From 35797e672ff0610224d80e3cc08393fef1032f9a Mon Sep 17 00:00:00 2001
From: Will McVicker <willmcvicker@google.com>
Date: Mon, 13 Jun 2022 17:26:11 -0500
Subject: PCI: dwc: Fix MSI msi_msg DMA mapping
As of 07940c369a6b ("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>
---
drivers/pci/controller/dwc/pcie-designware-host.c | 14 ++++++++------
drivers/pci/controller/dwc/pcie-designware.h | 2 +-
2 files changed, 9 insertions(+), 7 deletions(-)
(limited to 'drivers')
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 6993ce9e856d..ff3451a6b846 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -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;
}
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index c3e73ed9aff5..7c63204d23ba 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -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];
--
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