Files
linux-stable-mirror/drivers/cxl/core/core.h
T
Dan WilliamsandDave Jiang 4dd86ca99f cxl/region: Resolve region deletion races
Sungwoo noticed that the sysfs trigger to delete a region may try to delete
a region multiple times. It also has no exclusion relative to the kernel
releasing the region via CXL root device teardown.

Instead of installing new cxl root devres actions per region, use the
existing root decoder unregistration event to remove all remaining regions.
An xarray of regions replaces a devres list of regions.

This handles 3 separate issues with the old approach:

1/ sysfs users racing to delete the same region: no longer possible now
   that the regions_lock is held over the lookup and deletion.

2/ multiple actions triggering deletion of the same region: solved by
   erasing regions while holding @regions_lock, and only proceeding on
   successful erasure.

3/ userspace racing devres_release_all() to trigger the devres not found
   warning: solved by sysfs unregistration not requiring a release action

Fixes: 779dd20cfb ("cxl/region: Add region creation support")
Reported-by: Sungwoo Kim <iam@sung-woo.kim>
Closes: http://lore.kernel.org/20260427032010.916681-2-iam@sung-woo.kim
Signed-off-by: Dan Williams <djbw@kernel.org>
Reviewed-by: Alejandro Lucero <alucerop@amd.com>
Tested-by: ALejandro Lucero <alucerop@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260519210158.1499795-3-djbw@kernel.org
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2026-06-12 13:47:29 -07:00

