Messages in this thread | | | Date | Thu, 13 Oct 2022 13:30:16 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH 2/2] riscv: fix detection of toolchain Zihintpause support |
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On Thu, Oct 06, 2022 at 06:35:21PM +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 Zihintpause but GNU bintutils > 2.35.2 does not, leading build errors like so: > > riscv64-linux-gnu-ld: -march=rv64i2p0_m2p0_a2p0_c2p0_zihintpause2p0: Invalid or unknown z ISA extension: 'zihintpause' > > Add a TOOLCHAIN_HAS_ZIHINTPAUSE which checks if each of the compiler, > assembler and linker support the extension. Replace the ifdef in the > vdso with one depending on this new symbol. > > Fixes: 8eb060e10185 ("arch/riscv: add Zihintpause support") > Signed-off-by: Conor Dooley <conor.dooley@microchip.com> > --- > Palmer: > The VDSO change will conflict with Samuel's one, resolution should be > trivial.. I only made that change as you warned me about checking for > the __riscv_foo stuff if I made the march string depend on the Kconfig > entry rather than on the Makefile's cc-option check.
The versions look correct to me. I see the LLVM zihintpause commit [1] in llvmorg-15.0.0 and I see the binutils zihintpause commit [2] in binutils-2_36.
[1]: https://github.com/llvm/llvm-project/commit/005fd8aa702edbc532763038365575da96e5787d [2]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aa881ecde48c7a0224b92e2cfa43b37ee9ec9fa2
Similar comment as patch 1, I think we can just drop the cc-option checks. Regardless:
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> --- > arch/riscv/Kconfig | 7 +++++++ > arch/riscv/Makefile | 3 +-- > arch/riscv/include/asm/vdso/processor.h | 2 +- > 3 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 6da36553158b..d7c53896e24f 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -425,6 +425,13 @@ config RISCV_ISA_ZICBOM > > If you don't know what to do here, say Y. > > +config TOOLCHAIN_HAS_ZIHINTPAUSE > + bool > + default y > + depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zihintpause) > + depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zihintpause) > + depends on LLD_VERSION >= 150000 || LD_VERSION >= 23600 > + > config FPU > bool "FPU support" > default y > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > index 3607d38edb4f..6651517f3962 100644 > --- a/arch/riscv/Makefile > +++ b/arch/riscv/Makefile > @@ -60,8 +60,7 @@ riscv-march-$(toolchain-need-zicsr-zifencei) := $(riscv-march-y)_zicsr_zifencei > riscv-march-$(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) > -riscv-march-$(toolchain-supports-zihintpause) := $(riscv-march-y)_zihintpause > +riscv-march-$(CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE) := $(riscv-march-y)_zihintpause > > KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y)) > KBUILD_AFLAGS += -march=$(riscv-march-y) > diff --git a/arch/riscv/include/asm/vdso/processor.h b/arch/riscv/include/asm/vdso/processor.h > index 1e4f8b4aef79..fa70cfe507aa 100644 > --- a/arch/riscv/include/asm/vdso/processor.h > +++ b/arch/riscv/include/asm/vdso/processor.h > @@ -21,7 +21,7 @@ static inline void cpu_relax(void) > * Reduce instruction retirement. > * This assumes the PC changes. > */ > -#ifdef __riscv_zihintpause > +#ifdef CONFIG_TOOLCHAIN_HAS_ZIHINTPAUSE > __asm__ __volatile__ ("pause"); > #else > /* Encoding of the pause instruction */ > -- > 2.37.3 > >
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