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linux_dsm_epyc7002/drivers/gpu/drm/i915/intel_lrc.c
Chris Wilson 655250a8d1 drm/i915/execlists: Switch to rb_root_cached 
The kernel recently gained an augmented rbtree with the purpose of
cacheing the leftmost element of the rbtree, a frequent optimisation to
avoid calls to rb_first() which is also employed by the
execlists->queue. Switch from our open-coded cache to the library.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180629075348.27358-9-chris@chris-wilson.co.uk
2018-07-11 14:38:45 +01:00

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/*
* Copyright © 2014 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:
* Ben Widawsky <ben@bwidawsk.net>
* Michel Thierry <michel.thierry@intel.com>
* Thomas Daniel <thomas.daniel@intel.com>
* Oscar Mateo <oscar.mateo@intel.com>
*
*/
/**
* DOC: Logical Rings, Logical Ring Contexts and Execlists
*
* Motivation:
* GEN8 brings an expansion of the HW contexts: "Logical Ring Contexts".
* These expanded contexts enable a number of new abilities, especially
* "Execlists" (also implemented in this file).
*
* One of the main differences with the legacy HW contexts is that logical
* ring contexts incorporate many more things to the context's state, like
* PDPs or ringbuffer control registers:
*
* The reason why PDPs are included in the context is straightforward: as
* PPGTTs (per-process GTTs) are actually per-context, having the PDPs
* contained there mean you don't need to do a ppgtt->switch_mm yourself,
* instead, the GPU will do it for you on the context switch.
*
* But, what about the ringbuffer control registers (head, tail, etc..)?
* shouldn't we just need a set of those per engine command streamer? This is
* where the name "Logical Rings" starts to make sense: by virtualizing the
* rings, the engine cs shifts to a new "ring buffer" with every context
* switch. When you want to submit a workload to the GPU you: A) choose your
* context, B) find its appropriate virtualized ring, C) write commands to it
* and then, finally, D) tell the GPU to switch to that context.
*
* Instead of the legacy MI_SET_CONTEXT, the way you tell the GPU to switch
* to a contexts is via a context execution list, ergo "Execlists".
*
* LRC implementation:
* Regarding the creation of contexts, we have:
*
* - One global default context.
* - One local default context for each opened fd.
* - One local extra context for each context create ioctl call.
*
* Now that ringbuffers belong per-context (and not per-engine, like before)
* and that contexts are uniquely tied to a given engine (and not reusable,
* like before) we need:
*
* - One ringbuffer per-engine inside each context.
* - One backing object per-engine inside each context.
*
* The global default context starts its life with these new objects fully
* allocated and populated. The local default context for each opened fd is
* more complex, because we don't know at creation time which engine is going
* to use them. To handle this, we have implemented a deferred creation of LR
* contexts:
*
* The local context starts its life as a hollow or blank holder, that only
* gets populated for a given engine once we receive an execbuffer. If later
* on we receive another execbuffer ioctl for the same context but a different
* engine, we allocate/populate a new ringbuffer and context backing object and
* so on.
*
* Finally, regarding local contexts created using the ioctl call: as they are
* only allowed with the render ring, we can allocate & populate them right
* away (no need to defer anything, at least for now).
*
* Execlists implementation:
* Execlists are the new method by which, on gen8+ hardware, workloads are
* submitted for execution (as opposed to the legacy, ringbuffer-based, method).
* This method works as follows:
*
* When a request is committed, its commands (the BB start and any leading or
* trailing commands, like the seqno breadcrumbs) are placed in the ringbuffer
* for the appropriate context. The tail pointer in the hardware context is not
* updated at this time, but instead, kept by the driver in the ringbuffer
* structure. A structure representing this request is added to a request queue
* for the appropriate engine: this structure contains a copy of the context's
* tail after the request was written to the ring buffer and a pointer to the
* context itself.
*
* If the engine's request queue was empty before the request was added, the
* queue is processed immediately. Otherwise the queue will be processed during
* a context switch interrupt. In any case, elements on the queue will get sent
* (in pairs) to the GPU's ExecLists Submit Port (ELSP, for short) with a
* globally unique 20-bits submission ID.
*
* When execution of a request completes, the GPU updates the context status
* buffer with a context complete event and generates a context switch interrupt.
* During the interrupt handling, the driver examines the events in the buffer:
* for each context complete event, if the announced ID matches that on the head
* of the request queue, then that request is retired and removed from the queue.
*
* After processing, if any requests were retired and the queue is not empty
* then a new execution list can be submitted. The two requests at the front of
* the queue are next to be submitted but since a context may not occur twice in
* an execution list, if subsequent requests have the same ID as the first then
* the two requests must be combined. This is done simply by discarding requests
* at the head of the queue until either only one requests is left (in which case
* we use a NULL second context) or the first two requests have unique IDs.
*
* By always executing the first two requests in the queue the driver ensures
* that the GPU is kept as busy as possible. In the case where a single context
* completes but a second context is still executing, the request for this second
* context will be at the head of the queue when we remove the first one. This
* request will then be resubmitted along with a new request for a different context,
* which will cause the hardware to continue executing the second request and queue
* the new request (the GPU detects the condition of a context getting preempted
* with the same context and optimizes the context switch flow by not doing
* preemption, but just sampling the new tail pointer).
*
*/
#include <linux/interrupt.h>
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_gem_render_state.h"
#include "i915_vgpu.h"
#include "intel_lrc_reg.h"
#include "intel_mocs.h"
#include "intel_workarounds.h"
#define RING_EXECLIST_QFULL (1 << 0x2)
#define RING_EXECLIST1_VALID (1 << 0x3)
#define RING_EXECLIST0_VALID (1 << 0x4)
#define RING_EXECLIST_ACTIVE_STATUS (3 << 0xE)
#define RING_EXECLIST1_ACTIVE (1 << 0x11)
#define RING_EXECLIST0_ACTIVE (1 << 0x12)
#define GEN8_CTX_STATUS_IDLE_ACTIVE (1 << 0)
#define GEN8_CTX_STATUS_PREEMPTED (1 << 1)
#define GEN8_CTX_STATUS_ELEMENT_SWITCH (1 << 2)
#define GEN8_CTX_STATUS_ACTIVE_IDLE (1 << 3)
#define GEN8_CTX_STATUS_COMPLETE (1 << 4)
#define GEN8_CTX_STATUS_LITE_RESTORE (1 << 15)
#define GEN8_CTX_STATUS_COMPLETED_MASK \
(GEN8_CTX_STATUS_COMPLETE | GEN8_CTX_STATUS_PREEMPTED)
/* Typical size of the average request (2 pipecontrols and a MI_BB) */
#define EXECLISTS_REQUEST_SIZE 64 /* bytes */
#define WA_TAIL_DWORDS 2
#define WA_TAIL_BYTES (sizeof(u32) * WA_TAIL_DWORDS)
static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
struct intel_engine_cs *engine,
struct intel_context *ce);
static void execlists_init_reg_state(u32 *reg_state,
struct i915_gem_context *ctx,
struct intel_engine_cs *engine,
struct intel_ring *ring);
static inline struct i915_priolist *to_priolist(struct rb_node *rb)
{
return rb_entry(rb, struct i915_priolist, node);
}
static inline int rq_prio(const struct i915_request *rq)
{
return rq->sched.attr.priority;
}
static inline bool need_preempt(const struct intel_engine_cs *engine,
const struct i915_request *last,
int prio)
{
return (intel_engine_has_preemption(engine) &&
__execlists_need_preempt(prio, rq_prio(last)) &&
!i915_request_completed(last));
}
/*
* The context descriptor encodes various attributes of a context,
* including its GTT address and some flags. Because it's fairly
* expensive to calculate, we'll just do it once and cache the result,
* which remains valid until the context is unpinned.
*
* This is what a descriptor looks like, from LSB to MSB::
*
* bits 0-11: flags, GEN8_CTX_* (cached in ctx->desc_template)
* bits 12-31: LRCA, GTT address of (the HWSP of) this context
* bits 32-52: ctx ID, a globally unique tag (highest bit used by GuC)
* bits 53-54: mbz, reserved for use by hardware
* bits 55-63: group ID, currently unused and set to 0
*
* Starting from Gen11, the upper dword of the descriptor has a new format:
*
* bits 32-36: reserved
* bits 37-47: SW context ID
* bits 48:53: engine instance
* bit 54: mbz, reserved for use by hardware
* bits 55-60: SW counter
* bits 61-63: engine class
*
* engine info, SW context ID and SW counter need to form a unique number
* (Context ID) per lrc.
*/
static void
intel_lr_context_descriptor_update(struct i915_gem_context *ctx,
struct intel_engine_cs *engine,
struct intel_context *ce)
{
u64 desc;
BUILD_BUG_ON(MAX_CONTEXT_HW_ID > (BIT(GEN8_CTX_ID_WIDTH)));
BUILD_BUG_ON(GEN11_MAX_CONTEXT_HW_ID > (BIT(GEN11_SW_CTX_ID_WIDTH)));
desc = ctx->desc_template; /* bits 0-11 */
GEM_BUG_ON(desc & GENMASK_ULL(63, 12));
desc |= i915_ggtt_offset(ce->state) + LRC_HEADER_PAGES * PAGE_SIZE;
/* bits 12-31 */
GEM_BUG_ON(desc & GENMASK_ULL(63, 32));
/*
* The following 32bits are copied into the OA reports (dword 2).
* Consider updating oa_get_render_ctx_id in i915_perf.c when changing
* anything below.
*/
if (INTEL_GEN(ctx->i915) >= 11) {
GEM_BUG_ON(ctx->hw_id >= BIT(GEN11_SW_CTX_ID_WIDTH));
desc |= (u64)ctx->hw_id << GEN11_SW_CTX_ID_SHIFT;
/* bits 37-47 */
desc |= (u64)engine->instance << GEN11_ENGINE_INSTANCE_SHIFT;
/* bits 48-53 */
/* TODO: decide what to do with SW counter (bits 55-60) */
desc |= (u64)engine->class << GEN11_ENGINE_CLASS_SHIFT;
/* bits 61-63 */
} else {
GEM_BUG_ON(ctx->hw_id >= BIT(GEN8_CTX_ID_WIDTH));
desc |= (u64)ctx->hw_id << GEN8_CTX_ID_SHIFT; /* bits 32-52 */
}
ce->lrc_desc = desc;
}
static struct i915_priolist *
lookup_priolist(struct intel_engine_cs *engine, int prio)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct i915_priolist *p;
struct rb_node **parent, *rb;
bool first = true;
if (unlikely(execlists->no_priolist))
prio = I915_PRIORITY_NORMAL;
find_priolist:
/* most positive priority is scheduled first, equal priorities fifo */
rb = NULL;
parent = &execlists->queue.rb_root.rb_node;
while (*parent) {
rb = *parent;
p = to_priolist(rb);
if (prio > p->priority) {
parent = &rb->rb_left;
} else if (prio < p->priority) {
parent = &rb->rb_right;
first = false;
} else {
return p;
}
}
if (prio == I915_PRIORITY_NORMAL) {
p = &execlists->default_priolist;
} else {
p = kmem_cache_alloc(engine->i915->priorities, GFP_ATOMIC);
/* Convert an allocation failure to a priority bump */
if (unlikely(!p)) {
prio = I915_PRIORITY_NORMAL; /* recurses just once */
/* To maintain ordering with all rendering, after an
* allocation failure we have to disable all scheduling.
* Requests will then be executed in fifo, and schedule
* will ensure that dependencies are emitted in fifo.
* There will be still some reordering with existing
* requests, so if userspace lied about their
* dependencies that reordering may be visible.
