144 lines
4.7 KiB
C
144 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_MEMREMAP_H_
|
|
#define _LINUX_MEMREMAP_H_
|
|
#include <linux/ioport.h>
|
|
#include <linux/percpu-refcount.h>
|
|
|
|
struct resource;
|
|
struct device;
|
|
|
|
/**
|
|
* struct vmem_altmap - pre-allocated storage for vmemmap_populate
|
|
* @base_pfn: base of the entire dev_pagemap mapping
|
|
* @reserve: pages mapped, but reserved for driver use (relative to @base)
|
|
* @free: free pages set aside in the mapping for memmap storage
|
|
* @align: pages reserved to meet allocation alignments
|
|
* @alloc: track pages consumed, private to vmemmap_populate()
|
|
*/
|
|
struct vmem_altmap {
|
|
const unsigned long base_pfn;
|
|
const unsigned long reserve;
|
|
unsigned long free;
|
|
unsigned long align;
|
|
unsigned long alloc;
|
|
};
|
|
|
|
/*
|
|
* Specialize ZONE_DEVICE memory into multiple types each having differents
|
|
* usage.
|
|
*
|
|
* MEMORY_DEVICE_PRIVATE:
|
|
* Device memory that is not directly addressable by the CPU: CPU can neither
|
|
* read nor write private memory. In this case, we do still have struct pages
|
|
* backing the device memory. Doing so simplifies the implementation, but it is
|
|
* important to remember that there are certain points at which the struct page
|
|
* must be treated as an opaque object, rather than a "normal" struct page.
|
|
*
|
|
* A more complete discussion of unaddressable memory may be found in
|
|
* include/linux/hmm.h and Documentation/vm/hmm.rst.
|
|
*
|
|
* MEMORY_DEVICE_PUBLIC:
|
|
* Device memory that is cache coherent from device and CPU point of view. This
|
|
* is use on platform that have an advance system bus (like CAPI or CCIX). A
|
|
* driver can hotplug the device memory using ZONE_DEVICE and with that memory
|
|
* type. Any page of a process can be migrated to such memory. However no one
|
|
* should be allow to pin such memory so that it can always be evicted.
|
|
*
|
|
* MEMORY_DEVICE_FS_DAX:
|
|
* Host memory that has similar access semantics as System RAM i.e. DMA
|
|
* coherent and supports page pinning. In support of coordinating page
|
|
* pinning vs other operations MEMORY_DEVICE_FS_DAX arranges for a
|
|
* wakeup event whenever a page is unpinned and becomes idle. This
|
|
* wakeup is used to coordinate physical address space management (ex:
|
|
* fs truncate/hole punch) vs pinned pages (ex: device dma).
|
|
*
|
|
* MEMORY_DEVICE_PCI_P2PDMA:
|
|
* Device memory residing in a PCI BAR intended for use with Peer-to-Peer
|
|
* transactions.
|
|
*/
|
|
enum memory_type {
|
|
MEMORY_DEVICE_PRIVATE = 1,
|
|
MEMORY_DEVICE_PUBLIC,
|
|
MEMORY_DEVICE_FS_DAX,
|
|
MEMORY_DEVICE_PCI_P2PDMA,
|
|
};
|
|
|
|
/*
|
|
* Additional notes about MEMORY_DEVICE_PRIVATE may be found in
|
|
* include/linux/hmm.h and Documentation/vm/hmm.rst. There is also a brief
|
|
* explanation in include/linux/memory_hotplug.h.
|
|
*
|
|
* The page_free() callback is called once the page refcount reaches 1
|
|
* (ZONE_DEVICE pages never reach 0 refcount unless there is a refcount bug.
|
|
* This allows the device driver to implement its own memory management.)
|
|
*/
|
|
typedef void (*dev_page_free_t)(struct page *page, void *data);
|
|
|
|
/**
|
|
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
|
|
* @page_free: free page callback when page refcount reaches 1
|
|
* @altmap: pre-allocated/reserved memory for vmemmap allocations
|
|
* @res: physical address range covered by @ref
|
|
* @ref: reference count that pins the devm_memremap_pages() mapping
|
|
* @kill: callback to transition @ref to the dead state
|
|
* @dev: host device of the mapping for debug
|
|
* @data: private data pointer for page_free()
|
|
* @type: memory type: see MEMORY_* in memory_hotplug.h
|
|
*/
|
|
struct dev_pagemap {
|
|
dev_page_free_t page_free;
|
|
struct vmem_altmap altmap;
|
|
bool altmap_valid;
|
|
struct resource res;
|
|
struct percpu_ref *ref;
|
|
void (*kill)(struct percpu_ref *ref);
|
|
struct device *dev;
|
|
void *data;
|
|
enum memory_type type;
|
|
u64 pci_p2pdma_bus_offset;
|
|
};
|
|
|
|
#ifdef CONFIG_ZONE_DEVICE
|
|
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
|
|
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
|
|
struct dev_pagemap *pgmap);
|
|
|
|
unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
|
|
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
|
|
#else
|
|
static inline void *devm_memremap_pages(struct device *dev,
|
|
struct dev_pagemap *pgmap)
|
|
{
|
|
/*
|
|
* Fail attempts to call devm_memremap_pages() without
|
|
* ZONE_DEVICE support enabled, this requires callers to fall
|
|
* back to plain devm_memremap() based on config
|
|
*/
|
|
WARN_ON_ONCE(1);
|
|
return ERR_PTR(-ENXIO);
|
|
}
|
|
|
|
static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
|
|
struct dev_pagemap *pgmap)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void vmem_altmap_free(struct vmem_altmap *altmap,
|
|
unsigned long nr_pfns)
|
|
{
|
|
}
|
|
#endif /* CONFIG_ZONE_DEVICE */
|
|
|
|
static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
|
|
{
|
|
if (pgmap)
|
|
percpu_ref_put(pgmap->ref);
|
|
}
|
|
#endif /* _LINUX_MEMREMAP_H_ */
|