Re: Kernel Syscall from Ada?

["Dan'l Miller" <optikos@verizon.net>]

On Thursday, June 23, 2016 at 3:36:21 AM UTC-5, Diogenes wrote:
> Is there a simple way to make a direct (Linux)Kernel syscall from Ada without using the system C library? i.e. Make a direct call as in Assembler?
> 
> I'm asking because I've found a way to strip about 80k from a statically linked executable by not including Interfaces.C in the runtime.
> 
> I've gotten my code to work reasonably well (no segfaults or memory errors) using inline Assembler. But it seems like there should be an Abstract or Generic "syscall" feature as part of the System library that we could use for doing our own Kernel calls. Same thing for the vDSO.
> 
> Any tips?
> 
> Diogenes

Well, coming at the topic top down from the momentum of ISO/IEEE standardization, for system calls in POSIX.2 (C API) there does exist an analogous POSIX.5 (Ada API).  Whenever possible this should be utilized (and extended/maintained where stale).
front-matter preview:
https://webstore.iec.ch/preview/info_isoiec14519%7Bed2.0%7Den.pdf
available for purchase in each major national standards body, such as for $232 in the USA:
https://webstore.ansi.org/RecordDetail.aspx?sku=ISO%2FIEC%2014519:2001&source=preview

Coming at the topic bottom up from Linux kernel space, the C-language system calls could be augmented with a wholesale rethink of all the system calls into Ada-speak as a new Ada-centric distribution of Linux.
https://www.kernel.org/doc/html/v4.10/process/adding-syscalls.html