/* * Copyright © 2008-2015 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. * */ #include #include #include "i915_drv.h" static const char *i915_fence_get_driver_name(struct dma_fence *fence) { return "i915"; } static const char *i915_fence_get_timeline_name(struct dma_fence *fence) { /* Timelines are bound by eviction to a VM. However, since * we only have a global seqno at the moment, we only have * a single timeline. Note that each timeline will have * multiple execution contexts (fence contexts) as we allow * engines within a single timeline to execute in parallel. */ return "global"; } static bool i915_fence_signaled(struct dma_fence *fence) { return i915_gem_request_completed(to_request(fence)); } static bool i915_fence_enable_signaling(struct dma_fence *fence) { if (i915_fence_signaled(fence)) return false; intel_engine_enable_signaling(to_request(fence)); return true; } static signed long i915_fence_wait(struct dma_fence *fence, bool interruptible, signed long timeout) { return i915_wait_request(to_request(fence), interruptible, timeout); } static void i915_fence_value_str(struct dma_fence *fence, char *str, int size) { snprintf(str, size, "%u", fence->seqno); } static void i915_fence_timeline_value_str(struct dma_fence *fence, char *str, int size) { snprintf(str, size, "%u", intel_engine_get_seqno(to_request(fence)->engine)); } static void i915_fence_release(struct dma_fence *fence) { struct drm_i915_gem_request *req = to_request(fence); kmem_cache_free(req->i915->requests, req); } const struct dma_fence_ops i915_fence_ops = { .get_driver_name = i915_fence_get_driver_name, .get_timeline_name = i915_fence_get_timeline_name, .enable_signaling = i915_fence_enable_signaling, .signaled = i915_fence_signaled, .wait = i915_fence_wait, .release = i915_fence_release, .fence_value_str = i915_fence_value_str, .timeline_value_str = i915_fence_timeline_value_str, }; int i915_gem_request_add_to_client(struct drm_i915_gem_request *req, struct drm_file *file) { struct drm_i915_private *dev_private; struct drm_i915_file_private *file_priv; WARN_ON(!req || !file || req->file_priv); if (!req || !file) return -EINVAL; if (req->file_priv) return -EINVAL; dev_private = req->i915; file_priv = file->driver_priv; spin_lock(&file_priv->mm.lock); req->file_priv = file_priv; list_add_tail(&req->client_list, &file_priv->mm.request_list); spin_unlock(&file_priv->mm.lock); return 0; } static inline void i915_gem_request_remove_from_client(struct drm_i915_gem_request *request) { struct drm_i915_file_private *file_priv = request->file_priv; if (!file_priv) return; spin_lock(&file_priv->mm.lock); list_del(&request->client_list); request->file_priv = NULL; spin_unlock(&file_priv->mm.lock); } void i915_gem_retire_noop(struct i915_gem_active *active, struct drm_i915_gem_request *request) { /* Space left intentionally blank */ } static void i915_gem_request_retire(struct drm_i915_gem_request *request) { struct i915_gem_active *active, *next; trace_i915_gem_request_retire(request); list_del_init(&request->link); /* We know the GPU must have read the request to have * sent us the seqno + interrupt, so use the position * of tail of the request to update the last known position * of the GPU head. * * Note this requires that we are always called in request * completion order. */ list_del(&request->ring_link); request->ring->last_retired_head = request->postfix; /* Walk through the active list, calling retire on each. This allows * objects to track their GPU activity and mark themselves as idle * when their *last* active request is completed (updating state * tracking lists for eviction, active references for GEM, etc). * * As the ->retire() may free the node, we decouple it first and * pass along the auxiliary information (to avoid dereferencing * the node after the callback). */ list_for_each_entry_safe(active, next, &request->active_list, link) { /* In microbenchmarks or focusing upon time inside the kernel, * we may spend an inordinate amount of time simply handling * the retirement of requests and processing their callbacks. * Of which, this loop itself is particularly hot due to the * cache misses when jumping around the list of i915_gem_active. * So we try to keep this loop as streamlined as possible and * also prefetch the next i915_gem_active to try and hide * the likely cache miss. */ prefetchw(next); INIT_LIST_HEAD(&active->link); RCU_INIT_POINTER(active->request, NULL); active->retire(active, request); } i915_gem_request_remove_from_client(request); if (request->previous_context) { if (i915.enable_execlists) intel_lr_context_unpin(request->previous_context, request->engine); } i915_gem_context_put(request->ctx); i915_gem_request_put(request); } void i915_gem_request_retire_upto(struct drm_i915_gem_request *req) { struct intel_engine_cs *engine = req->engine; struct drm_i915_gem_request *tmp; lockdep_assert_held(&req->i915->drm.struct_mutex); if (list_empty(&req->link)) return; do { tmp = list_first_entry(&engine->request_list, typeof(*tmp), link); i915_gem_request_retire(tmp); } while (tmp != req); } static int i915_gem_check_wedge(struct drm_i915_private *dev_priv) { struct i915_gpu_error *error = &dev_priv->gpu_error; if (i915_terminally_wedged(error)) return -EIO; if (i915_reset_in_progress(error)) { /* Non-interruptible callers can't handle -EAGAIN, hence return * -EIO unconditionally for these. */ if (!dev_priv->mm.interruptible) return -EIO; return -EAGAIN; } return 0; } static int i915_gem_init_seqno(struct drm_i915_private *dev_priv, u32 seqno) { struct intel_engine_cs *engine; enum intel_engine_id id; int ret; /* Carefully retire all requests without writing to the rings */ for_each_engine(engine, dev_priv, id) { ret = intel_engine_idle(engine, I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED); if (ret) return ret; } i915_gem_retire_requests(dev_priv); /* If the seqno wraps around, we need to clear the breadcrumb rbtree */ if (!i915_seqno_passed(seqno, dev_priv->next_seqno)) { while (intel_kick_waiters(dev_priv) || intel_kick_signalers(dev_priv)) yield(); } /* Finally reset hw state */ for_each_engine(engine, dev_priv, id) intel_engine_init_seqno(engine, seqno); return 0; } int i915_gem_set_seqno(struct drm_device *dev, u32 seqno) { struct drm_i915_private *dev_priv = to_i915(dev); int ret; if (seqno == 0) return -EINVAL; /* HWS page needs to be set less than what we * will inject to ring */ ret = i915_gem_init_seqno(dev_priv, seqno - 1); if (ret) return ret; dev_priv->next_seqno = seqno; return 0; } static int i915_gem_get_seqno(struct drm_i915_private *dev_priv, u32 *seqno) { /* reserve 0 for non-seqno */ if (unlikely(dev_priv->next_seqno == 0)) { int ret; ret = i915_gem_init_seqno(dev_priv, 0); if (ret) return ret; dev_priv->next_seqno = 1; } *seqno = dev_priv->next_seqno++; return 0; } static int __i915_sw_fence_call submit_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state) { struct drm_i915_gem_request *request = container_of(fence, typeof(*request), submit); /* Will be called from irq-context when using foreign DMA fences */ switch (state) { case FENCE_COMPLETE: request->engine->last_submitted_seqno = request->fence.seqno; request->engine->submit_request(request); break; case FENCE_FREE: break; } return NOTIFY_DONE; } /** * i915_gem_request_alloc - allocate a request structure * * @engine: engine that we wish to issue the request on. * @ctx: context that the request will be associated with. * This can be NULL if the request is not directly related to * any specific user context, in which case this function will * choose an appropriate context to use. * * Returns a pointer to the allocated request if successful, * or an error code if not. */ struct drm_i915_gem_request * i915_gem_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx) { struct drm_i915_private *dev_priv = engine->i915; struct drm_i915_gem_request *req; u32 seqno; int ret; /* ABI: Before userspace accesses the GPU (e.g. execbuffer), report * EIO if