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+/*
+ * Copyright © 2015-2016 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:
+ * Robert Bragg <robert@sixbynine.org>
+ */
+
+
+/**
+ * DOC: i915 Perf Overview
+ *
+ * Gen graphics supports a large number of performance counters that can help
+ * driver and application developers understand and optimize their use of the
+ * GPU.
+ *
+ * This i915 perf interface enables userspace to configure and open a file
+ * descriptor representing a stream of GPU metrics which can then be read() as
+ * a stream of sample records.
+ *
+ * The interface is particularly suited to exposing buffered metrics that are
+ * captured by DMA from the GPU, unsynchronized with and unrelated to the CPU.
+ *
+ * Streams representing a single context are accessible to applications with a
+ * corresponding drm file descriptor, such that OpenGL can use the interface
+ * without special privileges. Access to system-wide metrics requires root
+ * privileges by default, unless changed via the dev.i915.perf_event_paranoid
+ * sysctl option.
+ *
+ */
+
+/**
+ * DOC: i915 Perf History and Comparison with Core Perf
+ *
+ * The interface was initially inspired by the core Perf infrastructure but
+ * some notable differences are:
+ *
+ * i915 perf file descriptors represent a "stream" instead of an "event"; where
+ * a perf event primarily corresponds to a single 64bit value, while a stream
+ * might sample sets of tightly-coupled counters, depending on the
+ * configuration. For example the Gen OA unit isn't designed to support
+ * orthogonal configurations of individual counters; it's configured for a set
+ * of related counters. Samples for an i915 perf stream capturing OA metrics
+ * will include a set of counter values packed in a compact HW specific format.
+ * The OA unit supports a number of different packing formats which can be
+ * selected by the user opening the stream. Perf has support for grouping
+ * events, but each event in the group is configured, validated and
+ * authenticated individually with separate system calls.
+ *
+ * i915 perf stream configurations are provided as an array of u64 (key,value)
+ * pairs, instead of a fixed struct with multiple miscellaneous config members,
+ * interleaved with event-type specific members.
+ *
+ * i915 perf doesn't support exposing metrics via an mmap'd circular buffer.
+ * The supported metrics are being written to memory by the GPU unsynchronized
+ * with the CPU, using HW specific packing formats for counter sets. Sometimes
+ * the constraints on HW configuration require reports to be filtered before it
+ * would be acceptable to expose them to unprivileged applications - to hide
+ * the metrics of other processes/contexts. For these use cases a read() based
+ * interface is a good fit, and provides an opportunity to filter data as it
+ * gets copied from the GPU mapped buffers to userspace buffers.
+ *
+ *
+ * Issues hit with first prototype based on Core Perf
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The first prototype of this driver was based on the core perf
+ * infrastructure, and while we did make that mostly work, with some changes to
+ * perf, we found we were breaking or working around too many assumptions baked
+ * into perf's currently cpu centric design.
+ *
+ * In the end we didn't see a clear benefit to making perf's implementation and
+ * interface more complex by changing design assumptions while we knew we still
+ * wouldn't be able to use any existing perf based userspace tools.
+ *
+ * Also considering the Gen specific nature of the Observability hardware and
+ * how userspace will sometimes need to combine i915 perf OA metrics with
+ * side-band OA data captured via MI_REPORT_PERF_COUNT commands; we're
+ * expecting the interface to be used by a platform specific userspace such as
+ * OpenGL or tools. This is to say; we aren't inherently missing out on having
+ * a standard vendor/architecture agnostic interface by not using perf.
+ *
+ *
+ * For posterity, in case we might re-visit trying to adapt core perf to be
+ * better suited to exposing i915 metrics these were the main pain points we
+ * hit:
+ *
+ * - The perf based OA PMU driver broke some significant design assumptions:
+ *
+ * Existing perf pmus are used for profiling work on a cpu and we were
+ * introducing the idea of _IS_DEVICE pmus with different security
+ * implications, the need to fake cpu-related data (such as user/kernel
+ * registers) to fit with perf's current design, and adding _DEVICE records
+ * as a way to forward device-specific status records.
+ *
+ * The OA unit writes reports of counters into a circular buffer, without
+ * involvement from the CPU, making our PMU driver the first of a kind.
+ *
+ * Given the way we were periodically forward data from the GPU-mapped, OA
+ * buffer to perf's buffer, those bursts of sample writes looked to perf like
+ * we were sampling too fast and so we had to subvert its throttling checks.
+ *
+ * Perf supports groups of counters and allows those to be read via
+ * transactions internally but transactions currently seem designed to be
+ * explicitly initiated from the cpu (say in response to a userspace read())
+ * and while we could pull a report out of the OA buffer we can't
+ * trigger a report from the cpu on demand.
+ *
+ * Related to being report based; the OA counters are configured in HW as a
+ * set while perf generally expects counter configurations to be orthogonal.
+ * Although counters can be associated with a group leader as they are
+ * opened, there's no clear precedent for being able to provide group-wide
+ * configuration attributes (for example we want to let userspace choose the
+ * OA unit report format used to capture all counters in a set, or specify a
+ * GPU context to filter metrics on). We avoided using perf's grouping
+ * feature and forwarded OA reports to userspace via perf's 'raw' sample
+ * field. This suited our userspace well considering how coupled the counters
+ * are when dealing with normalizing. It would be inconvenient to split
+ * counters up into separate events, only to require userspace to recombine
+ * them. For Mesa it's also convenient to be forwarded raw, periodic reports
+ * for combining with the side-band raw reports it captures using
+ * MI_REPORT_PERF_COUNT commands.
+ *
+ * - As a side note on perf's grouping feature; there was also some concern
+ * that using PERF_FORMAT_GROUP as a way to pack together counter values
+ * would quite drastically inflate our sample sizes, which would likely
+ * lower the effective sampling resolutions we could use when the available
+ * memory bandwidth is limited.
+ *
+ * With the OA unit's report formats, counters are packed together as 32
+ * or 40bit values, with the largest report size being 256 bytes.
+ *
+ * PERF_FORMAT_GROUP values are 64bit, but there doesn't appear to be a
+ * documented ordering to the values, implying PERF_FORMAT_ID must also be
+ * used to add a 64bit ID before each value; giving 16 bytes per counter.
