[parisc-linux] parisc Dump: lkcd port.

[Grant Grundler]

Bruno Vidal wrote:
> 	Hi
> I've already ask in the past, if there was a dump driver
> for the linux parisc. The answer was no. So, because I've 
> litle time for It I've restart this port.

Oh - excellent!

> Now I've a question
> about a function used for Alpha and i386. 

and mips and mips64.

> In arch/alpha/kernel/setup.c and arch/i386/mm/init.c, there is
> a function called page_is_ram. It seems that this function is 
> used by the dump driver to know if a page is a physical page or 
> not. So my question is: does this function exist for parisc ?

No. I can think of two or three people who should offhand know how
to write this pretty quickly though - one of them is in transit
and the other won't see your mail for a few more hours.

My guess is page_is_ram() for parisc would like something like
the mips or i386 versions but use npmem_ranges (count) and
pmem_ranges[] (table physical page ranges):

/* leveraged from arch/mips/mm/init.c */
static inline int page_is_ram(unsigned long pagenr)
{
        int i;

        for (i = 0; i < npmem_ranges; i++) {
                unsigned long addr, end;

		/* Need to look for holes?
		** parisc doesn't support CONFIG_DISCONTIGMEM (yet?)

                if (pmem_holes[i].start_pfn ...)
                        continue;
		*/

                end = addr = pmem_ranges[i].start_pfn;
                end += pmem_ranges[i].pages;

                if (pagenr >= addr && pagenr < end)
                        return 1;
        }

        return 0;
}

I might be missing some shifting (PAGE_SHIFT) but that should be
easy to figure out.

hth,
grant

ps. I'm very excited to hear you are looking at this again! wohoo!