*/
execlists->no_priolist = true;
goto find_priolist;
}
}
p->priority = prio;
INIT_LIST_HEAD(&p->requests);
rb_link_node(&p->node, rb, parent);
rb_insert_color_cached(&p->node, &execlists->queue, first);
return p;
}
static void unwind_wa_tail(struct i915_request *rq)
{
rq->tail = intel_ring_wrap(rq->ring, rq->wa_tail - WA_TAIL_BYTES);
assert_ring_tail_valid(rq->ring, rq->tail);
}
static void __unwind_incomplete_requests(struct intel_engine_cs *engine)
{
struct i915_request *rq, *rn;
struct i915_priolist *uninitialized_var(p);
int last_prio = I915_PRIORITY_INVALID;
lockdep_assert_held(&engine->timeline.lock);
list_for_each_entry_safe_reverse(rq, rn,
&engine->timeline.requests,
link) {
if (i915_request_completed(rq))
return;
__i915_request_unsubmit(rq);
unwind_wa_tail(rq);
GEM_BUG_ON(rq_prio(rq) == I915_PRIORITY_INVALID);
if (rq_prio(rq) != last_prio) {
last_prio = rq_prio(rq);
p = lookup_priolist(engine, last_prio);
}
GEM_BUG_ON(p->priority != rq_prio(rq));
list_add(&rq->sched.link, &p->requests);
}
}
void
execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists)
{
struct intel_engine_cs *engine =
container_of(execlists, typeof(*engine), execlists);
unsigned long flags;
spin_lock_irqsave(&engine->timeline.lock, flags);
__unwind_incomplete_requests(engine);
spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
static inline void
execlists_context_status_change(struct i915_request *rq, unsigned long status)
{
/*
* Only used when GVT-g is enabled now. When GVT-g is disabled,
* The compiler should eliminate this function as dead-code.
*/
if (!IS_ENABLED(CONFIG_DRM_I915_GVT))
return;
atomic_notifier_call_chain(&rq->engine->context_status_notifier,
status, rq);
}
inline void
execlists_user_begin(struct intel_engine_execlists *execlists,
const struct execlist_port *port)
{
execlists_set_active_once(execlists, EXECLISTS_ACTIVE_USER);
}
inline void
execlists_user_end(struct intel_engine_execlists *execlists)
{
execlists_clear_active(execlists, EXECLISTS_ACTIVE_USER);
}
static inline void
execlists_context_schedule_in(struct i915_request *rq)
{
execlists_context_status_change(rq, INTEL_CONTEXT_SCHEDULE_IN);
intel_engine_context_in(rq->engine);
}
static inline void
execlists_context_schedule_out(struct i915_request *rq, unsigned long status)
{
intel_engine_context_out(rq->engine);
execlists_context_status_change(rq, status);
trace_i915_request_out(rq);
}
static void
execlists_update_context_pdps(struct i915_hw_ppgtt *ppgtt, u32 *reg_state)
{
ASSIGN_CTX_PDP(ppgtt, reg_state, 3);
ASSIGN_CTX_PDP(ppgtt, reg_state, 2);
ASSIGN_CTX_PDP(ppgtt, reg_state, 1);
ASSIGN_CTX_PDP(ppgtt, reg_state, 0);
}
static u64 execlists_update_context(struct i915_request *rq)
{
struct intel_context *ce = rq->hw_context;
struct i915_hw_ppgtt *ppgtt =
rq->gem_context->ppgtt ?: rq->i915->mm.aliasing_ppgtt;
u32 *reg_state = ce->lrc_reg_state;
reg_state[CTX_RING_TAIL+1] = intel_ring_set_tail(rq->ring, rq->tail);
/* True 32b PPGTT with dynamic page allocation: update PDP
* registers and point the unallocated PDPs to scratch page.
* PML4 is allocated during ppgtt init, so this is not needed
* in 48-bit mode.
*/
if (ppgtt && !i915_vm_is_48bit(&ppgtt->vm))
execlists_update_context_pdps(ppgtt, reg_state);
return ce->lrc_desc;
}
static inline void write_desc(struct intel_engine_execlists *execlists, u64 desc, u32 port)
{
if (execlists->ctrl_reg) {
writel(lower_32_bits(desc), execlists->submit_reg + port * 2);
writel(upper_32_bits(desc), execlists->submit_reg + port * 2 + 1);
} else {
writel(upper_32_bits(desc), execlists->submit_reg);
writel(lower_32_bits(desc), execlists->submit_reg);
}
}
static void execlists_submit_ports(struct intel_engine_cs *engine)
{
struct intel_engine_execlists *execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
unsigned int n;
/*
* ELSQ note: the submit queue is not cleared after being submitted
* to the HW so we need to make sure we always clean it up. This is
* currently ensured by the fact that we always write the same number
* of elsq entries, keep this in mind before changing the loop below.
*/
for (n = execlists_num_ports(execlists); n--; ) {
struct i915_request *rq;
unsigned int count;
u64 desc;
rq = port_unpack(&port[n], &count);
if (rq) {
GEM_BUG_ON(count > !n);
if (!count++)
execlists_context_schedule_in(rq);
port_set(&port[n], port_pack(rq, count));
desc = execlists_update_context(rq);
GEM_DEBUG_EXEC(port[n].context_id = upper_32_bits(desc));
GEM_TRACE("%s in[%d]: ctx=%d.%d, global=%d (fence %llx:%d) (current %d), prio=%d\n",
engine->name, n,
port[n].context_id, count,
rq->global_seqno,
rq->fence.context, rq->fence.seqno,
intel_engine_get_seqno(engine),
rq_prio(rq));
} else {
GEM_BUG_ON(!n);
desc = 0;
}
write_desc(execlists, desc, n);
}
/* we need to manually load the submit queue */
if (execlists->ctrl_reg)
writel(EL_CTRL_LOAD, execlists->ctrl_reg);
execlists_clear_active(execlists, EXECLISTS_ACTIVE_HWACK);
}
static bool ctx_single_port_submission(const struct intel_context *ce)
{
return (IS_ENABLED(CONFIG_DRM_I915_GVT) &&
i915_gem_context_force_single_submission(ce->gem_context));
}
static bool can_merge_ctx(const struct intel_context *prev,
const struct intel_context *next)
{
if (prev != next)
return false;
if (ctx_single_port_submission(prev))
return false;
return true;
}
static void port_assign(struct execlist_port *port, struct i915_request *rq)
{
GEM_BUG_ON(rq == port_request(port));
if (port_isset(port))
i915_request_put(port_request(port));
port_set(port, port_pack(i915_request_get(rq), port_count(port)));
}
static void inject_preempt_context(struct intel_engine_cs *engine)
{
struct intel_engine_execlists *execlists = &engine->execlists;
struct intel_context *ce =
to_intel_context(engine->i915->preempt_context, engine);
unsigned int n;
GEM_BUG_ON(execlists->preempt_complete_status !=
upper_32_bits(ce->lrc_desc));
GEM_BUG_ON((ce->lrc_reg_state[CTX_CONTEXT_CONTROL + 1] &
_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT)) !=
_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT));
/*
* Switch to our empty preempt context so
* the state of the GPU is known (idle).
*/
GEM_TRACE("%s\n", engine->name);
for (n = execlists_num_ports(execlists); --n; )
write_desc(execlists, 0, n);
write_desc(execlists, ce->lrc_desc, n);
/* we need to manually load the submit queue */
if (execlists->ctrl_reg)
writel(EL_CTRL_LOAD, execlists->ctrl_reg);
execlists_clear_active(execlists, EXECLISTS_ACTIVE_HWACK);
execlists_set_active(execlists, EXECLISTS_ACTIVE_PREEMPT);
}
static void complete_preempt_context(struct intel_engine_execlists *execlists)
{
GEM_BUG_ON(!execlists_is_active(execlists, EXECLISTS_ACTIVE_PREEMPT));
execlists_cancel_port_requests(execlists);
__unwind_incomplete_requests(container_of(execlists,
struct intel_engine_cs,
execlists));
execlists_clear_active(execlists, EXECLISTS_ACTIVE_PREEMPT);
}
static void execlists_dequeue(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
const struct execlist_port * const last_port =
&execlists->port[execlists->port_mask];
struct i915_request *last = port_request(port);
struct rb_node *rb;
bool submit = false;
/*
* Hardware submission is through 2 ports. Conceptually each port
* has a (RING_START, RING_HEAD, RING_TAIL) tuple. RING_START is
* static for a context, and unique to each, so we only execute
* requests belonging to a single context from each ring. RING_HEAD
* is maintained by the CS in the context image, it marks the place
* where it got up to last time, and through RING_TAIL we tell the CS
* where we want to execute up to this time.
*
* In this list the requests are in order of execution. Consecutive
* requests from the same context are adjacent in the ringbuffer. We
* can combine these requests into a single RING_TAIL update:
*
* RING_HEAD...req1...req2
* ^- RING_TAIL
* since to execute req2 the CS must first execute req1.
*
* Our goal then is to point each port to the end of a consecutive
* sequence of requests as being the most optimal (fewest wake ups
* and context switches) submission.
*/
if (last) {
/*
* Don't resubmit or switch until all outstanding
* preemptions (lite-restore) are seen. Then we
* know the next preemption status we see corresponds
* to this ELSP update.
*/
GEM_BUG_ON(!execlists_is_active(execlists,
EXECLISTS_ACTIVE_USER));
GEM_BUG_ON(!port_count(&port[0]));
/*
* If we write to ELSP a second time before the HW has had
* a chance to respond to the previous write, we can confuse
* the HW and hit "undefined behaviour". After writing to ELSP,
* we must then wait until we see a context-switch event from
* the HW to indicate that it has had a chance to respond.
*/
if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_HWACK))
return;
if (need_preempt(engine, last, execlists->queue_priority)) {
inject_preempt_context(engine);
return;
}
/*
* In theory, we could coalesce more requests onto
* the second port (the first port is active, with
* no preemptions pending). However, that means we
* then have to deal with the possible lite-restore
* of the second port (as we submit the ELSP, there
* may be a context-switch) but also we may complete
* the resubmission before the context-switch. Ergo,
* coalescing onto the second port will cause a
* preemption event, but we cannot predict whether
* that will affect port[0] or port[1].
*
* If the second port is already active, we can wait
* until the next context-switch before contemplating
* new requests. The GPU will be busy and we should be
* able to resubmit the new ELSP before it idles,
* avoiding pipeline bubbles (momentary pauses where
* the driver is unable to keep up the supply of new
* work). However, we have to double check that the
* priorities of the ports haven't been switch.
*/
if (port_count(&port[1]))
return;
/*
* WaIdleLiteRestore:bdw,skl
* Apply the wa NOOPs to prevent
* ring:HEAD == rq:TAIL as we resubmit the
* request. See gen8_emit_breadcrumb() for
* where we prepare the padding after the
* end of the request.
*/
last->tail = last->wa_tail;
}
while ((rb = rb_first_cached(&execlists->queue))) {
struct i915_priolist *p = to_priolist(rb);
struct i915_request *rq, *rn;
list_for_each_entry_safe(rq, rn, &p->requests, sched.link) {
/*
* Can we combine this request with the current port?
* It has to be the same context/ringbuffer and not
* have any exceptions (e.g. GVT saying never to
* combine contexts).
*
* If we can combine the requests, we can execute both
* by updating the RING_TAIL to point to the end of the
* second request, and so we never need to tell the
* hardware about the first.
*/
if (last &&
!can_merge_ctx(rq->hw_context, last->hw_context)) {
/*
* If we are on the second port and cannot
* combine this request with the last, then we
* are done.
*/
if (port == last_port) {
__list_del_many(&p->requests,
&rq->sched.link);
goto done;
}
/*
* If GVT overrides us we only ever submit
* port[0], leaving port[1] empty. Note that we
* also have to be careful that we don't queue
* the same context (even though a different
* request) to the second port.
*/
if (ctx_single_port_submission(last->hw_context) ||
ctx_single_port_submission(rq->hw_context)) {
__list_del_many(&p->requests,
&rq->sched.link);
goto done;
}
GEM_BUG_ON(last->hw_context == rq->hw_context);
if (submit)
port_assign(port, last);
port++;
GEM_BUG_ON(port_isset(port));
}
INIT_LIST_HEAD(&rq->sched.link);
__i915_request_submit(rq);
trace_i915_request_in(rq, port_index(port, execlists));
last = rq;
submit = true;
}
rb_erase_cached(&p->node, &execlists->queue);
INIT_LIST_HEAD(&p->requests);
if (p->priority != I915_PRIORITY_NORMAL)
kmem_cache_free(engine->i915->priorities, p);
}
done:
/*
* Here be a bit of magic! Or sleight-of-hand, whichever you prefer.