+ *
+ * Related to counter orthogonality; we can't time share the OA unit, while
+ * event scheduling is a central design idea within perf for allowing
+ * userspace to open + enable more events than can be configured in HW at any
+ * one time. The OA unit is not designed to allow re-configuration while in
+ * use. We can't reconfigure the OA unit without losing internal OA unit
+ * state which we can't access explicitly to save and restore. Reconfiguring
+ * the OA unit is also relatively slow, involving ~100 register writes. From
+ * userspace Mesa also depends on a stable OA configuration when emitting
+ * MI_REPORT_PERF_COUNT commands and importantly the OA unit can't be
+ * disabled while there are outstanding MI_RPC commands lest we hang the
+ * command streamer.
+ *
+ * The contents of sample records aren't extensible by device drivers (i.e.
+ * the sample_type bits). As an example; Sourab Gupta had been looking to
+ * attach GPU timestamps to our OA samples. We were shoehorning OA reports
+ * into sample records by using the 'raw' field, but it's tricky to pack more
+ * than one thing into this field because events/core.c currently only lets a
+ * pmu give a single raw data pointer plus len which will be copied into the
+ * ring buffer. To include more than the OA report we'd have to copy the
+ * report into an intermediate larger buffer. I'd been considering allowing a
+ * vector of data+len values to be specified for copying the raw data, but
+ * it felt like a kludge to being using the raw field for this purpose.
+ *
+ * - It felt like our perf based PMU was making some technical compromises
+ * just for the sake of using perf:
+ *
+ * perf_event_open() requires events to either relate to a pid or a specific
+ * cpu core, while our device pmu related to neither. Events opened with a
+ * pid will be automatically enabled/disabled according to the scheduling of
+ * that process - so not appropriate for us. When an event is related to a
+ * cpu id, perf ensures pmu methods will be invoked via an inter process
+ * interrupt on that core. To avoid invasive changes our userspace opened OA
+ * perf events for a specific cpu. This was workable but it meant the
+ * majority of the OA driver ran in atomic context, including all OA report
+ * forwarding, which wasn't really necessary in our case and seems to make
+ * our locking requirements somewhat complex as we handled the interaction
+ * with the rest of the i915 driver.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/sizes.h>
+
+#include "i915_drv.h"
+#include "i915_oa_hsw.h"
+
+/* HW requires this to be a power of two, between 128k and 16M, though driver
+ * is currently generally designed assuming the largest 16M size is used such
+ * that the overflow cases are unlikely in normal operation.
+ */
+#define OA_BUFFER_SIZE SZ_16M
+
+#define OA_TAKEN(tail, head) ((tail - head) & (OA_BUFFER_SIZE - 1))
+
+/* There's a HW race condition between OA unit tail pointer register updates and
+ * writes to memory whereby the tail pointer can sometimes get ahead of what's
+ * been written out to the OA buffer so far.
+ *
+ * Although this can be observed explicitly by checking for a zeroed report-id
+ * field in tail reports, it seems preferable to account for this earlier e.g.
+ * as part of the _oa_buffer_is_empty checks to minimize -EAGAIN polling cycles
+ * in this situation.
+ *
+ * To give time for the most recent reports to land before they may be copied to
+ * userspace, the driver operates as if the tail pointer effectively lags behind
+ * the HW tail pointer by 'tail_margin' bytes. The margin in bytes is calculated
+ * based on this constant in nanoseconds, the current OA sampling exponent
+ * and current report size.
+ *
+ * There is also a fallback check while reading to simply skip over reports with
+ * a zeroed report-id.
+ */
+#define OA_TAIL_MARGIN_NSEC 100000ULL
+
+/* frequency for checking whether the OA unit has written new reports to the
+ * circular OA buffer...
+ */
+#define POLL_FREQUENCY 200
+#define POLL_PERIOD (NSEC_PER_SEC / POLL_FREQUENCY)
+
+/* for sysctl proc_dointvec_minmax of dev.i915.perf_stream_paranoid */
+static int zero;
+static int one = 1;
+static u32 i915_perf_stream_paranoid = true;
+
+/* The maximum exponent the hardware accepts is 63 (essentially it selects one
+ * of the 64bit timestamp bits to trigger reports from) but there's currently
+ * no known use case for sampling as infrequently as once per 47 thousand years.
+ *
+ * Since the timestamps included in OA reports are only 32bits it seems
+ * reasonable to limit the OA exponent where it's still possible to account for
+ * overflow in OA report timestamps.
+ */
+#define OA_EXPONENT_MAX 31
+
+#define INVALID_CTX_ID 0xffffffff
+
+
+/* For sysctl proc_dointvec_minmax of i915_oa_max_sample_rate
+ *
+ * 160ns is the smallest sampling period we can theoretically program the OA
+ * unit with on Haswell, corresponding to 6.25MHz.
+ */
+static int oa_sample_rate_hard_limit = 6250000;
+
+/* Theoretically we can program the OA unit to sample every 160ns but don't
+ * allow that by default unless root...
+ *
+ * The default threshold of 100000Hz is based on perf's similar
+ * kernel.perf_event_max_sample_rate sysctl parameter.
+ */
+static u32 i915_oa_max_sample_rate = 100000;
+
+/* XXX: beware if future OA HW adds new report formats that the current
+ * code assumes all reports have a power-of-two size and ~(size - 1) can
+ * be used as a mask to align the OA tail pointer.
+ */
+static struct i915_oa_format hsw_oa_formats[I915_OA_FORMAT_MAX] = {
+ [I915_OA_FORMAT_A13] = { 0, 64 },
+ [I915_OA_FORMAT_A29] = { 1, 128 },
+ [I915_OA_FORMAT_A13_B8_C8] = { 2, 128 },
+ /* A29_B8_C8 Disallowed as 192 bytes doesn't factor into buffer size */
+ [I915_OA_FORMAT_B4_C8] = { 4, 64 },
+ [I915_OA_FORMAT_A45_B8_C8] = { 5, 256 },
+ [I915_OA_FORMAT_B4_C8_A16] = { 6, 128 },
+ [I915_OA_FORMAT_C4_B8] = { 7, 64 },
+};
+
+#define SAMPLE_OA_REPORT (1<<0)
+
+/**
+ * struct perf_open_properties - for validated properties given to open a stream
+ * @sample_flags: `DRM_I915_PERF_PROP_SAMPLE_*` properties are tracked as flags
+ * @single_context: Whether a single or all gpu contexts should be monitored
+ * @ctx_handle: A gem ctx handle for use with @single_context
+ * @metrics_set: An ID for an OA unit metric set advertised via sysfs
+ * @oa_format: An OA unit HW report format
+ * @oa_periodic: Whether to enable periodic OA unit sampling
+ * @oa_period_exponent: The OA unit sampling period is derived from this
+ *
+ * As read_properties_unlocked() enumerates and validates the properties given
+ * to open a stream of metrics the configuration is built up in the structure
+ * which starts out zero initialized.
