powerpc/e6500: Make TLB lock recursive

Once special level interrupts are supported, we may take nested TLB
misses -- so allow the same thread to acquire the lock recursively.

The lock will not be effective against the nested TLB miss handler
trying to write the same entry as the interrupted TLB miss handler, but
that's also a problem on non-threaded CPUs that lack TLB write
conditional.  This will be addressed in the patch that enables crit/mc
support by invalidating the TLB on return from level exceptions.

Signed-off-by: Scott Wood <scottwood@freescale.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index da9c42f53bb1..4933909cc5c0 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -102,6 +102,8 @@ static void setup_tlb_core_data(void)
 {
         int cpu;
 
+        BUILD_BUG_ON(offsetof(struct tlb_core_data, lock) != 0);
+
         for_each_possible_cpu(cpu) {
                 int first = cpu_first_thread_sibling(cpu);