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authorDavid Mosberger-Tang <David.Mosberger@acm.org>2005-07-25 22:23:00 -0700
committerTony Luck <tony.luck@intel.com>2005-08-12 15:05:21 -0700
commitbadea125d7cbd93f1678a95cf009b3bdfe6065cd (patch)
treec9cd47cfc5f7474fdf60735548734e647a4f7a9d /include/asm-ia64/mmu.h
parent7d69fa6266770eeb6317eddd46b64456e8a515bf (diff)
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[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>
Diffstat (limited to 'include/asm-ia64/mmu.h')
-rw-r--r--include/asm-ia64/mmu.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/include/asm-ia64/mmu.h b/include/asm-ia64/mmu.h
index ae1525352a2..611432ba579 100644
--- a/include/asm-ia64/mmu.h
+++ b/include/asm-ia64/mmu.h
@@ -2,10 +2,12 @@
#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()).
+ * 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