On Wednesday, April 30, 2014 10:12 PM, Catalin Marinas wrote: > On Wed, Apr 30, 2014 at 07:41:40AM +0100, Jungseok Lee wrote: > > On Tuesday, April 29, 2014 11:48 PM, Catalin Marinas wrote: > > > On Tue, Apr 29, 2014 at 05:59:27AM +0100, Jungseok Lee wrote: > > > > --- a/Documentation/arm64/memory.txt > > > > +++ b/Documentation/arm64/memory.txt > > > > @@ -8,10 +8,11 @@ This document describes the virtual memory > > > > layout used by the AArch64 Linux kernel. The architecture allows > > > > up to 4 levels of translation tables with a 4KB page size and up to 3 levels with a 64KB page > size. > > > > > > > > -AArch64 Linux uses 3 levels of translation tables with the 4KB > > > > page -configuration, allowing 39-bit (512GB) virtual addresses for > > > > both user -and kernel. With 64KB pages, only 2 levels of > > > > translation tables are -used but the memory layout is the same. > > > > +AArch64 Linux uses 3 levels and 4 levels of translation tables > > > > +with the 4KB page configuration, allowing 39-bit (512GB) and > > > > +48-bit > > > > +(256TB) virtual addresses, respectively, for both user and kernel. > > > > +With 64KB pages, only 2 levels of translation tables are used but > > > > +the memory layout is the same. > > > > > > Any reason why we couldn't use 48-bit address space with 64K pages (implying 3 levels)? > > > > No technical reason. > > Since 64K+3levels is not implemented in this set, I didn't add it. > > > > Should 64K+3levels be prepared in this patchset? > > > > > > -AArch64 Linux memory layout with 64KB pages: > > > > +AArch64 Linux memory layout with 4KB pages + 4 levels: > > > > + > > > > +Start End Size Use > > > > +----------------------------------------------------------------------- > > > > +0000000000000000 0000ffffffffffff 256TB user > > > > + > > > > +ffff000000000000 ffff7bfffffeffff ~124TB vmalloc > > > > > > BTW, maybe as a separate patch we should change the "end" to be > > > exclusive. It becomes harder to modify (I've been through this a few times already ;)) and even > follow the changes. > > > > Does "exclusive" mean that 0000ffffffffffff is changed to 0001000000000000? > > Or Does it mean that "End" column is dropped? > > Not dropped but changed to 0001.... (the kernel already prints the memory layout in a similar way). I see. I will make it as a separate patch. Best Regards Jungseok Lee -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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