Revision e2093926a098a8ccf0f1d10f6df8dad452cb28d3 authored by Ross Zwisler on 02 June 2017, 21:46:37 UTC, committed by Linus Torvalds on 02 June 2017, 22:07:37 UTC
We currently have two related PMD vs PTE races in the DAX code. These can both be easily triggered by having two threads reading and writing simultaneously to the same private mapping, with the key being that private mapping reads can be handled with PMDs but private mapping writes are always handled with PTEs so that we can COW. Here is the first race: CPU 0 CPU 1 (private mapping write) __handle_mm_fault() create_huge_pmd() - FALLBACK handle_pte_fault() passes check for pmd_devmap() (private mapping read) __handle_mm_fault() create_huge_pmd() dax_iomap_pmd_fault() inserts PMD dax_iomap_pte_fault() does a PTE fault, but we already have a DAX PMD installed in our page tables at this spot. Here's the second race: CPU 0 CPU 1 (private mapping read) __handle_mm_fault() passes check for pmd_none() create_huge_pmd() dax_iomap_pmd_fault() inserts PMD (private mapping write) __handle_mm_fault() create_huge_pmd() - FALLBACK (private mapping read) __handle_mm_fault() passes check for pmd_none() create_huge_pmd() handle_pte_fault() dax_iomap_pte_fault() inserts PTE dax_iomap_pmd_fault() inserts PMD, but we already have a PTE at this spot. The core of the issue is that while there is isolation between faults to the same range in the DAX fault handlers via our DAX entry locking, there is no isolation between faults in the code in mm/memory.c. This means for instance that this code in __handle_mm_fault() can run: if (pmd_none(*vmf.pmd) && transparent_hugepage_enabled(vma)) { ret = create_huge_pmd(&vmf); But by the time we actually get to run the fault handler called by create_huge_pmd(), the PMD is no longer pmd_none() because a racing PTE fault has installed a normal PMD here as a parent. This is the cause of the 2nd race. The first race is similar - there is the following check in handle_pte_fault(): } else { /* See comment in pte_alloc_one_map() */ if (pmd_devmap(*vmf->pmd) || pmd_trans_unstable(vmf->pmd)) return 0; So if a pmd_devmap() PMD (a DAX PMD) has been installed at vmf->pmd, we will bail and retry the fault. This is correct, but there is nothing preventing the PMD from being installed after this check but before we actually get to the DAX PTE fault handlers. In my testing these races result in the following types of errors: BUG: Bad rss-counter state mm:ffff8800a817d280 idx:1 val:1 BUG: non-zero nr_ptes on freeing mm: 15 Fix this issue by having the DAX fault handlers verify that it is safe to continue their fault after they have taken an entry lock to block other racing faults. [ross.zwisler@linux.intel.com: improve fix for colliding PMD & PTE entries] Link: http://lkml.kernel.org/r/20170526195932.32178-1-ross.zwisler@linux.intel.com Link: http://lkml.kernel.org/r/20170522215749.23516-2-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Pawel Lebioda <pawel.lebioda@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Pawel Lebioda <pawel.lebioda@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Xiong Zhou <xzhou@redhat.com> Cc: Eryu Guan <eguan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent d0f0931
iommu.h
/*
* Copyright (C) 2007-2008 Advanced Micro Devices, Inc.
* Author: Joerg Roedel <joerg.roedel@amd.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __LINUX_IOMMU_H
#define __LINUX_IOMMU_H
#include <linux/scatterlist.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/of.h>
#define IOMMU_READ (1 << 0)
#define IOMMU_WRITE (1 << 1)
#define IOMMU_CACHE (1 << 2) /* DMA cache coherency */
#define IOMMU_NOEXEC (1 << 3)
#define IOMMU_MMIO (1 << 4) /* e.g. things like MSI doorbells */
/*
* Where the bus hardware includes a privilege level as part of its access type
* markings, and certain devices are capable of issuing transactions marked as
* either 'supervisor' or 'user', the IOMMU_PRIV flag requests that the other
* given permission flags only apply to accesses at the higher privilege level,
* and that unprivileged transactions should have as little access as possible.
* This would usually imply the same permissions as kernel mappings on the CPU,
* if the IOMMU page table format is equivalent.
