Re: sigset_t for new arches

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Mon, Nov 13, 2017 at 2:29 PM, Vineet Gupta
<Vineet.Gupta1@synopsys.com> wrote:
> Hi,
>
> This came to light when initial testing ARC port to glibc.
>
> ARC glibc sigaction wrapper was failing as Linux kernel expects sa_mask
> (sigset_t) to be 2 words (for the asm-generic syscall ABI mandated for newer
> arches) while glibc defines it to be 32 words.
>
> The quick fix is to lie to kernel about it - and following works. This is
> also approach taken by few other arches.
>
>         return INLINE_SYSCALL(rt_sigaction, 4,
> -                       sig, act, oact, sizeof(act->sa_mask));
> +                      sig, act, oact, _NSIG / 8);
>
>
> However, IMHO, it would be nicer to just define sigset_t to be 2 words wide
> for the relevant arch. If nothing else it would conserver some memory.
>
> My proposal is to define _SIGSET_NWORDS per arch in some header, with a
> fallback header defaulting to what the current value is. Does this make
> sense ? If yes, should this be in a new header or put in existing hdr etc.

No.  See:

https://sourceware.org/ml/libc-alpha/2017-11/msg00412.html

-- 
H.J.