+ */
+struct perf_open_properties {
+ u32 sample_flags;
+
+ u64 single_context:1;
+ u64 ctx_handle;
+
+ /* OA sampling state */
+ int metrics_set;
+ int oa_format;
+ bool oa_periodic;
+ int oa_period_exponent;
+};
+
+/* NB: This is either called via fops or the poll check hrtimer (atomic ctx)
+ *
+ * It's safe to read OA config state here unlocked, assuming that this is only
+ * called while the stream is enabled, while the global OA configuration can't
+ * be modified.
+ *
+ * Note: we don't lock around the head/tail reads even though there's the slim
+ * possibility of read() fop errors forcing a re-init of the OA buffer
+ * pointers. A race here could result in a false positive !empty status which
+ * is acceptable.
+ */
+static bool gen7_oa_buffer_is_empty_fop_unlocked(struct drm_i915_private *dev_priv)
+{
+ int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+ u32 oastatus2 = I915_READ(GEN7_OASTATUS2);
+ u32 oastatus1 = I915_READ(GEN7_OASTATUS1);
+ u32 head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
+ u32 tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
+
+ return OA_TAKEN(tail, head) <
+ dev_priv->perf.oa.tail_margin + report_size;
+}
+
+/**
+ * append_oa_status - Appends a status record to a userspace read() buffer.
+ * @stream: An i915-perf stream opened for OA metrics
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @offset: (inout): the current position for writing into @buf
+ * @type: The kind of status to report to userspace
+ *
+ * Writes a status record (such as `DRM_I915_PERF_RECORD_OA_REPORT_LOST`)
+ * into the userspace read() buffer.
+ *
+ * The @buf @offset will only be updated on success.
+ *
+ * Returns: 0 on success, negative error code on failure.
+ */
+static int append_oa_status(struct i915_perf_stream *stream,
+ char __user *buf,
+ size_t count,
+ size_t *offset,
+ enum drm_i915_perf_record_type type)
+{
+ struct drm_i915_perf_record_header header = { type, 0, sizeof(header) };
+
+ if ((count - *offset) < header.size)
+ return -ENOSPC;
+
+ if (copy_to_user(buf + *offset, &header, sizeof(header)))
+ return -EFAULT;
+
+ (*offset) += header.size;
+
+ return 0;
+}
+
+/**
+ * append_oa_sample - Copies single OA report into userspace read() buffer.
+ * @stream: An i915-perf stream opened for OA metrics
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @offset: (inout): the current position for writing into @buf
+ * @report: A single OA report to (optionally) include as part of the sample
+ *
+ * The contents of a sample are configured through `DRM_I915_PERF_PROP_SAMPLE_*`
+ * properties when opening a stream, tracked as `stream->sample_flags`. This
+ * function copies the requested components of a single sample to the given
+ * read() @buf.
+ *
+ * The @buf @offset will only be updated on success.
+ *
+ * Returns: 0 on success, negative error code on failure.
+ */
+static int append_oa_sample(struct i915_perf_stream *stream,
+ char __user *buf,
+ size_t count,
+ size_t *offset,
+ const u8 *report)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+ struct drm_i915_perf_record_header header;
+ u32 sample_flags = stream->sample_flags;
+
+ header.type = DRM_I915_PERF_RECORD_SAMPLE;
+ header.pad = 0;
+ header.size = stream->sample_size;
+
+ if ((count - *offset) < header.size)
+ return -ENOSPC;
+
+ buf += *offset;
+ if (copy_to_user(buf, &header, sizeof(header)))
+ return -EFAULT;
+ buf += sizeof(header);
+
+ if (sample_flags & SAMPLE_OA_REPORT) {
+ if (copy_to_user(buf, report, report_size))
+ return -EFAULT;
+ }
+
+ (*offset) += header.size;
+
+ return 0;
+}
+
+/**
+ * Copies all buffered OA reports into userspace read() buffer.
+ * @stream: An i915-perf stream opened for OA metrics
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @offset: (inout): the current position for writing into @buf
+ * @head_ptr: (inout): the current oa buffer cpu read position
+ * @tail: the current oa buffer gpu write position
+ *
+ * Notably any error condition resulting in a short read (-%ENOSPC or
+ * -%EFAULT) will be returned even though one or more records may
+ * have been successfully copied. In this case it's up to the caller
+ * to decide if the error should be squashed before returning to
+ * userspace.
+ *
+ * Note: reports are consumed from the head, and appended to the
+ * tail, so the head chases the tail?... If you think that's mad
+ * and back-to-front you're not alone, but this follows the
+ * Gen PRM naming convention.
+ *
+ * Returns: 0 on success, negative error code on failure.
+ */
+static int gen7_append_oa_reports(struct i915_perf_stream *stream,
+ char __user *buf,
+ size_t count,
+ size_t *offset,
+ u32 *head_ptr,
+ u32 tail)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+ u8 *oa_buf_base = dev_priv->perf.oa.oa_buffer.vaddr;
+ int tail_margin = dev_priv->perf.oa.tail_margin;
+ u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
+ u32 mask = (OA_BUFFER_SIZE - 1);
+ u32 head;
+ u32 taken;
+ int ret = 0;
+
+ if (WARN_ON(!stream->enabled))
+ return -EIO;
+
+ head = *head_ptr - gtt_offset;
+ tail -= gtt_offset;
+
+ /* The OA unit is expected to wrap the tail pointer according to the OA
+ * buffer size and since we should never write a misaligned head
+ * pointer we don't expect to read one back either...
+ */
+ if (tail > OA_BUFFER_SIZE || head > OA_BUFFER_SIZE ||
+ head % report_size) {
+ DRM_ERROR("Inconsistent OA buffer pointer (head = %u, tail = %u): force restart\n",
+ head, tail);
+ dev_priv->perf.oa.ops.oa_disable(dev_priv);
+ dev_priv->perf.oa.ops.oa_enable(dev_priv);
+ *head_ptr = I915_READ(GEN7_OASTATUS2) &
+ GEN7_OASTATUS2_HEAD_MASK;
+ return -EIO;
+ }
+
+
+ /* The tail pointer increases in 64 byte increments, not in report_size
+ * steps...