*
* We choose queue_priority such that if we add a request of greater
* priority than this, we kick the submission tasklet to decide on
* the right order of submitting the requests to hardware. We must
* also be prepared to reorder requests as they are in-flight on the
* HW. We derive the queue_priority then as the first "hole" in
* the HW submission ports and if there are no available slots,
* the priority of the lowest executing request, i.e. last.
*
* When we do receive a higher priority request ready to run from the
* user, see queue_request(), the queue_priority is bumped to that
* request triggering preemption on the next dequeue (or subsequent
* interrupt for secondary ports).
*/
execlists->queue_priority =
port != execlists->port ? rq_prio(last) : INT_MIN;
if (submit) {
port_assign(port, last);
execlists_submit_ports(engine);
}
/* We must always keep the beast fed if we have work piled up */
GEM_BUG_ON(rb_first_cached(&execlists->queue) &&
!port_isset(execlists->port));
/* Re-evaluate the executing context setup after each preemptive kick */
if (last)
execlists_user_begin(execlists, execlists->port);
/* If the engine is now idle, so should be the flag; and vice versa. */
GEM_BUG_ON(execlists_is_active(&engine->execlists,
EXECLISTS_ACTIVE_USER) ==
!port_isset(engine->execlists.port));
}
void
execlists_cancel_port_requests(struct intel_engine_execlists * const execlists)
{
struct execlist_port *port = execlists->port;
unsigned int num_ports = execlists_num_ports(execlists);
while (num_ports-- && port_isset(port)) {
struct i915_request *rq = port_request(port);
GEM_TRACE("%s:port%u global=%d (fence %llx:%d), (current %d)\n",
rq->engine->name,
(unsigned int)(port - execlists->port),
rq->global_seqno,
rq->fence.context, rq->fence.seqno,
intel_engine_get_seqno(rq->engine));
GEM_BUG_ON(!execlists->active);
execlists_context_schedule_out(rq,
i915_request_completed(rq) ?
INTEL_CONTEXT_SCHEDULE_OUT :
INTEL_CONTEXT_SCHEDULE_PREEMPTED);
i915_request_put(rq);
memset(port, 0, sizeof(*port));
port++;
}
execlists_clear_active(execlists, EXECLISTS_ACTIVE_USER);
execlists_user_end(execlists);
}
static void clear_gtiir(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
int i;
/*
* Clear any pending interrupt state.
*
* We do it twice out of paranoia that some of the IIR are
* double buffered, and so if we only reset it once there may
* still be an interrupt pending.
*/
if (INTEL_GEN(dev_priv) >= 11) {
static const struct {
u8 bank;
u8 bit;
} gen11_gtiir[] = {
[RCS] = {0, GEN11_RCS0},
[BCS] = {0, GEN11_BCS},
[_VCS(0)] = {1, GEN11_VCS(0)},
[_VCS(1)] = {1, GEN11_VCS(1)},
[_VCS(2)] = {1, GEN11_VCS(2)},
[_VCS(3)] = {1, GEN11_VCS(3)},
[_VECS(0)] = {1, GEN11_VECS(0)},
[_VECS(1)] = {1, GEN11_VECS(1)},
};
unsigned long irqflags;
GEM_BUG_ON(engine->id >= ARRAY_SIZE(gen11_gtiir));
spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
for (i = 0; i < 2; i++) {
gen11_reset_one_iir(dev_priv,
gen11_gtiir[engine->id].bank,
gen11_gtiir[engine->id].bit);
}
spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
} else {
static const u8 gtiir[] = {
[RCS] = 0,
[BCS] = 0,
[VCS] = 1,
[VCS2] = 1,
[VECS] = 3,
};
GEM_BUG_ON(engine->id >= ARRAY_SIZE(gtiir));
for (i = 0; i < 2; i++) {
I915_WRITE(GEN8_GT_IIR(gtiir[engine->id]),
engine->irq_keep_mask);
POSTING_READ(GEN8_GT_IIR(gtiir[engine->id]));
}
GEM_BUG_ON(I915_READ(GEN8_GT_IIR(gtiir[engine->id])) &
engine->irq_keep_mask);
}
}
static void reset_irq(struct intel_engine_cs *engine)
{
/* Mark all CS interrupts as complete */
smp_store_mb(engine->execlists.active, 0);
clear_gtiir(engine);
}
static void reset_csb_pointers(struct intel_engine_execlists *execlists)
{
/*
* After a reset, the HW starts writing into CSB entry [0]. We
* therefore have to set our HEAD pointer back one entry so that
* the *first* entry we check is entry 0. To complicate this further,
* as we don't wait for the first interrupt after reset, we have to
* fake the HW write to point back to the last entry so that our
* inline comparison of our cached head position against the last HW
* write works even before the first interrupt.
*/
execlists->csb_head = execlists->csb_write_reset;
WRITE_ONCE(*execlists->csb_write, execlists->csb_write_reset);
}
static void execlists_cancel_requests(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct i915_request *rq, *rn;
struct rb_node *rb;
unsigned long flags;
GEM_TRACE("%s current %d\n",
engine->name, intel_engine_get_seqno(engine));
/*
* Before we call engine->cancel_requests(), we should have exclusive
* access to the submission state. This is arranged for us by the
* caller disabling the interrupt generation, the tasklet and other
* threads that may then access the same state, giving us a free hand
* to reset state. However, we still need to let lockdep be aware that
* we know this state may be accessed in hardirq context, so we
* disable the irq around this manipulation and we want to keep
* the spinlock focused on its duties and not accidentally conflate
* coverage to the submission's irq state. (Similarly, although we
* shouldn't need to disable irq around the manipulation of the
* submission's irq state, we also wish to remind ourselves that
* it is irq state.)
*/
spin_lock_irqsave(&engine->timeline.lock, flags);
/* Cancel the requests on the HW and clear the ELSP tracker. */
execlists_cancel_port_requests(execlists);
reset_irq(engine);
/* Mark all executing requests as skipped. */
list_for_each_entry(rq, &engine->timeline.requests, link) {
GEM_BUG_ON(!rq->global_seqno);
if (!i915_request_completed(rq))
dma_fence_set_error(&rq->fence, -EIO);
}
/* Flush the queued requests to the timeline list (for retiring). */
while ((rb = rb_first_cached(&execlists->queue))) {
struct i915_priolist *p = to_priolist(rb);
list_for_each_entry_safe(rq, rn, &p->requests, sched.link) {
INIT_LIST_HEAD(&rq->sched.link);
dma_fence_set_error(&rq->fence, -EIO);
__i915_request_submit(rq);
}
rb_erase_cached(&p->node, &execlists->queue);
INIT_LIST_HEAD(&p->requests);
if (p->priority != I915_PRIORITY_NORMAL)
kmem_cache_free(engine->i915->priorities, p);
}
/* Remaining _unready_ requests will be nop'ed when submitted */
execlists->queue_priority = INT_MIN;
execlists->queue = RB_ROOT_CACHED;
GEM_BUG_ON(port_isset(execlists->port));
spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
static inline bool
reset_in_progress(const struct intel_engine_execlists *execlists)
{
return unlikely(!__tasklet_is_enabled(&execlists->tasklet));
}
static void process_csb(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct execlist_port *port = execlists->port;
const u32 * const buf = execlists->csb_status;
u8 head, tail;
/*
* Note that csb_write, csb_status may be either in HWSP or mmio.
* When reading from the csb_write mmio register, we have to be
* careful to only use the GEN8_CSB_WRITE_PTR portion, which is
* the low 4bits. As it happens we know the next 4bits are always
* zero and so we can simply masked off the low u8 of the register
* and treat it identically to reading from the HWSP (without having
* to use explicit shifting and masking, and probably bifurcating
* the code to handle the legacy mmio read).
*/
head = execlists->csb_head;
tail = READ_ONCE(*execlists->csb_write);
GEM_TRACE("%s cs-irq head=%d, tail=%d\n", engine->name, head, tail);
if (unlikely(head == tail))
return;
/*
* Hopefully paired with a wmb() in HW!
*
* We must complete the read of the write pointer before any reads
* from the CSB, so that we do not see stale values. Without an rmb
* (lfence) the HW may speculatively perform the CSB[] reads *before*
* we perform the READ_ONCE(*csb_write).
*/
rmb();
do {
struct i915_request *rq;
unsigned int status;
unsigned int count;
if (++head == GEN8_CSB_ENTRIES)
head = 0;
/*
* We are flying near dragons again.
*
* We hold a reference to the request in execlist_port[]
* but no more than that. We are operating in softirq
* context and so cannot hold any mutex or sleep. That
* prevents us stopping the requests we are processing
* in port[] from being retired simultaneously (the
* breadcrumb will be complete before we see the
* context-switch). As we only hold the reference to the
* request, any pointer chasing underneath the request
* is subject to a potential use-after-free. Thus we
* store all of the bookkeeping within port[] as
* required, and avoid using unguarded pointers beneath
* request itself. The same applies to the atomic
* status notifier.
*/
GEM_TRACE("%s csb[%d]: status=0x%08x:0x%08x, active=0x%x\n",
engine->name, head,
buf[2 * head + 0], buf[2 * head + 1],
execlists->active);
status = buf[2 * head];
if (status & (GEN8_CTX_STATUS_IDLE_ACTIVE |
GEN8_CTX_STATUS_PREEMPTED))
execlists_set_active(execlists,
EXECLISTS_ACTIVE_HWACK);
if (status & GEN8_CTX_STATUS_ACTIVE_IDLE)
execlists_clear_active(execlists,
EXECLISTS_ACTIVE_HWACK);
if (!(status & GEN8_CTX_STATUS_COMPLETED_MASK))
continue;
/* We should never get a COMPLETED | IDLE_ACTIVE! */
GEM_BUG_ON(status & GEN8_CTX_STATUS_IDLE_ACTIVE);
if (status & GEN8_CTX_STATUS_COMPLETE &&
buf[2*head + 1] == execlists->preempt_complete_status) {
GEM_TRACE("%s preempt-idle\n", engine->name);
complete_preempt_context(execlists);
continue;
}
if (status & GEN8_CTX_STATUS_PREEMPTED &&
execlists_is_active(execlists,
EXECLISTS_ACTIVE_PREEMPT))
continue;
GEM_BUG_ON(!execlists_is_active(execlists,
EXECLISTS_ACTIVE_USER));
rq = port_unpack(port, &count);
GEM_TRACE("%s out[0]: ctx=%d.%d, global=%d (fence %llx:%d) (current %d), prio=%d\n",
engine->name,
port->context_id, count,
rq ? rq->global_seqno : 0,
rq ? rq->fence.context : 0,
rq ? rq->fence.seqno : 0,
intel_engine_get_seqno(engine),
rq ? rq_prio(rq) : 0);
/* Check the context/desc id for this event matches */
GEM_DEBUG_BUG_ON(buf[2 * head + 1] != port->context_id);
GEM_BUG_ON(count == 0);
if (--count == 0) {
/*
* On the final event corresponding to the
* submission of this context, we expect either
* an element-switch event or a completion
* event (and on completion, the active-idle
* marker). No more preemptions, lite-restore
* or otherwise.
*/
GEM_BUG_ON(status & GEN8_CTX_STATUS_PREEMPTED);
GEM_BUG_ON(port_isset(&port[1]) &&
!(status & GEN8_CTX_STATUS_ELEMENT_SWITCH));
GEM_BUG_ON(!port_isset(&port[1]) &&
!(status & GEN8_CTX_STATUS_ACTIVE_IDLE));
/*
* We rely on the hardware being strongly
* ordered, that the breadcrumb write is
* coherent (visible from the CPU) before the
* user interrupt and CSB is processed.
