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PCI: dwc: Fix MSI msi_msg DMA mapping

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As of 07940c369a ("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: Will McVicker <willmcvicker@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Will McVicker 2022-06-13 17:26:11 -05:00 committed by Bjorn Helgaas
parent ce06bf5703
commit 35797e672f
2 changed files with 9 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

14
drivers/pci/controller/dwc/pcie-designware-host.c
View file

@ -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;
}

2
drivers/pci/controller/dwc/pcie-designware.h
View file

@ -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];