mirror of https://gitee.com/openkylin/linux.git
883 lines
23 KiB
C
883 lines
23 KiB
C
/*
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* Copyright © 2012-2014 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <drm/drmP.h>
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#include <drm/i915_drm.h>
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#include "i915_drv.h"
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#include "i915_trace.h"
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#include "intel_drv.h"
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#include <linux/mmu_context.h>
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#include <linux/mmu_notifier.h>
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#include <linux/mempolicy.h>
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#include <linux/swap.h>
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struct i915_mm_struct {
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struct mm_struct *mm;
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struct drm_device *dev;
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struct i915_mmu_notifier *mn;
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struct hlist_node node;
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struct kref kref;
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struct work_struct work;
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};
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#if defined(CONFIG_MMU_NOTIFIER)
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#include <linux/interval_tree.h>
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struct i915_mmu_notifier {
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spinlock_t lock;
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struct hlist_node node;
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struct mmu_notifier mn;
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struct rb_root objects;
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struct list_head linear;
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unsigned long serial;
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bool has_linear;
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};
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struct i915_mmu_object {
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struct i915_mmu_notifier *mn;
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struct interval_tree_node it;
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struct list_head link;
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struct drm_i915_gem_object *obj;
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bool is_linear;
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};
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static unsigned long cancel_userptr(struct drm_i915_gem_object *obj)
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{
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struct drm_device *dev = obj->base.dev;
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unsigned long end;
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mutex_lock(&dev->struct_mutex);
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/* Cancel any active worker and force us to re-evaluate gup */
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obj->userptr.work = NULL;
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if (obj->pages != NULL) {
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struct drm_i915_private *dev_priv = to_i915(dev);
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struct i915_vma *vma, *tmp;
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bool was_interruptible;
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was_interruptible = dev_priv->mm.interruptible;
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dev_priv->mm.interruptible = false;
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list_for_each_entry_safe(vma, tmp, &obj->vma_list, vma_link) {
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int ret = i915_vma_unbind(vma);
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WARN_ON(ret && ret != -EIO);
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}
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WARN_ON(i915_gem_object_put_pages(obj));
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dev_priv->mm.interruptible = was_interruptible;
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}
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end = obj->userptr.ptr + obj->base.size;
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drm_gem_object_unreference(&obj->base);
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mutex_unlock(&dev->struct_mutex);
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return end;
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}
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static void *invalidate_range__linear(struct i915_mmu_notifier *mn,
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struct mm_struct *mm,
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unsigned long start,
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unsigned long end)
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{
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struct i915_mmu_object *mo;
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unsigned long serial;
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restart:
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serial = mn->serial;
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list_for_each_entry(mo, &mn->linear, link) {
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struct drm_i915_gem_object *obj;
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if (mo->it.last < start || mo->it.start > end)
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continue;
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obj = mo->obj;
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if (!kref_get_unless_zero(&obj->base.refcount))
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continue;
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spin_unlock(&mn->lock);
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cancel_userptr(obj);
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spin_lock(&mn->lock);
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if (serial != mn->serial)
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goto restart;
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}
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return NULL;
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}
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static void i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
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struct mm_struct *mm,
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unsigned long start,
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unsigned long end)
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{
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struct i915_mmu_notifier *mn = container_of(_mn, struct i915_mmu_notifier, mn);
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struct interval_tree_node *it = NULL;
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unsigned long next = start;
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unsigned long serial = 0;
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end--; /* interval ranges are inclusive, but invalidate range is exclusive */
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while (next < end) {
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struct drm_i915_gem_object *obj = NULL;
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spin_lock(&mn->lock);
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if (mn->has_linear)
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it = invalidate_range__linear(mn, mm, start, end);
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else if (serial == mn->serial)
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it = interval_tree_iter_next(it, next, end);
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else
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it = interval_tree_iter_first(&mn->objects, start, end);
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if (it != NULL) {
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obj = container_of(it, struct i915_mmu_object, it)->obj;
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/* The mmu_object is released late when destroying the
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* GEM object so it is entirely possible to gain a
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* reference on an object in the process of being freed
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* since our serialisation is via the spinlock and not
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* the struct_mutex - and consequently use it after it
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* is freed and then double free it.
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*/
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if (!kref_get_unless_zero(&obj->base.refcount)) {
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spin_unlock(&mn->lock);
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serial = 0;
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continue;
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}
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serial = mn->serial;
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}
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spin_unlock(&mn->lock);
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if (obj == NULL)
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return;
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next = cancel_userptr(obj);
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}
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}
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static const struct mmu_notifier_ops i915_gem_userptr_notifier = {
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.invalidate_range_start = i915_gem_userptr_mn_invalidate_range_start,
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};
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static struct i915_mmu_notifier *
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i915_mmu_notifier_create(struct mm_struct *mm)
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{
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struct i915_mmu_notifier *mn;
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int ret;
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mn = kmalloc(sizeof(*mn), GFP_KERNEL);
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if (mn == NULL)
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return ERR_PTR(-ENOMEM);
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spin_lock_init(&mn->lock);
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mn->mn.ops = &i915_gem_userptr_notifier;
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mn->objects = RB_ROOT;
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mn->serial = 1;
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INIT_LIST_HEAD(&mn->linear);
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mn->has_linear = false;
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/* Protected by mmap_sem (write-lock) */
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ret = __mmu_notifier_register(&mn->mn, mm);
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if (ret) {
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kfree(mn);
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return ERR_PTR(ret);
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}
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return mn;
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}
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static void __i915_mmu_notifier_update_serial(struct i915_mmu_notifier *mn)
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{
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if (++mn->serial == 0)
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mn->serial = 1;
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}
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static int
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i915_mmu_notifier_add(struct drm_device *dev,
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struct i915_mmu_notifier *mn,
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struct i915_mmu_object *mo)
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{
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struct interval_tree_node *it;
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int ret = 0;
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/* By this point we have already done a lot of expensive setup that
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* we do not want to repeat just because the caller (e.g. X) has a
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* signal pending (and partly because of that expensive setup, X
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* using an interrupt timer is likely to get stuck in an EINTR loop).
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*/
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mutex_lock(&dev->struct_mutex);
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/* Make sure we drop the final active reference (and thereby
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* remove the objects from the interval tree) before we do
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* the check for overlapping objects.
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*/
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i915_gem_retire_requests(dev);
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spin_lock(&mn->lock);
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it = interval_tree_iter_first(&mn->objects,
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mo->it.start, mo->it.last);
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if (it) {
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struct drm_i915_gem_object *obj;
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/* We only need to check the first object in the range as it
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* either has cancelled gup work queued and we need to
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* return back to the user to give time for the gup-workers
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* to flush their object references upon which the object will
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* be removed from the interval-tree, or the the range is
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* still in use by another client and the overlap is invalid.
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*
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* If we do have an overlap, we cannot use the interval tree
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* for fast range invalidation.
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*/
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obj = container_of(it, struct i915_mmu_object, it)->obj;
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if (!obj->userptr.workers)
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mn->has_linear = mo->is_linear = true;
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else
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ret = -EAGAIN;
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} else
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interval_tree_insert(&mo->it, &mn->objects);
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if (ret == 0) {
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list_add(&mo->link, &mn->linear);
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__i915_mmu_notifier_update_serial(mn);
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}
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spin_unlock(&mn->lock);
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mutex_unlock(&dev->struct_mutex);
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return ret;
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}
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static bool i915_mmu_notifier_has_linear(struct i915_mmu_notifier *mn)
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{
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struct i915_mmu_object *mo;
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list_for_each_entry(mo, &mn->linear, link)
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if (mo->is_linear)
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return true;
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return false;
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}
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static void
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i915_mmu_notifier_del(struct i915_mmu_notifier *mn,
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struct i915_mmu_object *mo)
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{
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spin_lock(&mn->lock);
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list_del(&mo->link);
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if (mo->is_linear)
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mn->has_linear = i915_mmu_notifier_has_linear(mn);
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else
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interval_tree_remove(&mo->it, &mn->objects);
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__i915_mmu_notifier_update_serial(mn);
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spin_unlock(&mn->lock);
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}
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static void
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i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
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{
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struct i915_mmu_object *mo;
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mo = obj->userptr.mmu_object;
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if (mo == NULL)
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return;
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i915_mmu_notifier_del(mo->mn, mo);
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kfree(mo);
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obj->userptr.mmu_object = NULL;
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}
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static struct i915_mmu_notifier *
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i915_mmu_notifier_find(struct i915_mm_struct *mm)
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{
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struct i915_mmu_notifier *mn = mm->mn;
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mn = mm->mn;
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if (mn)
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return mn;
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down_write(&mm->mm->mmap_sem);
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mutex_lock(&to_i915(mm->dev)->mm_lock);
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if ((mn = mm->mn) == NULL) {
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mn = i915_mmu_notifier_create(mm->mm);
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if (!IS_ERR(mn))
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mm->mn = mn;
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}
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mutex_unlock(&to_i915(mm->dev)->mm_lock);
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up_write(&mm->mm->mmap_sem);
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return mn;
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}
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static int
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i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
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unsigned flags)
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{
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struct i915_mmu_notifier *mn;
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struct i915_mmu_object *mo;
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int ret;
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if (flags & I915_USERPTR_UNSYNCHRONIZED)
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return capable(CAP_SYS_ADMIN) ? 0 : -EPERM;
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if (WARN_ON(obj->userptr.mm == NULL))
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return -EINVAL;
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mn = i915_mmu_notifier_find(obj->userptr.mm);
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if (IS_ERR(mn))
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return PTR_ERR(mn);
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mo = kzalloc(sizeof(*mo), GFP_KERNEL);
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if (mo == NULL)
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return -ENOMEM;
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mo->mn = mn;
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mo->it.start = obj->userptr.ptr;
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mo->it.last = mo->it.start + obj->base.size - 1;
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mo->obj = obj;
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ret = i915_mmu_notifier_add(obj->base.dev, mn, mo);
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if (ret) {
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kfree(mo);
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return ret;
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}
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obj->userptr.mmu_object = mo;
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return 0;
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}
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static void
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i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
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struct mm_struct *mm)
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{
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if (mn == NULL)
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return;
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mmu_notifier_unregister(&mn->mn, mm);
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kfree(mn);
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}
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#else
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static void
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i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
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{
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}
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static int
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i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
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unsigned flags)
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{
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if ((flags & I915_USERPTR_UNSYNCHRONIZED) == 0)
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return -ENODEV;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return 0;
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}
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static void
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i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
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struct mm_struct *mm)
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{
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}
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#endif
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static struct i915_mm_struct *
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__i915_mm_struct_find(struct drm_i915_private *dev_priv, struct mm_struct *real)
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{
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struct i915_mm_struct *mm;
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/* Protected by dev_priv->mm_lock */
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hash_for_each_possible(dev_priv->mm_structs, mm, node, (unsigned long)real)
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if (mm->mm == real)
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return mm;
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return NULL;
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}
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static int
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i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
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{
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struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
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struct i915_mm_struct *mm;
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int ret = 0;
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/* During release of the GEM object we hold the struct_mutex. This
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* precludes us from calling mmput() at that time as that may be
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* the last reference and so call exit_mmap(). exit_mmap() will
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* attempt to reap the vma, and if we were holding a GTT mmap
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* would then call drm_gem_vm_close() and attempt to reacquire
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* the struct mutex. So in order to avoid that recursion, we have
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* to defer releasing the mm reference until after we drop the
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* struct_mutex, i.e. we need to schedule a worker to do the clean
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* up.
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*/
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mutex_lock(&dev_priv->mm_lock);
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mm = __i915_mm_struct_find(dev_priv, current->mm);
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if (mm == NULL) {
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mm = kmalloc(sizeof(*mm), GFP_KERNEL);
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if (mm == NULL) {
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ret = -ENOMEM;
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goto out;
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}
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kref_init(&mm->kref);
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mm->dev = obj->base.dev;
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mm->mm = current->mm;
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atomic_inc(¤t->mm->mm_count);
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mm->mn = NULL;
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/* Protected by dev_priv->mm_lock */
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hash_add(dev_priv->mm_structs,
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&mm->node, (unsigned long)mm->mm);
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} else
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kref_get(&mm->kref);
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obj->userptr.mm = mm;
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out:
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mutex_unlock(&dev_priv->mm_lock);
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return ret;
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}
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static void
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__i915_mm_struct_free__worker(struct work_struct *work)
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{
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struct i915_mm_struct *mm = container_of(work, typeof(*mm), work);
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i915_mmu_notifier_free(mm->mn, mm->mm);
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mmdrop(mm->mm);
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kfree(mm);
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}
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static void
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__i915_mm_struct_free(struct kref *kref)
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{
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struct i915_mm_struct *mm = container_of(kref, typeof(*mm), kref);
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/* Protected by dev_priv->mm_lock */
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hash_del(&mm->node);
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mutex_unlock(&to_i915(mm->dev)->mm_lock);
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INIT_WORK(&mm->work, __i915_mm_struct_free__worker);
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schedule_work(&mm->work);
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}
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static void
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i915_gem_userptr_release__mm_struct(struct drm_i915_gem_object *obj)
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{
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if (obj->userptr.mm == NULL)
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return;
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kref_put_mutex(&obj->userptr.mm->kref,
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__i915_mm_struct_free,
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&to_i915(obj->base.dev)->mm_lock);
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obj->userptr.mm = NULL;
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}
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struct get_pages_work {
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struct work_struct work;
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struct drm_i915_gem_object *obj;
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struct task_struct *task;
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};
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#if IS_ENABLED(CONFIG_SWIOTLB)
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#define swiotlb_active() swiotlb_nr_tbl()
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#else
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#define swiotlb_active() 0
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#endif
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static int
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st_set_pages(struct sg_table **st, struct page **pvec, int num_pages)
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{
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struct scatterlist *sg;
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int ret, n;
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*st = kmalloc(sizeof(**st), GFP_KERNEL);
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if (*st == NULL)
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return -ENOMEM;
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if (swiotlb_active()) {
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ret = sg_alloc_table(*st, num_pages, GFP_KERNEL);
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if (ret)
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goto err;
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for_each_sg((*st)->sgl, sg, num_pages, n)
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sg_set_page(sg, pvec[n], PAGE_SIZE, 0);
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} else {
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ret = sg_alloc_table_from_pages(*st, pvec, num_pages,
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|
0, num_pages << PAGE_SHIFT,
|
|
GFP_KERNEL);
|
|
if (ret)
|
|
goto err;
|
|
}
|
|
|
|
return 0;
|
|
|
|
err:
|
|
kfree(*st);
|
|
*st = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
__i915_gem_userptr_set_pages(struct drm_i915_gem_object *obj,
|
|
struct page **pvec, int num_pages)
|
|
{
|
|
int ret;
|
|
|
|
ret = st_set_pages(&obj->pages, pvec, num_pages);
|
|
if (ret)
|
|
return ret;
|
|
|
|
ret = i915_gem_gtt_prepare_object(obj);
|
|
if (ret) {
|
|
sg_free_table(obj->pages);
|
|
kfree(obj->pages);
|
|
obj->pages = NULL;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void
|
|
__i915_gem_userptr_get_pages_worker(struct work_struct *_work)
|
|
{
|
|
struct get_pages_work *work = container_of(_work, typeof(*work), work);
|
|
struct drm_i915_gem_object *obj = work->obj;
|
|
struct drm_device *dev = obj->base.dev;
|
|
const int num_pages = obj->base.size >> PAGE_SHIFT;
|
|
struct page **pvec;
|
|
int pinned, ret;
|
|
|
|
ret = -ENOMEM;
|
|
pinned = 0;
|
|
|
|
pvec = kmalloc(num_pages*sizeof(struct page *),
|
|
GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
|
|
if (pvec == NULL)
|
|
pvec = drm_malloc_ab(num_pages, sizeof(struct page *));
|
|
if (pvec != NULL) {
|
|
struct mm_struct *mm = obj->userptr.mm->mm;
|
|
|
|
down_read(&mm->mmap_sem);
|
|
while (pinned < num_pages) {
|
|
ret = get_user_pages(work->task, mm,
|
|
obj->userptr.ptr + pinned * PAGE_SIZE,
|
|
num_pages - pinned,
|
|
!obj->userptr.read_only, 0,
|
|
pvec + pinned, NULL);
|
|
if (ret < 0)
|
|
break;
|
|
|
|
pinned += ret;
|
|
}
|
|
up_read(&mm->mmap_sem);
|
|
}
|
|
|
|
mutex_lock(&dev->struct_mutex);
|
|
if (obj->userptr.work != &work->work) {
|
|
ret = 0;
|
|
} else if (pinned == num_pages) {
|
|
ret = __i915_gem_userptr_set_pages(obj, pvec, num_pages);
|
|
if (ret == 0) {
|
|
list_add_tail(&obj->global_list, &to_i915(dev)->mm.unbound_list);
|
|
obj->get_page.sg = obj->pages->sgl;
|
|
obj->get_page.last = 0;
|
|
|
|
pinned = 0;
|
|
}
|
|
}
|
|
|
|
obj->userptr.work = ERR_PTR(ret);
|
|
obj->userptr.workers--;
|
|
drm_gem_object_unreference(&obj->base);
|
|
mutex_unlock(&dev->struct_mutex);
|
|
|
|
release_pages(pvec, pinned, 0);
|
|
drm_free_large(pvec);
|
|
|
|
put_task_struct(work->task);
|
|
kfree(work);
|
|
}
|
|
|
|
static int
|
|
i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
|
|
{
|
|
const int num_pages = obj->base.size >> PAGE_SHIFT;
|
|
struct page **pvec;
|
|
int pinned, ret;
|
|
|
|
/* If userspace should engineer that these pages are replaced in
|
|
* the vma between us binding this page into the GTT and completion
|
|
* of rendering... Their loss. If they change the mapping of their
|
|
* pages they need to create a new bo to point to the new vma.
|
|
*
|
|
* However, that still leaves open the possibility of the vma
|
|
* being copied upon fork. Which falls under the same userspace
|
|
* synchronisation issue as a regular bo, except that this time
|
|
* the process may not be expecting that a particular piece of
|
|
* memory is tied to the GPU.
|
|
*
|
|
* Fortunately, we can hook into the mmu_notifier in order to
|
|
* discard the page references prior to anything nasty happening
|
|
* to the vma (discard or cloning) which should prevent the more
|
|
* egregious cases from causing harm.
|
|
*/
|
|
|
|
pvec = NULL;
|
|
pinned = 0;
|
|
if (obj->userptr.mm->mm == current->mm) {
|
|
pvec = kmalloc(num_pages*sizeof(struct page *),
|
|
GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
|
|
if (pvec == NULL) {
|
|
pvec = drm_malloc_ab(num_pages, sizeof(struct page *));
|
|
if (pvec == NULL)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pinned = __get_user_pages_fast(obj->userptr.ptr, num_pages,
|
|
!obj->userptr.read_only, pvec);
|
|
}
|
|
if (pinned < num_pages) {
|
|
if (pinned < 0) {
|
|
ret = pinned;
|
|
pinned = 0;
|
|
} else {
|
|
/* Spawn a worker so that we can acquire the
|
|
* user pages without holding our mutex. Access
|
|
* to the user pages requires mmap_sem, and we have
|
|
* a strict lock ordering of mmap_sem, struct_mutex -
|
|
* we already hold struct_mutex here and so cannot
|
|
* call gup without encountering a lock inversion.
|
|
*
|
|
* Userspace will keep on repeating the operation
|
|
* (thanks to EAGAIN) until either we hit the fast
|
|
* path or the worker completes. If the worker is
|
|
* cancelled or superseded, the task is still run
|
|
* but the results ignored. (This leads to
|
|
* complications that we may have a stray object
|
|
* refcount that we need to be wary of when
|
|
* checking for existing objects during creation.)
