cxl/mem: Fix no cxl_nvd during pmem region auto-assembling
When CXL subsystem is auto-assembling a pmem region during cxl
endpoint port probing, always hit below calltrace.
BUG: kernel NULL pointer dereference, address: 0000000000000078
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
RIP: 0010:cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem]
Call Trace:
<TASK>
? __die+0x24/0x70
? page_fault_oops+0x82/0x160
? do_user_addr_fault+0x65/0x6b0
? exc_page_fault+0x7d/0x170
? asm_exc_page_fault+0x26/0x30
? cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem]
? cxl_pmem_region_probe+0x1ac/0x360 [cxl_pmem]
cxl_bus_probe+0x1b/0x60 [cxl_core]
really_probe+0x173/0x410
? __pfx___device_attach_driver+0x10/0x10
__driver_probe_device+0x80/0x170
driver_probe_device+0x1e/0x90
__device_attach_driver+0x90/0x120
bus_for_each_drv+0x84/0xe0
__device_attach+0xbc/0x1f0
bus_probe_device+0x90/0xa0
device_add+0x51c/0x710
devm_cxl_add_pmem_region+0x1b5/0x380 [cxl_core]
cxl_bus_probe+0x1b/0x60 [cxl_core]
The cxl_nvd of the memdev needs to be available during the pmem region
probe. Currently the cxl_nvd is registered after the endpoint port probe.
The endpoint probe, in the case of autoassembly of regions, can cause a
pmem region probe requiring the not yet available cxl_nvd. Adjust the
sequence so this dependency is met.
This requires adding a port parameter to cxl_find_nvdimm_bridge() that
can be used to query the ancestor root port. The endpoint port is not
yet available, but will share a common ancestor with its parent, so
start the query from there instead.
Fixes: f17b558d66
("cxl/pmem: Refactor nvdimm device registration, delete the workqueue")
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Li Ming <ming4.li@intel.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20240612064423.2567625-1-ming4.li@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
This commit is contained in:
parent
6ba59ff422
commit
84ec985944
@ -62,10 +62,14 @@ static int match_nvdimm_bridge(struct device *dev, void *data)
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return is_cxl_nvdimm_bridge(dev);
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}
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struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd)
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/**
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* cxl_find_nvdimm_bridge() - find a bridge device relative to a port
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* @port: any descendant port of an nvdimm-bridge associated
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* root-cxl-port
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*/
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struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_port *port)
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{
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struct cxl_root *cxl_root __free(put_cxl_root) =
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find_cxl_root(cxlmd->endpoint);
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struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
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struct device *dev;
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if (!cxl_root)
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@ -242,18 +246,20 @@ static void cxlmd_release_nvdimm(void *_cxlmd)
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/**
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* devm_cxl_add_nvdimm() - add a bridge between a cxl_memdev and an nvdimm
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* @parent_port: parent port for the (to be added) @cxlmd endpoint port
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* @cxlmd: cxl_memdev instance that will perform LIBNVDIMM operations
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*
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* Return: 0 on success negative error code on failure.
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*/
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int devm_cxl_add_nvdimm(struct cxl_memdev *cxlmd)
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int devm_cxl_add_nvdimm(struct cxl_port *parent_port,
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struct cxl_memdev *cxlmd)
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{
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struct cxl_nvdimm_bridge *cxl_nvb;
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struct cxl_nvdimm *cxl_nvd;
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struct device *dev;
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int rc;
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cxl_nvb = cxl_find_nvdimm_bridge(cxlmd);
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cxl_nvb = cxl_find_nvdimm_bridge(parent_port);
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if (!cxl_nvb)
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return -ENODEV;
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@ -2847,7 +2847,7 @@ static int cxl_pmem_region_alloc(struct cxl_region *cxlr)
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* bridge for one device is the same for all.
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*/
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if (i == 0) {
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cxl_nvb = cxl_find_nvdimm_bridge(cxlmd);
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cxl_nvb = cxl_find_nvdimm_bridge(cxlmd->endpoint);
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if (!cxl_nvb)
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return -ENODEV;
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cxlr->cxl_nvb = cxl_nvb;
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@ -855,8 +855,8 @@ struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
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struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);
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bool is_cxl_nvdimm(struct device *dev);
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bool is_cxl_nvdimm_bridge(struct device *dev);
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int devm_cxl_add_nvdimm(struct cxl_memdev *cxlmd);
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struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd);
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int devm_cxl_add_nvdimm(struct cxl_port *parent_port, struct cxl_memdev *cxlmd);
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struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_port *port);
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#ifdef CONFIG_CXL_REGION
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bool is_cxl_pmem_region(struct device *dev);
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@ -152,6 +152,15 @@ static int cxl_mem_probe(struct device *dev)
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return -ENXIO;
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}
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if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM)) {
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rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
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if (rc) {
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if (rc == -ENODEV)
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dev_info(dev, "PMEM disabled by platform\n");
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return rc;
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}
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}
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if (dport->rch)
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endpoint_parent = parent_port->uport_dev;
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else
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@ -174,14 +183,6 @@ unlock:
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if (rc)
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return rc;
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if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM)) {
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rc = devm_cxl_add_nvdimm(cxlmd);
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if (rc == -ENODEV)
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dev_info(dev, "PMEM disabled by platform\n");
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else
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return rc;
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}
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/*
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* The kernel may be operating out of CXL memory on this device,
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* there is no spec defined way to determine whether this device
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