Re: [PATCH 3/5] irqchip/bcm2836: Make IPIs use handle_percpu_devid_irq()
From: Valentin Schneider <hidden>
Date: 2020-12-15 11:16:24
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On 15/12/20 10:19, Marc Zyngier wrote:
Hi Gunter, On 2020-12-15 00:21, Guenter Roeck wrote:quoted
On Mon, Nov 09, 2020 at 09:41:19AM +0000, Valentin Schneider wrote:quoted
As done for the Arm GIC irqchips, move IPIs to handle_percpu_devid_irq() as handle_percpu_devid_fasteoi_ipi() isn't actually required. Signed-off-by: Valentin Schneider <redacted>This patch results in boot failures (silent stall) for the qemu raspi2 emulation. Unfortunately it can not be reverted because handle_percpu_devid_fasteoi_ipi no longer exists in next-20201214, so I don't know if it is the only problem.This is odd. This works just fine for me on both the RPi2 and 3 emulation, running a full Debian userspace. Could this be caused by the version of QEMU you are using? Here's what I have: $ qemu-system-arm --version QEMU emulator version 5.1.0 (Debian 1:5.1+dfsg-4+b1) Could you try the following hack and let me know if that helps?
Thanks for looking into this. It does look like I inverted the ordering of that mailbox write vs the handling of the IPI. I don't see how the IPI could mess with the mailbox (unless some creative use of irq_work / smp_call), but in any case having the write in irq_ack() as you've done below should restore said ordering.
quoted hunk ↗ jump to hunk
Thanks, M.diff --git a/drivers/irqchip/irq-bcm2836.cb/drivers/irqchip/irq-bcm2836.c index 5f5eb8877c41..25c9a9c06e41 100644--- a/drivers/irqchip/irq-bcm2836.c +++ b/drivers/irqchip/irq-bcm2836.c@@ -167,7 +167,7 @@ static void bcm2836_arm_irqchip_handle_ipi(structirq_desc *desc) chained_irq_exit(chip, desc); } -static void bcm2836_arm_irqchip_ipi_eoi(struct irq_data *d) +static void bcm2836_arm_irqchip_ipi_ack(struct irq_data *d) { int cpu = smp_processor_id();@@ -195,7 +195,7 @@ static struct irq_chip bcm2836_arm_irqchip_ipi = { .name = "IPI", .irq_mask = bcm2836_arm_irqchip_dummy_op, .irq_unmask = bcm2836_arm_irqchip_dummy_op, - .irq_eoi = bcm2836_arm_irqchip_ipi_eoi, + .irq_ack = bcm2836_arm_irqchip_ipi_ack, .ipi_send_mask = bcm2836_arm_irqchip_ipi_send_mask, };
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