the GPU is already wedged, or EAGAIN to drop the struct_mutex * and restart. */ ret = i915_gem_check_wedge(dev_priv); if (ret) return ERR_PTR(ret); /* Move the oldest request to the slab-cache (if not in use!) */ req = list_first_entry_or_null(&engine->request_list, typeof(*req), link); if (req && i915_gem_request_completed(req)) i915_gem_request_retire(req); /* Beware: Dragons be flying overhead. * * We use RCU to look up requests in flight. The lookups may * race with the request being allocated from the slab freelist. * That is the request we are writing to here, may be in the process * of being read by __i915_gem_active_get_rcu(). As such, * we have to be very careful when overwriting the contents. During * the RCU lookup, we change chase the request->engine pointer, * read the request->fence.seqno and increment the reference count. * * The reference count is incremented atomically. If it is zero, * the lookup knows the request is unallocated and complete. Otherwise, * it is either still in use, or has been reallocated and reset * with dma_fence_init(). This increment is safe for release as we * check that the request we have a reference to and matches the active * request. * * Before we increment the refcount, we chase the request->engine * pointer. We must not call kmem_cache_zalloc() or else we set * that pointer to NULL and cause a crash during the lookup. If * we see the request is completed (based on the value of the * old engine and seqno), the lookup is complete and reports NULL. * If we decide the request is not completed (new engine or seqno), * then we grab a reference and double check that it is still the * active request - which it won't be and restart the lookup. * * Do not use kmem_cache_zalloc() here! */ req = kmem_cache_alloc(dev_priv->requests, GFP_KERNEL); if (!req) return ERR_PTR(-ENOMEM); ret = i915_gem_get_seqno(dev_priv, &seqno); if (ret) goto err; spin_lock_init(&req->lock); dma_fence_init(&req->fence, &i915_fence_ops, &req->lock, engine->fence_context, seqno); i915_sw_fence_init(&req->submit, submit_notify); INIT_LIST_HEAD(&req->active_list); req->i915 = dev_priv; req->engine = engine; req->ctx = i915_gem_context_get(ctx); /* No zalloc, must clear what we need by hand */ req->previous_context = NULL; req->file_priv = NULL; req->batch = NULL; /* * Reserve space in the ring buffer for all the commands required to * eventually emit this request. This is to guarantee that the * i915_add_request() call can't fail. Note that the reserve may need * to be redone if the request is not actually submitted straight * away, e.g. because a GPU scheduler has deferred it. */ req->reserved_space = MIN_SPACE_FOR_ADD_REQUEST; if (i915.enable_execlists) ret = intel_logical_ring_alloc_request_extras(req); else ret = intel_ring_alloc_request_extras(req); if (ret) goto err_ctx; /* Record the position of the start of the request so that * should we detect the updated seqno part-way through the * GPU processing the request, we never over-estimate the * position of the head. */ req->head = req->ring->tail; return req; err_ctx: i915_gem_context_put(ctx); err: kmem_cache_free(dev_priv->requests, req); return ERR_PTR(ret); } static int i915_gem_request_await_request(struct drm_i915_gem_request *to, struct drm_i915_gem_request *from) { int idx, ret; GEM_BUG_ON(to == from); if (to->engine == from->engine) return 0; idx = intel_engine_sync_index(from->engine, to->engine); if (from->fence.seqno <= from->engine->semaphore.sync_seqno[idx]) return 0; trace_i915_gem_ring_sync_to(to, from); if (!i915.semaphores) { if (!i915_spin_request(from, TASK_INTERRUPTIBLE, 2)) { ret = i915_sw_fence_await_dma_fence(&to->submit, &from->fence, 0, GFP_KERNEL); if (ret < 0) return ret; } } else { ret = to->engine->semaphore.sync_to(to, from); if (ret) return ret; } from->engine->semaphore.sync_seqno[idx] = from->fence.seqno; return 0; } int i915_gem_request_await_dma_fence(struct drm_i915_gem_request *req, struct dma_fence *fence) { struct