Re: [v1 PATCH 2/2] RISC-V: Consolidate isa correctness check

[Christoph Hellwig <hch@infradead.org>]

> +int riscv_read_check_isa(struct device_node *node, const char **isa)
> +{
> +	u32 hart;
> +
> +	if (of_property_read_u32(node, "reg", &hart)) {
> +		pr_warn("Found CPU without hart ID\n");
> +		return -ENODEV;
> +	}
> +
> +	if (of_property_read_string(node, "riscv,isa", isa)) {
> +		pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n",
> +			hart);
> +		return -ENODEV;
> +	}
> +
> +	/*
> +	 * Linux doesn't support rv32e or rv128i, and we only support booting
> +	 * kernels on harts with the same ISA that the kernel is compiled for.
> +	 */
> +#if defined(CONFIG_32BIT)
> +	if (strncmp(*isa, "rv32i", 5) != 0)
> +		return -ENODEV;
> +#elif defined(CONFIG_64BIT)
> +	if (strncmp(*isa, "rv64i", 5) != 0)
> +		return -ENODEV;
> +#endif

Using IS_ENABLED here would clean the checks up a bit.

> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index b1ade9a49347..eaad5aa07403 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -38,10 +38,8 @@ void riscv_fill_hwcap(void)
>  		if (riscv_of_processor_hartid(node) < 0)
>  			continue;
>  
> -		if (of_property_read_string(node, "riscv,isa", &isa)) {
> -			pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> +		if (riscv_read_check_isa(node, &isa) < 0)
>  			continue;

Do we really get rid of warnings if we didn't find anything proper?