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sparc64: reset mm cpumask after wrap

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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>
This commit is contained in:
Pavel Tatashin 2017-05-31 11:25:20 -04:00 committed by David S. Miller
parent f322980b74
commit 5889748573
1 changed files with 2 additions and 0 deletions
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2
arch/sparc/mm/init_64.c
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@ -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: