Messages in this thread | | | Date | Thu, 13 Oct 2022 13:36:06 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH 1/2] riscv: fix detection of toolchain Zicbom support |
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On Thu, Oct 13, 2022 at 09:33:29PM +0100, Conor Dooley wrote: > On Thu, Oct 13, 2022 at 01:22:47PM -0700, Nathan Chancellor wrote: > > On Thu, Oct 06, 2022 at 06:35:20PM +0100, Conor Dooley wrote: > > > From: Conor Dooley <conor.dooley@microchip.com> > > > > > > It is not sufficient to check if a toolchain supports a particular > > > extension without checking if the linker supports that extension too. > > > For example, Clang 15 supports Zicbom but GNU bintutils 2.35.2 does > > > not, leading build errors like so: > > > > > > riscv64-linux-gnu-ld: -march=rv64i2p0_m2p0_a2p0_c2p0_zicbom1p0_zihintpause2p0: Invalid or unknown z ISA extension: 'zicbom' > > > > > > Convert CC_HAS_ZICBOM to TOOLCHAIN_HAS_ZICBOM & check if the linker > > > also supports Zicbom. > > > > > > Reported-by: Kevin Hilman <khilman@baylibre.com> > > > Link: https://github.com/ClangBuiltLinux/linux/issues/1714 > > > Link: https://storage.kernelci.org/next/master/next-20220920/riscv/defconfig+CONFIG_EFI=n/clang-16/logs/kernel.log > > > Fixes: 1631ba1259d6 ("riscv: Add support for non-coherent devices using zicbom extension") > > > Signed-off-by: Conor Dooley <conor.dooley@microchip.com> > > > > The versions look correct to me. I see the LLVM zicbom commit [1] in > > llvmorg-15.0.0 and I see the binutils zicbom commit [2] in > > binutils-2_39. > > > > FWIW, if we are adding explicit tool versions to the Kconfig, could you > > not also drop the cc-option checks? Typically, cc-option is only used > > when dynamically checking for a feature, in lieu of statically checking > > a version. No strong opinion though. > > Ehh, the explicit version checks are for linker support, but it could be > that your linker supports it but other things do not. The compilers > support can still be checked with cc-option, no? > > This error here happens when the compiler does support it, so the string > containing zicbom is emitted in the object files. That can't be checked > dynamically. For the opposite situation, dynamic checking is possible so > I tried retained them. If it's convention to do one or the other, I can > easily switch. > > I'm out of my comfort zone when it comes to kbuild plumbing so please, > please lmk if I'm missing something...
No, you are absolutely correct. That's what I get for reviewing changes right after being off for a week ;) the cc-option checks should remain in addition to the new linker checks, so please disregard that feedback on both changes.
> > > > Reviewed-by: Nathan Chancellor <nathan@kernel.org> > > > > [1]: https://github.com/llvm/llvm-project/commit/4f40ca53cefb725aca6564585d0ec4836a79e21a > > [2]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=41d6ac5da655a2e78109848f2db47e53552fd61a > > > > > --- > > > arch/riscv/Kconfig | 10 ++++++---- > > > arch/riscv/Makefile | 3 +-- > > > 2 files changed, 7 insertions(+), 6 deletions(-) > > > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > > index d557cc50295d..6da36553158b 100644 > > > --- a/arch/riscv/Kconfig > > > +++ b/arch/riscv/Kconfig > > > @@ -401,14 +401,16 @@ config RISCV_ISA_SVPBMT > > > > > > If you don't know what to do here, say Y. > > > > > > -config CC_HAS_ZICBOM > > > +config TOOLCHAIN_HAS_ZICBOM > > > bool > > > - default y if 64BIT && $(cc-option,-mabi=lp64 -march=rv64ima_zicbom) > > > - default y if 32BIT && $(cc-option,-mabi=ilp32 -march=rv32ima_zicbom) > > > + default y > > > + depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zicbom) > > > + depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zicbom) > > > + depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900 > > > > > > config RISCV_ISA_ZICBOM > > > bool "Zicbom extension support for non-coherent DMA operation" > > > - depends on CC_HAS_ZICBOM > > > + depends on TOOLCHAIN_HAS_ZICBOM > > > depends on !XIP_KERNEL && MMU > > > select RISCV_DMA_NONCOHERENT > > > select RISCV_ALTERNATIVE > > > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > > > index 3fa8ef336822..3607d38edb4f 100644 > > > --- a/arch/riscv/Makefile > > > +++ b/arch/riscv/Makefile > > > @@ -57,8 +57,7 @@ toolchain-need-zicsr-zifencei := $(call cc-option-yn, -march=$(riscv-march-y)_zi > > > riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei > > > > > > # Check if the toolchain supports Zicbom extension > > > -toolchain-supports-zicbom := $(call cc-option-yn, -march=$(riscv-march-y)_zicbom) > > > -riscv-march-$(toolchain-supports-zicbom) := $(riscv-march-y)_zicbom > > > +riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZICBOM) := $(riscv-march-y)_zicbom > > > > > > # Check if the toolchain supports Zihintpause extension > > > toolchain-supports-zihintpause := $(call cc-option-yn, -march=$(riscv-march-y)_zihintpause) > > > -- > > > 2.37.3 > > > > > >
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