+ */
+ tail &= ~(report_size - 1);
+
+ /* Move the tail pointer back by the current tail_margin to account for
+ * the possibility that the latest reports may not have really landed
+ * in memory yet...
+ */
+
+ if (OA_TAKEN(tail, head) < report_size + tail_margin)
+ return -EAGAIN;
+
+ tail -= tail_margin;
+ tail &= mask;
+
+ for (/* none */;
+ (taken = OA_TAKEN(tail, head));
+ head = (head + report_size) & mask) {
+ u8 *report = oa_buf_base + head;
+ u32 *report32 = (void *)report;
+
+ /* All the report sizes factor neatly into the buffer
+ * size so we never expect to see a report split
+ * between the beginning and end of the buffer.
+ *
+ * Given the initial alignment check a misalignment
+ * here would imply a driver bug that would result
+ * in an overrun.
+ */
+ if (WARN_ON((OA_BUFFER_SIZE - head) < report_size)) {
+ DRM_ERROR("Spurious OA head ptr: non-integral report offset\n");
+ break;
+ }
+
+ /* The report-ID field for periodic samples includes
+ * some undocumented flags related to what triggered
+ * the report and is never expected to be zero so we
+ * can check that the report isn't invalid before
+ * copying it to userspace...
+ */
+ if (report32[0] == 0) {
+ DRM_NOTE("Skipping spurious, invalid OA report\n");
+ continue;
+ }
+
+ ret = append_oa_sample(stream, buf, count, offset, report);
+ if (ret)
+ break;
+
+ /* The above report-id field sanity check is based on
+ * the assumption that the OA buffer is initially
+ * zeroed and we reset the field after copying so the
+ * check is still meaningful once old reports start
+ * being overwritten.
+ */
+ report32[0] = 0;
+ }
+
+ *head_ptr = gtt_offset + head;
+
+ return ret;
+}
+
+/**
+ * gen7_oa_read - copy status records then buffered OA reports
+ * @stream: An i915-perf stream opened for OA metrics
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @offset: (inout): the current position for writing into @buf
+ *
+ * Checks Gen 7 specific OA unit status registers and if necessary appends
+ * corresponding status records for userspace (such as for a buffer full
+ * condition) and then initiate appending any buffered OA reports.
+ *
+ * Updates @offset according to the number of bytes successfully copied into
+ * the userspace buffer.
+ *
+ * Returns: zero on success or a negative error code
+ */
+static int gen7_oa_read(struct i915_perf_stream *stream,
+ char __user *buf,
+ size_t count,
+ size_t *offset)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ int report_size = dev_priv->perf.oa.oa_buffer.format_size;
+ u32 oastatus2;
+ u32 oastatus1;
+ u32 head;
+ u32 tail;
+ int ret;
+
+ if (WARN_ON(!dev_priv->perf.oa.oa_buffer.vaddr))
+ return -EIO;
+
+ oastatus2 = I915_READ(GEN7_OASTATUS2);
+ oastatus1 = I915_READ(GEN7_OASTATUS1);
+
+ head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
+ tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
+
+ /* XXX: On Haswell we don't have a safe way to clear oastatus1
+ * bits while the OA unit is enabled (while the tail pointer
+ * may be updated asynchronously) so we ignore status bits
+ * that have already been reported to userspace.
+ */
+ oastatus1 &= ~dev_priv->perf.oa.gen7_latched_oastatus1;
+
+ /* We treat OABUFFER_OVERFLOW as a significant error:
+ *
+ * - The status can be interpreted to mean that the buffer is
+ * currently full (with a higher precedence than OA_TAKEN()
+ * which will start to report a near-empty buffer after an
+ * overflow) but it's awkward that we can't clear the status
+ * on Haswell, so without a reset we won't be able to catch
+ * the state again.
+ *
+ * - Since it also implies the HW has started overwriting old
+ * reports it may also affect our sanity checks for invalid
+ * reports when copying to userspace that assume new reports
+ * are being written to cleared memory.
+ *
+ * - In the future we may want to introduce a flight recorder
+ * mode where the driver will automatically maintain a safe
+ * guard band between head/tail, avoiding this overflow
+ * condition, but we avoid the added driver complexity for
+ * now.
+ */
+ if (unlikely(oastatus1 & GEN7_OASTATUS1_OABUFFER_OVERFLOW)) {
+ ret = append_oa_status(stream, buf, count, offset,
+ DRM_I915_PERF_RECORD_OA_BUFFER_LOST);
+ if (ret)
+ return ret;
+
+ DRM_DEBUG("OA buffer overflow: force restart\n");
+
+ dev_priv->perf.oa.ops.oa_disable(dev_priv);
+ dev_priv->perf.oa.ops.oa_enable(dev_priv);
+
+ oastatus2 = I915_READ(GEN7_OASTATUS2);
+ oastatus1 = I915_READ(GEN7_OASTATUS1);
+
+ head = oastatus2 & GEN7_OASTATUS2_HEAD_MASK;
+ tail = oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
+ }
+
+ if (unlikely(oastatus1 & GEN7_OASTATUS1_REPORT_LOST)) {
+ ret = append_oa_status(stream, buf, count, offset,
+ DRM_I915_PERF_RECORD_OA_REPORT_LOST);
+ if (ret)
+ return ret;
+ dev_priv->perf.oa.gen7_latched_oastatus1 |=
+ GEN7_OASTATUS1_REPORT_LOST;
+ }
+
+ ret = gen7_append_oa_reports(stream, buf, count, offset,
+ &head, tail);
+
+ /* All the report sizes are a power of two and the
+ * head should always be incremented by some multiple
+ * of the report size.
+ *
+ * A warning here, but notably if we later read back a
+ * misaligned pointer we will treat that as a bug since
+ * it could lead to a buffer overrun.
+ */
+ WARN_ONCE(head & (report_size - 1),
+ "i915: Writing misaligned OA head pointer");
+
+ /* Note: we update the head pointer here even if an error
+ * was returned since the error may represent a short read
+ * where some some reports were successfully copied.
+ */
+ I915_WRITE(GEN7_OASTATUS2,
+ ((head & GEN7_OASTATUS2_HEAD_MASK) |
+ OA_MEM_SELECT_GGTT));
+
+ return ret;
+}
+
+/**
+ * i915_oa_wait_unlocked - handles blocking IO until OA data available
+ * @stream: An i915-perf stream opened for OA metrics
+ *
+ * Called when userspace tries to read() from a blocking stream FD opened
+ * for OA metrics. It waits until the hrtimer callback finds a non-empty
+ * OA buffer and wakes us.
