diff options
author | Gustavo Padovan <gustavo.padovan@collabora.co.uk> | 2016-08-11 18:26:44 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-08-15 17:41:46 +0300 |
commit | 35538d7822e86cb38015c21bb708a433f8814af0 (patch) | |
tree | 36aa2ccfe355aa93ad345715988a36ceba2498ea /drivers/dma-buf/sw_sync.c | |
parent | fc0c9a03b57efb769a74fa8b33d68d90153b5950 (diff) |
dma-buf/sw_sync: de-stage SW_SYNC
SW_SYNC allows to run tests on the sync_file framework via debugfs on
<debugfs>/sync/sw_sync
Opening and closing the file triggers creation and release of a sync
timeline. To create fences on this timeline the SW_SYNC_IOC_CREATE_FENCE
ioctl should be used. To increment the timeline value use SW_SYNC_IOC_INC.
Also it exports Sync information on
<debugfs>/sync/info
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/dma-buf/sw_sync.c')
-rw-r--r-- | drivers/dma-buf/sw_sync.c | 375 |
1 files changed, 375 insertions, 0 deletions
diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c new file mode 100644 index 000000000000..62e8e6dc7953 --- /dev/null +++ b/drivers/dma-buf/sw_sync.c @@ -0,0 +1,375 @@ +/* + * Sync File validation framework + * + * Copyright (C) 2012 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/uaccess.h> +#include <linux/slab.h> +#include <linux/sync_file.h> + +#include "sync_debug.h" + +#define CREATE_TRACE_POINTS +#include "sync_trace.h" + +/* + * SW SYNC validation framework + * + * A sync object driver that uses a 32bit counter to coordinate + * synchronization. Useful when there is no hardware primitive backing + * the synchronization. + * + * To start the framework just open: + * + * <debugfs>/sync/sw_sync + * + * That will create a sync timeline, all fences created under this timeline + * file descriptor will belong to the this timeline. + * + * The 'sw_sync' file can be opened many times as to create different + * timelines. + * + * Fences can be created with SW_SYNC_IOC_CREATE_FENCE ioctl with struct + * sw_sync_ioctl_create_fence as parameter. + * + * To increment the timeline counter, SW_SYNC_IOC_INC ioctl should be used + * with the increment as u32. This will update the last signaled value + * from the timeline and signal any fence that has a seqno smaller or equal + * to it. + * + * struct sw_sync_ioctl_create_fence + * @value: the seqno to initialise the fence with + * @name: the name of the new sync point + * @fence: return the fd of the new sync_file with the created fence + */ +struct sw_sync_create_fence_data { + __u32 value; + char name[32]; + __s32 fence; /* fd of new fence */ +}; + +#define SW_SYNC_IOC_MAGIC 'W' + +#define SW_SYNC_IOC_CREATE_FENCE _IOWR(SW_SYNC_IOC_MAGIC, 0,\ + struct sw_sync_create_fence_data) + +#define SW_SYNC_IOC_INC _IOW(SW_SYNC_IOC_MAGIC, 1, __u32) + +static const struct fence_ops timeline_fence_ops; + +static inline struct sync_pt *fence_to_sync_pt(struct fence *fence) +{ + if (fence->ops != &timeline_fence_ops) + return NULL; + return container_of(fence, struct sync_pt, base); +} + +/** + * sync_timeline_create() - creates a sync object + * @name: sync_timeline name + * + * Creates a new sync_timeline. Returns the sync_timeline object or NULL in + * case of error. + */ +struct sync_timeline *sync_timeline_create(const char *name) +{ + struct sync_timeline *obj; + + obj = kzalloc(sizeof(*obj), GFP_KERNEL); + if (!obj) + return NULL; + + kref_init(&obj->kref); + obj->context = fence_context_alloc(1); + strlcpy(obj->name, name, sizeof(obj->name)); + + INIT_LIST_HEAD(&obj->child_list_head); + INIT_LIST_HEAD(&obj->active_list_head); + spin_lock_init(&obj->child_list_lock); + + sync_timeline_debug_add(obj); + + return obj; +} + +static void sync_timeline_free(struct kref *kref) +{ + struct sync_timeline *obj = + container_of(kref, struct sync_timeline, kref); + + sync_timeline_debug_remove(obj); + + kfree(obj); +} + +static void sync_timeline_get(struct sync_timeline *obj) +{ + kref_get(&obj->kref); +} + +static void sync_timeline_put(struct sync_timeline *obj) +{ + kref_put(&obj->kref, sync_timeline_free); +} + +/** + * sync_timeline_signal() - signal a status change on a sync_timeline + * @obj: sync_timeline to signal + * @inc: num to increment on timeline->value + * + * A sync implementation should call this any time one of it's fences + * has signaled or has an error condition. + */ +static void sync_timeline_signal(struct sync_timeline *obj, unsigned int inc) +{ + unsigned long flags; + struct sync_pt *pt, *next; + + trace_sync_timeline(obj); + + spin_lock_irqsave(&obj->child_list_lock, flags); + + obj->value += inc; + + list_for_each_entry_safe(pt, next, &obj->active_list_head, + active_list) { + if (fence_is_signaled_locked(&pt->base)) + list_del_init(&pt->active_list); + } + + spin_unlock_irqrestore(&obj->child_list_lock, flags); +} + +/** + * sync_pt_create() - creates a sync pt + * @parent: fence's parent sync_timeline + * @size: size to allocate for this pt + * @inc: value of the fence + * + * Creates a new sync_pt