--- /dev/null
+// 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");
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <malloc.h>
+
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <linux/memfd.h>
+#include <linux/udmabuf.h>
+
+#define TEST_PREFIX "drivers/dma-buf/udmabuf"
+#define NUM_PAGES 4
+
+static int memfd_create(const char *name, unsigned int flags)
+{
+ return syscall(__NR_memfd_create, name, flags);
+}
+
+int main(int argc, char *argv[])
+{
+ struct udmabuf_create create;
+ int devfd, memfd, buf, ret;
+ off_t size;
+ void *mem;
+
+ devfd = open("/dev/udmabuf", O_RDWR);
+ if (devfd < 0) {
+ printf("%s: [skip,no-udmabuf]\n", TEST_PREFIX);
+ exit(77);
+ }
+
+ memfd = memfd_create("udmabuf-test", MFD_CLOEXEC);
+ if (memfd < 0) {
+ printf("%s: [skip,no-memfd]\n", TEST_PREFIX);
+ exit(77);
+ }
+
+ size = getpagesize() * NUM_PAGES;
+ ret = ftruncate(memfd, size);
+ if (ret == -1) {
+ printf("%s: [FAIL,memfd-truncate]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ memset(&create, 0, sizeof(create));
+
+ /* should fail (offset not page aligned) */
+ create.memfd = memfd;
+ create.offset = getpagesize()/2;
+ create.size = getpagesize();
+ buf = ioctl(devfd, UDMABUF_CREATE, &create);
+ if (buf >= 0) {
+ printf("%s: [FAIL,test-1]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ /* should fail (size not multiple of page) */
+ create.memfd = memfd;
+ create.offset = 0;
+ create.size = getpagesize()/2;
+ buf = ioctl(devfd, UDMABUF_CREATE, &create);
+ if (buf >= 0) {
+ printf("%s: [FAIL,test-2]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ /* should fail (not memfd) */
+ create.memfd = 0; /* stdin */
+ create.offset = 0;
+ create.size = size;
+ buf = ioctl(devfd, UDMABUF_CREATE, &create);
+ if (buf >= 0) {
+ printf("%s: [FAIL,test-3]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ /* should work */
+ create.memfd = memfd;
+ create.offset = 0;
+ create.size = size;
+ buf = ioctl(devfd, UDMABUF_CREATE, &create);
+ if (buf < 0) {
+ printf("%s: [FAIL,test-4]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ fprintf(stderr, "%s: ok\n", TEST_PREFIX);
+ close(buf);
+ close(memfd);
+ close(devfd);
+ return 0;
+}
projects / mirror_ubuntu-jammy-kernel.git / commitdiff