From: Zwane Mwaikambo [mailto:zwane@linux.realnet.co.sz] Sent: Thursday, May 30, 2002 12:26 PM > You can access userland address space from kernel context > *and* interrupt > context LDD chapter 6 page 192: A number of actions require the context of a process in order to be executed. When you are outside of process context (i.e., in interrupt mode), you must observe the following rules: No access to user space is allowed. Because there is no process context, there is no path to the user space associated with any particular process. The current pointer is not valid in interrupt mode, and cannot be used. No sleeping or scheduling may be performed. Interrupt-mode code may not call schedule or sleep_on; it also may not call any other function that may sleep. For example, calling kmalloc(..., GFP_KERNEL) is against the rules. Semaphores also may not be used since they can sleep. -- Martin Hansen Student at SDU Sonderborg. www.sdu.dk Writing final project at Danfoss drives A/S. http://drives.danfoss.com Tlf: 74 88 54 62 -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
