[Adding Linux and linux-arch. The context is that get_user/put_user don't work on 64 bit values on i386.] On 08/11/2010 05:33 PM, Andrew Morton wrote: > > Anyway, this should be fixed in x86 core, I suspect. After looking at it -- and suffering a bad case of déjà vu -- I'm reluctant to change it, as get/put_user are specified to work only on locally atomic data: * This macro copies a single simple variable from user space to kernel * space. It supports simple types like char and int, but not larger * data types like structures or arrays. Given that u64 is not a simple type on 32 bits, it would appear that the behavior is intentional. A user might very well find that supporting u64 and/or structure types would be beneficial, but it would a) be a semantic change, and b) would introduce the possibility of a partially completed transfer. That is a semantic change to the interface. However, it may very well be nicer to have a generally available get_user()/put_user() for the cases which would just kick an EFAULT up the stack when they fail anyway. If there is consensus for making get_user/put_user a general interface, I'm more than willing to do the x86 changes, but I don't want to do them a) unilaterally and b) for 2.6.36. This seems like .37 material at this point. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
