On Fri, Aug 24, 2012 at 05:30:21PM -0700, H. Peter Anvin wrote:
> On 08/24/2012 04:55 PM, Jacob Shin wrote:
> >+
> >+ for (i = 0; i < e820.nr_map; i++) {
> >+ struct e820entry *ei = &e820.map[i];
> >+ u64 start = ei->addr;
> >+ u64 end = ei->addr + ei->size;
> >+
> >+ /* we only map E820_RAM */
> >+ if (ei->type != E820_RAM)
> >+ continue;
> >+
> >+ if (end <= ISA_END_ADDRESS)
> >+ continue;
> >+
> >+ if (start <= ISA_END_ADDRESS)
> >+ start = 0;
> >+#ifdef CONFIG_X86_32
> >+ /* on 32 bit, we only map up to max_low_pfn */
> >+ if ((start >> PAGE_SHIFT) >= max_low_pfn)
> >+ continue;
> >+
> >+ if ((end >> PAGE_SHIFT) > max_low_pfn)
> >+ end = max_low_pfn << PAGE_SHIFT;
> >+#endif
> >+ /* the ISA range is always mapped regardless of holes */
> >+ if (!pfn_range_is_mapped(0, ISA_END_ADDRESS << PAGE_SHIFT) &&
> >+ start != 0)
> >+ init_memory_mapping(0, ISA_END_ADDRESS);
> >+
> >+ init_memory_mapping(start, end);
> >+ }
> >+
>
> The ISA range mapping doesn't really make sense *inside* the loop,
> no? It seems you could do that before you enter the loop and then
> simply have:
>
> + if (end <= ISA_END_ADDRESS)
> + continue;
> +
> + if (start <= ISA_END_ADDRESS)
> + start = ISA_END_ADDRESS;
>
> ... no?
Right, I think what I was attempting to do was to merge the 1MB
with E820_RAM right above 1MB:
So instead of:
init_memory_mapping(0, 1MB)
init_memory_mapping(1MB, 2GB)
It would be:
init_memory_mapping(0, 2GB)
While taking care of the odd case where there is a gap right after
1MB.
But if its not worth it, I can move it out of the loop.
>
> -hpa
>
> --
> H. Peter Anvin, Intel Open Source Technology Center
> I work for Intel. I don't speak on their behalf.
>
>
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