1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2020 Intel Corporation
4  */
5 
6 #include <linux/iosys-map.h>
7 #include <linux/mm.h>
8 #include <linux/pagemap.h>
9 #include <linux/shmem_fs.h>
10 
11 #include "gem/i915_gem_object.h"
12 #include "gem/i915_gem_lmem.h"
13 #include "shmem_utils.h"
14 
shmem_create_from_data(const char * name,void * data,size_t len)15 struct file *shmem_create_from_data(const char *name, void *data, size_t len)
16 {
17 	struct file *file;
18 	int err;
19 
20 	file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
21 	if (IS_ERR(file))
22 		return file;
23 
24 	err = shmem_write(file, 0, data, len);
25 	if (err) {
26 		fput(file);
27 		return ERR_PTR(err);
28 	}
29 
30 	return file;
31 }
32 
shmem_create_from_object(struct drm_i915_gem_object * obj)33 struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
34 {
35 	struct file *file;
36 	void *ptr;
37 
38 	if (i915_gem_object_is_shmem(obj)) {
39 		file = obj->base.filp;
40 		atomic_long_inc(&file->f_count);
41 		return file;
42 	}
43 
44 	ptr = i915_gem_object_pin_map_unlocked(obj, i915_gem_object_is_lmem(obj) ?
45 						I915_MAP_WC : I915_MAP_WB);
46 	if (IS_ERR(ptr))
47 		return ERR_CAST(ptr);
48 
49 	file = shmem_create_from_data("", ptr, obj->base.size);
50 	i915_gem_object_unpin_map(obj);
51 
52 	return file;
53 }
54 
shmem_pin_map(struct file * file)55 void *shmem_pin_map(struct file *file)
56 {
57 	struct page **pages;
58 	size_t n_pages, i;
59 	void *vaddr;
60 
61 	n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
62 	pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
63 	if (!pages)
64 		return NULL;
65 
66 	for (i = 0; i < n_pages; i++) {
67 		pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
68 						       GFP_KERNEL);
69 		if (IS_ERR(pages[i]))
70 			goto err_page;
71 	}
72 
73 	vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
74 	if (!vaddr)
75 		goto err_page;
76 	mapping_set_unevictable(file->f_mapping);
77 	return vaddr;
78 err_page:
79 	while (i--)
80 		put_page(pages[i]);
81 	kvfree(pages);
82 	return NULL;
83 }
84 
shmem_unpin_map(struct file * file,void * ptr)85 void shmem_unpin_map(struct file *file, void *ptr)
86 {
87 	mapping_clear_unevictable(file->f_mapping);
88 	vfree(ptr);
89 }
90 
__shmem_rw(struct file * file,loff_t off,void * ptr,size_t len,bool write)91 static int __shmem_rw(struct file *file, loff_t off,
92 		      void *ptr, size_t len,
93 		      bool write)
94 {
95 	unsigned long pfn;
96 
97 	for (pfn = off >> PAGE_SHIFT; len; pfn++) {
98 		unsigned int this =
99 			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
100 		struct page *page;
101 		void *vaddr;
102 
103 		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
104 						   GFP_KERNEL);
105 		if (IS_ERR(page))
106 			return PTR_ERR(page);
107 
108 		vaddr = kmap(page);
109 		if (write) {
110 			memcpy(vaddr + offset_in_page(off), ptr, this);
111 			set_page_dirty(page);
112 		} else {
113 			memcpy(ptr, vaddr + offset_in_page(off), this);
114 		}
115 		mark_page_accessed(page);
116 		kunmap(page);
117 		put_page(page);
118 
119 		len -= this;
120 		ptr += this;
121 		off = 0;
122 	}
123 
124 	return 0;
125 }
126 
shmem_read_to_iosys_map(struct file * file,loff_t off,struct iosys_map * map,size_t map_off,size_t len)127 int shmem_read_to_iosys_map(struct file *file, loff_t off,
128 			    struct iosys_map *map, size_t map_off, size_t len)
129 {
130 	unsigned long pfn;
131 
132 	for (pfn = off >> PAGE_SHIFT; len; pfn++) {
133 		unsigned int this =
134 			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
135 		struct page *page;
136 		void *vaddr;
137 
138 		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
139 						   GFP_KERNEL);
140 		if (IS_ERR(page))
141 			return PTR_ERR(page);
142 
143 		vaddr = kmap(page);
144 		iosys_map_memcpy_to(map, map_off, vaddr + offset_in_page(off),
145 				    this);
146 		mark_page_accessed(page);
147 		kunmap(page);
148 		put_page(page);
149 
150 		len -= this;
151 		map_off += this;
152 		off = 0;
153 	}
154 
155 	return 0;
156 }
157 
shmem_read(struct file * file,loff_t off,void * dst,size_t len)158 int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
159 {
160 	return __shmem_rw(file, off, dst, len, false);
161 }
162 
shmem_write(struct file * file,loff_t off,void * src,size_t len)163 int shmem_write(struct file *file, loff_t off, void *src, size_t len)
164 {
165 	return __shmem_rw(file, off, src, len, true);
166 }
167 
168 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
169 #include "st_shmem_utils.c"
170 #endif
171