Commit 35797e67 authored by Will McVicker's avatar Will McVicker Committed by Bjorn Helgaas
Browse files

PCI: dwc: Fix MSI msi_msg DMA mapping 

As of 07940c36 ("PCI: dwc: Fix MSI page leakage in suspend/resume"),
the PCIe designware host driver has been using the driver data allocation
for the msi_msg DMA mapping which can result in a DMA_MAPPING_ERROR due to
the DMA overflow check in dma_direct_map_page() when the address is greater
than 32 bits (reported in [1]). The commit was trying to address a memory
leak on suspend/resume by moving the MSI mapping to dw_pcie_host_init(),
but subsequently dropped the page allocation thinking it wasn't needed.

To fix the DMA mapping issue as well as make msi_msg DMA'able, switch back
to allocating a 32-bit page for the msi_msg. To avoid the suspend/resume
leak, allocate the page in dw_pcie_host_init() since that shouldn't be
called during suspend/resume.

[1] https://lore.kernel.org/all/Yo0soniFborDl7+C@google.com/



Signed-off-by: default avatarWill McVicker <willmcvicker@google.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
parent ce06bf57

drivers/pci/controller/dwc/pcie-designware-host.c

+8 −6
Original line number Diff line number Diff line
@@ -267,8 +267,9 @@ static void dw_pcie_free_msi(struct dw_pcie_rp *pp) 
		struct dw_pcie *pci = to_dw_pcie_from_pp(pp);

		struct device *dev = pci->dev;



		dma_unmap_single_attrs(dev, pp->msi_data, sizeof(pp->msi_msg),

				       DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);

		dma_unmap_page(dev, pp->msi_data, PAGE_SIZE, DMA_FROM_DEVICE);

		if (pp->msi_page)

			__free_page(pp->msi_page);

	}

}
@@ -395,13 +396,14 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) 
			if (ret)

				dev_warn(dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n");



			pp->msi_data = dma_map_single_attrs(dev, &pp->msi_msg,

						      sizeof(pp->msi_msg),

						      DMA_FROM_DEVICE,

						      DMA_ATTR_SKIP_CPU_SYNC);

			pp->msi_page = alloc_page(GFP_DMA32);

			pp->msi_data = dma_map_page(dev, pp->msi_page, 0,

						    PAGE_SIZE, DMA_FROM_DEVICE);

			ret = dma_mapping_error(dev, pp->msi_data);

			if (ret) {

				dev_err(pci->dev, "Failed to map MSI data\n");

				__free_page(pp->msi_page);

				pp->msi_page = NULL;

				pp->msi_data = 0;

				goto err_free_msi;

			}

drivers/pci/controller/dwc/pcie-designware.h

+1 −1
Original line number Diff line number Diff line
@@ -203,8 +203,8 @@ struct dw_pcie_rp { 
	int			msi_irq;

	struct irq_domain	*irq_domain;

	struct irq_domain	*msi_domain;

	u16			msi_msg;

	dma_addr_t		msi_data;

	struct page		*msi_page;

	struct irq_chip		*msi_irq_chip;

	u32			num_vectors;

	u32			irq_mask[MAX_MSI_CTRLS];