[linux-sh:03196] Re: [linuxsh-dev] cache info

On Sat, Mar 20, 2004 at 12:54:00PM +0900, Kaz Kojima wrote:
> Hi,
> 
> There is a request for a function replying to the queries about
> cache specifications like cache sizes, ways and line sizes, from
> the latest glibc.
> Unfortunately, /proc can't be used because it might be required at
> very early stage of the userland.  Some other archs read CPU id
> register and other cache-related registers which are readable in
> user mode.
> For SH, such registers are readable only in kernel mode and anyway
> kernel has to give such informations to the userland.  It seems
> saveral ways to implement such function:
> 
> (1)  SH specific system call to get the cache info,
> (2)  interface (including system call) to read hurmless CPU
>      registers,
> (3)  special device,
> (4)  ...
> 
> Perhaps (1) is cleaner as an interface than another methods though
> I'm a bit concerned with SH specific system call number.  We have
> "holes" in system call numbers but there might be no guarantee
> that they won't be used for another purpose.
> 
> Thoughts?  Implementations will be more welcome :-)

PowerPC does this using ELF auxilliary data.  Would that do?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer