+/*
+ * Make sure the floating-point register state in the
+ * the thread_struct is up to date for task tsk.
+ */
+void flush_fp_to_thread(struct task_struct *tsk)
+{
+ if (tsk->thread.regs) {
+ /*
+ * We need to disable preemption here because if we didn't,
+ * another process could get scheduled after the regs->msr
+ * test but before we have finished saving the FP registers
+ * to the thread_struct. That process could take over the
+ * FPU, and then when we get scheduled again we would store
+ * bogus values for the remaining FP registers.
+ */
+ preempt_disable();
+ if (tsk->thread.regs->msr & MSR_FP) {
+#ifdef CONFIG_SMP
+ /*
+ * This should only ever be called for current or
+ * for a stopped child process. Since we save away
+ * the FP register state on context switch on SMP,
+ * there is something wrong if a stopped child appears
+ * to still have its FP state in the CPU registers.
+ */
+ BUG_ON(tsk != current);
+#endif
+ giveup_fpu(current);
+ }
+ preempt_enable();
+ }
+}
+