+ *
+ * Note: it's acceptable to have this return with some false positives
+ * since any subsequent read handling will return -EAGAIN if there isn't
+ * really data ready for userspace yet.
+ *
+ * Returns: zero on success or a negative error code
+ */
+static int i915_oa_wait_unlocked(struct i915_perf_stream *stream)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ /* We would wait indefinitely if periodic sampling is not enabled */
+ if (!dev_priv->perf.oa.periodic)
+ return -EIO;
+
+ /* Note: the oa_buffer_is_empty() condition is ok to run unlocked as it
+ * just performs mmio reads of the OA buffer head + tail pointers and
+ * it's assumed we're handling some operation that implies the stream
+ * can't be destroyed until completion (such as a read()) that ensures
+ * the device + OA buffer can't disappear
+ */
+ return wait_event_interruptible(dev_priv->perf.oa.poll_wq,
+ !dev_priv->perf.oa.ops.oa_buffer_is_empty(dev_priv));
+}
+
+/**
+ * i915_oa_poll_wait - call poll_wait() for an OA stream poll()
+ * @stream: An i915-perf stream opened for OA metrics
+ * @file: An i915 perf stream file
+ * @wait: poll() state table
+ *
+ * For handling userspace polling on an i915 perf stream opened for OA metrics,
+ * this starts a poll_wait with the wait queue that our hrtimer callback wakes
+ * when it sees data ready to read in the circular OA buffer.
+ */
+static void i915_oa_poll_wait(struct i915_perf_stream *stream,
+ struct file *file,
+ poll_table *wait)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ poll_wait(file, &dev_priv->perf.oa.poll_wq, wait);
+}
+
+/**
+ * i915_oa_read - just calls through to &i915_oa_ops->read
+ * @stream: An i915-perf stream opened for OA metrics
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @offset: (inout): the current position for writing into @buf
+ *
+ * Updates @offset according to the number of bytes successfully copied into
+ * the userspace buffer.
+ *
+ * Returns: zero on success or a negative error code
+ */
+static int i915_oa_read(struct i915_perf_stream *stream,
+ char __user *buf,
+ size_t count,
+ size_t *offset)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ return dev_priv->perf.oa.ops.read(stream, buf, count, offset);
+}
+
+/**
+ * oa_get_render_ctx_id - determine and hold ctx hw id
+ * @stream: An i915-perf stream opened for OA metrics
+ *
+ * Determine the render context hw id, and ensure it remains fixed for the
+ * lifetime of the stream. This ensures that we don't have to worry about
+ * updating the context ID in OACONTROL on the fly.
+ *
+ * Returns: zero on success or a negative error code
+ */
+static int oa_get_render_ctx_id(struct i915_perf_stream *stream)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ struct intel_engine_cs *engine = dev_priv->engine[RCS];
+ int ret;
+
+ ret = i915_mutex_lock_interruptible(&dev_priv->drm);
+ if (ret)
+ return ret;
+
+ /* As the ID is the gtt offset of the context's vma we pin
+ * the vma to ensure the ID remains fixed.
+ *
+ * NB: implied RCS engine...
+ */
+ ret = engine->context_pin(engine, stream->ctx);
+ if (ret)
+ goto unlock;
+
+ /* Explicitly track the ID (instead of calling i915_ggtt_offset()
+ * on the fly) considering the difference with gen8+ and
+ * execlists
+ */
+ dev_priv->perf.oa.specific_ctx_id =
+ i915_ggtt_offset(stream->ctx->engine[engine->id].state);
+
+unlock:
+ mutex_unlock(&dev_priv->drm.struct_mutex);
+
+ return ret;
+}
+
+/**
+ * oa_put_render_ctx_id - counterpart to oa_get_render_ctx_id releases hold
+ * @stream: An i915-perf stream opened for OA metrics
+ *
+ * In case anything needed doing to ensure the context HW ID would remain valid
+ * for the lifetime of the stream, then that can be undone here.
+ */
+static void oa_put_render_ctx_id(struct i915_perf_stream *stream)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ struct intel_engine_cs *engine = dev_priv->engine[RCS];
+
+ mutex_lock(&dev_priv->drm.struct_mutex);
+
+ dev_priv->perf.oa.specific_ctx_id = INVALID_CTX_ID;
+ engine->context_unpin(engine, stream->ctx);
+
+ mutex_unlock(&dev_priv->drm.struct_mutex);
+}
+
+static void
+free_oa_buffer(struct drm_i915_private *i915)
+{
+ mutex_lock(&i915->drm.struct_mutex);
+
+ i915_gem_object_unpin_map(i915->perf.oa.oa_buffer.vma->obj);
+ i915_vma_unpin(i915->perf.oa.oa_buffer.vma);
+ i915_gem_object_put(i915->perf.oa.oa_buffer.vma->obj);
+
+ i915->perf.oa.oa_buffer.vma = NULL;
+ i915->perf.oa.oa_buffer.vaddr = NULL;
+
+ mutex_unlock(&i915->drm.struct_mutex);
+}
+
+static void i915_oa_stream_destroy(struct i915_perf_stream *stream)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ BUG_ON(stream != dev_priv->perf.oa.exclusive_stream);
+
+ dev_priv->perf.oa.ops.disable_metric_set(dev_priv);
+
+ free_oa_buffer(dev_priv);
+
+ intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+ intel_runtime_pm_put(dev_priv);
+
+ if (stream->ctx)
+ oa_put_render_ctx_id(stream);
+
+ dev_priv->perf.oa.exclusive_stream = NULL;
+}
+
+static void gen7_init_oa_buffer(struct drm_i915_private *dev_priv)
+{
+ u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
+
+ /* Pre-DevBDW: OABUFFER must be set with counters off,
+ * before OASTATUS1, but after OASTATUS2
+ */
+ I915_WRITE(GEN7_OASTATUS2, gtt_offset | OA_MEM_SELECT_GGTT); /* head */
+ I915_WRITE(GEN7_OABUFFER, gtt_offset);
+ I915_WRITE(GEN7_OASTATUS1, gtt_offset | OABUFFER_SIZE_16M); /* tail */
+
+ /* On Haswell we have to track which OASTATUS1 flags we've
+ * already seen since they can't be cleared while periodic
+ * sampling is enabled.
+ */
+ dev_priv->perf.oa.gen7_latched_oastatus1 = 0;
+
+ /* NB: although the OA buffer will initially be allocated
+ * zeroed via shmfs (and so this memset is redundant when
+ * first allocating), we may re-init the OA buffer, either
+ * when re-enabling a stream or in error/reset paths.
