Re: [PATCH] riscv: Make sure toolchain supports zba before using zba instructions
From: Clément Léger
Date: Fri Mar 28 2025 - 08:52:13 EST
On 28/03/2025 12:54, Alexandre Ghiti wrote:
> Old toolchain like gcc 8.5.0 does not support zba, so we must check that
> the toolchain supports this extension before using it in the kernel.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202503281836.8pntHm6I-lkp@xxxxxxxxx/
> Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
> ---
> arch/riscv/Kconfig | 8 ++++++++
> arch/riscv/include/asm/runtime-const.h | 5 +++--
> 2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 0d8def968a7e..ae6303f15b28 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -735,6 +735,14 @@ config TOOLCHAIN_HAS_VECTOR_CRYPTO
> def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb)
> depends on AS_HAS_OPTION_ARCH
>
> +config TOOLCHAIN_HAS_ZBA
> + bool
> + default y
> + depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zba)
> + depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zba)
> + depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
> + depends on AS_HAS_OPTION_ARCH
> +
> config RISCV_ISA_ZBA
Hi Alex,
Why not add a "depends on TOOLCHAIN_HAS_ZBA" here so you don't have to
check for that config option when using CONFIG_RISCV_ISA_ZBA ? This is
done like that for ZBB and ZBC.
Thanks,
Clément
> bool "Zba extension support for bit manipulation instructions"
> default y
> diff --git a/arch/riscv/include/asm/runtime-const.h b/arch/riscv/include/asm/runtime-const.h
> index ea2e49c7149c..c07d049fdd5d 100644
> --- a/arch/riscv/include/asm/runtime-const.h
> +++ b/arch/riscv/include/asm/runtime-const.h
> @@ -77,7 +77,8 @@
> ".long 1b - .\n\t" \
> ".popsection" \
>
> -#if defined(CONFIG_RISCV_ISA_ZBA) && defined(CONFIG_RISCV_ISA_ZBKB)
> +#if defined(CONFIG_RISCV_ISA_ZBA) && defined(CONFIG_TOOLCHAIN_HAS_ZBA) \
> + && defined(CONFIG_RISCV_ISA_ZBKB)
> #define runtime_const_ptr(sym) \
> ({ \
> typeof(sym) __ret, __tmp; \
> @@ -93,7 +94,7 @@
> : [__ret] "=r" (__ret), [__tmp] "=r" (__tmp)); \
> __ret; \
> })
> -#elif defined(CONFIG_RISCV_ISA_ZBA)
> +#elif defined(CONFIG_RISCV_ISA_ZBA) && defined(CONFIG_TOOLCHAIN_HAS_ZBA)
> #define runtime_const_ptr(sym) \
> ({ \
> typeof(sym) __ret, __tmp; \