*/
GEM_BUG_ON(!i915_request_completed(rq));
execlists_context_schedule_out(rq,
INTEL_CONTEXT_SCHEDULE_OUT);
i915_request_put(rq);
GEM_TRACE("%s completed ctx=%d\n",
engine->name, port->context_id);
port = execlists_port_complete(execlists, port);
if (port_isset(port))
execlists_user_begin(execlists, port);
else
execlists_user_end(execlists);
} else {
port_set(port, port_pack(rq, count));
}
} while (head != tail);
execlists->csb_head = head;
}
static void __execlists_submission_tasklet(struct intel_engine_cs *const engine)
{
lockdep_assert_held(&engine->timeline.lock);
/*
* We can skip acquiring intel_runtime_pm_get() here as it was taken
* on our behalf by the request (see i915_gem_mark_busy()) and it will
* not be relinquished until the device is idle (see
* i915_gem_idle_work_handler()). As a precaution, we make sure
* that all ELSP are drained i.e. we have processed the CSB,
* before allowing ourselves to idle and calling intel_runtime_pm_put().
*/
GEM_BUG_ON(!engine->i915->gt.awake);
process_csb(engine);
if (!execlists_is_active(&engine->execlists, EXECLISTS_ACTIVE_PREEMPT))
execlists_dequeue(engine);
}
/*
* Check the unread Context Status Buffers and manage the submission of new
* contexts to the ELSP accordingly.
*/
static void execlists_submission_tasklet(unsigned long data)
{
struct intel_engine_cs * const engine = (struct intel_engine_cs *)data;
unsigned long flags;
GEM_TRACE("%s awake?=%d, active=%x\n",
engine->name,
engine->i915->gt.awake,
engine->execlists.active);
spin_lock_irqsave(&engine->timeline.lock, flags);
if (engine->i915->gt.awake) /* we may be delayed until after we idle! */
__execlists_submission_tasklet(engine);
spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
static void queue_request(struct intel_engine_cs *engine,
struct i915_sched_node *node,
int prio)
{
list_add_tail(&node->link,
&lookup_priolist(engine, prio)->requests);
}
static void __update_queue(struct intel_engine_cs *engine, int prio)
{
engine->execlists.queue_priority = prio;
}
static void __submit_queue_imm(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
if (reset_in_progress(execlists))
return; /* defer until we restart the engine following reset */
if (execlists->tasklet.func == execlists_submission_tasklet)
__execlists_submission_tasklet(engine);
else
tasklet_hi_schedule(&execlists->tasklet);
}
static void submit_queue(struct intel_engine_cs *engine, int prio)
{
if (prio > engine->execlists.queue_priority) {
__update_queue(engine, prio);
__submit_queue_imm(engine);
}
}
static void execlists_submit_request(struct i915_request *request)
{
struct intel_engine_cs *engine = request->engine;
unsigned long flags;
/* Will be called from irq-context when using foreign fences. */
spin_lock_irqsave(&engine->timeline.lock, flags);
queue_request(engine, &request->sched, rq_prio(request));
GEM_BUG_ON(RB_EMPTY_ROOT(&engine->execlists.queue.rb_root));
GEM_BUG_ON(list_empty(&request->sched.link));
submit_queue(engine, rq_prio(request));
spin_unlock_irqrestore(&engine->timeline.lock, flags);
}
static struct i915_request *sched_to_request(struct i915_sched_node *node)
{
return container_of(node, struct i915_request, sched);
}
static struct intel_engine_cs *
sched_lock_engine(struct i915_sched_node *node, struct intel_engine_cs *locked)
{
struct intel_engine_cs *engine = sched_to_request(node)->engine;
GEM_BUG_ON(!locked);
if (engine != locked) {
spin_unlock(&locked->timeline.lock);
spin_lock(&engine->timeline.lock);
}
return engine;
}
static void execlists_schedule(struct i915_request *request,
const struct i915_sched_attr *attr)
{
struct i915_priolist *uninitialized_var(pl);
struct intel_engine_cs *engine, *last;
struct i915_dependency *dep, *p;
struct i915_dependency stack;
const int prio = attr->priority;
LIST_HEAD(dfs);
GEM_BUG_ON(prio == I915_PRIORITY_INVALID);
if (i915_request_completed(request))
return;
if (prio <= READ_ONCE(request->sched.attr.priority))
return;
/* Need BKL in order to use the temporary link inside i915_dependency */
lockdep_assert_held(&request->i915->drm.struct_mutex);
stack.signaler = &request->sched;
list_add(&stack.dfs_link, &dfs);
/*
* Recursively bump all dependent priorities to match the new request.
*
* A naive approach would be to use recursion:
* static void update_priorities(struct i915_sched_node *node, prio) {
* list_for_each_entry(dep, &node->signalers_list, signal_link)
* update_priorities(dep->signal, prio)
* queue_request(node);
* }
* but that may have unlimited recursion depth and so runs a very
* real risk of overunning the kernel stack. Instead, we build
* a flat list of all dependencies starting with the current request.
* As we walk the list of dependencies, we add all of its dependencies
* to the end of the list (this may include an already visited
* request) and continue to walk onwards onto the new dependencies. The
* end result is a topological list of requests in reverse order, the
* last element in the list is the request we must execute first.
*/
list_for_each_entry(dep, &dfs, dfs_link) {
struct i915_sched_node *node = dep->signaler;
/*
* Within an engine, there can be no cycle, but we may
* refer to the same dependency chain multiple times
* (redundant dependencies are not eliminated) and across
* engines.
*/
list_for_each_entry(p, &node->signalers_list, signal_link) {
GEM_BUG_ON(p == dep); /* no cycles! */
if (i915_sched_node_signaled(p->signaler))
continue;
GEM_BUG_ON(p->signaler->attr.priority < node->attr.priority);
if (prio > READ_ONCE(p->signaler->attr.priority))
list_move_tail(&p->dfs_link, &dfs);
}
}
/*
* If we didn't need to bump any existing priorities, and we haven't
* yet submitted this request (i.e. there is no potential race with
* execlists_submit_request()), we can set our own priority and skip
* acquiring the engine locks.
*/
if (request->sched.attr.priority == I915_PRIORITY_INVALID) {
GEM_BUG_ON(!list_empty(&request->sched.link));
request->sched.attr = *attr;
if (stack.dfs_link.next == stack.dfs_link.prev)
return;
__list_del_entry(&stack.dfs_link);
}
last = NULL;
engine = request->engine;
spin_lock_irq(&engine->timeline.lock);
/* Fifo and depth-first replacement ensure our deps execute before us */
list_for_each_entry_safe_reverse(dep, p, &dfs, dfs_link) {
struct i915_sched_node *node = dep->signaler;
INIT_LIST_HEAD(&dep->dfs_link);
engine = sched_lock_engine(node, engine);
if (prio <= node->attr.priority)
continue;
node->attr.priority = prio;
if (!list_empty(&node->link)) {
if (last != engine) {
pl = lookup_priolist(engine, prio);
last = engine;
}
GEM_BUG_ON(pl->priority != prio);
list_move_tail(&node->link, &pl->requests);
}
if (prio > engine->execlists.queue_priority &&
i915_sw_fence_done(&sched_to_request(node)->submit)) {
/* defer submission until after all of our updates */
__update_queue(engine, prio);
tasklet_hi_schedule(&engine->execlists.tasklet);
}
}
spin_unlock_irq(&engine->timeline.lock);
}
static void execlists_context_destroy(struct intel_context *ce)
{
GEM_BUG_ON(ce->pin_count);
if (!ce->state)
return;
intel_ring_free(ce->ring);
GEM_BUG_ON(i915_gem_object_is_active(ce->state->obj));
i915_gem_object_put(ce->state->obj);
}
static void execlists_context_unpin(struct intel_context *ce)
{
intel_ring_unpin(ce->ring);
ce->state->obj->pin_global--;
i915_gem_object_unpin_map(ce->state->obj);
i915_vma_unpin(ce->state);
i915_gem_context_put(ce->gem_context);
}
static int __context_pin(struct i915_gem_context *ctx, struct i915_vma *vma)
{
unsigned int flags;
int err;
/*
* Clear this page out of any CPU caches for coherent swap-in/out.
* We only want to do this on the first bind so that we do not stall
* on an active context (which by nature is already on the GPU).
*/
if (!(vma->flags & I915_VMA_GLOBAL_BIND)) {
err = i915_gem_object_set_to_gtt_domain(vma->obj, true);
if (err)
return err;
}
flags = PIN_GLOBAL | PIN_HIGH;
if (ctx->ggtt_offset_bias)
flags |= PIN_OFFSET_BIAS | ctx->ggtt_offset_bias;
return i915_vma_pin(vma, 0, GEN8_LR_CONTEXT_ALIGN, flags);
}
static struct intel_context *
__execlists_context_pin(struct intel_engine_cs *engine,
struct i915_gem_context *ctx,
struct intel_context *ce)
{
void *vaddr;
int ret;
ret = execlists_context_deferred_alloc(ctx, engine, ce);
if (ret)
goto err;
GEM_BUG_ON(!ce->state);
ret = __context_pin(ctx, ce->state);
if (ret)
goto err;
vaddr = i915_gem_object_pin_map(ce->state->obj, I915_MAP_WB);
if (IS_ERR(vaddr)) {
ret = PTR_ERR(vaddr);
goto unpin_vma;
}
ret = intel_ring_pin(ce->ring, ctx->i915, ctx->ggtt_offset_bias);
if (ret)
goto unpin_map;
intel_lr_context_descriptor_update(ctx, engine, ce);
ce->lrc_reg_state = vaddr + LRC_STATE_PN * PAGE_SIZE;
ce->lrc_reg_state[CTX_RING_BUFFER_START+1] =
i915_ggtt_offset(ce->ring->vma);
GEM_BUG_ON(!intel_ring_offset_valid(ce->ring, ce->ring->head));
ce->lrc_reg_state[CTX_RING_HEAD+1] = ce->ring->head;
ce->state->obj->pin_global++;
i915_gem_context_get(ctx);
return ce;
unpin_map:
i915_gem_object_unpin_map(ce->state->obj);
unpin_vma:
__i915_vma_unpin(ce->state);
err:
ce->pin_count = 0;
return ERR_PTR(ret);
}
static const struct intel_context_ops execlists_context_ops = {
.unpin = execlists_context_unpin,
.destroy = execlists_context_destroy,
};
static struct intel_context *
execlists_context_pin(struct intel_engine_cs *engine,
struct i915_gem_context *ctx)
{
struct intel_context *ce = to_intel_context(ctx, engine);
lockdep_assert_held(&ctx->i915->drm.struct_mutex);
if (likely(ce->pin_count++))
return ce;
GEM_BUG_ON(!ce->pin_count); /* no overflow please! */
ce->ops = &execlists_context_ops;
return __execlists_context_pin(engine, ctx, ce);
}
static int execlists_request_alloc(struct i915_request *request)
{
int ret;
GEM_BUG_ON(!request->hw_context->pin_count);
/* Flush enough space to reduce the likelihood of waiting after
* we start building the request - in which case we will just
* have to repeat work.
*/
request->reserved_space += EXECLISTS_REQUEST_SIZE;
ret = intel_ring_wait_for_space(request->ring, request->reserved_space);
if (ret)
return ret;
/* Note that after this point, we have committed to using
* this request as it is being used to both track the
* state of engine initialisation and liveness of the
* golden renderstate above. Think twice before you try
* to cancel/unwind this request now.
*/
request->reserved_space -= EXECLISTS_REQUEST_SIZE;
return 0;
}
/*
* In this WA we need to set GEN8_L3SQCREG4[21:21] and reset it after
* PIPE_CONTROL instruction. This is required for the flush to happen correctly
* but there is a slight complication as this is applied in WA batch where the
* values are only initialized once so we cannot take register value at the
* beginning and reuse it further; hence we save its value to memory, upload a
* constant value with bit21 set and then we restore it back with the saved value.
