Re: [PATCH v2 1/2] RISC-V: sbi: turn sbi_ecall into variadic macro

[Paul Walmsley <pjw@kernel.org>]

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On Thu, 19 Jun 2025, Radim Krčmář wrote:

> The SBI ecall interface has 0~6 arguments in a0~a5, and undefined
> arguments are not reserved, so we don't have to zero the registers.
> 
> The current sbi_ecall forces programmers to pad the argument count,
> which makes it hard to distinguish what is a value 0, and what is the
> padding, because 0 was traditionally used for padding as well.
> 
> Turn sbi_ecall into a variadic macro that accepts 2~8 arguments, and
> where only the specified arguments get passed to the ecall instruction.
> 
> The register a1 is zeroed if unused, to prevent unnecessary leaks of
> kernel register state from the tracepoints.
> 
> Signed-off-by: Radim Krčmář <rkrcmar@ventanamicro.com>

Thanks, queued for v7.4.


- Paul