On Mon, May 06, 2019 at 06:30:49PM +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. > > strncpy_from_user and strnlen_user accept user addresses as arguments, and > do not go through the same path as copy_from_user and others, so here we > need to handle the case of tagged user addresses separately. > > Untag user pointers passed to these functions. > > Note, that this patch only temporarily untags the pointers to perform > validity checks, but then uses them as is to perform user memory accesses. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Just to keep track of where I am with the reviews while the ABI discussion continues: Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