*/
#define IOMMU_PRIV (1 << 5)
struct iommu_ops;
struct iommu_group;
struct bus_type;
struct device;
struct iommu_domain;
struct notifier_block;
/* iommu fault flags */
#define IOMMU_FAULT_READ 0x0
#define IOMMU_FAULT_WRITE 0x1
typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
struct device *, unsigned long, int, void *);
struct iommu_domain_geometry {
dma_addr_t aperture_start; /* First address that can be mapped */
dma_addr_t aperture_end; /* Last address that can be mapped */
bool force_aperture; /* DMA only allowed in mappable range? */
};
/* Domain feature flags */
#define __IOMMU_DOMAIN_PAGING (1U << 0) /* Support for iommu_map/unmap */
#define __IOMMU_DOMAIN_DMA_API (1U << 1) /* Domain for use in DMA-API
implementation */
#define __IOMMU_DOMAIN_PT (1U << 2) /* Domain is identity mapped */
/*
* This are the possible domain-types
*
* IOMMU_DOMAIN_BLOCKED - All DMA is blocked, can be used to isolate
* devices
* IOMMU_DOMAIN_IDENTITY - DMA addresses are system physical addresses
* IOMMU_DOMAIN_UNMANAGED - DMA mappings managed by IOMMU-API user, used
* for VMs
* IOMMU_DOMAIN_DMA - Internally used for DMA-API implementations.
* This flag allows IOMMU drivers to implement
* certain optimizations for these domains
*/
#define IOMMU_DOMAIN_BLOCKED (0U)
#define IOMMU_DOMAIN_IDENTITY (__IOMMU_DOMAIN_PT)
#define IOMMU_DOMAIN_UNMANAGED (__IOMMU_DOMAIN_PAGING)
#define IOMMU_DOMAIN_DMA (__IOMMU_DOMAIN_PAGING | \
__IOMMU_DOMAIN_DMA_API)
struct iommu_domain {
unsigned type;
const struct iommu_ops *ops;
unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */
iommu_fault_handler_t handler;
void *handler_token;
struct iommu_domain_geometry geometry;
void *iova_cookie;
};
enum iommu_cap {
IOMMU_CAP_CACHE_COHERENCY, /* IOMMU can enforce cache coherent DMA
transactions */
IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
};
/*
* Following constraints are specifc to FSL_PAMUV1:
* -aperture must be power of 2, and naturally aligned
* -number of windows must be power of 2, and address space size
* of each window is determined by aperture size / # of windows
* -the actual size of the mapped region of a window must be power
* of 2 starting with 4KB and physical address must be naturally
* aligned.
* DOMAIN_ATTR_FSL_PAMUV1 corresponds to the above mentioned contraints.
* The caller can invoke iommu_domain_get_attr to check if the underlying
* iommu implementation supports these constraints.
*/
enum iommu_attr {
DOMAIN_ATTR_GEOMETRY,
DOMAIN_ATTR_PAGING,
DOMAIN_ATTR_WINDOWS,
DOMAIN_ATTR_FSL_PAMU_STASH,
DOMAIN_ATTR_FSL_PAMU_ENABLE,
DOMAIN_ATTR_FSL_PAMUV1,
DOMAIN_ATTR_NESTING, /* two stages of translation */
DOMAIN_ATTR_MAX,
};
/* These are the possible reserved region types */
enum iommu_resv_type {
/* Memory regions which must be mapped 1:1 at all times */
IOMMU_RESV_DIRECT,
/* Arbitrary "never map this or give it to a device" address ranges */
IOMMU_RESV_RESERVED,
/* Hardware MSI region (untranslated) */
IOMMU_RESV_MSI,
/* Software-managed MSI translation window */
IOMMU_RESV_SW_MSI,
};
/**
* struct iommu_resv_region - descriptor for a reserved memory region
* @list: Linked list pointers
* @start: System physical start address of the region
* @length: Length of the region in bytes
* @prot: IOMMU Protection flags (READ/WRITE/...)
