On Mon, Jul 31 2023 at 19:35, Peter Zijlstra wrote: > On Mon, Jul 31, 2023 at 07:16:29PM +0200, Thomas Gleixner wrote: >> On Mon, Jul 31 2023 at 18:11, Thomas Gleixner wrote: >> > On Fri, Jul 21 2023 at 12:22, Peter Zijlstra wrote: >> >> -#define FUTEX2_MASK (FUTEX2_32 | FUTEX2_PRIVATE) >> >> +#define FUTEX2_MASK (FUTEX2_64 | FUTEX2_PRIVATE) >> >> >> >> /** >> >> * futex_parse_waitv - Parse a waitv array from userspace >> >> @@ -207,7 +207,12 @@ static int futex_parse_waitv(struct fute >> >> if ((aux.flags & ~FUTEX2_MASK) || aux.__reserved) >> >> return -EINVAL; >> > >> > With the above aux.flags with FUTEX2_32 set will result in -EINVAL. I >> > don't think that's intentional. >> >> Also if you allow 64bit wide futexes, how is that supposed to work with >> the existing code, which clearly expects a 32bit uval throughout the >> place? > > Not allowed yet, these patches only allow 8,16,32. I still need to audit > the whole futex core and do 'u32 -> unsigned long' (and everything else > that follows from that), and only when that's done can the futex2 > syscalls allow FUTEX2_64 on 64bit archs. > > So for now, these patches: > > - add the FUTEX2_64 flag, > - add 'unsigned long' interface such that > 64bit can potentiall use it, > - explicitly disallow having it set. I figured that out very late. This flags having a size fields which claims to be flags had confused the hell out of me.
