Messages in this thread |  | | | Date | Wed, 9 Feb 2000 09:28:14 +0900 | | From | NIIBE Yutaka <> | | Subject | Re: Memory Started not at 0x00000000 |
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Hello!
Roman Zippel wrote: > I would suggest to change init_bootmem(), too, AFAIK the default of zero > is only for i386 helpful, all other have to fiddle with the mem node > interface and IMO we shouldn't begin to mix them if it's not really > necessary. I don't know if it's too late for this, but maybe we should > rename the *_core() functions into *_node() functions and make the other > ones small special inline functions that call the generic versions. That > would remove the bulk of (IMO unnecessary) small functions at the end of > bootmem.c
It'd be good idea. Besides, I'm always confused by the mix of absolute address and PFN. If I remember correctly, Ingo once has tidy up the interface. It seems that it's good chance to define good interface.
> BTW did someone try the patch below? This make a mm mapping possible, > where several physical memory chunks are mapped together in one single > virtual mapping (like we do it currently on m68k). If it doesn't break > anything, it could be integrated?
> @@ -624,7 +624,7 @@ > > void __init free_area_init(unsigned int *zones_size) > { > - free_area_init_core(0, NODE_DATA(0), &mem_map, zones_size, 0); > + free_area_init_core(0, NODE_DATA(0), &mem_map, zones_size, PAGE_OFFSET); > } > > static int __init setup_mem_frac(char *str)
Well, it seems that you are using mm tricks mapping physical memory start address to virtual address PAGE_OFFSET. It can't be applicable to SuperH architecture (or MIPS, I believe). For SuperH, the kernel space mapping are done with *no* TLB lookup, but just mask the address. I don't know if it is usual or not for the MIPS architecture where memory starts not at 0x00000000, but for SuperH, main memory start not at 0x00000000. For example, my evaluation board of SH-3 it starts at 0x0c000000, and evaluation board of SH-4 it start at 0x08000000. Regards, -- Niibe Yutaka
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