* @type: Type of the reserved region
*/
struct iommu_resv_region {
struct list_head list;
phys_addr_t start;
size_t length;
int prot;
enum iommu_resv_type type;
};
#ifdef CONFIG_IOMMU_API
/**
* struct iommu_ops - iommu ops and capabilities
* @capable: check capability
* @domain_alloc: allocate iommu domain
* @domain_free: free iommu domain
* @attach_dev: attach device to an iommu domain
* @detach_dev: detach device from an iommu domain
* @map: map a physically contiguous memory region to an iommu domain
* @unmap: unmap a physically contiguous memory region from an iommu domain
* @map_sg: map a scatter-gather list of physically contiguous memory chunks
* to an iommu domain
* @iova_to_phys: translate iova to physical address
* @add_device: add device to iommu grouping
* @remove_device: remove device from iommu grouping
* @device_group: find iommu group for a particular device
* @domain_get_attr: Query domain attributes
* @domain_set_attr: Change domain attributes
* @get_resv_regions: Request list of reserved regions for a device
* @put_resv_regions: Free list of reserved regions for a device
* @apply_resv_region: Temporary helper call-back for iova reserved ranges
* @domain_window_enable: Configure and enable a particular window for a domain
* @domain_window_disable: Disable a particular window for a domain
* @domain_set_windows: Set the number of windows for a domain
* @domain_get_windows: Return the number of windows for a domain
* @of_xlate: add OF master IDs to iommu grouping
* @pgsize_bitmap: bitmap of all possible supported page sizes
*/
struct iommu_ops {
bool (*capable)(enum iommu_cap);
/* Domain allocation and freeing by the iommu driver */
struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
void (*domain_free)(struct iommu_domain *);
int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
int (*map)(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot);
size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
size_t size);
size_t (*map_sg)(struct iommu_domain *domain, unsigned long iova,
struct scatterlist *sg, unsigned int nents, int prot);
phys_addr_t (*iova_to_phys)(struct iommu_domain *domain, dma_addr_t iova);
int (*add_device)(struct device *dev);
void (*remove_device)(struct device *dev);
struct iommu_group *(*device_group)(struct device *dev);
int (*domain_get_attr)(struct iommu_domain *domain,
enum iommu_attr attr, void *data);
int (*domain_set_attr)(struct iommu_domain *domain,
enum iommu_attr attr, void *data);
/* Request/Free a list of reserved regions for a device */
void (*get_resv_regions)(struct device *dev, struct list_head *list);
void (*put_resv_regions)(struct device *dev, struct list_head *list);
void (*apply_resv_region)(struct device *dev,
struct iommu_domain *domain,
struct iommu_resv_region *region);
/* Window handling functions */
int (*domain_window_enable)(struct iommu_domain *domain, u32 wnd_nr,
phys_addr_t paddr, u64 size, int prot);
void (*domain_window_disable)(struct iommu_domain *domain, u32 wnd_nr);
/* Set the number of windows per domain */
int (*domain_set_windows)(struct iommu_domain *domain, u32 w_count);
/* Get the number of windows per domain */
u32 (*domain_get_windows)(struct iommu_domain *domain);
int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
unsigned long pgsize_bitmap;
};
/**
* struct iommu_device - IOMMU core representation of one IOMMU hardware
* instance
* @list: Used by the iommu-core to keep a list of registered iommus
* @ops: iommu-ops for talking to this iommu
* @dev: struct device for sysfs handling
*/
struct iommu_device {
struct list_head list;
const struct iommu_ops *ops;
struct fwnode_handle *fwnode;
struct device dev;
};
int iommu_device_register(struct iommu_device *iommu);
void iommu_device_unregister(struct iommu_device *iommu);
int iommu_device_sysfs_add(struct iommu_device *iommu,
struct device *parent,
const struct attribute_group **groups,
const char *fmt, ...) __printf(4, 5);
void iommu_device_sysfs_remove(struct iommu_device *iommu);
int iommu_device_link(struct iommu_device *iommu, struct device *link);
void iommu_device_unlink(struct iommu_device *iommu, struct device *link);
static inline void iommu_device_set_ops(struct iommu_device *iommu,
const struct iommu_ops *ops)
{
iommu->ops = ops;
}
static inline void iommu_device_set_fwnode(struct iommu_device *iommu,
struct fwnode_handle *fwnode)
{
iommu->fwnode = fwnode;
}
#define IOMMU_GROUP_NOTIFY_ADD_DEVICE 1 /* Device added */
#define IOMMU_GROUP_NOTIFY_DEL_DEVICE 2 /* Pre Device removed */
#define IOMMU_GROUP_NOTIFY_BIND_DRIVER 3 /* Pre Driver bind */
#define IOMMU_GROUP_NOTIFY_BOUND_DRIVER 4 /* Post Driver bind */
