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-rw-r--r--arch/powerpc/mm/icswx.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/arch/powerpc/mm/icswx.c b/arch/powerpc/mm/icswx.c
index 5d9a59eaad93..8cdbd8634a58 100644
--- a/arch/powerpc/mm/icswx.c
+++ b/arch/powerpc/mm/icswx.c
@@ -163,7 +163,7 @@ EXPORT_SYMBOL_GPL(drop_cop);
static int acop_use_cop(int ct)
{
- /* todo */
+ /* There is no alternate policy, yet */
return -1;
}
@@ -227,11 +227,30 @@ int acop_handle_fault(struct pt_regs *regs, unsigned long address,
ct = (ccw >> 16) & 0x3f;
}
+ /*
+ * We could be here because another thread has enabled acop
+ * but the ACOP register has yet to be updated.
+ *
+ * This should have been taken care of by the IPI to sync all
+ * the threads (see smp_call_function(sync_cop, mm, 1)), but
+ * that could take forever if there are a significant amount
+ * of threads.
+ *
+ * Given the number of threads on some of these systems,
+ * perhaps this is the best way to sync ACOP rather than whack
+ * every thread with an IPI.
+ */
+ if ((acop_copro_type_bit(ct) & current->active_mm->context.acop) != 0) {
+ sync_cop(current->active_mm);
+ return 0;
+ }
+
+ /* check for alternate policy */
if (!acop_use_cop(ct))
return 0;
/* at this point the CT is unknown to the system */
- pr_warn("%s[%d]: Coprocessor %d is unavailable",
+ pr_warn("%s[%d]: Coprocessor %d is unavailable\n",
current->comm, current->pid, ct);
/* get inst if we don't already have it */