On Mon, Dec 19, 2011 at 02:58:13PM +0100, Michal Simek wrote:I have reached some problems with memblock and bootmem code for some configurations.
We can completely setup the whole system and all addresses in it.
The problem happens if we place main memory to the end of address space when
mem_start + size reach 4GB limit.
For example:
mem_start 0xF000 0000
mem_size 0x1000 0000 (or better lowmem size)
mem_end 0xFFFF FFFF
start + size 0x1 0000 0000 (u32 limit reached).
I have done some patches which completely remove start + size values from architecture specific
code but I have found some problem in generic code too.
For example in bootmem code where are three places where physaddr + size is used.
I would prefer to retype it to u64 because baseaddr and size don't need to be 2^n.
Is it correct solution? If yes, I will create proper patch.
Yeah, that's an inherent problem in using [) ranges but I think
chopping off the last page probably is simpler and more robust
solution. Currently, memblock_add_region() would simply ignore if
address range overflows but making it just ignore the last page is
several lines of addition. Wouldn't that be effective enough while
staying very simple?