#define IOMMU_GROUP_NOTIFY_UNBIND_DRIVER 5 /* Pre Driver unbind */
#define IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER 6 /* Post Driver unbind */
extern int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops);
extern bool iommu_present(struct bus_type *bus);
extern bool iommu_capable(struct bus_type *bus, enum iommu_cap cap);
extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
extern struct iommu_group *iommu_group_get_by_id(int id);
extern void iommu_domain_free(struct iommu_domain *domain);
extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
extern void iommu_detach_device(struct iommu_domain *domain,
struct device *dev);
extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot);
extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
size_t size);
extern size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
struct scatterlist *sg,unsigned int nents,
int prot);
extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova);
extern void iommu_set_fault_handler(struct iommu_domain *domain,
iommu_fault_handler_t handler, void *token);
extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);
extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);
extern int iommu_request_dm_for_dev(struct device *dev);
extern struct iommu_resv_region *
iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot,
enum iommu_resv_type type);
extern int iommu_get_group_resv_regions(struct iommu_group *group,
struct list_head *head);
extern int iommu_attach_group(struct iommu_domain *domain,
struct iommu_group *group);
extern void iommu_detach_group(struct iommu_domain *domain,
struct iommu_group *group);
extern struct iommu_group *iommu_group_alloc(void);
extern void *iommu_group_get_iommudata(struct iommu_group *group);
extern void iommu_group_set_iommudata(struct iommu_group *group,
void *iommu_data,
void (*release)(void *iommu_data));
extern int iommu_group_set_name(struct iommu_group *group, const char *name);
extern int iommu_group_add_device(struct iommu_group *group,
struct device *dev);
extern void iommu_group_remove_device(struct device *dev);
extern int iommu_group_for_each_dev(struct iommu_group *group, void *data,
int (*fn)(struct device *, void *));
extern struct iommu_group *iommu_group_get(struct device *dev);
extern struct iommu_group *iommu_group_ref_get(struct iommu_group *group);
extern void iommu_group_put(struct iommu_group *group);
extern int iommu_group_register_notifier(struct iommu_group *group,
struct notifier_block *nb);
extern int iommu_group_unregister_notifier(struct iommu_group *group,
struct notifier_block *nb);
extern int iommu_group_id(struct iommu_group *group);
extern struct iommu_group *iommu_group_get_for_dev(struct device *dev);
extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *);
extern int iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr,
void *data);
extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
void *data);
/* Window handling function prototypes */
extern int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
phys_addr_t offset, u64 size,
int prot);
extern void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr);
extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
unsigned long iova, int flags);
static inline size_t iommu_map_sg(struct iommu_domain *domain,
unsigned long iova, struct scatterlist *sg,
unsigned int nents, int prot)
{
return domain->ops->map_sg(domain, iova, sg, nents, prot);
}
/* PCI device grouping function */
extern struct iommu_group *pci_device_group(struct device *dev);
/* Generic device grouping function */
extern struct iommu_group *generic_device_group(struct device *dev);
/**
* struct iommu_fwspec - per-device IOMMU instance data
* @ops: ops for this device's IOMMU
* @iommu_fwnode: firmware handle for this device's IOMMU
* @iommu_priv: IOMMU driver private data for this device
* @num_ids: number of associated device IDs
* @ids: IDs which this device may present to the IOMMU
*/
struct iommu_fwspec {
const struct iommu_ops *ops;
struct fwnode_handle *iommu_fwnode;
void *iommu_priv;
unsigned int num_ids;
u32 ids[1];
};
int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
const struct iommu_ops *ops);
void iommu_fwspec_free(struct device *dev);
int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode);
#else /* CONFIG_IOMMU_API */
struct iommu_ops {};
struct iommu_group {};
struct iommu_fwspec {};
struct iommu_device {};
static inline bool iommu_present(struct bus_type *bus)
{
return false;
}
static inline bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
{
return false;
}
