Messages in this thread | | | Date | Wed, 31 Aug 2011 09:25:25 -0700 | From | "H. Peter Anvin" <> | Subject | Re: RFD: x32 ABI system call numbers |
| |
On 08/31/2011 09:14 AM, Arnd Bergmann wrote: > > Ok, but I think we do need to consider the potential problems in this. > I would expect a number of things to break if we just define it to > 'long long' on new architectures, including: > > * pre-c99 C compilers or programs that rely on --std=c89
This is a very long time ago by now. Pre-C99 compilers without the long long extension probably don't exist for these new architectures; applications is a little bit messier, but still.
> * padding in struct timespec when you have a long long tv_sec and > 32-bit long tv_nsec. This might cause kernel stack data leakage > in some kernel interfaces when they don't clear the padding.
Don't to that then. For what it's worth, I think we currently use the same size for both fields.
> * random broken applications assuming that timespec/timeval has > two 'long' members, instead of using the proper header files. > > Obviously these are all fixable for any new ABI, but will cause > some annoyance. > > I've added a few people to Cc who are in various stages of the > process to finalize their upstream kernel ports. It's clearly > the right decision to have time_t 64-bit eventually, the question > is how much work is everyone willing to spend in the short run, > and who is going to test it. In particular, openrisc has just > been merged, so we should not be changing it any more unless > there is a serious problem, but if there is not much legacy user > space with the current ABI yet, it may still be worth switching > over.
Either way, all of this applies to x32 even more, sadly.
The other thing is that we probably need to do is to set a date when we redefine legacy 32-bit time_t to be unsigned. A good time might be some time around (time_t)0x60000000 = Thu Jan 14 08:25:36 UTC 2021 if not sooner.
-hpa
| |