On 10/26/2017 01:26 AM, Andy Lutomirski wrote: > +GLOBAL(restore_regs_and_return_to_usermode) > +#ifdef CONFIG_DEBUG_ENTRY > + testl $3, CS(%rsp) > + jnz 1f > + ud2
A nit from the mere mortals in the audience: Could we start commenting or make a constant for the user segment bits in CS? Also, it would be nice to explain what's going on here. Maybe: /* * We think we are returning to the kernel. Check the * registers we are about to restore and if we appear to * be returning to userspace, do something that will cause * a fault and hopefully an oops report. */ Otherwise, I really like this change. It's really hard to figure out what the context is in the entry assembly in a lot of cases. It's a place where code reuse actually makes things harder to follow.