+ *
+ * The reason we clear the buffer for each re-init is for the
+ * sanity check in gen7_append_oa_reports() that looks at the
+ * report-id field to make sure it's non-zero which relies on
+ * the assumption that new reports are being written to zeroed
+ * memory...
+ */
+ memset(dev_priv->perf.oa.oa_buffer.vaddr, 0, OA_BUFFER_SIZE);
+
+ /* Maybe make ->pollin per-stream state if we support multiple
+ * concurrent streams in the future.
+ */
+ dev_priv->perf.oa.pollin = false;
+}
+
+static int alloc_oa_buffer(struct drm_i915_private *dev_priv)
+{
+ struct drm_i915_gem_object *bo;
+ struct i915_vma *vma;
+ int ret;
+
+ if (WARN_ON(dev_priv->perf.oa.oa_buffer.vma))
+ return -ENODEV;
+
+ ret = i915_mutex_lock_interruptible(&dev_priv->drm);
+ if (ret)
+ return ret;
+
+ BUILD_BUG_ON_NOT_POWER_OF_2(OA_BUFFER_SIZE);
+ BUILD_BUG_ON(OA_BUFFER_SIZE < SZ_128K || OA_BUFFER_SIZE > SZ_16M);
+
+ bo = i915_gem_object_create(dev_priv, OA_BUFFER_SIZE);
+ if (IS_ERR(bo)) {
+ DRM_ERROR("Failed to allocate OA buffer\n");
+ ret = PTR_ERR(bo);
+ goto unlock;
+ }
+
+ ret = i915_gem_object_set_cache_level(bo, I915_CACHE_LLC);
+ if (ret)
+ goto err_unref;
+
+ /* PreHSW required 512K alignment, HSW requires 16M */
+ vma = i915_gem_object_ggtt_pin(bo, NULL, 0, SZ_16M, 0);
+ if (IS_ERR(vma)) {
+ ret = PTR_ERR(vma);
+ goto err_unref;
+ }
+ dev_priv->perf.oa.oa_buffer.vma = vma;
+
+ dev_priv->perf.oa.oa_buffer.vaddr =
+ i915_gem_object_pin_map(bo, I915_MAP_WB);
+ if (IS_ERR(dev_priv->perf.oa.oa_buffer.vaddr)) {
+ ret = PTR_ERR(dev_priv->perf.oa.oa_buffer.vaddr);
+ goto err_unpin;
+ }
+
+ dev_priv->perf.oa.ops.init_oa_buffer(dev_priv);
+
+ DRM_DEBUG_DRIVER("OA Buffer initialized, gtt offset = 0x%x, vaddr = %p\n",
+ i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma),
+ dev_priv->perf.oa.oa_buffer.vaddr);
+
+ goto unlock;
+
+err_unpin:
+ __i915_vma_unpin(vma);
+
+err_unref:
+ i915_gem_object_put(bo);
+
+ dev_priv->perf.oa.oa_buffer.vaddr = NULL;
+ dev_priv->perf.oa.oa_buffer.vma = NULL;
+
+unlock:
+ mutex_unlock(&dev_priv->drm.struct_mutex);
+ return ret;
+}
+
+static void config_oa_regs(struct drm_i915_private *dev_priv,
+ const struct i915_oa_reg *regs,
+ int n_regs)
+{
+ int i;
+
+ for (i = 0; i < n_regs; i++) {
+ const struct i915_oa_reg *reg = regs + i;
+
+ I915_WRITE(reg->addr, reg->value);
+ }
+}
+
+static int hsw_enable_metric_set(struct drm_i915_private *dev_priv)
+{
+ int ret = i915_oa_select_metric_set_hsw(dev_priv);
+
+ if (ret)
+ return ret;
+
+ I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) |
+ GT_NOA_ENABLE));
+
+ /* PRM:
+ *
+ * OA unit is using “crclk” for its functionality. When trunk
+ * level clock gating takes place, OA clock would be gated,
+ * unable to count the events from non-render clock domain.
+ * Render clock gating must be disabled when OA is enabled to
+ * count the events from non-render domain. Unit level clock
+ * gating for RCS should also be disabled.
+ */
+ I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) &
+ ~GEN7_DOP_CLOCK_GATE_ENABLE));
+ I915_WRITE(GEN6_UCGCTL1, (I915_READ(GEN6_UCGCTL1) |
+ GEN6_CSUNIT_CLOCK_GATE_DISABLE));
+
+ config_oa_regs(dev_priv, dev_priv->perf.oa.mux_regs,
+ dev_priv->perf.oa.mux_regs_len);
+
+ /* It apparently takes a fairly long time for a new MUX
+ * configuration to be be applied after these register writes.
+ * This delay duration was derived empirically based on the
+ * render_basic config but hopefully it covers the maximum
+ * configuration latency.
+ *
+ * As a fallback, the checks in _append_oa_reports() to skip
+ * invalid OA reports do also seem to work to discard reports
+ * generated before this config has completed - albeit not
+ * silently.
+ *
+ * Unfortunately this is essentially a magic number, since we
+ * don't currently know of a reliable mechanism for predicting
+ * how long the MUX config will take to apply and besides
+ * seeing invalid reports we don't know of a reliable way to
+ * explicitly check that the MUX config has landed.
+ *
+ * It's even possible we've miss characterized the underlying
+ * problem - it just seems like the simplest explanation why
+ * a delay at this location would mitigate any invalid reports.
