From 725005897ec4ba07d6227a1ac3121048153eb3ce Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 25 Feb 2020 23:16:08 +0100 Subject: [PATCH] x86/entry/64: Avoid pointless code when CONTEXT_TRACKING=n GAS cannot optimize out the test and conditional jump when context tracking is disabled and CALL_enter_from_user_mode is an empty macro. Wrap it in #ifdeffery. Will go away once all this is moved to C. Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Frederic Weisbecker Acked-by: Andy Lutomirski Acked-by: Peter Zijlstra Link: https://lkml.kernel.org/r/20200505134058.955968069@linutronix.de --- arch/x86/entry/entry_64.S | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 87ffa792bc99..a15b70ac87b5 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -889,12 +889,14 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt TRACE_IRQS_OFF .endif +#ifdef CONFIG_CONTEXT_TRACKING .if \paranoid == 0 testb $3, CS(%rsp) jz .Lfrom_kernel_no_context_tracking_\@ CALL_enter_from_user_mode .Lfrom_kernel_no_context_tracking_\@: .endif +#endif movq %rsp, %rdi /* pt_regs pointer */ -- 2.34.1