static inline struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
{
return NULL;
}
static inline struct iommu_group *iommu_group_get_by_id(int id)
{
return NULL;
}
static inline void iommu_domain_free(struct iommu_domain *domain)
{
}
static inline int iommu_attach_device(struct iommu_domain *domain,
struct device *dev)
{
return -ENODEV;
}
static inline void iommu_detach_device(struct iommu_domain *domain,
struct device *dev)
{
}
static inline struct iommu_domain *iommu_get_domain_for_dev(struct device *dev)
{
return NULL;
}
static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, int gfp_order, int prot)
{
return -ENODEV;
}
static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
int gfp_order)
{
return -ENODEV;
}
static inline size_t iommu_map_sg(struct iommu_domain *domain,
unsigned long iova, struct scatterlist *sg,
unsigned int nents, int prot)
{
return -ENODEV;
}
static inline int iommu_domain_window_enable(struct iommu_domain *domain,
u32 wnd_nr, phys_addr_t paddr,
u64 size, int prot)
{
return -ENODEV;
}
static inline void iommu_domain_window_disable(struct iommu_domain *domain,
u32 wnd_nr)
{
}
static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
{
return 0;
}
static inline void iommu_set_fault_handler(struct iommu_domain *domain,
iommu_fault_handler_t handler, void *token)
{
}
static inline void iommu_get_resv_regions(struct device *dev,
struct list_head *list)
{
}
static inline void iommu_put_resv_regions(struct device *dev,
struct list_head *list)
{
}
static inline int iommu_get_group_resv_regions(struct iommu_group *group,
struct list_head *head)
{
return -ENODEV;
}
static inline int iommu_request_dm_for_dev(struct device *dev)
{
return -ENODEV;
}
static inline int iommu_attach_group(struct iommu_domain *domain,
struct iommu_group *group)
{
return -ENODEV;
}
static inline void iommu_detach_group(struct iommu_domain *domain,
struct iommu_group *group)
{
}
static inline struct iommu_group *iommu_group_alloc(void)
{
return ERR_PTR(-ENODEV);
}
static inline void *iommu_group_get_iommudata(struct iommu_group *group)
{
return NULL;
}
static inline void iommu_group_set_iommudata(struct iommu_group *group,
void *iommu_data,
void (*release)(void *iommu_data))
{
}
static inline int iommu_group_set_name(struct iommu_group *group,
const char *name)
{
return -ENODEV;
}
static inline int iommu_group_add_device(struct iommu_group *group,
struct device *dev)
{
return -ENODEV;
}
static inline void iommu_group_remove_device(struct device *dev)
{
}
static inline int iommu_group_for_each_dev(struct iommu_group *group,
void *data,
int (*fn)(struct device *, void *))
{
return -ENODEV;
}
static inline struct iommu_group *iommu_group_get(struct device *dev)
{
return NULL;
}
static inline void iommu_group_put(struct iommu_group *group)
{
}
static inline int iommu_group_register_notifier(struct iommu_group *group,
struct notifier_block *nb)
{
return -ENODEV;
}
static inline int iommu_group_unregister_notifier(struct iommu_group *group,
struct notifier_block *nb)
{
return 0;
}
static inline int iommu_group_id(struct iommu_group *group)
{
return -ENODEV;
}
static inline int iommu_domain_get_attr(struct iommu_domain *domain,
enum iommu_attr attr, void *data)
{
return -EINVAL;
}
static inline int iommu_domain_set_attr(struct iommu_domain *domain,
enum iommu_attr attr, void *data)
{
return -EINVAL;
}
static inline int iommu_device_register(struct iommu_device *iommu)
{
return -ENODEV;
}
static inline void iommu_device_set_ops(struct iommu_device *iommu,
const struct iommu_ops *ops)
{
}
static inline void iommu_device_set_fwnode(struct iommu_device *iommu,
struct fwnode_handle *fwnode)
{
}
static inline void iommu_device_unregister(struct iommu_device *iommu)
{
}
static inline int iommu_device_sysfs_add(struct iommu_device *iommu,
struct device *parent,
const struct attribute_group **groups,
const char *fmt, ...)
{
return -ENODEV;
}
static inline void iommu_device_sysfs_remove(struct iommu_device *iommu)
{
}
static inline int iommu_device_link(struct device *dev, struct device *link)
{
return -EINVAL;
}
static inline void iommu_device_unlink(struct device *dev, struct device *link)
{
}
static inline int iommu_fwspec_init(struct device *dev,
struct fwnode_handle *iommu_fwnode,
const struct iommu_ops *ops)
{
return -ENODEV;
}
static inline void iommu_fwspec_free(struct device *dev)
{
}
static inline int iommu_fwspec_add_ids(struct device *dev, u32 *ids,
int num_ids)
{
return -ENODEV;
}
static inline
const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
{
return NULL;
}
#endif /* CONFIG_IOMMU_API */
#endif /* __LINUX_IOMMU_H */
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