+ */
+ usleep_range(15000, 20000);
+
+ config_oa_regs(dev_priv, dev_priv->perf.oa.b_counter_regs,
+ dev_priv->perf.oa.b_counter_regs_len);
+
+ return 0;
+}
+
+static void hsw_disable_metric_set(struct drm_i915_private *dev_priv)
+{
+ I915_WRITE(GEN6_UCGCTL1, (I915_READ(GEN6_UCGCTL1) &
+ ~GEN6_CSUNIT_CLOCK_GATE_DISABLE));
+ I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) |
+ GEN7_DOP_CLOCK_GATE_ENABLE));
+
+ I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) &
+ ~GT_NOA_ENABLE));
+}
+
+static void gen7_update_oacontrol_locked(struct drm_i915_private *dev_priv)
+{
+ assert_spin_locked(&dev_priv->perf.hook_lock);
+
+ if (dev_priv->perf.oa.exclusive_stream->enabled) {
+ struct i915_gem_context *ctx =
+ dev_priv->perf.oa.exclusive_stream->ctx;
+ u32 ctx_id = dev_priv->perf.oa.specific_ctx_id;
+
+ bool periodic = dev_priv->perf.oa.periodic;
+ u32 period_exponent = dev_priv->perf.oa.period_exponent;
+ u32 report_format = dev_priv->perf.oa.oa_buffer.format;
+
+ I915_WRITE(GEN7_OACONTROL,
+ (ctx_id & GEN7_OACONTROL_CTX_MASK) |
+ (period_exponent <<
+ GEN7_OACONTROL_TIMER_PERIOD_SHIFT) |
+ (periodic ? GEN7_OACONTROL_TIMER_ENABLE : 0) |
+ (report_format << GEN7_OACONTROL_FORMAT_SHIFT) |
+ (ctx ? GEN7_OACONTROL_PER_CTX_ENABLE : 0) |
+ GEN7_OACONTROL_ENABLE);
+ } else
+ I915_WRITE(GEN7_OACONTROL, 0);
+}
+
+static void gen7_oa_enable(struct drm_i915_private *dev_priv)
+{
+ unsigned long flags;
+
+ /* Reset buf pointers so we don't forward reports from before now.
+ *
+ * Think carefully if considering trying to avoid this, since it
+ * also ensures status flags and the buffer itself are cleared
+ * in error paths, and we have checks for invalid reports based
+ * on the assumption that certain fields are written to zeroed
+ * memory which this helps maintains.
+ */
+ gen7_init_oa_buffer(dev_priv);
+
+ spin_lock_irqsave(&dev_priv->perf.hook_lock, flags);
+ gen7_update_oacontrol_locked(dev_priv);
+ spin_unlock_irqrestore(&dev_priv->perf.hook_lock, flags);
+}
+
+/**
+ * i915_oa_stream_enable - handle `I915_PERF_IOCTL_ENABLE` for OA stream
+ * @stream: An i915 perf stream opened for OA metrics
+ *
+ * [Re]enables hardware periodic sampling according to the period configured
+ * when opening the stream. This also starts a hrtimer that will periodically
+ * check for data in the circular OA buffer for notifying userspace (e.g.
+ * during a read() or poll()).
+ */
+static void i915_oa_stream_enable(struct i915_perf_stream *stream)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ dev_priv->perf.oa.ops.oa_enable(dev_priv);
+
+ if (dev_priv->perf.oa.periodic)
+ hrtimer_start(&dev_priv->perf.oa.poll_check_timer,
+ ns_to_ktime(POLL_PERIOD),
+ HRTIMER_MODE_REL_PINNED);
+}
+
+static void gen7_oa_disable(struct drm_i915_private *dev_priv)
+{
+ I915_WRITE(GEN7_OACONTROL, 0);
+}
+
+/**
+ * i915_oa_stream_disable - handle `I915_PERF_IOCTL_DISABLE` for OA stream
+ * @stream: An i915 perf stream opened for OA metrics
+ *
+ * Stops the OA unit from periodically writing counter reports into the
+ * circular OA buffer. This also stops the hrtimer that periodically checks for
+ * data in the circular OA buffer, for notifying userspace.
+ */
+static void i915_oa_stream_disable(struct i915_perf_stream *stream)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ dev_priv->perf.oa.ops.oa_disable(dev_priv);
+
+ if (dev_priv->perf.oa.periodic)
+ hrtimer_cancel(&dev_priv->perf.oa.poll_check_timer);
+}
+
+static u64 oa_exponent_to_ns(struct drm_i915_private *dev_priv, int exponent)
+{
+ return div_u64(1000000000ULL * (2ULL << exponent),
+ dev_priv->perf.oa.timestamp_frequency);
+}
+
+static const struct i915_perf_stream_ops i915_oa_stream_ops = {
+ .destroy = i915_oa_stream_destroy,
+ .enable = i915_oa_stream_enable,
+ .disable = i915_oa_stream_disable,
+ .wait_unlocked = i915_oa_wait_unlocked,
+ .poll_wait = i915_oa_poll_wait,
+ .read = i915_oa_read,
+};
+
+/**
+ * i915_oa_stream_init - validate combined props for OA stream and init
+ * @stream: An i915 perf stream
+ * @param: The open parameters passed to `DRM_I915_PERF_OPEN`
+ * @props: The property state that configures stream (individually validated)
+ *
+ * While read_properties_unlocked() validates properties in isolation it
+ * doesn't ensure that the combination necessarily makes sense.
+ *
+ * At this point it has been determined that userspace wants a stream of
+ * OA metrics, but still we need to further validate the combined
+ * properties are OK.
+ *
+ * If the configuration makes sense then we can allocate memory for
+ * a circular OA buffer and apply the requested metric set configuration.
+ *
+ * Returns: zero on success or a negative error code.
+ */
+static int i915_oa_stream_init(struct i915_perf_stream *stream,
+ struct drm_i915_perf_open_param *param,
+ struct perf_open_properties *props)
+{
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ int format_size;
+ int ret;
+
+ /* If the sysfs metrics/ directory wasn't registered for some
+ * reason then don't let userspace try their luck with config
+ * IDs
+ */
+ if (!dev_priv->perf.metrics_kobj) {
+ DRM_DEBUG("OA metrics weren't advertised via sysfs\n");
+ return -EINVAL;
+ }
+
+ if (!(props->sample_flags & SAMPLE_OA_REPORT)) {
+ DRM_DEBUG("Only OA report sampling supported\n");
+ return -EINVAL;
+ }
+
+ if (!dev_priv->perf.oa.ops.init_oa_buffer) {
+ DRM_DEBUG("OA unit not supported\n");
+ return -ENODEV;
+ }
+
+ /* To avoid the complexity of having to accurately filter
+ * counter reports and marshal to the appropriate client
+ * we currently only allow exclusive access
+ */
+ if (dev_priv->perf.oa.exclusive_stream) {
+ DRM_DEBUG("OA unit already in use\n");
+ return -EBUSY;
+ }
+
+ if (!props->metrics_set) {
+ DRM_DEBUG("OA metric set not specified\n");
+ return -EINVAL;
+ }
+
+ if (!props->oa_format) {
+ DRM_DEBUG("OA report format not specified\n");
+ return -EINVAL;
+ }
+
+ stream->sample_size = sizeof(struct drm_i915_perf_record_header);
+
+ format_size = dev_priv->perf.oa.oa_formats[props->oa_format].size;
+
+ stream->sample_flags |= SAMPLE_OA_REPORT;
+ stream->sample_size += format_size;
+
+ dev_priv->perf.oa.oa_buffer.format_size = format_size;
+ if (WARN_ON(dev_priv->perf.oa.oa_buffer.format_size == 0))
+ return -EINVAL;
+
+ dev_priv->perf.oa.oa_buffer.format =
+ dev_priv->perf.oa.oa_formats[props->oa_format].format;
+
+ dev_priv->perf.oa.metrics_set = props->metrics_set;
+
+ dev_priv->perf.oa.periodic = props->oa_periodic;
+ if (dev_priv->perf.oa.periodic) {
+ u32 tail;
+
+ dev_priv->perf.oa.period_exponent = props->oa_period_exponent;
+
+ /* See comment for OA_TAIL_MARGIN_NSEC for details
+ * about this tail_margin...
