On 05/01/2015 11:55 AM, Andy Lutomirski wrote: > On Thu, Apr 30, 2015 at 6:30 PM, Rik van Riel <r...@redhat.com> wrote:
>> I suspect it would be possible to stick a call to a new function >> (return_to_user ?) right after the DISABLE_INTERRUPTS below, which >> could be used to do the context tracking user_enter just once, and >> later on also to load the user FPU context (patches I have sitting >> around). >> >> syscall_return: >> /* The IRETQ could re-enable interrupts: */ >> DISABLE_INTERRUPTS(CLBR_ANY) >> TRACE_IRQS_IRETQ >> >> Andy, Denys, do you guys see any issues with that idea? > > Ick. Let's make the mess better before we make it worse. Now that > Denys disentangled the syscall exit path from the interrupt exit path, > let me see if I can just rewrite the syscall exit path entirely later > this week. I suspect we probably only need two possible function calls at syscall exit time: 1) A function that is called with interrupts still enabled, testing flags that could be set again if something happens (eg. preemption) between when the function is called, and we return to user space. 2) A function that is called after the point of no return, with interrupts disabled, which does (mostly) small things that only happen once. -- All rights reversed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
