--- /dev/null
+/*
+ * Copyright © 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Eric Anholt <eric@anholt.net>
+ *
+ */
+
+/** @file mmfs.h
+ * This file provides ioctl and ioctl argument definitions for using the
+ * mmfs device.
+ */
+#ifdef __KERNEL__
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+
+/** @file mmfs_priv.h
+ * This file provides internal structure definitions for mmfs..
+ */
+
+/**
+ * This structure defines the mmfs memory object, which will be used by the
+ * DRM for its buffer objects.
+ */
+struct mmfs_object {
+ /** File representing the shmem storage */
+ struct file *filp;
+
+ spinlock_t lock;
+
+ size_t size;
+ /** Reference count of this object, protected by object_lock */
+ int refcount;
+};
+
+/**
+ * This structure defines the process (actually per-fd) mapping of object
+ * handles to mmfs objects.
+ */
+struct mmfs_file {
+ /** Mapping of object handles to object pointers. */
+ struct idr object_idr;
+ /**
+ * Lock for synchronization of access to object->refcount and
+ * object_idr. See note in mmfs_unreference_ioctl.
+ */
+ spinlock_t delete_lock;
+};
+
+void mmfs_object_reference(struct mmfs_object *obj);
+void mmfs_object_unreference(struct mmfs_object *obj);
+
+#endif /* __KERNEL__ */
+
+#define MMFS_DEVICE_PATH "/dev/mmfs"
+/* XXX: Choose non-experimental major */
+#define MMFS_DEVICE_MAJOR 246
+
+struct mmfs_alloc_args {
+ /**
+ * Requested size for the object.
+ *
+ * The (page-aligned) allocated size for the object will be returned.
+ */
+ uint32_t size;
+ /** Returned handle for the object. */
+ uint32_t handle;
+};
+
+struct mmfs_unreference_args {
+ /** Handle of the object to be unreferenced. */
+ uint32_t handle;
+};
+
+struct mmfs_link_args {
+ /** Handle for the object being given a name. */
+ uint32_t handle;
+ /** Requested file name to export the object under. */
+ char *name;
+ /** Requested file mode to export the object under. */
+ mode_t mode;
+};
+
+struct mmfs_pread_args {
+ /** Handle for the object being read. */
+ uint32_t handle;
+ /** Offset into the object to read from */
+ off_t offset;
+ /** Length of data to read */
+ size_t size;
+ /** Pointer to write the data into. */
+ void *data;
+};
+
+struct mmfs_pwrite_args {
+ /** Handle for the object being written to. */
+ uint32_t handle;
+ /** Offset into the object to write to */
+ off_t offset;
+ /** Length of data to write */
+ size_t size;
+ /** Pointer to read the data from. */
+ void *data;
+};
+
+struct mmfs_mmap_args {
+ /** Handle for the object being mapped. */
+ uint32_t handle;
+ /** Offset in the object to map. */
+ off_t offset;
+ /**
+ * Length of data to map.
+ *
+ * The value will be page-aligned.
+ */
+ size_t size;
+ /** Returned pointer the data was mapped at */
+ void *addr;
+};
+
+/**
+ * \name Ioctls Definitions
+ */
+/* @{ */
+
+#define MMFS_IOCTL_BASE 'm'
+#define MMFS_IO(nr) _IO(MMFS_IOCTL_BASE, nr)
+#define MMFS_IOR(nr,type) _IOR(MMFS_IOCTL_BASE, nr, type)
+#define MMFS_IOW(nr,type) _IOW(MMFS_IOCTL_BASE, nr, type)
+#define MMFS_IOWR(nr,type) _IOWR(MMFS_IOCTL_BASE, nr, type)
+
+/** This ioctl allocates an object and returns a handle referencing it. */
+#define MMFS_IOCTL_ALLOC MMFS_IOWR(0x00, struct mmfs_alloc_args)
+
+/**
+ * This ioctl releases the reference on the handle returned from
+ * MMFS_IOCTL_ALLOC.
+ */
+#define MMFS_IOCTL_UNREFERENCE MMFS_IOR(0x01, struct mmfs_unreference_args)
+
+/**
+ * This ioctl creates a file in the mmfs filesystem representing an object.
+ *
+ * XXX: Need a way to get handle from fd or name.
