kernel-ark/include/asm-ia64/mmu.h
David Mosberger-Tang badea125d7 [IA64] Fix race in mm-context wrap-around logic.
The patch below should fix a race which could cause stale TLB entries.
Specifically, when 2 CPUs ended up racing for entrance to
wrap_mmu_context().  The losing CPU would find that by the time it
acquired ctx.lock, mm->context already had a valid value, but then it
failed to (re-)check the delayed TLB flushing logic and hence could
end up using a context number when there were still stale entries in
its TLB.  The fix is to check for delayed TLB flushes only after
mm->context is valid (non-zero).  The patch also makes GCC v4.x
happier by defining a non-volatile variant of mm_context_t called
nv_mm_context_t.

Signed-off-by: David Mosberger-Tang <David.Mosberger@acm.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2005-08-12 15:05:21 -07:00

14 lines
335 B
C

#ifndef __MMU_H
#define __MMU_H
/*
* Type for a context number. We declare it volatile to ensure proper
* ordering when it's accessed outside of spinlock'd critical sections
* (e.g., as done in activate_mm() and init_new_context()).
*/
typedef volatile unsigned long mm_context_t;
typedef unsigned long nv_mm_context_t;
#endif