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 "i915_drv.h"
 12#include "gem/i915_gem_object.h"
 13#include "gem/i915_gem_lmem.h"
 14#include "shmem_utils.h"
 15
 16struct file *shmem_create_from_data(const char *name, void *data, size_t len)
 17{
 18	struct file *file;
 19	int err;
 20
 21	file = shmem_file_setup(name, PAGE_ALIGN(len), VM_NORESERVE);
 22	if (IS_ERR(file))
 23		return file;
 24
 25	err = shmem_write(file, 0, data, len);
 26	if (err) {
 27		fput(file);
 28		return ERR_PTR(err);
 29	}
 30
 31	return file;
 32}
 33
 34struct file *shmem_create_from_object(struct drm_i915_gem_object *obj)
 35{
 36	enum i915_map_type map_type;
 37	struct file *file;
 38	void *ptr;
 39
 40	if (i915_gem_object_is_shmem(obj)) {
 41		file = obj->base.filp;
 42		atomic_long_inc(&file->f_count);
 43		return file;
 44	}
 45
 46	map_type = i915_gem_object_is_lmem(obj) ? I915_MAP_WC : I915_MAP_WB;
 47	ptr = i915_gem_object_pin_map_unlocked(obj, map_type);
 48	if (IS_ERR(ptr))
 49		return ERR_CAST(ptr);
 50
 51	file = shmem_create_from_data("", ptr, obj->base.size);
 52	i915_gem_object_unpin_map(obj);
 53
 54	return file;
 55}
 56
 57void *shmem_pin_map(struct file *file)
 58{
 59	struct page **pages;
 60	size_t n_pages, i;
 61	void *vaddr;
 62
 63	n_pages = file->f_mapping->host->i_size >> PAGE_SHIFT;
 64	pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
 65	if (!pages)
 66		return NULL;
 67
 68	for (i = 0; i < n_pages; i++) {
 69		pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
 70						       GFP_KERNEL);
 71		if (IS_ERR(pages[i]))
 72			goto err_page;
 73	}
 74
 75	vaddr = vmap(pages, n_pages, VM_MAP_PUT_PAGES, PAGE_KERNEL);
 76	if (!vaddr)
 77		goto err_page;
 78	mapping_set_unevictable(file->f_mapping);
 79	return vaddr;
 80err_page:
 81	while (i--)
 82		put_page(pages[i]);
 83	kvfree(pages);
 84	return NULL;
 85}
 86
 87void shmem_unpin_map(struct file *file, void *ptr)
 88{
 89	mapping_clear_unevictable(file->f_mapping);
 90	vfree(ptr);
 91}
 92
 93static int __shmem_rw(struct file *file, loff_t off,
 94		      void *ptr, size_t len,
 95		      bool write)
 96{
 97	unsigned long pfn;
 98
 99	for (pfn = off >> PAGE_SHIFT; len; pfn++) {
100		unsigned int this =
101			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
102		struct page *page;
103		void *vaddr;
104
105		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
106						   GFP_KERNEL);
107		if (IS_ERR(page))
108			return PTR_ERR(page);
109
110		vaddr = kmap(page);
111		if (write) {
112			memcpy(vaddr + offset_in_page(off), ptr, this);
113			set_page_dirty(page);
114		} else {
115			memcpy(ptr, vaddr + offset_in_page(off), this);
116		}
117		mark_page_accessed(page);
118		kunmap(page);
119		put_page(page);
120
121		len -= this;
122		ptr += this;
123		off = 0;
124	}
125
126	return 0;
127}
128
129int shmem_read_to_iosys_map(struct file *file, loff_t off,
130			    struct iosys_map *map, size_t map_off, size_t len)
131{
132	unsigned long pfn;
133
134	for (pfn = off >> PAGE_SHIFT; len; pfn++) {
135		unsigned int this =
136			min_t(size_t, PAGE_SIZE - offset_in_page(off), len);
137		struct page *page;
138		void *vaddr;
139
140		page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
141						   GFP_KERNEL);
142		if (IS_ERR(page))
143			return PTR_ERR(page);
144
145		vaddr = kmap(page);
146		iosys_map_memcpy_to(map, map_off, vaddr + offset_in_page(off),
147				    this);
148		mark_page_accessed(page);
149		kunmap(page);
150		put_page(page);
151
152		len -= this;
153		map_off += this;
154		off = 0;
155	}
156
157	return 0;
158}
159
160int shmem_read(struct file *file, loff_t off, void *dst, size_t len)
161{
162	return __shmem_rw(file, off, dst, len, false);
163}
164
165int shmem_write(struct file *file, loff_t off, void *src, size_t len)
166{
167	return __shmem_rw(file, off, src, len, true);
168}
169
170#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
171#include "st_shmem_utils.c"
172#endif