On Wed, Apr 01, 2020 at 04:58:13PM -0700, Alan Mikhak wrote: > From: Alan Mikhak <alan.mikhak@xxxxxxxxxx> > > Function dw_pcie_prog_outbound_atu_unroll() does not program the upper > 32-bit ATU limit register. Since ATU programming functions limit the > size of the translated region to 4GB by using a u32 size parameter, > these issues may combine into undefined behavior for resource sizes > with non-zero upper 32-bits. > > For example, a 128GB address space starting at physical CPU address of > 0x2000000000 with size of 0x2000000000 needs the following values > programmed into the lower and upper 32-bit limit registers: > 0x3fffffff in the upper 32-bit limit register > 0xffffffff in the lower 32-bit limit register > > Currently, only the lower 32-bit limit register is programmed with a > value of 0xffffffff but the upper 32-bit limit register is not being > programmed. As a result, the upper 32-bit limit register remains at its > default value after reset of 0x0. > > These issues may combine to produce undefined behavior since the ATU > limit address may be lower than the ATU base address. Programming the > upper ATU limit address register prevents such undefined behavior despite > the region size getting truncated due to the 32-bit size limit. > > Signed-off-by: Alan Mikhak <alan.mikhak@xxxxxxxxxx> > --- > drivers/pci/controller/dwc/pcie-designware.c | 7 +++++-- > drivers/pci/controller/dwc/pcie-designware.h | 3 ++- > 2 files changed, 7 insertions(+), 3 deletions(-) I would appreciate some feedback and possibly and ACK from DWC maintainers. Should this go to stable kernels ? It seems so, let me know if we want to add a stable tag. I will merge it, along with: https://patchwork.kernel.org/patch/11468465/ Lorenzo > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c > index 681548c88282..c92496e36fd5 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.c > +++ b/drivers/pci/controller/dwc/pcie-designware.c > @@ -244,13 +244,16 @@ static void dw_pcie_prog_outbound_atu_unroll(struct dw_pcie *pci, int index, > u64 pci_addr, u32 size) > { > u32 retries, val; > + u64 limit_addr = cpu_addr + size - 1; > > dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_LOWER_BASE, > lower_32_bits(cpu_addr)); > dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_UPPER_BASE, > upper_32_bits(cpu_addr)); > - dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_LIMIT, > - lower_32_bits(cpu_addr + size - 1)); > + dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_LOWER_LIMIT, > + lower_32_bits(limit_addr)); > + dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_UPPER_LIMIT, > + upper_32_bits(limit_addr)); > dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_LOWER_TARGET, > lower_32_bits(pci_addr)); > dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_UPPER_TARGET, > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h > index a22ea5982817..5ce1aef706c5 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.h > +++ b/drivers/pci/controller/dwc/pcie-designware.h > @@ -112,9 +112,10 @@ > #define PCIE_ATU_UNR_REGION_CTRL2 0x04 > #define PCIE_ATU_UNR_LOWER_BASE 0x08 > #define PCIE_ATU_UNR_UPPER_BASE 0x0C > -#define PCIE_ATU_UNR_LIMIT 0x10 > +#define PCIE_ATU_UNR_LOWER_LIMIT 0x10 > #define PCIE_ATU_UNR_LOWER_TARGET 0x14 > #define PCIE_ATU_UNR_UPPER_TARGET 0x18 > +#define PCIE_ATU_UNR_UPPER_LIMIT 0x20 > > /* > * The default address offset between dbi_base and atu_base. Root controller > -- > 2.7.4 >
