On 1/7/25 17:26, Sebastian Andrzej Siewior wrote:
On 2024-12-26 11:12:38 [-0800], Robert Joslyn wrote:
This branch is needed to allow preemptible IRQs to be scheduled,
otherwise the kernel hangs during boot on my e300 based platforms.
This branch is needed for both CONFIG_PREEMPT and CONFIG_PREEMPT_RT,
Hi Robert.
Are you running with preempt=full or enabled preempt_rt ?
rt is yet to be supported on powerpc. are you having it enabled out of tree?
Also, I have sent out patch to enable dynamic preemption. It uses preempt_model_preemptible.
I think it should work for you as well. If you could give that a try and ensure it works, it would be great.
https://lore.kernel.org/all/20250106051919.55020-2-sshegde@xxxxxxxxxxxxx/
so broaden the check to CONFIG_PREEMPTION, which is selected by both.
This was previously set to CONFIG_PREEMPTION, but was reverted as part
of removing LAZY_PREEMPT support.
I remember I pointed this out while Shrikanth posted the preempt-lazy
patches but didn't realize that I need this in RT tree, too.
The lazy-preempt patches for powerpc were merged upstream, I am going to
pull them into the v6.6-series.
I am going to Cc you, hopefully you can confirm that it is working.
Fixes: b33022a48c79
Signed-off-by: Robert Joslyn <robert_joslyn@xxxxxxxxxx>
---
arch/powerpc/kernel/interrupt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index af62ec974b97..970039af8e92 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -396,7 +396,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs)
/* Returning to a kernel context with local irqs enabled. */
WARN_ON_ONCE(!(regs->msr & MSR_EE));
again:
- if (IS_ENABLED(CONFIG_PREEMPT)) {
+ if (IS_ENABLED(CONFIG_PREEMPTION)) {
/* Return to preemptible kernel context */
if (unlikely(read_thread_flags() & _TIF_NEED_RESCHED)) {
if (preempt_count() == 0)
Sebastian
