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? If you are okay, 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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