1 // SPDX-License-Identifier: MIT
2 /*
3 * Copyright © 2020 Intel Corporation
4 */
5
6 #include <linux/mm.h>
7 #include <linux/pagemap.h>
8 #include <linux/shmem_fs.h>
9
10 #include "gem/i915_gem_object.h"
11 #include "shmem_utils.h"
12
shmem_create_from_data(const char * name,void * data,size_t len)13 struct file *shmem_create_from_data(const char *name, void *data, size_t len)
14 {
15 struct file *file;
16 int err;
17
18 file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
19 if (IS_ERR(file))
20 return file;
21
22 err = shmem_write(file, 0, data, len);
23 if (err) {
24 fput(file);
25 return ERR_PTR(err);
26 }
27
28 return file;
29 }
30
shmem_create_from_object(struct drm_i915_gem_object * obj)31 struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
32 {
33 struct file *file;
34 void *ptr;
35
36 if (obj->ops == &i915_gem_shmem_ops) {
37 file = obj->base.filp;
38 atomic_long_inc(&file->f_count);
39 return file;
40 }
41
42 ptr = i915_gem_object_pin_map(obj, I915_MAP_WB);
43 if (IS_ERR(ptr))
44 return ERR_CAST(ptr);
45
46 file = shmem_create_from_data("", ptr, obj->base.size);
47 i915_gem_object_unpin_map(obj);
48
49 return file;
50 }
51
shmem_pin_map(struct file * file)52 void *shmem_pin_map(struct file *file)
53 {
54 struct page **pages;
55 size_t n_pages, i;
56 void *vaddr;
57
58 n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
59 pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
60 if (!pages)
61 return NULL;
62
63 for (i = 0; i < n_pages; i++) {
64 pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
65 GFP_KERNEL);
66 if (IS_ERR(pages[i]))
67 goto err_page;
68 }
69
70 vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
71 if (!vaddr)
72 goto err_page;
73 mapping_set_unevictable(file->f_mapping);
74 return vaddr;
75 err_page:
76 while (i--)
77 put_page(pages[i]);
78 kvfree(pages);
79 return NULL;
80 }
81
shmem_unpin_map(struct file * file,void * ptr)82 void shmem_unpin_map(struct file *file, void *ptr)
83 {
84 mapping_clear_unevictable(file->f_mapping);
85 vfree(ptr);
86 }
87
__shmem_rw(struct file * file,loff_t off,void * ptr,size_t len,bool write)88 static int __shmem_rw(struct file *file, loff_t off,
89 void *ptr, size_t len,
90 bool write)
91 {
92 unsigned long pfn;
93
94 for (pfn = off >> PAGE_SHIFT; len; pfn++) {
95 unsigned int this =
96 min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
97 struct page *page;
98 void *vaddr;
99
100 page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
101 GFP_KERNEL);
102 if (IS_ERR(page))
103 return PTR_ERR(page);
104
105 vaddr = kmap(page);
106 if (write) {
107 memcpy(vaddr + offset_in_page(off), ptr, this);
108 set_page_dirty(page);
109 } else {
110 memcpy(ptr, vaddr + offset_in_page(off), this);
111 }
112 mark_page_accessed(page);
113 kunmap(page);
114 put_page(page);
115
116 len -= this;
117 ptr += this;
118 off = 0;
119 }
120
121 return 0;
122 }
123
shmem_read(struct file * file,loff_t off,void * dst,size_t len)124 int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
125 {
126 return __shmem_rw(file, off, dst, len, false);
127 }
128
shmem_write(struct file * file,loff_t off,void * src,size_t len)129 int shmem_write(struct file *file, loff_t off, void *src, size_t len)
130 {
131 return __shmem_rw(file, off, src, len, true);
132 }
133
134 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
135 #include "st_shmem_utils.c"
136 #endif
137