sparc64: reset mm cpumask after wrap

[ Upstream commit 588974857359861891f478a070b1dc7ae04a3880 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 965655afdbb6da2c867887ff5281fe345446fa7a..667468edd05ea7b846da05fc402cf3470fdf2d85 100644 (file)
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -708,6 +708,8 @@ 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: