[linux-2.6-block.git] / drivers / dma-buf / udmabuf.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/miscdevice.h>
#include <linux/dma-buf.h>
#include <linux/highmem.h>
#include <linux/cred.h>
#include <linux/shmem_fs.h>
#include <linux/memfd.h>

#include <uapi/linux/udmabuf.h>

struct udmabuf {
	u32 pagecount;
	struct page **pages;
};

static int udmabuf_vm_fault(struct vm_fault *vmf)
{
	struct vm_area_struct *vma = vmf->vma;
	struct udmabuf *ubuf = vma->vm_private_data;

	if (WARN_ON(vmf->pgoff >= ubuf->pagecount))
		return VM_FAULT_SIGBUS;

	vmf->page = ubuf->pages[vmf->pgoff];
	get_page(vmf->page);
	return 0;
}

static const struct vm_operations_struct udmabuf_vm_ops = {
	.fault = udmabuf_vm_fault,
};

static int mmap_udmabuf(struct dma_buf *buf, struct vm_area_struct *vma)
{
	struct udmabuf *ubuf = buf->priv;

	if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
		return -EINVAL;

	vma->vm_ops = &udmabuf_vm_ops;
	vma->vm_private_data = ubuf;
	return 0;
}

static struct sg_table *map_udmabuf(struct dma_buf_attachment *at,
				    enum dma_data_direction direction)
{
	struct udmabuf *ubuf = at->dmabuf->priv;
	struct sg_table *sg;

	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
	if (!sg)
		goto err1;
	if (sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount,
				      0, ubuf->pagecount << PAGE_SHIFT,
				      GFP_KERNEL) < 0)
		goto err2;
	if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction))
		goto err3;

	return sg;

err3:
	sg_free_table(sg);
err2:
	kfree(sg);
err1:
	return ERR_PTR(-ENOMEM);
}

static void unmap_udmabuf(struct dma_buf_attachment *at,
			  struct sg_table *sg,
			  enum dma_data_direction direction)
{
	sg_free_table(sg);
	kfree(sg);
}

static void release_udmabuf(struct dma_buf *buf)
{
	struct udmabuf *ubuf = buf->priv;
	pgoff_t pg;

	for (pg = 0; pg < ubuf->pagecount; pg++)
		put_page(ubuf->pages[pg]);
	kfree(ubuf->pages);
	kfree(ubuf);
}

static void *kmap_udmabuf(struct dma_buf *buf, unsigned long page_num)
{
	struct udmabuf *ubuf = buf->priv;
	struct page *page = ubuf->pages[page_num];

	return kmap(page);
}

static void kunmap_udmabuf(struct dma_buf *buf, unsigned long page_num,
			   void *vaddr)
{
	kunmap(vaddr);
}

static struct dma_buf_ops udmabuf_ops = {
	.map_dma_buf	  = map_udmabuf,
	.unmap_dma_buf	  = unmap_udmabuf,
	.release	  = release_udmabuf,
	.map		  = kmap_udmabuf,
	.unmap		  = kunmap_udmabuf,
	.mmap		  = mmap_udmabuf,
};

#define SEALS_WANTED (F_SEAL_SHRINK)
#define SEALS_DENIED (F_SEAL_WRITE)

static long udmabuf_create(struct udmabuf_create_list *head,
			   struct udmabuf_create_item *list)
{
	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
	struct file *memfd = NULL;
	struct udmabuf *ubuf;
	struct dma_buf *buf;
	pgoff_t pgoff, pgcnt, pgidx, pgbuf;
	struct page *page;
	int seals, ret = -EINVAL;
	u32 i, flags;

	ubuf = kzalloc(sizeof(struct udmabuf), GFP_KERNEL);
	if (!ubuf)
		return -ENOMEM;

	for (i = 0; i < head->count; i++) {
		if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
			goto err_free_ubuf;
		if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
			goto err_free_ubuf;
		ubuf->pagecount += list[i].size >> PAGE_SHIFT;
	}
	ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page *),
				    GFP_KERNEL);
	if (!ubuf->pages) {
		ret = -ENOMEM;
		goto err_free_ubuf;
	}

	pgbuf = 0;
	for (i = 0; i < head->count; i++) {
		memfd = fget(list[i].memfd);
		if (!memfd)
			goto err_put_pages;
		if (!shmem_mapping(file_inode(memfd)->i_mapping))
			goto err_put_pages;
		seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
		if (seals == -EINVAL ||
		    (seals & SEALS_WANTED) != SEALS_WANTED ||
		    (seals & SEALS_DENIED) != 0)
			goto err_put_pages;
		pgoff = list[i].offset >> PAGE_SHIFT;
		pgcnt = list[i].size   >> PAGE_SHIFT;
		for (pgidx = 0; pgidx < pgcnt; pgidx++) {
			page = shmem_read_mapping_page(
				file_inode(memfd)->i_mapping, pgoff + pgidx);
			if (IS_ERR(page)) {
				ret = PTR_ERR(page);
				goto err_put_pages;
			}
			ubuf->pages[pgbuf++] = page;
		}
		fput(memfd);
	}
	memfd = NULL;

	exp_info.ops  = &udmabuf_ops;
	exp_info.size = ubuf->pagecount << PAGE_SHIFT;
	exp_info.priv = ubuf;

	buf = dma_buf_export(&exp_info);
	if (IS_ERR(buf)) {
		ret = PTR_ERR(buf);
		goto err_put_pages;
	}

	flags = 0;
	if (head->flags & UDMABUF_FLAGS_CLOEXEC)
		flags |= O_CLOEXEC;
	return dma_buf_fd(buf, flags);

err_put_pages:
	while (pgbuf > 0)
		put_page(ubuf->pages[--pgbuf]);
err_free_ubuf:
	fput(memfd);
	kfree(ubuf->pages);
	kfree(ubuf);
	return ret;
}

static long udmabuf_ioctl_create(struct file *filp, unsigned long arg)
{
	struct udmabuf_create create;
	struct udmabuf_create_list head;
	struct udmabuf_create_item list;

	if (copy_from_user(&create, (void __user *)arg,
			   sizeof(struct udmabuf_create)))
		return -EFAULT;

	head.flags  = create.flags;
	head.count  = 1;
	list.memfd  = create.memfd;
	list.offset = create.offset;
	list.size   = create.size;

	return udmabuf_create(&head, &list);
}

static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg)
{
	struct udmabuf_create_list head;
	struct udmabuf_create_item *list;
	int ret = -EINVAL;
	u32 lsize;

	if (copy_from_user(&head, (void __user *)arg, sizeof(head)))
		return -EFAULT;
	if (head.count > 1024)
		return -EINVAL;
	lsize = sizeof(struct udmabuf_create_item) * head.count;
	list = memdup_user((void __user *)(arg + sizeof(head)), lsize);
	if (IS_ERR(list))
		return PTR_ERR(list);

	ret = udmabuf_create(&head, list);
	kfree(list);
	return ret;
}

static long udmabuf_ioctl(struct file *filp, unsigned int ioctl,
			  unsigned long arg)
{
	long ret;

	switch (ioctl) {
	case UDMABUF_CREATE:
		ret = udmabuf_ioctl_create(filp, arg);
		break;
	case UDMABUF_CREATE_LIST:
		ret = udmabuf_ioctl_create_list(filp, arg);
		break;
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

static const struct file_operations udmabuf_fops = {
	.owner		= THIS_MODULE,
	.unlocked_ioctl = udmabuf_ioctl,
};

static struct miscdevice udmabuf_misc = {
	.minor          = MISC_DYNAMIC_MINOR,
	.name           = "udmabuf",
	.fops           = &udmabuf_fops,
};

static int __init udmabuf_dev_init(void)
{
	return misc_register(&udmabuf_misc);
}

static void __exit udmabuf_dev_exit(void)
{
	misc_deregister(&udmabuf_misc);
}

module_init(udmabuf_dev_init)
module_exit(udmabuf_dev_exit)

MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
fbb0de79 GH	1	// SPDX-License-Identifier: GPL-2.0
	2	#include <linux/init.h>
	3	#include <linux/module.h>
	4	#include <linux/device.h>
	5	#include <linux/kernel.h>
	6	#include <linux/slab.h>
	7	#include <linux/miscdevice.h>
	8	#include <linux/dma-buf.h>
	9	#include <linux/highmem.h>
	10	#include <linux/cred.h>
	11	#include <linux/shmem_fs.h>
	12	#include <linux/memfd.h>
	13
	14	#include <uapi/linux/udmabuf.h>
	15
	16	struct udmabuf {
	17	u32 pagecount;
	18	struct page **pages;
	19	};
	20
	21	static int udmabuf_vm_fault(struct vm_fault *vmf)
	22	{
	23	struct vm_area_struct *vma = vmf->vma;
	24	struct udmabuf *ubuf = vma->vm_private_data;
	25
	26	if (WARN_ON(vmf->pgoff >= ubuf->pagecount))
	27	return VM_FAULT_SIGBUS;
	28
	29	vmf->page = ubuf->pages[vmf->pgoff];
	30	get_page(vmf->page);
	31	return 0;
	32	}
	33
	34	static const struct vm_operations_struct udmabuf_vm_ops = {
	35	.fault = udmabuf_vm_fault,
	36	};
	37
	38	static int mmap_udmabuf(struct dma_buf buf, struct vm_area_struct vma)
	39	{
	40	struct udmabuf *ubuf = buf->priv;
	41
	42	if ((vma->vm_flags & (VM_SHARED \| VM_MAYSHARE)) == 0)
	43	return -EINVAL;
	44
	45	vma->vm_ops = &udmabuf_vm_ops;
	46	vma->vm_private_data = ubuf;
	47	return 0;
	48	}
	49
	50	static struct sg_table map_udmabuf(struct dma_buf_attachment at,
	51	enum dma_data_direction direction)
	52	{
	53	struct udmabuf *ubuf = at->dmabuf->priv;
	54	struct sg_table *sg;
	55
	56	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
	57	if (!sg)
	58	goto err1;
	59	if (sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount,
	60	0, ubuf->pagecount << PAGE_SHIFT,
	61	GFP_KERNEL) < 0)
	62	goto err2;
	63	if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction))
	64	goto err3;
65
66	return sg;
67
68	err3:
69	sg_free_table(sg);
70	err2:
71	kfree(sg);
72	err1:
73	return ERR_PTR(-ENOMEM);
74	}
75
76	static void unmap_udmabuf(struct dma_buf_attachment *at,
77	struct sg_table *sg,
78	enum dma_data_direction direction)
79	{
80	sg_free_table(sg);
81	kfree(sg);
82	}
83
84	static void release_udmabuf(struct dma_buf *buf)
85	{
86	struct udmabuf *ubuf = buf->priv;
87	pgoff_t pg;
88
89	for (pg = 0; pg < ubuf->pagecount; pg++)
90	put_page(ubuf->pages[pg]);
91	kfree(ubuf->pages);
92	kfree(ubuf);
93	}
94
95	static void kmap_udmabuf(struct dma_buf buf, unsigned long page_num)
96	{
97	struct udmabuf *ubuf = buf->priv;
98	struct page *page = ubuf->pages[page_num];
99
100	return kmap(page);
101	}
102
103	static void kunmap_udmabuf(struct dma_buf *buf, unsigned long page_num,
104	void *vaddr)
105	{
106	kunmap(vaddr);
107	}
108
109	static struct dma_buf_ops udmabuf_ops = {
110	.map_dma_buf = map_udmabuf,
111	.unmap_dma_buf = unmap_udmabuf,
112	.release = release_udmabuf,
113	.map = kmap_udmabuf,
114	.unmap = kunmap_udmabuf,
115	.mmap = mmap_udmabuf,
116	};
117
118	#define SEALS_WANTED (F_SEAL_SHRINK)
119	#define SEALS_DENIED (F_SEAL_WRITE)
120
121	static long udmabuf_create(struct udmabuf_create_list *head,
122	struct udmabuf_create_item *list)
123	{
124	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
125	struct file *memfd = NULL;
126	struct udmabuf *ubuf;
127	struct dma_buf *buf;
128	pgoff_t pgoff, pgcnt, pgidx, pgbuf;
129	struct page *page;
130	int seals, ret = -EINVAL;
131	u32 i, flags;
132
133	ubuf = kzalloc(sizeof(struct udmabuf), GFP_KERNEL);
134	if (!ubuf)
135	return -ENOMEM;
136
137	for (i = 0; i < head->count; i++) {
138	if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
139	goto err_free_ubuf;
140	if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
141	goto err_free_ubuf;
