site_archiver@lists.apple.com Delivered-To: Darwin-kernel@lists.apple.com On 07 Apr 2010, at 08:08, Alain Renaud wrote: So my question on a 32bit kernel is it possible to transform a 64bit userspace uio to a 32bit userspace uio? Jonas _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... I am not sure this is possible but here goes. I am working on a filesystem kernel driver on a 10.6 32bit kernel userspace application can send me write request (vnop_write_desc) with a UIO_USERSPACE64 uio. In my code path I pass this uio to the physio() function which try to assign the iovec to a bp->b_datap, to do so it CASTDOWN the 64bit iov_base address to 32bit breaking it. I'm no expert in file system kernel programming, but if I understand you correctly it is certainly possible. At least OpenAFS supports UIO_USERSPACE64 requests on Mac OS X 10.5 and higher. Search for UIO_USERSPACE64 in http://openafs.sourcearchive.com/documentation/1.4.10plus-pdfsg1/DARWIN_2osi... This email sent to site_archiver@lists.apple.com