+ */
+#define MMFS_IOCTL_LINK MMFS_IOWR(0x02, struct mmfs_link_args)
+
+/** This ioctl copies data from an object into a user address. */
+#define MMFS_IOCTL_PREAD MMFS_IOWR(0x03, struct mmfs_pread_args)
+
+/** This ioctl copies data from a user address into an object. */
+#define MMFS_IOCTL_PWRITE MMFS_IOWR(0x04, struct mmfs_pwrite_args)
+
+/** This ioctl maps data from the object into the user address space. */
+#define MMFS_IOCTL_MMAP MMFS_IOWR(0x05, struct mmfs_mmap_args)
+
+/* }@ */
--- /dev/null
+/*
+ * Copyright © 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Eric Anholt <eric@anholt.net>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/uaccess.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/module.h>
+#include "mmfs.h"
+
+/** @file mmfs.c
+ *
+ * This file provides the filesystem for memory manager objects used by the
+ * DRM.
+ *
+ * The goal is to have swap-backed object allocation managed through
+ * struct file. However, file descriptors as handles to a struct file have
+ * two major failings:
+ * - Process limits prevent more than 1024 or so being used at a time by
+ * default.
+ * - Inability to allocate high fds will aggravate the X Server's select()
+ * handling, and likely that of many GL client applications as well.
+ *
+ * This led to a plan of using our own integer IDs (called handles, following
+ * DRM terminology) to mimic fds, and implement the fd syscalls we need as
+ * ioctls. The objects themselves will still include the struct file so
+ * that we can transition to fds if the required kernel infrastructure shows
+ * up at a later data, and as our interface with shmfs for memory allocation.
+ */
+
+static struct mmfs_object *
+mmfs_object_alloc(size_t size)
+{
+ struct mmfs_object *obj;
+
+ BUG_ON((size & (PAGE_SIZE - 1)) != 0);
+
+ obj = kcalloc(1, sizeof(*obj), GFP_KERNEL);
+
+ obj->filp = shmem_file_setup("mmfs object", size, 0);
+ if (IS_ERR(obj->filp)) {
+ kfree(obj);
+ return NULL;
+ }
+
+ obj->refcount = 1;
+
+ return obj;
+}
+
+/**
+ * Removes the mapping from handle to filp for this object.
+ */
+static int
+mmfs_handle_delete(struct mmfs_file *mmfs_filp, int handle)
+{
+ struct mmfs_object *obj;
+
+ /* This is gross. The idr system doesn't let us try a delete and
+ * return an error code. It just spews if you fail at deleting.
+ * So, we have to grab a lock around finding the object and then
+ * doing the delete on it and dropping the refcount, or the user
+ * could race us to double-decrement the refcount and cause a
+ * use-after-free later. Given the frequency of our handle lookups,
+ * we may want to use ida for number allocation and a hash table
+ * for the pointers, anyway.
+ */
+ spin_lock(&mmfs_filp->delete_lock);
+
+ /* Check if we currently have a reference on the object */
+ obj = idr_find(&mmfs_filp->object_idr, handle);
+ if (obj == NULL) {
+ spin_unlock(&mmfs_filp->delete_lock);
+ return -EINVAL;
+ }
+
+ /* Release reference and decrement refcount. */
+ idr_remove(&mmfs_filp->object_idr, handle);
+ mmfs_object_unreference(obj);
+
+ spin_unlock(&mmfs_filp->delete_lock);
+
+ return 0;
+}
+
+/**
+ * Allocates a new mmfs object and returns a handle to it.
+ */
+static int
+mmfs_alloc_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mmfs_file *mmfs_filp = filp->private_data;
+ struct mmfs_alloc_args args;
+ struct mmfs_object *obj;
+ int handle, ret;
+
+ if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
+ return -EFAULT;
+
+ /* Round requested size up to page size */
+ args.size = (args.size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
+
+ /* Allocate the new object */
+ obj = mmfs_object_alloc(args.size);
+ if (obj == NULL)
+ return -ENOMEM;
+
+ /* Get the user-visible handle using idr.
+ *
+ * I'm not really sure why the idr api needs us to do this in two
+ * repeating steps. It handles internal locking of its data
+ * structure, yet insists that we keep its memory allocation step
+ * separate from its slot-finding step for locking purposes.
+ */
+ do {
+ if (idr_pre_get(&mmfs_filp->object_idr, GFP_KERNEL) == 0) {
+ kfree(obj);
+ return -EFAULT;
+ }
+
+ ret = idr_get_new(&mmfs_filp->object_idr, obj, &handle);
+ } while (ret == -EAGAIN);
+
+ if (ret != 0) {
+ mmfs_object_unreference(obj);
+ return -EFAULT;
+ }
+
+ args.handle = handle;
+
+ if (copy_to_user((void __user *)arg, &args, sizeof(args))) {
+ mmfs_handle_delete(mmfs_filp, args.handle);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+/**
+ * Allocates a new mmfs object and returns a handle to it.
