forked from luck/tmp_suning_uos_patched
badea125d7
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>
14 lines
335 B
C
14 lines
335 B
C
#ifndef __MMU_H
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#define __MMU_H
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/*
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* Type for a context number. We declare it volatile to ensure proper
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* ordering when it's accessed outside of spinlock'd critical sections
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* (e.g., as done in activate_mm() and init_new_context()).
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*/
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typedef volatile unsigned long mm_context_t;
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typedef unsigned long nv_mm_context_t;
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#endif
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