blob: 62e8e6dc7953bba8148c32787c17f1bbd1388ee7 [file] [log] [blame]
/*
* 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,
};