FAILED: patch "[PATCH] PCI: xilinx-nwl: Fix off-by-one in INTx IRQ handler" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 0199d2f2bd8cd97b310f7ed82a067247d7456029
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024100101-neatness-unmapped-e049@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

0199d2f2bd8c ("PCI: xilinx-nwl: Fix off-by-one in INTx IRQ handler") e56427068a8d ("PCI: xilinx-nwl: Use irq_data_get_irq_chip_data()")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0199d2f2bd8cd97b310f7ed82a067247d7456029 Mon Sep 17 00:00:00 2001
From: Sean Anderson <[email protected]>
Date: Fri, 31 May 2024 12:13:32 -0400
Subject: [PATCH] PCI: xilinx-nwl: Fix off-by-one in INTx IRQ handler

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 bug would cause INTx interrupts not to be delivered, as enabling INTB would actually enable INTA, and enabling INTA wouldn't enable anything at all. It is likely that this got overlooked for so long since most PCIe hardware uses MSIs. This fixes the following UBSAN error:

  UBSAN: shift-out-of-bounds in ../drivers/pci/controller/pcie-xilinx-nwl.c:389:11
  shift exponent 18446744073709551615 is too large for 32-bit type 'int'
  CPU: 1 PID: 61 Comm: kworker/u10:1 Not tainted 6.6.20+ #268
  Hardware name: xlnx,zynqmp (DT)
  Workqueue: events_unbound deferred_probe_work_func
  Call trace:
  dump_backtrace (arch/arm64/kernel/stacktrace.c:235)
  show_stack (arch/arm64/kernel/stacktrace.c:242)
  dump_stack_lvl (lib/dump_stack.c:107)
  dump_stack (lib/dump_stack.c:114)
  __ubsan_handle_shift_out_of_bounds (lib/ubsan.c:218 lib/ubsan.c:387)
  nwl_unmask_leg_irq (drivers/pci/controller/pcie-xilinx-nwl.c:389 (discriminator 1))
  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)
  __irq_startup (kernel/irq/internals.h:239 kernel/irq/chip.c:180 kernel/irq/chip.c:250)
  irq_startup (kernel/irq/chip.c:270)
  __setup_irq (kernel/irq/manage.c:1800)
  request_threaded_irq (kernel/irq/manage.c:2206)
  pcie_pme_probe (include/linux/interrupt.h:168 drivers/pci/pcie/pme.c:348)

index 0408f4d612b5..437927e3bcca 100644
@@ -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);