|
|
* If the worker encounters an error, it reports
|
|
* that error back to this function through
|
|
* obj->userptr.work = ERR_PTR.
|
|
*/
|
|
ret = -EAGAIN;
|
|
if (obj->userptr.work == NULL &&
|
|
obj->userptr.workers < I915_GEM_USERPTR_MAX_WORKERS) {
|
|
struct get_pages_work *work;
|
|
|
|
work = kmalloc(sizeof(*work), GFP_KERNEL);
|
|
if (work != NULL) {
|
|
obj->userptr.work = &work->work;
|
|
obj->userptr.workers++;
|
|
|
|
work->obj = obj;
|
|
drm_gem_object_reference(&obj->base);
|
|
|
|
work->task = current;
|
|
get_task_struct(work->task);
|
|
|
|
INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);
|
|
schedule_work(&work->work);
|
|
} else
|
|
ret = -ENOMEM;
|
|
} else {
|
|
if (IS_ERR(obj->userptr.work)) {
|
|
ret = PTR_ERR(obj->userptr.work);
|
|
obj->userptr.work = NULL;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
ret = __i915_gem_userptr_set_pages(obj, pvec, num_pages);
|
|
if (ret == 0) {
|
|
obj->userptr.work = NULL;
|
|
pinned = 0;
|
|
}
|
|
}
|
|
|
|
release_pages(pvec, pinned, 0);
|
|
drm_free_large(pvec);
|
|
return ret;
|
|
}
|
|
|
|
static void
|
|
i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj)
|
|
{
|
|
struct sg_page_iter sg_iter;
|
|
|
|
BUG_ON(obj->userptr.work != NULL);
|
|
|
|
if (obj->madv != I915_MADV_WILLNEED)
|
|
obj->dirty = 0;
|
|
|
|
i915_gem_gtt_finish_object(obj);
|
|
|
|
for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
|
|
struct page *page = sg_page_iter_page(&sg_iter);
|
|
|
|
if (obj->dirty)
|
|
set_page_dirty(page);
|
|
|
|
mark_page_accessed(page);
|
|
page_cache_release(page);
|
|
}
|
|
obj->dirty = 0;
|
|
|
|
sg_free_table(obj->pages);
|
|
kfree(obj->pages);
|
|
}
|
|
|
|
static void
|
|
i915_gem_userptr_release(struct drm_i915_gem_object *obj)
|
|
{
|
|
i915_gem_userptr_release__mmu_notifier(obj);
|
|
i915_gem_userptr_release__mm_struct(obj);
|
|
}
|
|
|
|
static int
|
|
i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
|
|
{
|
|
if (obj->userptr.mmu_object)
|
|
return 0;
|
|
|
|
return i915_gem_userptr_init__mmu_notifier(obj, 0);
|
|
}
|
|
|
|
static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
|
|
.dmabuf_export = i915_gem_userptr_dmabuf_export,
|
|
.get_pages = i915_gem_userptr_get_pages,
|
|
.put_pages = i915_gem_userptr_put_pages,
|
|
.release = i915_gem_userptr_release,
|
|
};
|
|
|
|
/**
|
|
* Creates a new mm object that wraps some normal memory from the process
|
|
* context - user memory.
|
|
*
|
|
* We impose several restrictions upon the memory being mapped
|
|
* into the GPU.
|
|
* 1. It must be page aligned (both start/end addresses, i.e ptr and size).
|
|
* 2. It must be normal system memory, not a pointer into another map of IO
|
|
* space (e.g. it must not be a GTT mmapping of another object).
|
|
* 3. We only allow a bo as large as we could in theory map into the GTT,
|
|
* that is we limit the size to the total size of the GTT.
|
|
* 4. The bo is marked as being snoopable. The backing pages are left
|
|
* accessible directly by the CPU, but reads and writes by the GPU may
|
|
* incur the cost of a snoop (unless you have an LLC architecture).