dma_fence_array *array; int ret; int i; if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) return 0; if (dma_fence_is_i915(fence)) return i915_gem_request_await_request(req, to_request(fence)); if (!dma_fence_is_array(fence)) { ret = i915_sw_fence_await_dma_fence(&req->submit, fence, I915_FENCE_TIMEOUT, GFP_KERNEL); return ret < 0 ? ret : 0; } /* Note that if the fence-array was created in signal-on-any mode, * we should *not* decompose it into its individual fences. However, * we don't currently store which mode the fence-array is operating * in. Fortunately, the only user of signal-on-any is private to * amdgpu and we should not see any incoming fence-array from * sync-file being in signal-on-any mode. */ array = to_dma_fence_array(fence); for (i = 0; i < array->num_fences; i++) { struct dma_fence *child = array->fences[i]; if (dma_fence_is_i915(child)) ret = i915_gem_request_await_request(req, to_request(child)); else ret = i915_sw_fence_await_dma_fence(&req->submit, child, I915_FENCE_TIMEOUT, GFP_KERNEL); if (ret < 0) return ret; } return 0; } /** * i915_gem_request_await_object - set this request to (async) wait upon a bo * * @to: request we are wishing to use * @obj: object which may be in use on another ring. * * This code is meant to abstract object synchronization with the GPU. * Conceptually we serialise writes between engines inside the GPU. * We only allow one engine to write into a buffer at any time, but * multiple readers. To ensure each has a coherent view of memory, we must: * * - If there is an outstanding write request to the object, the new * request must wait for it to complete (either CPU or in hw, requests * on the same ring will be naturally ordered). * * - If we are a write request (pending_write_domain is set), the new * request must wait for outstanding read requests to complete. * * Returns 0 if successful, else propagates up the lower layer error. */ int i915_gem_request_await_object(struct drm_i915_gem_request *to, struct drm_i915_gem_object *obj, bool write) { struct i915_gem_active *active; unsigned long active_mask; int idx; if (write) { active_mask = i915_gem_object_get_active(obj); active = obj->last_read; } else { active_mask = 1; active = &obj->last_write; } for_each_active(active_mask, idx) { struct drm_i915_gem_request *request; int ret; request = i915_gem_active_peek(&active[idx], &obj->base.dev->struct_mutex); if (!request) continue; ret = i915_gem_request_await_request(to, request); if (ret) return ret; } return 0; } static void i915_gem_mark_busy(const struct intel_engine_cs *engine) { struct drm_i915_private *dev_priv = engine->i915; dev_priv->gt.active_engines |= intel_engine_flag(engine); if (dev_priv->gt.awake) return; intel_runtime_pm_get_noresume(dev_priv); dev_priv->gt.awake = true; intel_enable_gt_powersave(dev_priv); i915_update_gfx_val(dev_priv); if (INTEL_GEN(dev_priv) >= 6) gen6_rps_busy(dev_priv); queue_delayed_work(dev_priv->wq, &dev_priv->gt.retire_work, round_jiffies_up_relative(HZ)); } /* * NB: This function is not allowed to fail. Doing so would mean the the * request is not being tracked for completion but the work itself is * going to happen on the hardware. This would be a Bad Thing(tm). */ void __i915_add_request(struct drm_i915_gem_request *request, bool flush_caches) { struct intel_engine_cs *engine = request->engine; struct intel_ring *ring = request->ring; struct drm_i915_gem_request *prev; u32 request_start; u32 reserved_tail; int ret; trace_i915_gem_request_add(request); /* * To ensure that this call will not fail, space for its emissions * should already have been reserved in the ring buffer. Let the ring * know that it is time to use that space up. */ request_start = ring->tail; reserved_tail = request->reserved_space; request->reserved_space = 0; /* * Emit any outstanding flushes - execbuf can fail to emit the flush * after having emitted the batchbuffer command. Hence we need to fix * things up similar to emitting the lazy request. The difference here * is that the flush _must_ happen before the next request, no matter * what. */ if (flush_caches) { ret = engine->emit_flush(request, EMIT_FLUSH); /* Not allowed to fail! */ WARN(ret, "engine->emit_flush() failed: %d!