DESC
i386-specific code.
EDESC
The main chunk of i386-specific code. Various fixes have not yet been merged
in this part.
Some have been, instead:

* SKAS: rename modify_ldt to avoid conflicts

SKAS adds a function modify_ldt (closely related to sys_modify_ldt) but the
declaration conflicts with some external code (ATI kernel modules). Since the
name is not important, rename the function to __modify_ldt.

* Description of the SMP hack in include/asm-i386/mmu_context.h:

From: Jeff Dike <jdike@addtoit.com> and me, Paolo Giarrusso
The removed panic can be triggered if it happens that:
1) a UML thread sleeps
2) a kernel-thread is scheduled on the same CPU and lazy-TLB switching is used
3) on any other CPU PTRACE_SWITCH_MM is called onto the sleeping thread
4) and the sleeping thread is rescheduled onto the same CPU; the same task is
going back BUT you need a context switch, since that task has changed its ->mm.

By the way, the combination of 1), 3) and 4) is likely to occur (I think it
happens on every context switch inside the guest); the 2) part is the one not
always happening (when the CPU goes to sleep, indeed it runs with lazy-TLB the
idle thread, so 2) is happening).