. > >> > >> Fixes: 12624fe2d707 ("ARM: implement ARCH_HAS_KERNEL_FPU_SUPPORT") > > > > This commit is not in mainline yet. Could we just drop the original > > patch instead? > > No, like I mentioned in the original thread, later patches in the series (for > example bbce5cac4f5a ("lib/raid6: use CC_FLAGS_FPU for NEON CFLAGS")) depend on > CC_FLAGS_FPU being defined for both arm and arm64. > > arm can't select ARCH_HAS_KERNEL_FPU_SUPPORT because the contract of that option > is not fully implemented, but in my opinion it doesn't hurt to keep the part > that is implemented. > Fair enough. But that still doesn't mean we have to add the 'select ARCH_HAS_KERNEL_FPU_SUPPORT' only to back it out again.
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index b1751c2cab87..b14aed3a17ab 100644 --- a/arch/arm/Kconfig +++ b/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
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. Fixes: 12624fe2d707 ("ARM: implement ARCH_HAS_KERNEL_FPU_SUPPORT") Reported-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org> Closes: https://lore.kernel.org/lkml/87wmp4oo3y.fsf@linaro.org/ Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202404042327.jRpt81kP-lkp@intel.com/ Suggested-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Samuel Holland <samuel.holland@sifive.com> --- arch/arm/Kconfig | 1 - 1 file changed, 1 deletion(-)