powerpc: Make flush_fp_to_thread() nop when CONFIG_PPC_FPU is disabled
In the current kernel, the function flush_fp_to_thread() is not
dependent on CONFIG_PPC_FPU. So most invocations of this function
is not wrapped by CONFIG_PPC_FPU. Even through we don't really
save the FPRs to the thread struct if CONFIG_PPC_FPU is not enabled,
but there does have some runtime overhead such as the check for
tsk->thread.regs and preempt disable and enable. It really make
no sense to do that. So make it a nop when CONFIG_PPC_FPU is
disabled. Also remove the wrapped #ifdef CONFIG_PPC_FPU
when invoking this function.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index c517dbe..0ec255a 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -74,6 +74,7 @@
struct task_struct *last_task_used_spe = NULL;
#endif
+#ifdef CONFIG_PPC_FPU
/*
* Make sure the floating-point register state in the
* the thread_struct is up to date for task tsk.
@@ -107,6 +108,7 @@
}
}
EXPORT_SYMBOL_GPL(flush_fp_to_thread);
+#endif
void enable_kernel_fp(void)
{