[PATCH AUTOSEL 6.6 01/47] hwtracing: hisi_ptt: Handle the interrupt in hardirq context

Sasha Levin
2023-12-11T13:51:56Z

From: Yicong Yang <yangyicong@hisilicon.com>

[ Upstream commit e0dd27ad8af00f147ac3c9de88e0687986afc3ea ]

Handle the trace interrupt in the hardirq context, make sure the irq
core won't threaded it by declaring IRQF_NO_THREAD and userspace won't
balance it by declaring IRQF_NOBALANCING. Otherwise we may violate the
synchronization requirements of the perf core, referenced to the
change of arm-ccn PMU
commit 0811ef7e2f54 ("bus: arm-ccn: fix PMU interrupt flags").

In the interrupt handler we mainly doing 2 things:
- Copy the data from the local DMA buffer to the AUX buffer
- Commit the data in the AUX buffer

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
[ Fixed commit description to suppress checkpatch warning ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231010084731.30450-3-yangyicong@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwtracing/ptt/hisi_ptt.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
index 49ea1b0f74890..7d2127d86c728 100644
--- a/drivers/hwtracing/ptt/hisi_ptt.c
+++ b/drivers/hwtracing/ptt/hisi_ptt.c
@@ -342,9 +342,9 @@ static int hisi_ptt_register_irq(struct hisi_ptt *hisi_ptt)
return ret;

hisi_ptt->trace_irq = pci_irq_vector(pdev, HISI_PTT_TRACE_DMA_IRQ);
- ret = devm_request_threaded_irq(&pdev->dev, hisi_ptt->trace_irq,
- NULL, hisi_ptt_isr, 0,
- DRV_NAME, hisi_ptt);
+ ret = devm_request_irq(&pdev->dev, hisi_ptt->trace_irq, hisi_ptt_isr,
+ IRQF_NOBALANCING | IRQF_NO_THREAD, DRV_NAME,
+ hisi_ptt);
if (ret) {
pci_err(pdev, "failed to request irq %d, ret = %d\n",
hisi_ptt->trace_irq, ret);
--
2.42.0