* To simplify the WA, a constant value is formed by using the default value
* of this register. This shouldn't be a problem because we are only modifying
* it for a short period and this batch in non-premptible. We can ofcourse
* use additional instructions that read the actual value of the register
* at that time and set our bit of interest but it makes the WA complicated.
*
* This WA is also required for Gen9 so extracting as a function avoids
* code duplication.
*/
static u32 *
gen8_emit_flush_coherentl3_wa(struct intel_engine_cs *engine, u32 *batch)
{
*batch++ = MI_STORE_REGISTER_MEM_GEN8 | MI_SRM_LRM_GLOBAL_GTT;
*batch++ = i915_mmio_reg_offset(GEN8_L3SQCREG4);
*batch++ = i915_ggtt_offset(engine->scratch) + 256;
*batch++ = 0;
*batch++ = MI_LOAD_REGISTER_IMM(1);
*batch++ = i915_mmio_reg_offset(GEN8_L3SQCREG4);
*batch++ = 0x40400000 | GEN8_LQSC_FLUSH_COHERENT_LINES;
batch = gen8_emit_pipe_control(batch,
PIPE_CONTROL_CS_STALL |
PIPE_CONTROL_DC_FLUSH_ENABLE,
0);
*batch++ = MI_LOAD_REGISTER_MEM_GEN8 | MI_SRM_LRM_GLOBAL_GTT;
*batch++ = i915_mmio_reg_offset(GEN8_L3SQCREG4);
*batch++ = i915_ggtt_offset(engine->scratch) + 256;
*batch++ = 0;
return batch;
}
/*
* Typically we only have one indirect_ctx and per_ctx batch buffer which are
* initialized at the beginning and shared across all contexts but this field
* helps us to have multiple batches at different offsets and select them based
* on a criteria. At the moment this batch always start at the beginning of the page
* and at this point we don't have multiple wa_ctx batch buffers.
*
* The number of WA applied are not known at the beginning; we use this field
* to return the no of DWORDS written.
*
* It is to be noted that this batch does not contain MI_BATCH_BUFFER_END
* so it adds NOOPs as padding to make it cacheline aligned.
* MI_BATCH_BUFFER_END will be added to perctx batch and both of them together
* makes a complete batch buffer.
*/
static u32 *gen8_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
{
/* WaDisableCtxRestoreArbitration:bdw,chv */
*batch++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
/* WaFlushCoherentL3CacheLinesAtContextSwitch:bdw */
if (IS_BROADWELL(engine->i915))
batch = gen8_emit_flush_coherentl3_wa(engine, batch);
/* WaClearSlmSpaceAtContextSwitch:bdw,chv */
/* Actual scratch location is at 128 bytes offset */
batch = gen8_emit_pipe_control(batch,
PIPE_CONTROL_FLUSH_L3 |
PIPE_CONTROL_GLOBAL_GTT_IVB |
PIPE_CONTROL_CS_STALL |
PIPE_CONTROL_QW_WRITE,
i915_ggtt_offset(engine->scratch) +
2 * CACHELINE_BYTES);
*batch++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
/* Pad to end of cacheline */
while ((unsigned long)batch % CACHELINE_BYTES)
*batch++ = MI_NOOP;
/*
* MI_BATCH_BUFFER_END is not required in Indirect ctx BB because
* execution depends on the length specified in terms of cache lines
* in the register CTX_RCS_INDIRECT_CTX
*/
return batch;
}
struct lri {
i915_reg_t reg;
u32 value;
};
static u32 *emit_lri(u32 *batch, const struct lri *lri, unsigned int count)
{
GEM_BUG_ON(!count || count > 63);
*batch++ = MI_LOAD_REGISTER_IMM(count);
do {
*batch++ = i915_mmio_reg_offset(lri->reg);
*batch++ = lri->value;
} while (lri++, --count);
*batch++ = MI_NOOP;
return batch;
}
static u32 *gen9_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
{
static const struct lri lri[] = {
/* WaDisableGatherAtSetShaderCommonSlice:skl,bxt,kbl,glk */
{
COMMON_SLICE_CHICKEN2,
__MASKED_FIELD(GEN9_DISABLE_GATHER_AT_SET_SHADER_COMMON_SLICE,
0),
},
/* BSpec: 11391 */
{
FF_SLICE_CHICKEN,
__MASKED_FIELD(FF_SLICE_CHICKEN_CL_PROVOKING_VERTEX_FIX,
FF_SLICE_CHICKEN_CL_PROVOKING_VERTEX_FIX),
},
/* BSpec: 11299 */
{
_3D_CHICKEN3,
__MASKED_FIELD(_3D_CHICKEN_SF_PROVOKING_VERTEX_FIX,
_3D_CHICKEN_SF_PROVOKING_VERTEX_FIX),
}
};
*batch++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
/* WaFlushCoherentL3CacheLinesAtContextSwitch:skl,bxt,glk */
batch = gen8_emit_flush_coherentl3_wa(engine, batch);
batch = emit_lri(batch, lri, ARRAY_SIZE(lri));
/* WaClearSlmSpaceAtContextSwitch:kbl */
/* Actual scratch location is at 128 bytes offset */
if (IS_KBL_REVID(engine->i915, 0, KBL_REVID_A0)) {
batch = gen8_emit_pipe_control(batch,
PIPE_CONTROL_FLUSH_L3 |
PIPE_CONTROL_GLOBAL_GTT_IVB |
PIPE_CONTROL_CS_STALL |
PIPE_CONTROL_QW_WRITE,
i915_ggtt_offset(engine->scratch)
+ 2 * CACHELINE_BYTES);
}
/* WaMediaPoolStateCmdInWABB:bxt,glk */
if (HAS_POOLED_EU(engine->i915)) {
/*
* EU pool configuration is setup along with golden context
* during context initialization. This value depends on
* device type (2x6 or 3x6) and needs to be updated based
* on which subslice is disabled especially for 2x6
* devices, however it is safe to load default
* configuration of 3x6 device instead of masking off
* corresponding bits because HW ignores bits of a disabled
* subslice and drops down to appropriate config. Please
* see render_state_setup() in i915_gem_render_state.c for
* possible configurations, to avoid duplication they are
* not shown here again.
*/
*batch++ = GEN9_MEDIA_POOL_STATE;
*batch++ = GEN9_MEDIA_POOL_ENABLE;
*batch++ = 0x00777000;
*batch++ = 0;
*batch++ = 0;
*batch++ = 0;
}
*batch++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
/* Pad to end of cacheline */
while ((unsigned long)batch % CACHELINE_BYTES)
*batch++ = MI_NOOP;
return batch;
}
static u32 *
gen10_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
{
int i;
/*
* WaPipeControlBefore3DStateSamplePattern: cnl
*
* Ensure the engine is idle prior to programming a
* 3DSTATE_SAMPLE_PATTERN during a context restore.
*/
batch = gen8_emit_pipe_control(batch,
PIPE_CONTROL_CS_STALL,
0);
/*
* WaPipeControlBefore3DStateSamplePattern says we need 4 dwords for
* the PIPE_CONTROL followed by 12 dwords of 0x0, so 16 dwords in
* total. However, a PIPE_CONTROL is 6 dwords long, not 4, which is
* confusing. Since gen8_emit_pipe_control() already advances the
* batch by 6 dwords, we advance the other 10 here, completing a
* cacheline. It's not clear if the workaround requires this padding
* before other commands, or if it's just the regular padding we would
* already have for the workaround bb, so leave it here for now.
*/
for (i = 0; i < 10; i++)
*batch++ = MI_NOOP;
/* Pad to end of cacheline */
while ((unsigned long)batch % CACHELINE_BYTES)
*batch++ = MI_NOOP;
return batch;
}
#define CTX_WA_BB_OBJ_SIZE (PAGE_SIZE)
static int lrc_setup_wa_ctx(struct intel_engine_cs *engine)
{
struct drm_i915_gem_object *obj;
struct i915_vma *vma;
int err;
obj = i915_gem_object_create(engine->i915, CTX_WA_BB_OBJ_SIZE);
if (IS_ERR(obj))
return PTR_ERR(obj);
vma = i915_vma_instance(obj, &engine->i915->ggtt.vm, NULL);
if (IS_ERR(vma)) {
err = PTR_ERR(vma);
goto err;
}
err = i915_vma_pin(vma, 0, PAGE_SIZE, PIN_GLOBAL | PIN_HIGH);
if (err)
goto err;
engine->wa_ctx.vma = vma;
return 0;
err:
i915_gem_object_put(obj);
return err;
}
static void lrc_destroy_wa_ctx(struct intel_engine_cs *engine)
{
i915_vma_unpin_and_release(&engine->wa_ctx.vma);
}
typedef u32 *(*wa_bb_func_t)(struct intel_engine_cs *engine, u32 *batch);
static int intel_init_workaround_bb(struct intel_engine_cs *engine)
{
struct i915_ctx_workarounds *wa_ctx = &engine->wa_ctx;
struct i915_wa_ctx_bb *wa_bb[2] = { &wa_ctx->indirect_ctx,
&wa_ctx->per_ctx };
wa_bb_func_t wa_bb_fn[2];
struct page *page;
void *batch, *batch_ptr;
unsigned int i;
int ret;
if (GEM_WARN_ON(engine->id != RCS))
return -EINVAL;
switch (INTEL_GEN(engine->i915)) {
case 11:
return 0;
case 10:
wa_bb_fn[0] = gen10_init_indirectctx_bb;
wa_bb_fn[1] = NULL;
break;
case 9:
wa_bb_fn[0] = gen9_init_indirectctx_bb;
wa_bb_fn[1] = NULL;
break;
case 8:
wa_bb_fn[0] = gen8_init_indirectctx_bb;
wa_bb_fn[1] = NULL;
break;
default:
MISSING_CASE(INTEL_GEN(engine->i915));
return 0;
}
ret = lrc_setup_wa_ctx(engine);
if (ret) {
DRM_DEBUG_DRIVER("Failed to setup context WA page: %d\n", ret);
return ret;
}
page = i915_gem_object_get_dirty_page(wa_ctx->vma->obj, 0);
batch = batch_ptr = kmap_atomic(page);
/*
* Emit the two workaround batch buffers, recording the offset from the
* start of the workaround batch buffer object for each and their
* respective sizes.
*/
for (i = 0; i < ARRAY_SIZE(wa_bb_fn); i++) {
wa_bb[i]->offset = batch_ptr - batch;
if (GEM_WARN_ON(!IS_ALIGNED(wa_bb[i]->offset,
CACHELINE_BYTES))) {
ret = -EINVAL;
break;
}
if (wa_bb_fn[i])
batch_ptr = wa_bb_fn[i](engine, batch_ptr);
wa_bb[i]->size = batch_ptr - (batch + wa_bb[i]->offset);
}
BUG_ON(batch_ptr - batch > CTX_WA_BB_OBJ_SIZE);
kunmap_atomic(batch);
if (ret)
lrc_destroy_wa_ctx(engine);
return ret;
}
static void enable_execlists(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
I915_WRITE(RING_HWSTAM(engine->mmio_base), 0xffffffff);
/*
* Make sure we're not enabling the new 12-deep CSB
* FIFO as that requires a slightly updated handling
* in the ctx switch irq. Since we're currently only
* using only 2 elements of the enhanced execlists the
* deeper FIFO it's not needed and it's not worth adding
* more statements to the irq handler to support it.
