site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com On Mar 6, 2007, at 4:35 PM, Bhavesh Davda wrote: What's the equivalent of Linux's kmap to map a user virtual address into the kernel memory space so that it is accessible "magically" (i.e. without any additional mapping/unmapping required) to all other tasks and kernel threads? What do you mean by 'accessible "magically"'? = Mike _______________________________________________ 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... Are you just trying to make a portion of a user map visible in the kernel map, or are you trying to project that space into other maps as well? From what I can tell, the Linux 'kmap' call just maps a single user page somewhere into the kernel address space, so I'm assuming that you mean "so that other processes can call code in the kernel and see this page from there". Typically, you don't want to map user data into the kernel in the first place; it's expensive and kernel VM is a scarce resource - typically you will find it's faster just to copy the page in/out. If you are trying to establish a shared page for the purposes of communication, I'd be inclined to encourage you to consider the system's native communication primitives instead. There are lots of ways of moving map entries around depending on what you're trying to achieve. I've already looked at vm_map and AFAICT, that ain't it. If you're doing this in an I/O Kit kext, the canonical tool for handling memory in another address space is the IOMemoryDescriptor. You can use this to map said memory, if you really need it. This email sent to site_archiver@lists.apple.com