\n", ret); } /* Record the position of the start of the breadcrumb so that * should we detect the updated seqno part-way through the * GPU processing the request, we never over-estimate the * position of the ring's HEAD. */ request->postfix = ring->tail; /* Not allowed to fail! */ ret = engine->emit_request(request); WARN(ret, "(%s)->emit_request failed: %d!\n", engine->name, ret); /* Sanity check that the reserved size was large enough. */ ret = ring->tail - request_start; if (ret < 0) ret += ring->size; WARN_ONCE(ret > reserved_tail, "Not enough space reserved (%d bytes) " "for adding the request (%d bytes)\n", reserved_tail, ret); /* Seal the request and mark it as pending execution. Note that * we may inspect this state, without holding any locks, during * hangcheck. Hence we apply the barrier to ensure that we do not * see a more recent value in the hws than we are tracking. */ prev = i915_gem_active_raw(&engine->last_request, &request->i915->drm.struct_mutex); if (prev) i915_sw_fence_await_sw_fence(&request->submit, &prev->submit, &request->submitq); request->emitted_jiffies = jiffies; request->previous_seqno = engine->last_pending_seqno; engine->last_pending_seqno = request->fence.seqno; i915_gem_active_set(&engine->last_request, request); list_add_tail(&request->link, &engine->request_list); list_add_tail(&request->ring_link, &ring->request_list); i915_gem_mark_busy(engine); local_bh_disable(); i915_sw_fence_commit(&request->submit); local_bh_enable(); /* Kick the execlists tasklet if just scheduled */ } static void reset_wait_queue(wait_queue_head_t *q, wait_queue_t *wait) { unsigned long flags; spin_lock_irqsave(&q->lock, flags); if (list_empty(&wait->task_list)) __add_wait_queue(q, wait); spin_unlock_irqrestore(&q->lock, flags); } static unsigned long local_clock_us(unsigned int *cpu) { unsigned long t; /* Cheaply and approximately convert from nanoseconds to microseconds. * The result and subsequent calculations are also defined in the same * approximate microseconds units. The principal source of timing * error here is from the simple truncation. * * Note that local_clock() is only defined wrt to the current CPU; * the comparisons are no longer valid if we switch CPUs. Instead of * blocking preemption for the entire busywait, we can detect the CPU * switch and use that as indicator of system load and a reason to * stop busywaiting, see busywait_stop(). */ *cpu = get_cpu(); t = local_clock() >> 10; put_cpu(); return t; } static bool busywait_stop(unsigned long timeout, unsigned int cpu) { unsigned int this_cpu; if (time_after(local_clock_us(&this_cpu), timeout)) return true; return this_cpu != cpu; } bool __i915_spin_request(const struct drm_i915_gem_request *req, int state, unsigned long timeout_us) { unsigned int cpu; /* When waiting for high frequency requests, e.g. during synchronous * rendering split between the CPU and GPU, the finite amount of time * required to set up the irq and wait upon it limits the response * rate. By busywaiting on the request completion for a short while we * can service the high frequency waits as quick as possible. However, * if it is a slow request, we want to sleep as quickly as possible. * The tradeoff between waiting and sleeping is roughly the time it * takes to sleep on a request, on the order of a microsecond. */ timeout_us += local_clock_us(&cpu); do { if (i915_gem_request_completed(req)) return true; if (signal_pending_state(state, current)) break; if (busywait_stop(timeout_us, cpu)) break; cpu_relax_lowlatency(); } while (!need_resched()); return false; } /** * i915_wait_request - wait until execution of request has finished * @req: the request to wait upon * @flags: how to wait * @timeout: how long to wait in jiffies * * i915_wait_request() waits