From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/include/linux/memremap.h | 150 +++++++++++++++++++++++++++++--------------------
1 files changed, 89 insertions(+), 61 deletions(-)
diff --git a/kernel/include/linux/memremap.h b/kernel/include/linux/memremap.h
index a84572c..f5b464d 100644
--- a/kernel/include/linux/memremap.h
+++ b/kernel/include/linux/memremap.h
@@ -1,10 +1,9 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MEMREMAP_H_
#define _LINUX_MEMREMAP_H_
+#include <linux/range.h>
#include <linux/ioport.h>
#include <linux/percpu-refcount.h>
-
-#include <asm/pgtable.h>
struct resource;
struct device;
@@ -19,6 +18,7 @@
*/
struct vmem_altmap {
const unsigned long base_pfn;
+ const unsigned long end_pfn;
const unsigned long reserve;
unsigned long free;
unsigned long align;
@@ -39,13 +39,6 @@
* 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
@@ -53,84 +46,102 @@
* 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_GENERIC:
+ * Host memory that has similar access semantics as System RAM i.e. DMA
+ * coherent and supports page pinning. This is for example used by DAX devices
+ * that expose memory using a character device.
+ *
+ * MEMORY_DEVICE_PCI_P2PDMA:
+ * Device memory residing in a PCI BAR intended for use with Peer-to-Peer
+ * transactions.
*/
enum memory_type {
+ /* 0 is reserved to catch uninitialized type fields */
MEMORY_DEVICE_PRIVATE = 1,
- MEMORY_DEVICE_PUBLIC,
MEMORY_DEVICE_FS_DAX,
+ MEMORY_DEVICE_GENERIC,
+ MEMORY_DEVICE_PCI_P2PDMA,
};
-/*
- * For MEMORY_DEVICE_PRIVATE we use ZONE_DEVICE and extend it with two
- * callbacks:
- * page_fault()
- * page_free()
- *
- * 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_fault() callback must migrate page back, from device memory to
- * system memory, so that the CPU can access it. This might fail for various
- * reasons (device issues, device have been unplugged, ...). When such error
- * conditions happen, the page_fault() callback must return VM_FAULT_SIGBUS and
- * set the CPU page table entry to "poisoned".
- *
- * Note that because memory cgroup charges are transferred to the device memory,
- * this should never fail due to memory restrictions. However, allocation
- * of a regular system page might still fail because we are out of memory. If
- * that happens, the page_fault() callback must return VM_FAULT_OOM.
- *
- * The page_fault() callback can also try to migrate back multiple pages in one
- * chunk, as an optimization. It must, however, prioritize the faulting address
- * over all the others.
- *
- *
- * 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.)
- *
- * For MEMORY_DEVICE_PUBLIC only the page_free() callback matter.
- */
-typedef int (*dev_page_fault_t)(struct vm_area_struct *vma,
- unsigned long addr,
- const struct page *page,
- unsigned int flags,
- pmd_t *pmdp);
-typedef void (*dev_page_free_t)(struct page *page, void *data);
+struct dev_pagemap_ops {
+ /*
+ * 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.)
+ */
+ void (*page_free)(struct page *page);
+
+ /*
+ * Transition the refcount in struct dev_pagemap to the dead state.
+ */
+ void (*kill)(struct dev_pagemap *pgmap);
+
+ /*
+ * Wait for refcount in struct dev_pagemap to be idle and reap it.
+ */
+ void (*cleanup)(struct dev_pagemap *pgmap);
+
+ /*
+ * Used for private (un-addressable) device memory only. Must migrate
+ * the page back to a CPU accessible page.
+ */
+ vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
+};
+
+#define PGMAP_ALTMAP_VALID (1 << 0)
/**
* struct dev_pagemap - metadata for ZONE_DEVICE mappings
- * @page_fault: callback when CPU fault on an unaddressable device page
- * @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()
+ * @internal_ref: internal reference if @ref is not provided by the caller
+ * @done: completion for @internal_ref
* @type: memory type: see MEMORY_* in memory_hotplug.h
+ * @flags: PGMAP_* flags to specify defailed behavior
+ * @ops: method table
+ * @owner: an opaque pointer identifying the entity that manages this
+ * instance. Used by various helpers to make sure that no
+ * foreign ZONE_DEVICE memory is accessed.
+ * @nr_range: number of ranges to be mapped
+ * @range: range to be mapped when nr_range == 1
+ * @ranges: array of ranges to be mapped when nr_range > 1
*/
struct dev_pagemap {
- dev_page_fault_t page_fault;
- 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;
+ struct percpu_ref internal_ref;
+ struct completion done;
enum memory_type type;
+ unsigned int flags;
+ const struct dev_pagemap_ops *ops;
+ void *owner;
+ int nr_range;
+ union {
+ struct range range;
+ struct range ranges[0];
+ };
};
+static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
+{
+ if (pgmap->flags & PGMAP_ALTMAP_VALID)
+ return &pgmap->altmap;
+ return NULL;
+}
+
#ifdef CONFIG_ZONE_DEVICE
+void *memremap_pages(struct dev_pagemap *pgmap, int nid);
+void memunmap_pages(struct dev_pagemap *pgmap);
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
+void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap);
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap);
+bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn);
unsigned long vmem_altmap_offset(struct vmem_altmap *altmap);
void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns);
+unsigned long memremap_compat_align(void);
#else
static inline void *devm_memremap_pages(struct device *dev,
struct dev_pagemap *pgmap)
@@ -144,10 +155,20 @@
return ERR_PTR(-ENXIO);
}
+static inline void devm_memunmap_pages(struct device *dev,
+ struct dev_pagemap *pgmap)
+{
+}
+
static inline struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap)
{
return NULL;
+}
+
+static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn)
+{
+ return false;
}
static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
@@ -159,6 +180,12 @@
unsigned long nr_pfns)
{
}
+
+/* when memremap_pages() is disabled all archs can remap a single page */
+static inline unsigned long memremap_compat_align(void)
+{
+ return PAGE_SIZE;
+}
#endif /* CONFIG_ZONE_DEVICE */
static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
@@ -166,4 +193,5 @@
if (pgmap)
percpu_ref_put(pgmap->ref);
}
+
#endif /* _LINUX_MEMREMAP_H_ */
--
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