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 <[email protected]>
---
arch/x86/entry/entry_64.S | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -884,12 +884,14 @@ apicinterrupt IRQ_WORK_VECTOR irq_work
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 */
On 2/25/20 2:16 PM, Thomas Gleixner wrote:
> 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.
Acked-by: Andy Lutomirski <[email protected]>
On 2/25/20 11:16 PM, Thomas Gleixner wrote:
> 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 <[email protected]>
> ---
> arch/x86/entry/entry_64.S | 2 ++
> 1 file changed, 2 insertions(+)
>
Reviewed-by: Alexandre Chartre <[email protected]>
alex.
On Tue, Feb 25, 2020 at 11:16:08PM +0100, Thomas Gleixner wrote:
> 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 <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>