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