for the request to be completed, for a * maximum of @timeout jiffies (with MAX_SCHEDULE_TIMEOUT implying an * unbounded wait). * * If the caller holds the struct_mutex, the caller must pass I915_WAIT_LOCKED * in via the flags, and vice versa if the struct_mutex is not held, the caller * must not specify that the wait is locked. * * Returns the remaining time (in jiffies) if the request completed, which may * be zero or -ETIME if the request is unfinished after the timeout expires. * May return -EINTR is called with I915_WAIT_INTERRUPTIBLE and a signal is * pending before the request completes. */ long i915_wait_request(struct drm_i915_gem_request *req, unsigned int flags, long timeout) { const int state = flags & I915_WAIT_INTERRUPTIBLE ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE; DEFINE_WAIT(reset); struct intel_wait wait; might_sleep(); #if IS_ENABLED(CONFIG_LOCKDEP) GEM_BUG_ON(debug_locks && !!lockdep_is_held(&req->i915->drm.struct_mutex) != !!(flags & I915_WAIT_LOCKED)); #endif GEM_BUG_ON(timeout < 0); if (i915_gem_request_completed(req)) return timeout; if (!timeout) return -ETIME; trace_i915_gem_request_wait_begin(req); /* Optimistic short spin before touching IRQs */ if (i915_spin_request(req, state, 5)) goto complete; set_current_state(state); if (flags & I915_WAIT_LOCKED) add_wait_queue(&req->i915->gpu_error.wait_queue, &reset); intel_wait_init(&wait, req->fence.seqno); if (intel_engine_add_wait(req->engine, &wait)) /* In order to check that we haven't missed the interrupt * as we enabled it, we need to kick ourselves to do a * coherent check on the seqno before we sleep. */ goto wakeup; for (;;) { if (signal_pending_state(state, current)) { timeout = -ERESTARTSYS; break; } if (!timeout) { timeout = -ETIME; break; } timeout = io_schedule_timeout(timeout); if (intel_wait_complete(&wait)) break; set_current_state(state); wakeup: /* Carefully check if the request is complete, giving time * for the seqno to be visible following the interrupt. * We also have to check in case we are kicked by the GPU * reset in order to drop the struct_mutex. */ if (__i915_request_irq_complete(req)) break; /* If the GPU is hung, and we hold the lock, reset the GPU * and then check for completion. On a full reset, the engine's * HW seqno will be advanced passed us and we are complete. * If we do a partial reset, we have to wait for the GPU to * resume and update the breadcrumb. * * If we don't hold the mutex, we can just wait for the worker * to come along and update the breadcrumb (either directly * itself, or indirectly by recovering the GPU). */ if (flags & I915_WAIT_LOCKED && i915_reset_in_progress(&req->i915->gpu_error)) { __set_current_state(TASK_RUNNING); i915_reset(req->i915); reset_wait_queue(&req->i915->gpu_error.wait_queue, &reset); continue; } /* Only spin if we know the GPU is processing this request */ if (i915_spin_request(req, state, 2)) break; } intel_engine_remove_wait(req->engine, &wait); if (flags & I915_WAIT_LOCKED) remove_wait_queue(&req->i915->gpu_error.wait_queue, &reset); __set_current_state(TASK_RUNNING); complete: trace_i915_gem_request_wait_end(req); return timeout; } static bool engine_retire_requests(struct intel_engine_cs *engine) { struct drm_i915_gem_request *request, *next; list_for_each_entry_safe(request, next, &engine->request_list, link) { if (!i915_gem_request_completed(request)) return false; i915_gem_request_retire(request); } return true; } void i915_gem_retire_requests(struct drm_i915_private *dev_priv) { struct intel_engine_cs *engine; unsigned int tmp; lockdep_assert_held(&dev_priv->drm.struct_mutex); if (dev_priv->gt.active_engines == 0) return; GEM_BUG_ON(!dev_priv->gt.awake); for_each_engine_masked(engine, dev_priv, dev_priv->gt.active_engines, tmp) if (engine_retire_requests(engine)) dev_priv->gt.active_engines &= ~intel_engine_flag(engine); if (dev_priv->gt.active_engines == 0) queue_delayed_work(dev_priv->wq, &dev_priv->gt.idle_work, msecs_to_jiffies(100)); }