+ */
+static int
+mmfs_unreference_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mmfs_file *mmfs_filp = filp->private_data;
+ struct mmfs_unreference_args args;
+ int ret;
+
+ if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
+ return -EFAULT;
+
+ ret = mmfs_handle_delete(mmfs_filp, args.handle);
+
+ return ret;
+}
+
+static int
+mmfs_ioctl(struct inode *inode, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+
+ switch (cmd) {
+ case MMFS_IOCTL_ALLOC:
+ return mmfs_alloc_ioctl(inode, filp, cmd, arg);
+ case MMFS_IOCTL_UNREFERENCE:
+ return mmfs_unreference_ioctl(inode, filp, cmd, arg);
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * Sets up the file private for keeping track of our mappings of handles to
+ * mmfs objects.
+ */
+int
+mmfs_open(struct inode *inode, struct file *filp)
+{
+ struct mmfs_file *mmfs_filp;
+
+ if (filp->f_flags & O_EXCL)
+ return -EBUSY; /* No exclusive opens */
+
+ mmfs_filp = kcalloc(1, sizeof(*mmfs_filp), GFP_KERNEL);
+ if (mmfs_filp == NULL)
+ return -ENOMEM;
+ filp->private_data = mmfs_filp;
+
+ idr_init(&mmfs_filp->object_idr);
+
+ return 0;
+}
+
+/** Called at device close to release the file's references on objects. */
+static int
+mmfs_object_release(int id, void *ptr, void *data)
+{
+ struct mmfs_object *obj = ptr;
+
+ mmfs_object_unreference(obj);
+
+ return 0;
+}
+
+/**
+ * Called at close time when the filp is going away.
+ *
+ * Releases any remaining references on objects by this filp.
+ */
+int
+mmfs_close(struct inode *inode, struct file *filp)
+{
+ struct mmfs_file *mmfs_filp = filp->private_data;
+
+ idr_for_each(&mmfs_filp->object_idr, &mmfs_object_release, NULL);
+
+ idr_destroy(&mmfs_filp->object_idr);
+
+ kfree(mmfs_filp);
+ filp->private_data = NULL;
+
+ return 0;
+}
+
+void
+mmfs_object_reference(struct mmfs_object *obj)
+{
+ spin_lock(&obj->lock);
+ obj->refcount++;
+ spin_unlock(&obj->lock);
+}
+
+void
+mmfs_object_unreference(struct mmfs_object *obj)
+{
+ spin_lock(&obj->lock);
+ obj->refcount--;
+ spin_unlock(&obj->lock);
+ if (obj->refcount == 0) {
+ fput(obj->filp);
+ kfree(obj);
+ }
+}
+
+/** File operations structure */
+static const struct file_operations mmfs_dev_fops = {
+ .owner = THIS_MODULE,
+ .open = mmfs_open,
+ .release = mmfs_close,
+ .ioctl = mmfs_ioctl,
+};
+
+static int __init mmfs_init(void)
+{
+ int ret;
+
+ ret = register_chrdev(MMFS_DEVICE_MAJOR, "mmfs", &mmfs_dev_fops);
+ if (ret != 0)
+ return ret;
+
+ return 0;
+}
+
+static void __exit mmfs_exit(void)
+{
+ unregister_chrdev(MMFS_DEVICE_MAJOR, "mmfs");
+}
+
+module_init(mmfs_init);
+module_exit(mmfs_exit);
+MODULE_LICENSE("GPL and additional rights");
--- /dev/null
+/*
+ * Copyright © 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Eric Anholt <eric@anholt.net>
+ *
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include "mmfs.h"
+
+static void
+create_mmfs_device()
+{
+ struct stat sb;
+ int ret;
+
+ ret = stat(MMFS_DEVICE_PATH, &sb);
+
+ if (ret == 0)
+ return;
+
+ ret = mknod(MMFS_DEVICE_PATH, S_IFCHR | S_IRUSR | S_IWUSR,
+ makedev(MMFS_DEVICE_MAJOR, 0));
+
+ if (ret != 0)
+ errx(1, "mknod()");
+}
+
+
+int main(int argc, char **argv)
+{
+ int fd;
+
+ create_mmfs_device();
+
+ fd = open(MMFS_DEVICE_PATH, O_RDWR);
+ if (fd == -1)
+ errx(1, "open()");
+
+ close(fd);
+
+ return 0;
+}
projects / platform / upstream / libdrm.git / commitdiff