Re: [PATCH v2 2/7] linux-user/alpha: Rename the sigaction restorer field

[Richard Henderson]

On 4/23/21 3:16 AM, Alex Bennée wrote:
> Richard Henderson <richard.henderson@linaro.org> writes:
>
> > Use ka_restorer, in line with TARGET_ARCH_HAS_KA_RESTORER
> > vs TARGET_ARCH_HAS_SA_RESTORER, since Alpha passes this
> > field as a syscall argument.
>
> I'm still slightly confused - but that's to be expected from signals :-/
>
> Anyway I understand that the SA_RESTORER points to the vdso trampoline
> (at least according to man sigreturn). What is ka_restorer - if this the
> in sigframe restorer?

Both sa_restorer and ka_restorer pre-date the vdso trampoline.  They allow libc 
to register a trampoline itself.

The difference is that sa_restorer is a field in struct sigaction, and 
ka_restorer is an extra argument to the sigaction syscall.  Different targets 
used different approaches.

> > -    abi_ulong sa_restorer;
> > +    abi_ulong ka_restorer;
> >   };
>
> Maybe this is something we could expand a little on in the difference
> between the two here (or maybe in the later commit?).

Perhaps elsewhere.  This change is simply to make alpha line up with the 
generic code that will replace it.


r~