as a child of @parent. @size bytes will be + * allocated allowing for implementation specific data to be kept after + * the generic sync_timeline struct. Returns the sync_pt object or + * NULL in case of error. + */ +static struct sync_pt *sync_pt_create(struct sync_timeline *obj, int size, + unsigned int value) +{ + unsigned long flags; + struct sync_pt *pt; + + if (size < sizeof(*pt)) + return NULL; + + pt = kzalloc(size, GFP_KERNEL); + if (!pt) + return NULL; + + spin_lock_irqsave(&obj->child_list_lock, flags); + sync_timeline_get(obj); + fence_init(&pt->base, &timeline_fence_ops, &obj->child_list_lock, + obj->context, value); + list_add_tail(&pt->child_list, &obj->child_list_head); + INIT_LIST_HEAD(&pt->active_list); + spin_unlock_irqrestore(&obj->child_list_lock, flags); + return pt; +} + +static const char *timeline_fence_get_driver_name(struct fence *fence) +{ + return "sw_sync"; +} + +static const char *timeline_fence_get_timeline_name(struct fence *fence) +{ + struct sync_timeline *parent = fence_parent(fence); + + return parent->name; +} + +static void timeline_fence_release(struct fence *fence) +{ + struct sync_pt *pt = fence_to_sync_pt(fence); + struct sync_timeline *parent = fence_parent(fence); + unsigned long flags; + + spin_lock_irqsave(fence->lock, flags); + list_del(&pt->child_list); + if (!list_empty(&pt->active_list)) + list_del(&pt->active_list); + spin_unlock_irqrestore(fence->lock, flags); + + sync_timeline_put(parent); + fence_free(fence); +} + +static bool timeline_fence_signaled(struct fence *fence) +{ + struct sync_timeline *parent = fence_parent(fence); + + return (fence->seqno > parent->value) ? false : true; +} + +static bool timeline_fence_enable_signaling(struct fence *fence) +{ + struct sync_pt *pt = fence_to_sync_pt(fence); + struct sync_timeline *parent = fence_parent(fence); + + if (timeline_fence_signaled(fence)) + return false; + + list_add_tail(&pt->active_list, &parent->active_list_head); + return true; +} + +static void timeline_fence_value_str(struct fence *fence, + char *str, int size) +{ + snprintf(str, size, "%d", fence->seqno); +} + +static void timeline_fence_timeline_value_str(struct fence *fence, + char *str, int size) +{ + struct sync_timeline *parent = fence_parent(fence); + + snprintf(str, size, "%d", parent->value); +} + +static const struct fence_ops timeline_fence_ops = { + .get_driver_name = timeline_fence_get_driver_name, + .get_timeline_name = timeline_fence_get_timeline_name, + .enable_signaling = timeline_fence_enable_signaling, + .signaled = timeline_fence_signaled, + .wait = fence_default_wait, + .release = timeline_fence_release, + .fence_value_str = timeline_fence_value_str, + .timeline_value_str = timeline_fence_timeline_value_str, +}; + +/* + * *WARNING* + * + * improper use of this can result in deadlocking kernel drivers from userspace. + */ + +/* opening sw_sync create a new sync obj */ +static int sw_sync_debugfs_open(struct inode *inode, struct file *file) +{ + struct sync_timeline *obj; + char task_comm[TASK_COMM_LEN]; + + get_task_comm(task_comm, current); + + obj = sync_timeline_create(task_comm); + if (!obj) + return -ENOMEM; + + file->private_data = obj; + + return 0; +} + +static int sw_sync_debugfs_release(struct inode *inode, struct file *file) +{ + struct sync_timeline *obj = file->private_data; + + smp_wmb(); + + sync_timeline_put(obj); + return 0; +} + +static long sw_sync_ioctl_create_fence(struct sync_timeline *obj, + unsigned long arg) +{ + int fd = get_unused_fd_flags(O_CLOEXEC); + int err; + struct sync_pt *pt; + struct sync_file *sync_file; + struct sw_sync_create_fence_data data; + + if (fd < 0) + return fd; + + if (copy_from_user(&data, (void __user *)arg, sizeof(data))) { + err = -EFAULT; + goto err; + } + + pt = sync_pt_create(obj, sizeof(*pt), data.value); + if (!pt) { + err = -ENOMEM; + goto err; + } + + sync_file = sync_file_create(&pt->base); + if (!sync_file) { + fence_put(&pt->base); + err = -ENOMEM; + goto err; + } + + data.fence = fd; + if (copy_to_user((void __user *)arg, &data, sizeof(data))) { + fput(sync_file->file); + err = -EFAULT; + goto err; + } + + fd_install(fd, sync_file->file); + + return 0; + +err: + put_unused_fd(fd); + return err; +} + +static long sw_sync_ioctl_inc(struct sync_timeline *obj, unsigned long arg) +{ + u32 value; + + if (copy_from_user(&value, (void __user *)arg, sizeof(value))) + return -EFAULT; + + sync_timeline_signal(obj, value); + + return 0; +} + +static long sw_sync_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct sync_timeline *obj = file->private_data; + + switch (cmd) { + case SW_SYNC_IOC_CREATE_FENCE: + return sw_sync_ioctl_create_fence(obj, arg); + + case SW_SYNC_IOC_INC: + return sw_sync_ioctl_inc(obj, arg); + + default: + return -ENOTTY; + } +} + +const struct file_operations sw_sync_debugfs_fops = { + .open = sw_sync_debugfs_open, + .release = sw_sync_debugfs_release, + .unlocked_ioctl = sw_sync_ioctl, + .compat_ioctl = sw_sync_ioctl, +}; |