Re: [PATCH Dovetail 2/2] arm64: irq_pipeline: Fix the demotion checks for el0 and el1 IRQs
Philippe Gerum <[email protected]>
| Newsgroups | dev.linux.lists.xenomai |
|---|---|
| Message-ID | <[email protected]> |
Florian Bezdeka <[email protected]> writes: > 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. > If the demotion happens from el1, you still want to check for a rescheduling opportunity (i.e. kernel preemption case). > 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; diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index e0227d467cef4..770fc4059e083 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -90,10 +90,8 @@ 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); - } + if (running_inband()) + goto out_irqentry; instrumentation_end(); mte_check_tfsr_exit(); return; @@ -109,6 +107,7 @@ static noinstr void arm64_pipeline_el1_irq(struct pt_regs *regs, trace_hardirqs_on(); unstall_inband_nocheck(); handle_irq_pipelined_finish(prevd, regs); +out_irqentry: stall_inband_nocheck(); trace_hardirqs_off(); instrumentation_end(); -- Philippe.