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-rw-r--r--arch/x86/mm/tlb.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 012d02624848..8dcc0607f805 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -229,6 +229,12 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
#endif
this_cpu_write(cpu_tlbstate.is_lazy, false);
+ /*
+ * The membarrier system call requires a full memory barrier and
+ * core serialization before returning to user-space, after
+ * storing to rq->curr. Writing to CR3 provides that full
+ * memory barrier and core serializing instruction.
+ */
if (real_prev == next) {
VM_WARN_ON(this_cpu_read(cpu_tlbstate.ctxs[prev_asid].ctx_id) !=
next->context.ctx_id);