From 3bb80da51b1c1dbf31af2226f57cbc258f5e994b Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Tue, 18 Oct 2022 15:23:30 +0200 Subject: [PATCH] cxl/core: Check physical address before mapping it in devm_cxl_iomap_block() 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 Link: https://lore.kernel.org/r/20221018132341.76259-3-rrichter@amd.com Signed-off-by: Dan Williams --- drivers/cxl/core/regs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c index 6522931df3f73..ec178e69b18f8 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; -- 2.30.2