*/
if (INTEL_GEN(dev_priv) >= 11)
I915_WRITE(RING_MODE_GEN7(engine),
_MASKED_BIT_DISABLE(GEN11_GFX_DISABLE_LEGACY_MODE));
else
I915_WRITE(RING_MODE_GEN7(engine),
_MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE));
I915_WRITE(RING_MI_MODE(engine->mmio_base),
_MASKED_BIT_DISABLE(STOP_RING));
I915_WRITE(RING_HWS_PGA(engine->mmio_base),
engine->status_page.ggtt_offset);
POSTING_READ(RING_HWS_PGA(engine->mmio_base));
}
static bool unexpected_starting_state(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
bool unexpected = false;
if (I915_READ(RING_MI_MODE(engine->mmio_base)) & STOP_RING) {
DRM_DEBUG_DRIVER("STOP_RING still set in RING_MI_MODE\n");
unexpected = true;
}
return unexpected;
}
static int gen8_init_common_ring(struct intel_engine_cs *engine)
{
int ret;
ret = intel_mocs_init_engine(engine);
if (ret)
return ret;
intel_engine_reset_breadcrumbs(engine);
if (GEM_SHOW_DEBUG() && unexpected_starting_state(engine)) {
struct drm_printer p = drm_debug_printer(__func__);
intel_engine_dump(engine, &p, NULL);
}
enable_execlists(engine);
return 0;
}
static int gen8_init_render_ring(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
int ret;
ret = gen8_init_common_ring(engine);
if (ret)
return ret;
intel_whitelist_workarounds_apply(engine);
/* We need to disable the AsyncFlip performance optimisations in order
* to use MI_WAIT_FOR_EVENT within the CS. It should already be
* programmed to '1' on all products.
*
* WaDisableAsyncFlipPerfMode:snb,ivb,hsw,vlv,bdw,chv
*/
I915_WRITE(MI_MODE, _MASKED_BIT_ENABLE(ASYNC_FLIP_PERF_DISABLE));
I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_FORCE_ORDERING));
return 0;
}
static int gen9_init_render_ring(struct intel_engine_cs *engine)
{
int ret;
ret = gen8_init_common_ring(engine);
if (ret)
return ret;
intel_whitelist_workarounds_apply(engine);
return 0;
}
static struct i915_request *
execlists_reset_prepare(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
struct i915_request *request, *active;
unsigned long flags;
GEM_TRACE("%s\n", engine->name);
/*
* Prevent request submission to the hardware until we have
* completed the reset in i915_gem_reset_finish(). If a request
* is completed by one engine, it may then queue a request
* to a second via its execlists->tasklet *just* as we are
* calling engine->init_hw() and also writing the ELSP.
* Turning off the execlists->tasklet until the reset is over
* prevents the race.
*/
__tasklet_disable_sync_once(&execlists->tasklet);
spin_lock_irqsave(&engine->timeline.lock, flags);
/*
* We want to flush the pending context switches, having disabled
* the tasklet above, we can assume exclusive access to the execlists.
* For this allows us to catch up with an inflight preemption event,
* and avoid blaming an innocent request if the stall was due to the
* preemption itself.
*/
process_csb(engine);
/*
* The last active request can then be no later than the last request
* now in ELSP[0]. So search backwards from there, so that if the GPU
* has advanced beyond the last CSB update, it will be pardoned.
*/
active = NULL;
request = port_request(execlists->port);
if (request) {
/*
* Prevent the breadcrumb from advancing before we decide
* which request is currently active.
*/
intel_engine_stop_cs(engine);
list_for_each_entry_from_reverse(request,
&engine->timeline.requests,
link) {
if (__i915_request_completed(request,
request->global_seqno))
break;
active = request;
}
}
spin_unlock_irqrestore(&engine->timeline.lock, flags);
return active;
}
static void execlists_reset(struct intel_engine_cs *engine,
struct i915_request *request)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
unsigned long flags;
u32 *regs;
GEM_TRACE("%s request global=%x, current=%d\n",
engine->name, request ? request->global_seqno : 0,
intel_engine_get_seqno(engine));
spin_lock_irqsave(&engine->timeline.lock, flags);
/*
* Catch up with any missed context-switch interrupts.
*
* Ideally we would just read the remaining CSB entries now that we
* know the gpu is idle. However, the CSB registers are sometimes^W
* often trashed across a GPU reset! Instead we have to rely on
* guessing the missed context-switch events by looking at what
* requests were completed.
*/
execlists_cancel_port_requests(execlists);
reset_irq(engine);
/* Push back any incomplete requests for replay after the reset. */
__unwind_incomplete_requests(engine);
/* Following the reset, we need to reload the CSB read/write pointers */
reset_csb_pointers(&engine->execlists);
spin_unlock_irqrestore(&engine->timeline.lock, flags);
/*
* If the request was innocent, we leave the request in the ELSP
* and will try to replay it on restarting. The context image may
* have been corrupted by the reset, in which case we may have
* to service a new GPU hang, but more likely we can continue on
* without impact.
*
* If the request was guilty, we presume the context is corrupt
* and have to at least restore the RING register in the context
* image back to the expected values to skip over the guilty request.
*/
if (!request || request->fence.error != -EIO)
return;
/*
* We want a simple context + ring to execute the breadcrumb update.
* We cannot rely on the context being intact across the GPU hang,
* so clear it and rebuild just what we need for the breadcrumb.
* All pending requests for this context will be zapped, and any
* future request will be after userspace has had the opportunity
* to recreate its own state.
*/
regs = request->hw_context->lrc_reg_state;
if (engine->pinned_default_state) {
memcpy(regs, /* skip restoring the vanilla PPHWSP */
engine->pinned_default_state + LRC_STATE_PN * PAGE_SIZE,
engine->context_size - PAGE_SIZE);
}
execlists_init_reg_state(regs,
request->gem_context, engine, request->ring);
/* Move the RING_HEAD onto the breadcrumb, past the hanging batch */
regs[CTX_RING_BUFFER_START + 1] = i915_ggtt_offset(request->ring->vma);
request->ring->head = intel_ring_wrap(request->ring, request->postfix);
regs[CTX_RING_HEAD + 1] = request->ring->head;
intel_ring_update_space(request->ring);
/* Reset WaIdleLiteRestore:bdw,skl as well */
unwind_wa_tail(request);
}
static void execlists_reset_finish(struct intel_engine_cs *engine)
{
struct intel_engine_execlists * const execlists = &engine->execlists;
/* After a GPU reset, we may have requests to replay */
if (!RB_EMPTY_ROOT(&execlists->queue.rb_root))
tasklet_schedule(&execlists->tasklet);
/*
* Flush the tasklet while we still have the forcewake to be sure
* that it is not allowed to sleep before we restart and reload a
* context.
*
* As before (with execlists_reset_prepare) we rely on the caller
* serialising multiple attempts to reset so that we know that we
* are the only one manipulating tasklet state.
*/
__tasklet_enable_sync_once(&execlists->tasklet);
GEM_TRACE("%s\n", engine->name);
}
static int intel_logical_ring_emit_pdps(struct i915_request *rq)
{
struct i915_hw_ppgtt *ppgtt = rq->gem_context->ppgtt;
struct intel_engine_cs *engine = rq->engine;
const int num_lri_cmds = GEN8_3LVL_PDPES * 2;
u32 *cs;
int i;
cs = intel_ring_begin(rq, num_lri_cmds * 2 + 2);
if (IS_ERR(cs))
return PTR_ERR(cs);
*cs++ = MI_LOAD_REGISTER_IMM(num_lri_cmds);
for (i = GEN8_3LVL_PDPES - 1; i >= 0; i--) {
const dma_addr_t pd_daddr = i915_page_dir_dma_addr(ppgtt, i);
*cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_UDW(engine, i));
*cs++ = upper_32_bits(pd_daddr);
*cs++ = i915_mmio_reg_offset(GEN8_RING_PDP_LDW(engine, i));
*cs++ = lower_32_bits(pd_daddr);
}
*cs++ = MI_NOOP;
intel_ring_advance(rq, cs);
return 0;
}
static int gen8_emit_bb_start(struct i915_request *rq,
u64 offset, u32 len,
const unsigned int flags)
{
u32 *cs;
int ret;
/* Don't rely in hw updating PDPs, specially in lite-restore.
* Ideally, we should set Force PD Restore in ctx descriptor,
* but we can't. Force Restore would be a second option, but
* it is unsafe in case of lite-restore (because the ctx is
* not idle). PML4 is allocated during ppgtt init so this is
* not needed in 48-bit.*/
if (rq->gem_context->ppgtt &&
(intel_engine_flag(rq->engine) & rq->gem_context->ppgtt->pd_dirty_rings) &&
!i915_vm_is_48bit(&rq->gem_context->ppgtt->vm) &&
!intel_vgpu_active(rq->i915)) {
ret = intel_logical_ring_emit_pdps(rq);
if (ret)
return ret;
rq->gem_context->ppgtt->pd_dirty_rings &= ~intel_engine_flag(rq->engine);
}
cs = intel_ring_begin(rq, 6);
if (IS_ERR(cs))
return PTR_ERR(cs);
/*
* WaDisableCtxRestoreArbitration:bdw,chv
*
* We don't need to perform MI_ARB_ENABLE as often as we do (in
* particular all the gen that do not need the w/a at all!), if we
* took care to make sure that on every switch into this context
* (both ordinary and for preemption) that arbitrartion was enabled
* we would be fine. However, there doesn't seem to be a downside to
* being paranoid and making sure it is set before each batch and
* every context-switch.
*
* Note that if we fail to enable arbitration before the request
* is complete, then we do not see the context-switch interrupt and
* the engine hangs (with RING_HEAD == RING_TAIL).
*
* That satisfies both the GPGPU w/a and our heavy-handed paranoia.
*/
*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
/* FIXME(BDW): Address space and security selectors. */
*cs++ = MI_BATCH_BUFFER_START_GEN8 |
(flags & I915_DISPATCH_SECURE ? 0 : BIT(8)) |
(flags & I915_DISPATCH_RS ? MI_BATCH_RESOURCE_STREAMER : 0);
*cs++ = lower_32_bits(offset);
*cs++ = upper_32_bits(offset);
*cs++ = MI_ARB_ON_OFF | MI_ARB_DISABLE;
*cs++ = MI_NOOP;
intel_ring_advance(rq, cs);
return 0;
}
static void gen8_logical_ring_enable_irq(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
I915_WRITE_IMR(engine,
~(engine->irq_enable_mask | engine->irq_keep_mask));
POSTING_READ_FW(RING_IMR(engine->mmio_base));
}
static void gen8_logical_ring_disable_irq(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
I915_WRITE_IMR(engine, ~engine->irq_keep_mask);
}
static int gen8_emit_flush(struct i915_request *request, u32 mode)
{
u32 cmd, *cs;
cs = intel_ring_begin(request, 4);
if (IS_ERR(cs))
return PTR_ERR(cs);
cmd = MI_FLUSH_DW + 1;
/* We always require a command barrier so that subsequent
* commands, such as breadcrumb interrupts, are strictly ordered
* wrt the contents of the write cache being flushed to memory
* (and thus being coherent from the CPU).
*/
cmd |= MI_FLUSH_DW_STORE_INDEX | MI_FLUSH_DW_OP_STOREDW;
if (mode & EMIT_INVALIDATE) {
cmd |= MI_INVALIDATE_TLB;
if (request->engine->id == VCS)
cmd |= MI_INVALIDATE_BSD;
}
*cs++ = cmd;
*cs++ = I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT;
*cs++ = 0; /* upper addr */
*cs++ = 0; /* value */
intel_ring_advance(request, cs);
return 0;
}
static int gen8_emit_flush_render(struct i915_request *request,
u32 mode)
{
struct intel_engine_cs *engine = request->engine;
u32 scratch_addr =
i915_ggtt_offset(engine->scratch) + 2 * CACHELINE_BYTES;
bool vf_flush_wa = false, dc_flush_wa = false;
u32 *cs, flags = 0;
int len;
flags |= PIPE_CONTROL_CS_STALL;
if (mode & EMIT_FLUSH) {
flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
flags |= PIPE_CONTROL_DEPTH_CACHE_FLUSH;
flags |= PIPE_CONTROL_DC_FLUSH_ENABLE;
flags |= PIPE_CONTROL_FLUSH_ENABLE;
}
if (mode & EMIT_INVALIDATE) {
flags |= PIPE_CONTROL_TLB_INVALIDATE;
flags |= PIPE_CONTROL_INSTRUCTION_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_TEXTURE_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_VF_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_CONST_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_STATE_CACHE_INVALIDATE;
flags |= PIPE_CONTROL_QW_WRITE;
flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
/*
* On GEN9: before VF_CACHE_INVALIDATE we need to emit a NULL
* pipe control.
