Cc: David Airlie <airlied@xxxxxxxx>
Cc: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
include/uapi/linux/udmabuf.h | 23 ++
drivers/dma-buf/udmabuf.c | 261 ++++++++++++++++++++++
tools/testing/selftests/drivers/dma-buf/udmabuf.c | 69 ++++++
drivers/dma-buf/Kconfig | 7 +
drivers/dma-buf/Makefile | 1 +
tools/testing/selftests/drivers/dma-buf/Makefile | 5 +
6 files changed, 366 insertions(+)
create mode 100644 include/uapi/linux/udmabuf.h
create mode 100644 drivers/dma-buf/udmabuf.c
create mode 100644 tools/testing/selftests/drivers/dma-buf/udmabuf.c
create mode 100644 tools/testing/selftests/drivers/dma-buf/Makefile
diff --git a/include/uapi/linux/udmabuf.h b/include/uapi/linux/udmabuf.h
new file mode 100644
index 0000000000..54ceba203a
--- /dev/null
+++ b/include/uapi/linux/udmabuf.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_UDMABUF_H
+#define _UAPI_LINUX_UDMABUF_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+struct udmabuf_iovec {
+ __u64 base;
+ __u64 len;
+};
+
+#define UDMABUF_FLAGS_CLOEXEC 0x01
+
+struct udmabuf_create {
+ __u32 flags;
+ __u32 niov;
+ struct udmabuf_iovec iovs[];
+};
+
+#define UDMABUF_CREATE _IOW(0x42, 0x23, struct udmabuf_create)
+
+#endif /* _UAPI_LINUX_UDMABUF_H */
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
new file mode 100644
index 0000000000..664ab4ee4e
--- /dev/null
+++ b/drivers/dma-buf/udmabuf.c
@@ -0,0 +1,261 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#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 <uapi/linux/udmabuf.h>
+
+struct udmabuf {
+ u32 pagecount;
+ struct page **pages;
+ struct user_struct *owner;
+};
+
+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) == 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]);
+ user_shm_unlock(ubuf->pagecount << PAGE_SHIFT, ubuf->owner);
+ free_uid(ubuf->owner);
+ kfree(ubuf->pages);
+ kfree(ubuf);
+}
+
+static void *kmap_atomic_udmabuf(struct dma_buf *buf, unsigned long page_num)
+{
+ struct udmabuf *ubuf = buf->priv;
+ struct page *page = ubuf->pages[page_num];
+
+ return kmap_atomic(page);
+}
+
+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 struct dma_buf_ops udmabuf_ops = {
+ .map_dma_buf = map_udmabuf,
+ .unmap_dma_buf = unmap_udmabuf,
+ .release = release_udmabuf,
+ .map_atomic = kmap_atomic_udmabuf,
+ .map = kmap_udmabuf,
+ .mmap = mmap_udmabuf,
+};
+
+static long udmabuf_ioctl_create(struct file *filp, unsigned long arg)
+{
+ struct udmabuf_create create;
+ struct udmabuf_iovec *iovs;
+ struct udmabuf *ubuf;
+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+ struct dma_buf *buf;
+ pgoff_t pgoff, pgcnt;
+ u32 iov, flags;
+ int ret;
+
+ if (copy_from_user(&create, (void __user *)arg,
+ sizeof(struct udmabuf_create)))
+ return -EFAULT;
+
+ iovs = kmalloc_array(create.niov, sizeof(struct udmabuf_iovec),
+ GFP_KERNEL);
+ if (!iovs)
+ return -ENOMEM;
+
+ arg += offsetof(struct udmabuf_create, iovs);
+ ret = -EFAULT;
+ if (copy_from_user(iovs, (void __user *)arg,
+ create.niov * sizeof(struct udmabuf_iovec)))
+ goto err_free_iovs;
+
+ ubuf = kzalloc(sizeof(struct udmabuf), GFP_KERNEL);
+ if (!ubuf)
+ goto err_free_iovs;
+
+ ret = -EINVAL;
+ for (iov = 0; iov < create.niov; iov++) {
+ if (!IS_ALIGNED(iovs[iov].base, PAGE_SIZE))
+ goto err_free_buf;
+ if (!IS_ALIGNED(iovs[iov].len, PAGE_SIZE))
+ goto err_free_buf;
+ ubuf->pagecount += iovs[iov].len >> PAGE_SHIFT;
+ }
+
+ /* this effectively mlocks the pages so account it accordingly */
+ ret = -ENOMEM;
+ ubuf->owner = current_user();
+ if (!user_shm_lock(ubuf->pagecount << PAGE_SHIFT, ubuf->owner))
+ goto err_free_buf;
+
+ ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page*),
+ GFP_KERNEL);
+ if (!ubuf->pages)
+ goto err_shm_unlock;
+
+ pgoff = 0;