|
|
*
|
|
* Synchronisation between multiple users and the GPU is left to userspace
|
|
* through the normal set-domain-ioctl. The kernel will enforce that the
|
|
* GPU relinquishes the VMA before it is returned back to the system
|
|
* i.e. upon free(), munmap() or process termination. However, the userspace
|
|
* malloc() library may not immediately relinquish the VMA after free() and
|
|
* instead reuse it whilst the GPU is still reading and writing to the VMA.
|
|
* Caveat emptor.
|
|
*
|
|
* Also note, that the object created here is not currently a "first class"
|
|
* object, in that several ioctls are banned. These are the CPU access
|
|
* ioctls: mmap(), pwrite and pread. In practice, you are expected to use
|
|
* direct access via your pointer rather than use those ioctls.
|
|
*
|
|
* If you think this is a good interface to use to pass GPU memory between
|
|
* drivers, please use dma-buf instead. In fact, wherever possible use
|
|
* dma-buf instead.
|
|
*/
|
|
int
|
|
i915_gem_userptr_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
|
|
{
|
|
struct drm_i915_private *dev_priv = dev->dev_private;
|
|
struct drm_i915_gem_userptr *args = data;
|
|
struct drm_i915_gem_object *obj;
|
|
int ret;
|
|
u32 handle;
|
|
|
|
if (args->flags & ~(I915_USERPTR_READ_ONLY |
|
|
I915_USERPTR_UNSYNCHRONIZED))
|
|
return -EINVAL;
|
|
|
|
if (offset_in_page(args->user_ptr | args->user_size))
|
|
return -EINVAL;
|
|
|
|
if (args->user_size > dev_priv->gtt.base.total)
|
|
return -E2BIG;
|
|
|
|
if (!access_ok(args->flags & I915_USERPTR_READ_ONLY ? VERIFY_READ : VERIFY_WRITE,
|
|
(char __user *)(unsigned long)args->user_ptr, args->user_size))
|
|
return -EFAULT;
|
|
|
|
if (args->flags & I915_USERPTR_READ_ONLY) {
|
|
/* On almost all of the current hw, we cannot tell the GPU that a
|
|
* page is readonly, so this is just a placeholder in the uAPI.
|
|
*/
|
|
return -ENODEV;
|
|
}
|
|
|
|
obj = i915_gem_object_alloc(dev);
|
|
if (obj == NULL)
|
|
return -ENOMEM;
|
|
|
|
drm_gem_private_object_init(dev, &obj->base, args->user_size);
|
|
i915_gem_object_init(obj, &i915_gem_userptr_ops);
|
|
obj->cache_level = I915_CACHE_LLC;
|
|
obj->base.write_domain = I915_GEM_DOMAIN_CPU;
|
|
obj->base.read_domains = I915_GEM_DOMAIN_CPU;
|
|
|
|
obj->userptr.ptr = args->user_ptr;
|
|
obj->userptr.read_only = !!(args->flags & I915_USERPTR_READ_ONLY);
|
|
|
|
/* And keep a pointer to the current->mm for resolving the user pages
|
|
* at binding. This means that we need to hook into the mmu_notifier
|
|
* in order to detect if the mmu is destroyed.
|
|
*/
|
|
ret = i915_gem_userptr_init__mm_struct(obj);
|
|
if (ret == 0)
|
|
ret = i915_gem_userptr_init__mmu_notifier(obj, args->flags);
|
|
if (ret == 0)
|
|
ret = drm_gem_handle_create(file, &obj->base, &handle);
|
|
|
|
/* drop reference from allocate - handle holds it now */
|
|
drm_gem_object_unreference_unlocked(&obj->base);
|
|
if (ret)
|
|
return ret;
|
|
|
|
args->handle = handle;
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
i915_gem_init_userptr(struct drm_device *dev)
|
|
{
|
|
struct drm_i915_private *dev_priv = to_i915(dev);
|
|
mutex_init(&dev_priv->mm_lock);
|
|
hash_init(dev_priv->mm_structs);
|
|
return 0;
|
|
}
|