*/
if (IS_GEN9(request->i915))
vf_flush_wa = true;
/* WaForGAMHang:kbl */
if (IS_KBL_REVID(request->i915, 0, KBL_REVID_B0))
dc_flush_wa = true;
}
len = 6;
if (vf_flush_wa)
len += 6;
if (dc_flush_wa)
len += 12;
cs = intel_ring_begin(request, len);
if (IS_ERR(cs))
return PTR_ERR(cs);
if (vf_flush_wa)
cs = gen8_emit_pipe_control(cs, 0, 0);
if (dc_flush_wa)
cs = gen8_emit_pipe_control(cs, PIPE_CONTROL_DC_FLUSH_ENABLE,
0);
cs = gen8_emit_pipe_control(cs, flags, scratch_addr);
if (dc_flush_wa)
cs = gen8_emit_pipe_control(cs, PIPE_CONTROL_CS_STALL, 0);
intel_ring_advance(request, cs);
return 0;
}
/*
* Reserve space for 2 NOOPs at the end of each request to be
* used as a workaround for not being allowed to do lite
* restore with HEAD==TAIL (WaIdleLiteRestore).
*/
static void gen8_emit_wa_tail(struct i915_request *request, u32 *cs)
{
/* Ensure there's always at least one preemption point per-request. */
*cs++ = MI_ARB_CHECK;
*cs++ = MI_NOOP;
request->wa_tail = intel_ring_offset(request, cs);
}
static void gen8_emit_breadcrumb(struct i915_request *request, u32 *cs)
{
/* w/a: bit 5 needs to be zero for MI_FLUSH_DW address. */
BUILD_BUG_ON(I915_GEM_HWS_INDEX_ADDR & (1 << 5));
cs = gen8_emit_ggtt_write(cs, request->global_seqno,
intel_hws_seqno_address(request->engine));
*cs++ = MI_USER_INTERRUPT;
*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
request->tail = intel_ring_offset(request, cs);
assert_ring_tail_valid(request->ring, request->tail);
gen8_emit_wa_tail(request, cs);
}
static const int gen8_emit_breadcrumb_sz = 6 + WA_TAIL_DWORDS;
static void gen8_emit_breadcrumb_rcs(struct i915_request *request, u32 *cs)
{
/* We're using qword write, seqno should be aligned to 8 bytes. */
BUILD_BUG_ON(I915_GEM_HWS_INDEX & 1);
cs = gen8_emit_ggtt_write_rcs(cs, request->global_seqno,
intel_hws_seqno_address(request->engine));
*cs++ = MI_USER_INTERRUPT;
*cs++ = MI_ARB_ON_OFF | MI_ARB_ENABLE;
request->tail = intel_ring_offset(request, cs);
assert_ring_tail_valid(request->ring, request->tail);
gen8_emit_wa_tail(request, cs);
}
static const int gen8_emit_breadcrumb_rcs_sz = 8 + WA_TAIL_DWORDS;
static int gen8_init_rcs_context(struct i915_request *rq)
{
int ret;
ret = intel_ctx_workarounds_emit(rq);
if (ret)
return ret;
ret = intel_rcs_context_init_mocs(rq);
/*
* Failing to program the MOCS is non-fatal.The system will not
* run at peak performance. So generate an error and carry on.
*/
if (ret)
DRM_ERROR("MOCS failed to program: expect performance issues.\n");
return i915_gem_render_state_emit(rq);
}
/**
* intel_logical_ring_cleanup() - deallocate the Engine Command Streamer
* @engine: Engine Command Streamer.
*/
void intel_logical_ring_cleanup(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv;
/*
* Tasklet cannot be active at this point due intel_mark_active/idle
* so this is just for documentation.
*/
if (WARN_ON(test_bit(TASKLET_STATE_SCHED,
&engine->execlists.tasklet.state)))
tasklet_kill(&engine->execlists.tasklet);
dev_priv = engine->i915;
if (engine->buffer) {
WARN_ON((I915_READ_MODE(engine) & MODE_IDLE) == 0);
}
if (engine->cleanup)
engine->cleanup(engine);
intel_engine_cleanup_common(engine);
lrc_destroy_wa_ctx(engine);
engine->i915 = NULL;
dev_priv->engine[engine->id] = NULL;
kfree(engine);
}
static void execlists_set_default_submission(struct intel_engine_cs *engine)
{
engine->submit_request = execlists_submit_request;
engine->cancel_requests = execlists_cancel_requests;
engine->schedule = execlists_schedule;
engine->execlists.tasklet.func = execlists_submission_tasklet;
engine->reset.prepare = execlists_reset_prepare;
engine->park = NULL;
engine->unpark = NULL;
engine->flags |= I915_ENGINE_SUPPORTS_STATS;
if (engine->i915->preempt_context)
engine->flags |= I915_ENGINE_HAS_PREEMPTION;
engine->i915->caps.scheduler =
I915_SCHEDULER_CAP_ENABLED |
I915_SCHEDULER_CAP_PRIORITY;
if (intel_engine_has_preemption(engine))
engine->i915->caps.scheduler |= I915_SCHEDULER_CAP_PREEMPTION;
}
static void
logical_ring_default_vfuncs(struct intel_engine_cs *engine)
{
/* Default vfuncs which can be overriden by each engine. */
engine->init_hw = gen8_init_common_ring;
engine->reset.prepare = execlists_reset_prepare;
engine->reset.reset = execlists_reset;
engine->reset.finish = execlists_reset_finish;
engine->context_pin = execlists_context_pin;
engine->request_alloc = execlists_request_alloc;
engine->emit_flush = gen8_emit_flush;
engine->emit_breadcrumb = gen8_emit_breadcrumb;
engine->emit_breadcrumb_sz = gen8_emit_breadcrumb_sz;
engine->set_default_submission = execlists_set_default_submission;
if (INTEL_GEN(engine->i915) < 11) {
engine->irq_enable = gen8_logical_ring_enable_irq;
engine->irq_disable = gen8_logical_ring_disable_irq;
} else {
/*
* TODO: On Gen11 interrupt masks need to be clear
* to allow C6 entry. Keep interrupts enabled at
* and take the hit of generating extra interrupts
* until a more refined solution exists.
*/
}
engine->emit_bb_start = gen8_emit_bb_start;
}
static inline void
logical_ring_default_irqs(struct intel_engine_cs *engine)
{
unsigned int shift = 0;
if (INTEL_GEN(engine->i915) < 11) {
const u8 irq_shifts[] = {
[RCS] = GEN8_RCS_IRQ_SHIFT,
[BCS] = GEN8_BCS_IRQ_SHIFT,
[VCS] = GEN8_VCS1_IRQ_SHIFT,
[VCS2] = GEN8_VCS2_IRQ_SHIFT,
[VECS] = GEN8_VECS_IRQ_SHIFT,
};
shift = irq_shifts[engine->id];
}
engine->irq_enable_mask = GT_RENDER_USER_INTERRUPT << shift;
engine->irq_keep_mask = GT_CONTEXT_SWITCH_INTERRUPT << shift;
}
static void
logical_ring_setup(struct intel_engine_cs *engine)
{
intel_engine_setup_common(engine);
/* Intentionally left blank. */
engine->buffer = NULL;
tasklet_init(&engine->execlists.tasklet,
execlists_submission_tasklet, (unsigned long)engine);
logical_ring_default_vfuncs(engine);
logical_ring_default_irqs(engine);
}
static bool csb_force_mmio(struct drm_i915_private *i915)
{
/* Older GVT emulation depends upon intercepting CSB mmio */
return intel_vgpu_active(i915) && !intel_vgpu_has_hwsp_emulation(i915);
}
static int logical_ring_init(struct intel_engine_cs *engine)
{
struct drm_i915_private *i915 = engine->i915;
struct intel_engine_execlists * const execlists = &engine->execlists;
int ret;
ret = intel_engine_init_common(engine);
if (ret)
goto error;
if (HAS_LOGICAL_RING_ELSQ(i915)) {
execlists->submit_reg = i915->regs +
i915_mmio_reg_offset(RING_EXECLIST_SQ_CONTENTS(engine));
execlists->ctrl_reg = i915->regs +
i915_mmio_reg_offset(RING_EXECLIST_CONTROL(engine));
} else {
execlists->submit_reg = i915->regs +
i915_mmio_reg_offset(RING_ELSP(engine));
}
execlists->preempt_complete_status = ~0u;
if (i915->preempt_context) {
struct intel_context *ce =
to_intel_context(i915->preempt_context, engine);
execlists->preempt_complete_status =
upper_32_bits(ce->lrc_desc);
}
execlists->csb_read =
i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_PTR(engine));
if (csb_force_mmio(i915)) {
execlists->csb_status = (u32 __force *)
(i915->regs + i915_mmio_reg_offset(RING_CONTEXT_STATUS_BUF_LO(engine, 0)));
execlists->csb_write = (u32 __force *)execlists->csb_read;
execlists->csb_write_reset =
_MASKED_FIELD(GEN8_CSB_WRITE_PTR_MASK,
GEN8_CSB_ENTRIES - 1);
} else {
execlists->csb_status =
&engine->status_page.page_addr[I915_HWS_CSB_BUF0_INDEX];
execlists->csb_write =
&engine->status_page.page_addr[intel_hws_csb_write_index(i915)];
execlists->csb_write_reset = GEN8_CSB_ENTRIES - 1;
}
reset_csb_pointers(execlists);
return 0;
error:
intel_logical_ring_cleanup(engine);
return ret;
}
int logical_render_ring_init(struct intel_engine_cs *engine)
{
struct drm_i915_private *dev_priv = engine->i915;
int ret;
logical_ring_setup(engine);
if (HAS_L3_DPF(dev_priv))
engine->irq_keep_mask |= GT_RENDER_L3_PARITY_ERROR_INTERRUPT;
/* Override some for render ring. */
if (INTEL_GEN(dev_priv) >= 9)
engine->init_hw = gen9_init_render_ring;
else
engine->init_hw = gen8_init_render_ring;
engine->init_context = gen8_init_rcs_context;
engine->emit_flush = gen8_emit_flush_render;
engine->emit_breadcrumb = gen8_emit_breadcrumb_rcs;
engine->emit_breadcrumb_sz = gen8_emit_breadcrumb_rcs_sz;
ret = intel_engine_create_scratch(engine, PAGE_SIZE);
if (ret)
return ret;
ret = intel_init_workaround_bb(engine);
if (ret) {
/*
* We continue even if we fail to initialize WA batch
* because we only expect rare glitches but nothing
* critical to prevent us from using GPU
*/
DRM_ERROR("WA batch buffer initialization failed: %d\n",
ret);
}
return logical_ring_init(engine);
}
int logical_xcs_ring_init(struct intel_engine_cs *engine)
{
logical_ring_setup(engine);
return logical_ring_init(engine);
}
static u32
make_rpcs(struct drm_i915_private *dev_priv)
{
u32 rpcs = 0;
/*
* No explicit RPCS request is needed to ensure full
* slice/subslice/EU enablement prior to Gen9.
*/
if (INTEL_GEN(dev_priv) < 9)
return 0;
/*
* Starting in Gen9, render power gating can leave
* slice/subslice/EU in a partially enabled state. We
* must make an explicit request through RPCS for full
* enablement.