+ for (iov = 0; iov < create.niov; iov++) {
+ pgcnt = iovs[iov].len >> PAGE_SHIFT;
+ while (pgcnt > 0) {
+ ret = get_user_pages_fast(iovs[iov].base, pgcnt,
+ true, /* write */
+ ubuf->pages + pgoff);
+ if (ret < 0)
+ goto err_put_pages;
+ pgoff += ret;
+ pgcnt -= ret;
+ }
+ }
+
+ 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 (create.flags & UDMABUF_FLAGS_CLOEXEC)
+ flags |= O_CLOEXEC;
+
+ kfree(iovs);
+ return dma_buf_fd(buf, flags);
+
+err_put_pages:
+ while (pgoff > 0)
+ put_page(ubuf->pages[--pgoff]);
+err_shm_unlock:
+ user_shm_unlock(ubuf->pagecount << PAGE_SHIFT, ubuf->owner);
+err_free_buf:
+ free_uid(ubuf->owner);
+ kfree(ubuf->pages);
+ kfree(ubuf);
+err_free_iovs:
+ kfree(iovs);
+ 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;
+ 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@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/tools/testing/selftests/drivers/dma-buf/udmabuf.c b/tools/testing/selftests/drivers/dma-buf/udmabuf.c
new file mode 100644
index 0000000000..3472c8ee49
--- /dev/null
+++ b/tools/testing/selftests/drivers/dma-buf/udmabuf.c
@@ -0,0 +1,69 @@
+#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 <linux/udmabuf.h>
+
+#define TEST_PREFIX "drivers/dma-buf/udmabuf"
+#define NUM_PAGES 4
+
+int main(int argc, char *argv[])
+{
+ struct udmabuf_create *create;
+ void *mem;
+ int dev, fd;
+
+ dev = open("/dev/udmabuf", O_RDWR);
+ if (dev < 0) {
+ printf("%s: [skip]\n", TEST_PREFIX);
+ exit(77);
+ }
+
+ mem = memalign(getpagesize(), getpagesize() * NUM_PAGES);
+ if (mem == NULL) {
+ printf("%s: [FAIL]\n", TEST_PREFIX);
+ exit (1);
+ }
+
+ create = malloc(sizeof(struct udmabuf_create) +
+ sizeof(struct udmabuf_iovec));
+ create->flags = 0;
+ create->niov = 1;
+
+ /* should fail (base not page aligned) */
+ create->iovs[0].base = (intptr_t)mem + getpagesize()/2;
+ create->iovs[0].len = getpagesize();
+ fd = ioctl(dev, UDMABUF_CREATE, create);
+ if (fd >= 0) {
+ printf("%s: [FAIL]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ /* should fail (size not multiple of page) */
+ create->iovs[0].base = (intptr_t)mem;
+ create->iovs[0].len = getpagesize()/2;
+ fd = ioctl(dev, UDMABUF_CREATE, create);
+ if (fd >= 0) {
+ printf("%s: [FAIL]\n", TEST_PREFIX);
+ exit(1);
+ }
+
+ /* should work */
+ create->iovs[0].base = (intptr_t)mem;
+ create->iovs[0].len = getpagesize() * NUM_PAGES;
+ fd = ioctl(dev, UDMABUF_CREATE, create);
+ if (fd < 0) {
+ printf("%s: [FAIL]\n", TEST_PREFIX);
+ exit(1);
+ }
+ close(fd);
+
+ fprintf(stderr, "%s: ok\n", TEST_PREFIX);
+ close(dev);
+ return 0;
+}
diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
index ed3b785bae..19be3ec62d 100644
--- a/drivers/dma-buf/Kconfig
+++ b/drivers/dma-buf/Kconfig
@@ -30,4 +30,11 @@ config SW_SYNC
WARNING: improper use of this can result in deadlocking kernel
drivers from userspace. Intended for test and debug only.
+config UDMABUF
+ bool "userspace dmabuf misc driver"
+ default n
+ depends on DMA_SHARED_BUFFER
+ ---help---
+ A driver to let userspace turn iovs into dma-bufs.
+
endmenu
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index c33bf88631..0913a6ccab 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -1,3 +1,4 @@
obj-y := dma-buf.o dma-fence.o dma-fence-array.o reservation.o seqno-fence.o
obj-$(CONFIG_SYNC_FILE) += sync_file.o
obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o
+obj-$(CONFIG_UDMABUF) += udmabuf.o
diff --git a/tools/testing/selftests/drivers/dma-buf/Makefile b/tools/testing/selftests/drivers/dma-buf/Makefile
new file mode 100644
index 0000000000..4154c3d7aa
--- /dev/null
+++ b/tools/testing/selftests/drivers/dma-buf/Makefile
@@ -0,0 +1,5 @@
+CFLAGS += -I../../../../../usr/include/
+
+TEST_GEN_PROGS := udmabuf
+
+include ../../lib.mk
