On Fri, May 15, 2020 at 10:16 AM Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > To enable tagging on a memory range, the user must explicitly opt in via > a new PROT_MTE flag passed to mmap() or mprotect(). Since this is a new > memory type in the AttrIndx field of a pte, simplify the or'ing of these > bits over the protection_map[] attributes by making MT_NORMAL index 0. Should the userspace stack always be mapped as if with PROT_MTE if the hardware supports it? Such a change would be invisible to non-MTE aware userspace since it would already need to opt in to tag checking via prctl. This would let userspace avoid a complex stack initialization sequence when running with stack tagging enabled on the main thread. Peter
