| Message ID | 20221018132341.76259-3-rrichter@amd.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | cxl: Add support for Restricted CXL hosts (RCD mode) | expand |
Robert Richter wrote: > The physical base address of a CXL range can be invalid and is then > set to CXL_RESOURCE_NONE. In general software shall prevent such > situations, but it is hard to proof this may never happen. E.g. in > add_port_attach_ep() there this the following: > > component_reg_phys = find_component_registers(uport_dev); > port = devm_cxl_add_port(&parent_port->dev, uport_dev, > component_reg_phys, parent_dport); > > find_component_registers() and subsequent functions (e.g. > cxl_regmap_to_base()) may return CXL_RESOURCE_NONE. But it is written > to port without any further check in cxl_port_alloc(): > > port->component_reg_phys = component_reg_phys; > > It is then later directly used in devm_cxl_setup_hdm() to map io > ranges with devm_cxl_iomap_block(). Just an example... > > Check this condition. Also do not fail silently like an ioremap() > failure, use a WARN_ON_ONCE() for it. > > Signed-off-by: Robert Richter <rrichter@amd.com> Looks good to me, applied for v6.2
diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c index 6522931df3f7..ec178e69b18f 100644 --- a/drivers/cxl/core/regs.c +++ b/drivers/cxl/core/regs.c @@ -167,6 +167,9 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr, void __iomem *ret_val; struct resource *res; + if (WARN_ON_ONCE(addr == CXL_RESOURCE_NONE)) + return NULL; + res = devm_request_mem_region(dev, addr, length, dev_name(dev)); if (!res) { resource_size_t end = addr + length - 1;
The physical base address of a CXL range can be invalid and is then set to CXL_RESOURCE_NONE. In general software shall prevent such situations, but it is hard to proof this may never happen. E.g. in add_port_attach_ep() there this the following: component_reg_phys = find_component_registers(uport_dev); port = devm_cxl_add_port(&parent_port->dev, uport_dev, component_reg_phys, parent_dport); find_component_registers() and subsequent functions (e.g. cxl_regmap_to_base()) may return CXL_RESOURCE_NONE. But it is written to port without any further check in cxl_port_alloc(): port->component_reg_phys = component_reg_phys; It is then later directly used in devm_cxl_setup_hdm() to map io ranges with devm_cxl_iomap_block(). Just an example... Check this condition. Also do not fail silently like an ioremap() failure, use a WARN_ON_ONCE() for it. Signed-off-by: Robert Richter <rrichter@amd.com> --- drivers/cxl/core/regs.c | 3 +++ 1 file changed, 3 insertions(+)