On Mon, Jun 03, 2019 at 06:55:07PM +0200, Andrey Konovalov wrote: > This patch is a part of a series that extends arm64 kernel ABI to allow to > pass tagged user pointers (with the top byte set to something else other > than 0x00) as syscall arguments. > > This patch allows tagged pointers to be passed to the following memory > syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect, > mremap, msync, munlock. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> I would add in the commit log (and possibly in the code with a comment) that mremap() and mmap() do not currently accept tagged hint addresses. Architectures may interpret the hint tag as a background colour for the corresponding vma. With this: Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> -- Catalin