142	ubuf->pagecount += list[i].size >> PAGE_SHIFT;
143	}
144	ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page *),
145	GFP_KERNEL);
146	if (!ubuf->pages) {
147	ret = -ENOMEM;
148	goto err_free_ubuf;
149	}
150
151	pgbuf = 0;
152	for (i = 0; i < head->count; i++) {
153	memfd = fget(list[i].memfd);
154	if (!memfd)
155	goto err_put_pages;
156	if (!shmem_mapping(file_inode(memfd)->i_mapping))
157	goto err_put_pages;
158	seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
159	if (seals == -EINVAL \|\|
160	(seals & SEALS_WANTED) != SEALS_WANTED \|\|
161	(seals & SEALS_DENIED) != 0)
162	goto err_put_pages;
163	pgoff = list[i].offset >> PAGE_SHIFT;
164	pgcnt = list[i].size >> PAGE_SHIFT;
165	for (pgidx = 0; pgidx < pgcnt; pgidx++) {
166	page = shmem_read_mapping_page(
167	file_inode(memfd)->i_mapping, pgoff + pgidx);
168	if (IS_ERR(page)) {
169	ret = PTR_ERR(page);
170	goto err_put_pages;
171	}
172	ubuf->pages[pgbuf++] = page;
173	}
174	fput(memfd);
175	}
176	memfd = NULL;
177
178	exp_info.ops = &udmabuf_ops;
179	exp_info.size = ubuf->pagecount << PAGE_SHIFT;
180	exp_info.priv = ubuf;
181
182	buf = dma_buf_export(&exp_info);
183	if (IS_ERR(buf)) {
184	ret = PTR_ERR(buf);
185	goto err_put_pages;
186	}
187
188	flags = 0;
189	if (head->flags & UDMABUF_FLAGS_CLOEXEC)
190	flags \|= O_CLOEXEC;
191	return dma_buf_fd(buf, flags);
192
193	err_put_pages:
194	while (pgbuf > 0)
195	put_page(ubuf->pages[--pgbuf]);
196	err_free_ubuf:
197	fput(memfd);
198	kfree(ubuf->pages);
199	kfree(ubuf);
200	return ret;
201	}
202
203	static long udmabuf_ioctl_create(struct file *filp, unsigned long arg)
204	{
205	struct udmabuf_create create;
206	struct udmabuf_create_list head;
207	struct udmabuf_create_item list;
208
209	if (copy_from_user(&create, (void __user *)arg,
210	sizeof(struct udmabuf_create)))
211	return -EFAULT;
212
213	head.flags = create.flags;
214	head.count = 1;
215	list.memfd = create.memfd;
216	list.offset = create.offset;
217	list.size = create.size;
218
219	return udmabuf_create(&head, &list);
220	}
221
222	static long udmabuf_ioctl_create_list(struct file *filp, unsigned long arg)
223	{
224	struct udmabuf_create_list head;
225	struct udmabuf_create_item *list;
226	int ret = -EINVAL;
227	u32 lsize;
228
229	if (copy_from_user(&head, (void __user *)arg, sizeof(head)))
230	return -EFAULT;
231	if (head.count > 1024)
232	return -EINVAL;
233	lsize = sizeof(struct udmabuf_create_item) * head.count;
234	list = memdup_user((void __user *)(arg + sizeof(head)), lsize);
235	if (IS_ERR(list))
236	return PTR_ERR(list);
237
238	ret = udmabuf_create(&head, list);
239	kfree(list);
240	return ret;
241	}
242
243	static long udmabuf_ioctl(struct file *filp, unsigned int ioctl,
244	unsigned long arg)
245	{
246	long ret;
247
248	switch (ioctl) {
249	case UDMABUF_CREATE:
250	ret = udmabuf_ioctl_create(filp, arg);
251	break;
252	case UDMABUF_CREATE_LIST:
253	ret = udmabuf_ioctl_create_list(filp, arg);
254	break;
255	default:
256	ret = -EINVAL;
257	break;
258	}
259	return ret;
260	}
261
262	static const struct file_operations udmabuf_fops = {
263	.owner = THIS_MODULE,
264	.unlocked_ioctl = udmabuf_ioctl,
265	};
266
267	static struct miscdevice udmabuf_misc = {
268	.minor = MISC_DYNAMIC_MINOR,
269	.name = "udmabuf",
270	.fops = &udmabuf_fops,
271	};
272
273	static int __init udmabuf_dev_init(void)
274	{
275	return misc_register(&udmabuf_misc);
276	}
277
278	static void __exit udmabuf_dev_exit(void)
279	{
280	misc_deregister(&udmabuf_misc);
281	}
282
283	module_init(udmabuf_dev_init)
284	module_exit(udmabuf_dev_exit)
285
286	MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
287	MODULE_LICENSE("GPL v2");