sparc64: reset mm cpumask after wrap

After a wrap (getting a new context version) a process must get a new
context id, which means that we would need to flush the context id from
the TLB before running for the first time with this ID on every CPU. But,
we use mm_cpumask to determine if this process has been running on this CPU
before, and this mask is not reset after a wrap. So, there are two possible
fixes for this issue:

1. Clear mm cpumask whenever mm gets a new context id
2. Unconditionally flush context every time process is running on a CPU

This patch implements the first solution

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 7ca1b9dc7d6456c36a05a31e747af60d410d0b81..f8e30a3906bea1681c830d76da256c03cc8cc755 100644 (file)
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -759,6 +759,8 @@ void get_new_mmu_context(struct mm_struct *mm)
                        goto out;
                }
        }
+       if (mm->context.sparc64_ctx_val)
+               cpumask_clear(mm_cpumask(mm));
        mmu_context_bmap[new_ctx>>6] |= (1UL << (new_ctx & 63));
        new_ctx |= (tlb_context_cache & CTX_VERSION_MASK);
 out: