1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (c) 2024, Google LLC.
4 * Pasha Tatashin <pasha.tatashin@soleen.com>
5 */
6
7#ifndef __IOMMU_PAGES_H
8#define __IOMMU_PAGES_H
9
10#include <linux/iommu.h>
11
12/**
13 * struct ioptdesc - Memory descriptor for IOMMU page tables
14 * @iopt_freelist_elm: List element for a struct iommu_pages_list
15 *
16 * This struct overlays struct page for now. Do not modify without a good
17 * understanding of the issues.
18 */
19struct ioptdesc {
20 unsigned long __page_flags;
21
22 struct list_head iopt_freelist_elm;
23 unsigned long __page_mapping;
24 union {
25 u8 incoherent;
26 pgoff_t __index;
27 };
28 void *_private;
29
30 unsigned int __page_type;
31 atomic_t __page_refcount;
32#ifdef CONFIG_MEMCG
33 unsigned long memcg_data;
34#endif
35};
36
37static inline struct ioptdesc *folio_ioptdesc(struct folio *folio)
38{
39 return (struct ioptdesc *)folio;
40}
41
42static inline struct folio *ioptdesc_folio(struct ioptdesc *iopt)
43{
44 return (struct folio *)iopt;
45}
46
47static inline struct ioptdesc *virt_to_ioptdesc(void *virt)
48{
49 return folio_ioptdesc(folio: virt_to_folio(x: virt));
50}
51
52void *iommu_alloc_pages_node_sz(int nid, gfp_t gfp, size_t size);
53void iommu_free_pages(void *virt);
54void iommu_put_pages_list(struct iommu_pages_list *list);
55
56/**
57 * iommu_pages_list_add - add the page to a iommu_pages_list
58 * @list: List to add the page to
59 * @virt: Address returned from iommu_alloc_pages_node_sz()
60 */
61static inline void iommu_pages_list_add(struct iommu_pages_list *list,
62 void *virt)
63{
64 list_add_tail(new: &virt_to_ioptdesc(virt)->iopt_freelist_elm, head: &list->pages);
65}
66
67/**
68 * iommu_pages_list_splice - Put all the pages in list from into list to
69 * @from: Source list of pages
70 * @to: Destination list of pages
71 *
72 * from must be re-initialized after calling this function if it is to be
73 * used again.
74 */
75static inline void iommu_pages_list_splice(struct iommu_pages_list *from,
76 struct iommu_pages_list *to)
77{
78 list_splice(list: &from->pages, head: &to->pages);
79}
80
81/**
82 * iommu_pages_list_empty - True if the list is empty
83 * @list: List to check
84 */
85static inline bool iommu_pages_list_empty(struct iommu_pages_list *list)
86{
87 return list_empty(head: &list->pages);
88}
89
90/**
91 * iommu_alloc_pages_sz - Allocate a zeroed page of a given size from
92 * specific NUMA node
93 * @nid: memory NUMA node id
94 * @gfp: buddy allocator flags
95 * @size: Memory size to allocate, this is rounded up to a power of 2
96 *
97 * Returns the virtual address of the allocated page.
98 */
99static inline void *iommu_alloc_pages_sz(gfp_t gfp, size_t size)
100{
101 return iommu_alloc_pages_node_sz(NUMA_NO_NODE, gfp, size);
102}
103
104int iommu_pages_start_incoherent(void *virt, struct device *dma_dev);
105int iommu_pages_start_incoherent_list(struct iommu_pages_list *list,
106 struct device *dma_dev);
107
108#ifdef CONFIG_X86
109#define IOMMU_PAGES_USE_DMA_API 0
110#include <linux/cacheflush.h>
111
112static inline void iommu_pages_flush_incoherent(struct device *dma_dev,
113 void *virt, size_t offset,
114 size_t len)
115{
116 clflush_cache_range(addr: virt + offset, size: len);
117}
118static inline void
119iommu_pages_stop_incoherent_list(struct iommu_pages_list *list,
120 struct device *dma_dev)
121{
122 /*
123 * For performance leave the incoherent flag alone which turns this into
124 * a NOP. For X86 the rest of the stop/free flow ignores the flag.
125 */
126}
127static inline void iommu_pages_free_incoherent(void *virt,
128 struct device *dma_dev)
129{
130 iommu_free_pages(virt);
131}
132#else
133#define IOMMU_PAGES_USE_DMA_API 1
134#include <linux/dma-mapping.h>
135
136static inline void iommu_pages_flush_incoherent(struct device *dma_dev,
137 void *virt, size_t offset,
138 size_t len)
139{
140 dma_sync_single_for_device(dma_dev, (uintptr_t)virt + offset, len,
141 DMA_TO_DEVICE);
142}
143void iommu_pages_stop_incoherent_list(struct iommu_pages_list *list,
144 struct device *dma_dev);
145void iommu_pages_free_incoherent(void *virt, struct device *dma_dev);
146#endif
147
148#endif /* __IOMMU_PAGES_H */
149

source code of linux/drivers/iommu/iommu-pages.h