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6575b26815
When the CXL subsystem is built-in the module init order is determined by Makefile order. That order violates expectations. The expectation is that cxl_acpi and cxl_mem can race to attach. If cxl_acpi wins the race, cxl_mem will find the enabled CXL root ports it needs. If cxl_acpi loses the race it will retrigger cxl_mem to attach via cxl_bus_rescan(). That flow only works if cxl_acpi can assume ports are enabled immediately upon cxl_acpi_probe() return. That in turn can only happen in the CONFIG_CXL_ACPI=y case if the cxl_port driver is registered before cxl_acpi_probe() runs. Fix up the order to prevent initialization failures. Ensure that cxl_port is built-in when cxl_acpi is also built-in, arrange for Makefile order to resolve the subsys_initcall() order of cxl_port and cxl_acpi, and arrange for Makefile order to resolve the device_initcall() (module_init()) order of the remaining objects. As for what contributed to this not being found earlier, the CXL regression environment, cxl_test, builds all CXL functionality as a module to allow to symbol mocking and other dynamic reload tests. As a result there is no regression coverage for the built-in case. Reported-by: Gregory Price <gourry@gourry.net> Closes: http://lore.kernel.org/20241004212504.1246-1-gourry@gourry.net Tested-by: Gregory Price <gourry@gourry.net> Fixes: 8dd2bc0f8e02 ("cxl/mem: Add the cxl_mem driver") Cc: stable@vger.kernel.org Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Jonathan Cameron <jonathan.cameron@huawei.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Alison Schofield <alison.schofield@intel.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Tested-by: Alejandro Lucero <alucerop@amd.com> Reviewed-by: Alejandro Lucero <alucerop@amd.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/172988474904.476062.7961350937442459266.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Ira Weiny <ira.weiny@intel.com>
22 lines
688 B
Makefile
22 lines
688 B
Makefile
# SPDX-License-Identifier: GPL-2.0
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# Order is important here for the built-in case:
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# - 'core' first for fundamental init
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# - 'port' before platform root drivers like 'acpi' so that CXL-root ports
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# are immediately enabled
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# - 'mem' and 'pmem' before endpoint drivers so that memdevs are
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# immediately enabled
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# - 'pci' last, also mirrors the hardware enumeration hierarchy
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obj-y += core/
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obj-$(CONFIG_CXL_PORT) += cxl_port.o
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obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
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obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
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obj-$(CONFIG_CXL_MEM) += cxl_mem.o
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obj-$(CONFIG_CXL_PCI) += cxl_pci.o
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cxl_port-y := port.o
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cxl_acpi-y := acpi.o
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cxl_pmem-y := pmem.o security.o
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cxl_mem-y := mem.o
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cxl_pci-y := pci.o
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