Unverified Commit 129f6af7 authored by Niklas Cassel's avatar Niklas Cassel Committed by Krzysztof Wilczyński
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PCI: dwc: ep: Add 'address' alignment to 'size' check in dw_pcie_prog_ep_inbound_atu() 

dw_pcie_prog_ep_inbound_atu() is used to program an inbound iATU in
"BAR Match Mode".

A memory address returned by e.g. kmalloc() is guaranteed to have natural
alignment (aligned to the size of the allocation). It is however not
guaranteed that pci_epc_set_bar() (and thus dw_pcie_prog_ep_inbound_atu())
is supplied an address that has natural alignment. (An EPF driver can send
in an arbitrary physical address to pci_epc_set_bar().)

The DWC Databook description for the LWR_TARGET_RW and LWR_TARGET_HW fields
in the IATU_LWR_TARGET_ADDR_OFF_INBOUND_i registers state that:
"Field size depends on log2(BAR_MASK+1) in BAR match mode."

I.e. only the upper bits are writable, and the number of writable bits is
dependent on the configured BAR_MASK.

Add a check to ensure that the physical address programmed in the iATU is
aligned to the size of the BAR (BAR_MASK+1), as without this, we can get
hard to debug errors, as we could write to bits that are read-only (without
getting a write error), which could cause the iATU to end up redirecting to
a physical address that is different from the address that we intended.

Link: https://lore.kernel.org/r/20241213143301.4158431-11-cassel@kernel.org


Signed-off-by: default avatarNiklas Cassel <cassel@kernel.org>
Signed-off-by: default avatarKrzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
parent 3708acbd

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

+5 −3
Original line number Diff line number Diff line
@@ -128,7 +128,8 @@ static int dw_pcie_ep_write_header(struct pci_epc *epc, u8 func_no, u8 vfunc_no, 
}



static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,

				  dma_addr_t cpu_addr, enum pci_barno bar)

				  dma_addr_t cpu_addr, enum pci_barno bar,

				  size_t size)

{

	int ret;

	u32 free_win;
@@ -145,7 +146,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type, 
	}



	ret = dw_pcie_prog_ep_inbound_atu(pci, func_no, free_win, type,

					  cpu_addr, bar);

					  cpu_addr, bar, size);

	if (ret < 0) {

		dev_err(pci->dev, "Failed to program IB window\n");

		return ret;
@@ -265,7 +266,8 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, 
	else

		type = PCIE_ATU_TYPE_IO;



	ret = dw_pcie_ep_inbound_atu(ep, func_no, type, epf_bar->phys_addr, bar);

	ret = dw_pcie_ep_inbound_atu(ep, func_no, type, epf_bar->phys_addr, bar,

				     size);

	if (ret)

		return ret;

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

+3 −2
Original line number Diff line number Diff line
@@ -597,11 +597,12 @@ int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type, 
}



int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index,

				int type, u64 cpu_addr, u8 bar)

				int type, u64 cpu_addr, u8 bar, size_t size)

{

	u32 retries, val;



	if (!IS_ALIGNED(cpu_addr, pci->region_align))

	if (!IS_ALIGNED(cpu_addr, pci->region_align) ||

	    !IS_ALIGNED(cpu_addr, size))

		return -EINVAL;



	dw_pcie_writel_atu_ib(pci, index, PCIE_ATU_LOWER_TARGET,

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

+1 −1
Original line number Diff line number Diff line
@@ -491,7 +491,7 @@ int dw_pcie_prog_outbound_atu(struct dw_pcie *pci, 
int dw_pcie_prog_inbound_atu(struct dw_pcie *pci, int index, int type,

			     u64 cpu_addr, u64 pci_addr, u64 size);

int dw_pcie_prog_ep_inbound_atu(struct dw_pcie *pci, u8 func_no, int index,

				int type, u64 cpu_addr, u8 bar);

				int type, u64 cpu_addr, u8 bar, size_t size);

void dw_pcie_disable_atu(struct dw_pcie *pci, u32 dir, int index);

void dw_pcie_setup(struct dw_pcie *pci);

void dw_pcie_iatu_detect(struct dw_pcie *pci);