*/
if (INTEL_INFO(dev_priv)->sseu.has_slice_pg) {
rpcs |= GEN8_RPCS_S_CNT_ENABLE;
rpcs |= hweight8(INTEL_INFO(dev_priv)->sseu.slice_mask) <<
GEN8_RPCS_S_CNT_SHIFT;
rpcs |= GEN8_RPCS_ENABLE;
}
if (INTEL_INFO(dev_priv)->sseu.has_subslice_pg) {
rpcs |= GEN8_RPCS_SS_CNT_ENABLE;
rpcs |= hweight8(INTEL_INFO(dev_priv)->sseu.subslice_mask[0]) <<
GEN8_RPCS_SS_CNT_SHIFT;
rpcs |= GEN8_RPCS_ENABLE;
}
if (INTEL_INFO(dev_priv)->sseu.has_eu_pg) {
rpcs |= INTEL_INFO(dev_priv)->sseu.eu_per_subslice <<
GEN8_RPCS_EU_MIN_SHIFT;
rpcs |= INTEL_INFO(dev_priv)->sseu.eu_per_subslice <<
GEN8_RPCS_EU_MAX_SHIFT;
rpcs |= GEN8_RPCS_ENABLE;
}
return rpcs;
}
static u32 intel_lr_indirect_ctx_offset(struct intel_engine_cs *engine)
{
u32 indirect_ctx_offset;
switch (INTEL_GEN(engine->i915)) {
default:
MISSING_CASE(INTEL_GEN(engine->i915));
/* fall through */
case 11:
indirect_ctx_offset =
GEN11_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
break;
case 10:
indirect_ctx_offset =
GEN10_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
break;
case 9:
indirect_ctx_offset =
GEN9_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
break;
case 8:
indirect_ctx_offset =
GEN8_CTX_RCS_INDIRECT_CTX_OFFSET_DEFAULT;
break;
}
return indirect_ctx_offset;
}
static void execlists_init_reg_state(u32 *regs,
struct i915_gem_context *ctx,
struct intel_engine_cs *engine,
struct intel_ring *ring)
{
struct drm_i915_private *dev_priv = engine->i915;
struct i915_hw_ppgtt *ppgtt = ctx->ppgtt ?: dev_priv->mm.aliasing_ppgtt;
u32 base = engine->mmio_base;
bool rcs = engine->class == RENDER_CLASS;
/* A context is actually a big batch buffer with several
* MI_LOAD_REGISTER_IMM commands followed by (reg, value) pairs. The
* values we are setting here are only for the first context restore:
* on a subsequent save, the GPU will recreate this batchbuffer with new
* values (including all the missing MI_LOAD_REGISTER_IMM commands that
* we are not initializing here).
*/
regs[CTX_LRI_HEADER_0] = MI_LOAD_REGISTER_IMM(rcs ? 14 : 11) |
MI_LRI_FORCE_POSTED;
CTX_REG(regs, CTX_CONTEXT_CONTROL, RING_CONTEXT_CONTROL(engine),
_MASKED_BIT_DISABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT) |
_MASKED_BIT_ENABLE(CTX_CTRL_INHIBIT_SYN_CTX_SWITCH |
(HAS_RESOURCE_STREAMER(dev_priv) ?
CTX_CTRL_RS_CTX_ENABLE : 0)));
CTX_REG(regs, CTX_RING_HEAD, RING_HEAD(base), 0);
CTX_REG(regs, CTX_RING_TAIL, RING_TAIL(base), 0);
CTX_REG(regs, CTX_RING_BUFFER_START, RING_START(base), 0);
CTX_REG(regs, CTX_RING_BUFFER_CONTROL, RING_CTL(base),
RING_CTL_SIZE(ring->size) | RING_VALID);
CTX_REG(regs, CTX_BB_HEAD_U, RING_BBADDR_UDW(base), 0);
CTX_REG(regs, CTX_BB_HEAD_L, RING_BBADDR(base), 0);
CTX_REG(regs, CTX_BB_STATE, RING_BBSTATE(base), RING_BB_PPGTT);
CTX_REG(regs, CTX_SECOND_BB_HEAD_U, RING_SBBADDR_UDW(base), 0);
CTX_REG(regs, CTX_SECOND_BB_HEAD_L, RING_SBBADDR(base), 0);
CTX_REG(regs, CTX_SECOND_BB_STATE, RING_SBBSTATE(base), 0);
if (rcs) {
struct i915_ctx_workarounds *wa_ctx = &engine->wa_ctx;
CTX_REG(regs, CTX_RCS_INDIRECT_CTX, RING_INDIRECT_CTX(base), 0);
CTX_REG(regs, CTX_RCS_INDIRECT_CTX_OFFSET,
RING_INDIRECT_CTX_OFFSET(base), 0);
if (wa_ctx->indirect_ctx.size) {
u32 ggtt_offset = i915_ggtt_offset(wa_ctx->vma);
regs[CTX_RCS_INDIRECT_CTX + 1] =
(ggtt_offset + wa_ctx->indirect_ctx.offset) |
(wa_ctx->indirect_ctx.size / CACHELINE_BYTES);
regs[CTX_RCS_INDIRECT_CTX_OFFSET + 1] =
intel_lr_indirect_ctx_offset(engine) << 6;
}
CTX_REG(regs, CTX_BB_PER_CTX_PTR, RING_BB_PER_CTX_PTR(base), 0);
if (wa_ctx->per_ctx.size) {
u32 ggtt_offset = i915_ggtt_offset(wa_ctx->vma);
regs[CTX_BB_PER_CTX_PTR + 1] =
(ggtt_offset + wa_ctx->per_ctx.offset) | 0x01;
}
}
regs[CTX_LRI_HEADER_1] = MI_LOAD_REGISTER_IMM(9) | MI_LRI_FORCE_POSTED;
CTX_REG(regs, CTX_CTX_TIMESTAMP, RING_CTX_TIMESTAMP(base), 0);
/* PDP values well be assigned later if needed */
CTX_REG(regs, CTX_PDP3_UDW, GEN8_RING_PDP_UDW(engine, 3), 0);
CTX_REG(regs, CTX_PDP3_LDW, GEN8_RING_PDP_LDW(engine, 3), 0);
CTX_REG(regs, CTX_PDP2_UDW, GEN8_RING_PDP_UDW(engine, 2), 0);
CTX_REG(regs, CTX_PDP2_LDW, GEN8_RING_PDP_LDW(engine, 2), 0);
CTX_REG(regs, CTX_PDP1_UDW, GEN8_RING_PDP_UDW(engine, 1), 0);
CTX_REG(regs, CTX_PDP1_LDW, GEN8_RING_PDP_LDW(engine, 1), 0);
CTX_REG(regs, CTX_PDP0_UDW, GEN8_RING_PDP_UDW(engine, 0), 0);
CTX_REG(regs, CTX_PDP0_LDW, GEN8_RING_PDP_LDW(engine, 0), 0);
if (ppgtt && i915_vm_is_48bit(&ppgtt->vm)) {
/* 64b PPGTT (48bit canonical)
* PDP0_DESCRIPTOR contains the base address to PML4 and
* other PDP Descriptors are ignored.
*/
ASSIGN_CTX_PML4(ppgtt, regs);
}
if (rcs) {
regs[CTX_LRI_HEADER_2] = MI_LOAD_REGISTER_IMM(1);
CTX_REG(regs, CTX_R_PWR_CLK_STATE, GEN8_R_PWR_CLK_STATE,
make_rpcs(dev_priv));
i915_oa_init_reg_state(engine, ctx, regs);
}
}
static int
populate_lr_context(struct i915_gem_context *ctx,
struct drm_i915_gem_object *ctx_obj,
struct intel_engine_cs *engine,
struct intel_ring *ring)
{
void *vaddr;
u32 *regs;
int ret;
ret = i915_gem_object_set_to_cpu_domain(ctx_obj, true);
if (ret) {
DRM_DEBUG_DRIVER("Could not set to CPU domain\n");
return ret;
}
vaddr = i915_gem_object_pin_map(ctx_obj, I915_MAP_WB);
if (IS_ERR(vaddr)) {
ret = PTR_ERR(vaddr);
DRM_DEBUG_DRIVER("Could not map object pages! (%d)\n", ret);
return ret;
}
ctx_obj->mm.dirty = true;
if (engine->default_state) {
/*
* We only want to copy over the template context state;
* skipping over the headers reserved for GuC communication,
* leaving those as zero.
*/
const unsigned long start = LRC_HEADER_PAGES * PAGE_SIZE;
void *defaults;
defaults = i915_gem_object_pin_map(engine->default_state,
I915_MAP_WB);
if (IS_ERR(defaults)) {
ret = PTR_ERR(defaults);
goto err_unpin_ctx;
}
memcpy(vaddr + start, defaults + start, engine->context_size);
i915_gem_object_unpin_map(engine->default_state);
}
/* The second page of the context object contains some fields which must
* be set up prior to the first execution. */
regs = vaddr + LRC_STATE_PN * PAGE_SIZE;
execlists_init_reg_state(regs, ctx, engine, ring);
if (!engine->default_state)
regs[CTX_CONTEXT_CONTROL + 1] |=
_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT);
if (ctx == ctx->i915->preempt_context && INTEL_GEN(engine->i915) < 11)
regs[CTX_CONTEXT_CONTROL + 1] |=
_MASKED_BIT_ENABLE(CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT |
CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT);
err_unpin_ctx:
i915_gem_object_unpin_map(ctx_obj);
return ret;
}
static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
struct intel_engine_cs *engine,
struct intel_context *ce)
{
struct drm_i915_gem_object *ctx_obj;
struct i915_vma *vma;
uint32_t context_size;
struct intel_ring *ring;
struct i915_timeline *timeline;
int ret;
if (ce->state)
return 0;
context_size = round_up(engine->context_size, I915_GTT_PAGE_SIZE);
/*
* Before the actual start of the context image, we insert a few pages
* for our own use and for sharing with the GuC.
*/
context_size += LRC_HEADER_PAGES * PAGE_SIZE;
ctx_obj = i915_gem_object_create(ctx->i915, context_size);
if (IS_ERR(ctx_obj))
return PTR_ERR(ctx_obj);
vma = i915_vma_instance(ctx_obj, &ctx->i915->ggtt.vm, NULL);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto error_deref_obj;
}
timeline = i915_timeline_create(ctx->i915, ctx->name);
if (IS_ERR(timeline)) {
ret = PTR_ERR(timeline);
goto error_deref_obj;
}
ring = intel_engine_create_ring(engine, timeline, ctx->ring_size);
i915_timeline_put(timeline);
if (IS_ERR(ring)) {
ret = PTR_ERR(ring);
goto error_deref_obj;
}
ret = populate_lr_context(ctx, ctx_obj, engine, ring);
if (ret) {
DRM_DEBUG_DRIVER("Failed to populate LRC: %d\n", ret);
goto error_ring_free;
}
ce->ring = ring;
ce->state = vma;
return 0;
error_ring_free:
intel_ring_free(ring);
error_deref_obj:
i915_gem_object_put(ctx_obj);
return ret;
}
void intel_lr_context_resume(struct drm_i915_private *dev_priv)
{
struct intel_engine_cs *engine;
struct i915_gem_context *ctx;
enum intel_engine_id id;
/* Because we emit WA_TAIL_DWORDS there may be a disparity
* between our bookkeeping in ce->ring->head and ce->ring->tail and
* that stored in context. As we only write new commands from
* ce->ring->tail onwards, everything before that is junk. If the GPU
* starts reading from its RING_HEAD from the context, it may try to
* execute that junk and die.
*
* So to avoid that we reset the context images upon resume. For
* simplicity, we just zero everything out.
*/
list_for_each_entry(ctx, &dev_priv->contexts.list, link) {
for_each_engine(engine, dev_priv, id) {
struct intel_context *ce =
to_intel_context(ctx, engine);
u32 *reg;
if (!ce->state)
continue;
reg = i915_gem_object_pin_map(ce->state->obj,
I915_MAP_WB);
if (WARN_ON(IS_ERR(reg)))
continue;
reg += LRC_STATE_PN * PAGE_SIZE / sizeof(*reg);
reg[CTX_RING_HEAD+1] = 0;
reg[CTX_RING_TAIL+1] = 0;
ce->state->obj->mm.dirty = true;
i915_gem_object_unpin_map(ce->state->obj);
intel_ring_reset(ce->ring, 0);
}
}
}
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
#include "selftests/intel_lrc.c"
#endif
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