[PATCH Dovetail 2/2] arm64: irq_pipeline: Fix the demotion checks for el0 and el1 IRQs

While reviewing some of the low level pipeline code I realized that
the checks for task demotion are wrong on arm64.

el0: The demotion check was missing in the oob case. We have to check
     for running_inband() only as user_mode(regs) will always be true.
     We are serving an IRQ over el0, so application / user mode.

el1: The demotion check was unnecessary and "inactive" as
     user_mode(regs) is never true on el1, we are serving an IRQ over
     kernel mode.

Signed-off-by: Florian Bezdeka <[email protected]>
---
 arch/arm64/kernel/entry-common.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 07fa70713ce04eaf3df9223354babcecde923280..9c99eb3d18c459a90e1f7ce4e4c307e235e457a2 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -73,6 +73,10 @@ static noinstr void arm64_pipeline_el0_irq(struct pt_regs *regs,
 	do_interrupt_handler(regs, handler);
 	/* Done, unwind now. */
 	handle_irq_pipelined_finish(prevd, regs);
+	if (running_inband()) {
+		stall_inband_nocheck();
+		irqentry_exit_to_user_mode(regs);
+	}
 	instrumentation_end();
 	arm64_exit_to_user_mode(regs);
 }
@@ -90,10 +94,6 @@ static noinstr void arm64_pipeline_el1_irq(struct pt_regs *regs,
 		prevd = handle_irq_pipelined_prepare(regs);
 		do_interrupt_handler(regs, handler);
 		handle_irq_pipelined_finish(prevd, regs);
-		if (running_inband() && user_mode(regs)) {
-			stall_inband_nocheck();
-			irqentry_exit_to_user_mode(regs);
-		}
 		instrumentation_end();
 		mte_check_tfsr_exit();
 		return;

-- 
2.53.0