[PATCH v3 2/7] PCI: xilinx-nwl: Fix off-by-one in IRQ handler

Sean Anderson
2024-05-20T14:54:18Z

MSGF_LEG_MASK is laid out with INTA in bit 0, INTB in bit 1, INTC in bit
2, and INTD in bit 3. Hardware IRQ numbers start at 0, and we register
PCI_NUM_INTX irqs. So to enable INTA (aka hwirq 0) we should set bit 0.
Remove the subtraction of one. This fixes the following UBSAN error:

[ 5.037483] ================================================================================
[ 5.046260] UBSAN: shift-out-of-bounds in ../drivers/pci/controller/pcie-xilinx-nwl.c:389:11
[ 5.054983] shift exponent 18446744073709551615 is too large for 32-bit type 'int'
[ 5.062813] CPU: 1 PID: 61 Comm: kworker/u10:1 Not tainted 6.6.20+ #268
[ 5.070008] Hardware name: xlnx,zynqmp (DT)
[ 5.074348] Workqueue: events_unbound deferred_probe_work_func
[ 5.080410] Call trace:
[ 5.082958] dump_backtrace (arch/arm64/kernel/stacktrace.c:235)
[ 5.086850] show_stack (arch/arm64/kernel/stacktrace.c:242)
[ 5.090292] dump_stack_lvl (lib/dump_stack.c:107)
[ 5.094095] dump_stack (lib/dump_stack.c:114)
[ 5.097540] __ubsan_handle_shift_out_of_bounds (lib/ubsan.c:218 lib/ubsan.c:387)
[ 5.103227] nwl_unmask_leg_irq (drivers/pci/controller/pcie-xilinx-nwl.c:389 (discriminator 1))
[ 5.107386] irq_enable (kernel/irq/internals.h:234 kernel/irq/chip.c:170 kernel/irq/chip.c:439 kernel/irq/chip.c:432 kernel/irq/chip.c:345)
[ 5.110838] __irq_startup (kernel/irq/internals.h:239 kernel/irq/chip.c:180 kernel/irq/chip.c:250)
[ 5.114552] irq_startup (kernel/irq/chip.c:270)
[ 5.118266] __setup_irq (kernel/irq/manage.c:1800)
[ 5.121982] request_threaded_irq (kernel/irq/manage.c:2206)
[ 5.126412] pcie_pme_probe (include/linux/interrupt.h:168 drivers/pci/pcie/pme.c:348)
[ 5.130303] pcie_port_probe_service (drivers/pci/pcie/portdrv.c:528)
[ 5.134915] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658)
[ 5.138720] __driver_probe_device (drivers/base/dd.c:800)
[ 5.143236] driver_probe_device (drivers/base/dd.c:830)
[ 5.147571] __device_attach_driver (drivers/base/dd.c:959)
[ 5.152179] bus_for_each_drv (drivers/base/bus.c:457)
[ 5.156163] __device_attach (drivers/base/dd.c:1032)
[ 5.160147] device_initial_probe (drivers/base/dd.c:1080)
[ 5.164488] bus_probe_device (drivers/base/bus.c:532)
[ 5.168471] device_add (drivers/base/core.c:3638)
[ 5.172098] device_register (drivers/base/core.c:3714)
[ 5.175994] pcie_portdrv_probe (drivers/pci/pcie/portdrv.c:309 drivers/pci/pcie/portdrv.c:363 drivers/pci/pcie/portdrv.c:695)
[ 5.180338] pci_device_probe (drivers/pci/pci-driver.c:324 drivers/pci/pci-driver.c:392 drivers/pci/pci-driver.c:417 drivers/pci/pci-driver.c:460)
[ 5.184410] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658)
[ 5.188213] __driver_probe_device (drivers/base/dd.c:800)
[ 5.192729] driver_probe_device (drivers/base/dd.c:830)
[ 5.197064] __device_attach_driver (drivers/base/dd.c:959)
[ 5.201672] bus_for_each_drv (drivers/base/bus.c:457)
[ 5.205657] __device_attach (drivers/base/dd.c:1032)
[ 5.209641] device_attach (drivers/base/dd.c:1074)
[ 5.213357] pci_bus_add_device (drivers/pci/bus.c:352)
[ 5.217518] pci_bus_add_devices (drivers/pci/bus.c:371 (discriminator 2))
[ 5.221774] pci_host_probe (drivers/pci/probe.c:3099)
[ 5.225581] nwl_pcie_probe (drivers/pci/controller/pcie-xilinx-nwl.c:938)
[ 5.229562] platform_probe (drivers/base/platform.c:1404)
[ 5.233367] really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658)
[ 5.237169] __driver_probe_device (drivers/base/dd.c:800)
[ 5.241685] driver_probe_device (drivers/base/dd.c:830)
[ 5.246020] __device_attach_driver (drivers/base/dd.c:959)
[ 5.250628] bus_for_each_drv (drivers/base/bus.c:457)
[ 5.254612] __device_attach (drivers/base/dd.c:1032)
[ 5.258596] device_initial_probe (drivers/base/dd.c:1080)
[ 5.262938] bus_probe_device (drivers/base/bus.c:532)
[ 5.266920] deferred_probe_work_func (drivers/base/dd.c:124)
[ 5.271619] process_one_work (arch/arm64/include/asm/jump_label.h:21 include/linux/jump_label.h:207 include/trace/events/workqueue.h:108 kernel/workqueue.c:2632)
[ 5.275788] worker_thread (kernel/workqueue.c:2694 (discriminator 2) kernel/workqueue.c:2781 (discriminator 2))
[ 5.279686] kthread (kernel/kthread.c:388)
[ 5.283048] ret_from_fork (arch/arm64/kernel/entry.S:862)
[ 5.286765] ================================================================================

Fixes: 9a181e1093af ("PCI: xilinx-nwl: Modify IRQ chip for legacy interrupts")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

Changes in v3:
- Expand commit message

drivers/pci/controller/pcie-xilinx-nwl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
index 0408f4d612b5..437927e3bcca 100644
--- a/drivers/pci/controller/pcie-xilinx-nwl.c
+++ b/drivers/pci/controller/pcie-xilinx-nwl.c
@@ -371,7 +371,7 @@ static void nwl_mask_intx_irq(struct irq_data *data)
u32 mask;
u32 val;

- mask = 1 << (data->hwirq - 1);
+ mask = 1 << data->hwirq;
raw_spin_lock_irqsave(&pcie->leg_mask_lock, flags);
val = nwl_bridge_readl(pcie, MSGF_LEG_MASK);
nwl_bridge_writel(pcie, (val & (~mask)), MSGF_LEG_MASK);
@@ -385,7 +385,7 @@ static void nwl_unmask_intx_irq(struct irq_data *data)
u32 mask;
u32 val;

- mask = 1 << (data->hwirq - 1);
+ mask = 1 << data->hwirq;
raw_spin_lock_irqsave(&pcie->leg_mask_lock, flags);
val = nwl_bridge_readl(pcie, MSGF_LEG_MASK);
nwl_bridge_writel(pcie, (val | mask), MSGF_LEG_MASK);
--
2.35.1.1320.gc452695387.dirty