[PATCH 5.12 167/292] PCI: rockchip: Register IRQ handlers after device and data are ready

From: Greg Kroah-Hartman
Date: Mon Jul 19 2021 - 14:09:07 EST

From: Javier Martinez Canillas <javierm@xxxxxxxxxx>

[ Upstream commit 3cf5f7ab230e2b886e493c7a8449ed50e29d2b98 ]

An IRQ handler may be called at any time after it is registered, so
anything it relies on must be ready before registration.

rockchip_pcie_subsys_irq_handler() and rockchip_pcie_client_irq_handler()
read registers in the PCIe controller, but we registered them before
turning on clocks to the controller. If either is called before the clocks
are turned on, the register reads fail and the machine hangs.

Similarly, rockchip_pcie_legacy_int_handler() uses rockchip->irq_domain,
but we installed it before initializing irq_domain.

Register IRQ handlers after their data structures are initialized and
clocks are enabled.

Found by enabling CONFIG_DEBUG_SHIRQ, which calls the IRQ handler when it
is being unregistered. An error during the probe path might cause this
unregistration and IRQ handler execution before the device or data
structure init has finished.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20210608080409.1729276-1-javierm@xxxxxxxxxx
Reported-by: Peter Robinson <pbrobinson@xxxxxxxxx>
Tested-by: Peter Robinson <pbrobinson@xxxxxxxxx>
Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/pci/controller/pcie-rockchip-host.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c
index f1d08a1b1591..78d04ac29cd5 100644
--- a/drivers/pci/controller/pcie-rockchip-host.c
+++ b/drivers/pci/controller/pcie-rockchip-host.c
@@ -592,10 +592,6 @@ static int rockchip_pcie_parse_host_dt(struct rockchip_pcie *rockchip)
if (err)
return err;

- err = rockchip_pcie_setup_irq(rockchip);
- if (err)
- return err;
rockchip->vpcie12v = devm_regulator_get_optional(dev, "vpcie12v");
if (IS_ERR(rockchip->vpcie12v)) {
if (PTR_ERR(rockchip->vpcie12v) != -ENODEV)
@@ -973,8 +969,6 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
if (err)
goto err_vpcie;

- rockchip_pcie_enable_interrupts(rockchip);
err = rockchip_pcie_init_irq_domain(rockchip);
if (err < 0)
goto err_deinit_port;
@@ -992,6 +986,12 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
bridge->sysdata = rockchip;
bridge->ops = &rockchip_pcie_ops;

+ err = rockchip_pcie_setup_irq(rockchip);
+ if (err)
+ goto err_remove_irq_domain;
+ rockchip_pcie_enable_interrupts(rockchip);
err = pci_host_probe(bridge);
if (err < 0)
goto err_remove_irq_domain;