234 lines
7.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright(c) 2020 Intel Corporation. */
#ifndef __CXL_CORE_H__
#define __CXL_CORE_H__
#include <cxl/mailbox.h>
#include <linux/rwsem.h>
extern const struct device_type cxl_nvdimm_bridge_type;
extern const struct device_type cxl_nvdimm_type;
extern const struct device_type cxl_pmu_type;
extern struct attribute_group cxl_base_attribute_group;
enum cxl_detach_mode {
DETACH_ONLY,
DETACH_INVALIDATE,
};
#ifdef CONFIG_CXL_REGION
struct cxl_region_context {
struct cxl_endpoint_decoder *cxled;
struct range hpa_range;
int interleave_ways;
int interleave_granularity;
};
extern struct device_attribute dev_attr_create_pmem_region;
extern struct device_attribute dev_attr_create_ram_region;
extern struct device_attribute dev_attr_delete_region;
extern struct device_attribute dev_attr_region;
extern const struct device_type cxl_pmem_region_type;
extern const struct device_type cxl_dax_region_type;
extern const struct device_type cxl_region_type;
int cxl_decoder_detach(struct cxl_region *cxlr,
struct cxl_endpoint_decoder *cxled, int pos,
enum cxl_detach_mode mode);
#define CXL_REGION_ATTR(x) (&dev_attr_##x.attr)
#define CXL_REGION_TYPE(x) (&cxl_region_type)
#define SET_CXL_REGION_ATTR(x) (&dev_attr_##x.attr),
#define CXL_PMEM_REGION_TYPE(x) (&cxl_pmem_region_type)
#define CXL_DAX_REGION_TYPE(x) (&cxl_dax_region_type)
int cxl_region_init(void);
void cxl_region_exit(void);
int cxl_get_poison_by_endpoint(struct cxl_port *port);
struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
u64 dpa);
int devm_cxl_add_dax_region(struct cxl_region *cxlr);
int devm_cxl_add_pmem_region(struct cxl_region *cxlr);
void kill_regions(struct cxl_root_decoder *cxlrd);
#else
static inline u64 cxl_dpa_to_hpa(struct cxl_region *cxlr,
const struct cxl_memdev *cxlmd, u64 dpa)
{
return ULLONG_MAX;
}
static inline
struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa)
{
return NULL;
}
static inline int cxl_get_poison_by_endpoint(struct cxl_port *port)
{
return 0;
}
static inline int cxl_decoder_detach(struct cxl_region *cxlr,
struct cxl_endpoint_decoder *cxled,
int pos, enum cxl_detach_mode mode)
{
return 0;
}
static inline int cxl_region_init(void)
{
return 0;
}
static inline void cxl_region_exit(void)
{
}
static inline void kill_regions(struct cxl_root_decoder *cxlrd) { };
#define CXL_REGION_ATTR(x) NULL
#define CXL_REGION_TYPE(x) NULL
#define SET_CXL_REGION_ATTR(x)
#define CXL_PMEM_REGION_TYPE(x) NULL
#define CXL_DAX_REGION_TYPE(x) NULL
#endif
struct cxl_send_command;
struct cxl_mem_query_commands;
int cxl_query_cmd(struct cxl_mailbox *cxl_mbox,
struct cxl_mem_query_commands __user *q);
int cxl_send_cmd(struct cxl_mailbox *cxl_mbox, struct cxl_send_command __user *s);
void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
resource_size_t length);
struct dentry *cxl_debugfs_create_dir(const char *dir);
int cxl_dpa_set_part(struct cxl_endpoint_decoder *cxled,
enum cxl_partition_mode mode);
int cxl_dpa_alloc(struct cxl_endpoint_decoder *cxled, u64 size);
int cxl_dpa_free(struct cxl_endpoint_decoder *cxled);
resource_size_t cxl_dpa_size(struct cxl_endpoint_decoder *cxled);
resource_size_t cxl_dpa_resource_start(struct cxl_endpoint_decoder *cxled);
bool cxl_resource_contains_addr(const struct resource *res, const resource_size_t addr);
enum cxl_rcrb {
CXL_RCRB_DOWNSTREAM,
CXL_RCRB_UPSTREAM,
};
struct cxl_rcrb_info;
resource_size_t __rcrb_to_component(struct device *dev,
struct cxl_rcrb_info *ri,
enum cxl_rcrb which);
u16 cxl_rcrb_to_aer(struct device *dev, resource_size_t rcrb);
#define PCI_RCRB_CAP_LIST_ID_MASK GENMASK(7, 0)
#define PCI_RCRB_CAP_HDR_ID_MASK GENMASK(7, 0)
#define PCI_RCRB_CAP_HDR_NEXT_MASK GENMASK(15, 8)
#define PCI_CAP_EXP_SIZEOF 0x3c
struct cxl_rwsem {
/*
* All changes to HPA (interleave configuration) occur with this
* lock held for write.
*/
struct rw_semaphore region;
/*
* All changes to a device DPA space occur with this lock held
* for write.
*/
struct rw_semaphore dpa;
};
extern struct cxl_rwsem cxl_rwsem;
int cxl_memdev_init(void);
void cxl_memdev_exit(void);
void cxl_mbox_init(void);
enum cxl_poison_trace_type {
CXL_POISON_TRACE_LIST,
CXL_POISON_TRACE_INJECT,
CXL_POISON_TRACE_CLEAR,
};
enum poison_cmd_enabled_bits;
bool cxl_memdev_has_poison_cmd(struct cxl_memdev *cxlmd,
enum poison_cmd_enabled_bits cmd);
long cxl_pci_get_latency(struct pci_dev *pdev);
int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c);
int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
struct access_coordinate *c);
static inline struct device *port_to_host(struct cxl_port *port)
{
struct cxl_port *parent = is_cxl_root(port) ? NULL :
to_cxl_port(port->dev.parent);
/*
* The host of CXL root port and the first level of ports is
* the platform firmware device, the host of all other ports
* is their parent port.
*/
if (!parent)
return port->uport_dev;
else if (is_cxl_root(parent))
return parent->uport_dev;
else
return &parent->dev;
}
static inline struct device *dport_to_host(struct cxl_dport *dport)
{
struct cxl_port *port = dport->port;
if (is_cxl_root(port))
return port->uport_dev;
return &port->dev;
}
#ifdef CONFIG_CXL_RAS
int cxl_ras_init(void);
void cxl_ras_exit(void);
bool cxl_handle_ras(struct device *dev, void __iomem *ras_base);
void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base);
void cxl_dport_map_rch_aer(struct cxl_dport *dport);
void cxl_disable_rch_root_ints(struct cxl_dport *dport);
void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds);
void devm_cxl_dport_ras_setup(struct cxl_dport *dport);
#else
static inline int cxl_ras_init(void)
{
return 0;
}
static inline void cxl_ras_exit(void) { }
static inline bool cxl_handle_ras(struct device *dev, void __iomem *ras_base)
{
return false;
}
static inline void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base) { }
static inline void cxl_dport_map_rch_aer(struct cxl_dport *dport) { }
static inline void cxl_disable_rch_root_ints(struct cxl_dport *dport) { }
static inline void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { }
static inline void devm_cxl_dport_ras_setup(struct cxl_dport *dport) { }
#endif /* CONFIG_CXL_RAS */
int cxl_gpf_port_setup(struct cxl_dport *dport);
struct cxl_hdm;
int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
struct cxl_endpoint_dvsec_info *info);
int cxl_port_get_possible_dports(struct cxl_port *port);
#ifdef CONFIG_CXL_FEATURES
struct cxl_feat_entry *
cxl_feature_info(struct cxl_features_state *cxlfs, const uuid_t *uuid);
size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
enum cxl_get_feat_selection selection,
void *feat_out, size_t feat_out_size, u16 offset,
u16 *return_code);
int cxl_set_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
u8 feat_version, const void *feat_data,
size_t feat_data_size, u32 feat_flag, u16 offset,
u16 *return_code);
#endif
resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
struct cxl_dport *dport);
#endif /* __CXL_CORE_H__ */