On Friday 29 April 2016 14:07:54 Yang Shi wrote: > Inspired by the counterpart of powerpc [1], which shows there is no negative > effect on code generation from enabling STRICT_MM_TYPECHECKS with a modern > compiler. > > And, Arnd's comment [2] about that patch says STRICT_MM_TYPECHECKS could > be default as long as the architecture can pass structures in registers as > function arguments. ARM64 can do it as long as the size of structure <= 16 > bytes. All the page table value types are u64 on ARM64. > > The below disassembly demonstrates it, entry is pte_t type: > > entry = arch_make_huge_pte(entry, vma, page, writable); > 0xffff00000826fc38 <+80>: and x0, x0, #0xfffffffffffffffd > 0xffff00000826fc3c <+84>: mov w3, w21 > 0xffff00000826fc40 <+88>: mov x2, x20 > 0xffff00000826fc44 <+92>: mov x1, x19 > 0xffff00000826fc48 <+96>: orr x0, x0, #0x400 > 0xffff00000826fc4c <+100>: bl 0xffff00000809bcc0 > <arch_make_huge_pte> > > [1] http://www.spinics.net/lists/linux-mm/msg105951.html > [2] http://www.spinics.net/lists/linux-mm/msg105969.html > > Signed-off-by: Yang Shi <yang....@linaro.org> > CC: Arnd Bergmann <a...@arndb.de> > CC: Ard Biesheuvel <ard.biesheu...@linaro.org> > --- >
Acked-by: Arnd Bergmann <a...@arndb.de>
