On Mon, Nov 23, 2015 at 10:55:16AM -0800, Daniel Cashman wrote: > On 11/23/2015 07:04 AM, Will Deacon wrote: > > On Wed, Nov 18, 2015 at 03:20:07PM -0800, Daniel Cashman wrote: > >> +config ARCH_MMAP_RND_BITS_MAX > >> + default 20 if ARM64_64K_PAGES && ARCH_VA_BITS=39 Where is ARCH_VA_BITS defined? We only have options like ARM64_VA_BITS_39. BTW, we no longer allow the 64K pages and 39-bit VA combination. > >> + default 24 if ARCH_VA_BITS=39 > >> + default 23 if ARM64_64K_PAGES && ARCH_VA_BITS=42 > >> + default 27 if ARCH_VA_BITS=42 > >> + default 29 if ARM64_64K_PAGES && ARCH_VA_BITS=48 > >> + default 33 if ARCH_VA_BITS=48 > >> + default 15 if ARM64_64K_PAGES > >> + default 19 > >> + > >> +config ARCH_MMAP_RND_COMPAT_BITS_MIN > >> + default 7 if ARM64_64K_PAGES > >> + default 11 > > > > FYI: we now support 16k pages too, so this might need updating. It would > > be much nicer if this was somehow computed rather than have the results > > all open-coded like this. > > Yes, I ideally wanted this to be calculated based on the different page > options and VA_BITS (which itself has a similar stanza), but I don't > know how to do that/if it is currently supported in Kconfig. This would > be even more desirable with the addition of 16K_PAGES, as with this > setup we have a combinatorial problem. For KASan, we ended up calculating KASAN_SHADOW_OFFSET in arch/arm64/Makefile. What would the formula be for the above ARCH_MMAP_RND_BITS_MAX? -- Catalin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>