Re: [PATCH v2 0/2] RISC-V: turn sbi_ecall into a variadic macro

[David Laight]

On Mon, 23 Jun 2025 15:53:58 -0700 (PDT)
Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote:

> On Thu, 19 Jun 2025 12:03:12 PDT (-0700), rkrcmar@xxxxxxxxxxxxxxxx wrote:
> > v2 has a completely rewritten [1/2], and fixes some missed trailing
> > zeroes in [2/2].  The fixes in [2/2] are important for v2, because
> > sbi_ecall doesn't fill the registers with zeroes anymore.  
> 
> The SBI spec says "Registers that are not defined in the SBI function 
> call are not reserved." and I'm not really sure what to make of that.  
> Specifically: does that mean implementations are allowed to ascribe 
> custom meaning to those parameters and might start doing stuff if 
> they're not set to zero?

Or does it mean they aren't guaranteed to be preserved?

	David