+ */
+ tail = div64_u64(OA_TAIL_MARGIN_NSEC,
+ oa_exponent_to_ns(dev_priv,
+ props->oa_period_exponent));
+ dev_priv->perf.oa.tail_margin = (tail + 1) * format_size;
+ }
+
+ if (stream->ctx) {
+ ret = oa_get_render_ctx_id(stream);
+ if (ret)
+ return ret;
+ }
+
+ ret = alloc_oa_buffer(dev_priv);
+ if (ret)
+ goto err_oa_buf_alloc;
+
+ /* PRM - observability performance counters:
+ *
+ * OACONTROL, performance counter enable, note:
+ *
+ * "When this bit is set, in order to have coherent counts,
+ * RC6 power state and trunk clock gating must be disabled.
+ * This can be achieved by programming MMIO registers as
+ * 0xA094=0 and 0xA090[31]=1"
+ *
+ * In our case we are expecting that taking pm + FORCEWAKE
+ * references will effectively disable RC6.
+ */
+ intel_runtime_pm_get(dev_priv);
+ intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+
+ ret = dev_priv->perf.oa.ops.enable_metric_set(dev_priv);
+ if (ret)
+ goto err_enable;
+
+ stream->ops = &i915_oa_stream_ops;
+
+ dev_priv->perf.oa.exclusive_stream = stream;
+
+ return 0;
+
+err_enable:
+ intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
+ intel_runtime_pm_put(dev_priv);
+ free_oa_buffer(dev_priv);
+
+err_oa_buf_alloc:
+ if (stream->ctx)
+ oa_put_render_ctx_id(stream);
+
+ return ret;
+}
+
+/**
+ * i915_perf_read_locked - &i915_perf_stream_ops->read with error normalisation
+ * @stream: An i915 perf stream
+ * @file: An i915 perf stream file
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @ppos: (inout) file seek position (unused)
+ *
+ * Besides wrapping &i915_perf_stream_ops->read this provides a common place to
+ * ensure that if we've successfully copied any data then reporting that takes
+ * precedence over any internal error status, so the data isn't lost.
+ *
+ * For example ret will be -ENOSPC whenever there is more buffered data than
+ * can be copied to userspace, but that's only interesting if we weren't able
+ * to copy some data because it implies the userspace buffer is too small to
+ * receive a single record (and we never split records).
+ *
+ * Another case with ret == -EFAULT is more of a grey area since it would seem
+ * like bad form for userspace to ask us to overrun its buffer, but the user
+ * knows best:
+ *
+ * http://yarchive.net/comp/linux/partial_reads_writes.html
+ *
+ * Returns: The number of bytes copied or a negative error code on failure.
+ */
+static ssize_t i915_perf_read_locked(struct i915_perf_stream *stream,
+ struct file *file,
+ char __user *buf,
+ size_t count,
+ loff_t *ppos)
+{
+ /* Note we keep the offset (aka bytes read) separate from any
+ * error status so that the final check for whether we return
+ * the bytes read with a higher precedence than any error (see
+ * comment below) doesn't need to be handled/duplicated in
+ * stream->ops->read() implementations.
+ */
+ size_t offset = 0;
+ int ret = stream->ops->read(stream, buf, count, &offset);
+
+ return offset ?: (ret ?: -EAGAIN);
+}
+
+/**
+ * i915_perf_read - handles read() FOP for i915 perf stream FDs
+ * @file: An i915 perf stream file
+ * @buf: destination buffer given by userspace
+ * @count: the number of bytes userspace wants to read
+ * @ppos: (inout) file seek position (unused)
+ *
+ * The entry point for handling a read() on a stream file descriptor from
+ * userspace. Most of the work is left to the i915_perf_read_locked() and
+ * &i915_perf_stream_ops->read but to save having stream implementations (of
+ * which we might have multiple later) we handle blocking read here.
+ *
+ * We can also consistently treat trying to read from a disabled stream
+ * as an IO error so implementations can assume the stream is enabled
+ * while reading.
+ *
+ * Returns: The number of bytes copied or a negative error code on failure.
+ */
+static ssize_t i915_perf_read(struct file *file,
+ char __user *buf,
+ size_t count,
+ loff_t *ppos)
+{
+ struct i915_perf_stream *stream = file->private_data;
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ ssize_t ret;
+
+ /* To ensure it's handled consistently we simply treat all reads of a
+ * disabled stream as an error. In particular it might otherwise lead
+ * to a deadlock for blocking file descriptors...
+ */
+ if (!stream->enabled)
+ return -EIO;
+
+ if (!(file->f_flags & O_NONBLOCK)) {
+ /* There's the small chance of false positives from
+ * stream->ops->wait_unlocked.
+ *
+ * E.g. with single context filtering since we only wait until
+ * oabuffer has >= 1 report we don't immediately know whether
+ * any reports really belong to the current context
+ */
+ do {
+ ret = stream->ops->wait_unlocked(stream);
+ if (ret)
+ return ret;
+
+ mutex_lock(&dev_priv->perf.lock);
+ ret = i915_perf_read_locked(stream, file,
+ buf, count, ppos);
+ mutex_unlock(&dev_priv->perf.lock);
+ } while (ret == -EAGAIN);
+ } else {
+ mutex_lock(&dev_priv->perf.lock);
+ ret = i915_perf_read_locked(stream, file, buf, count, ppos);
+ mutex_unlock(&dev_priv->perf.lock);
+ }
+
+ if (ret >= 0) {
+ /* Maybe make ->pollin per-stream state if we support multiple
+ * concurrent streams in the future.
+ */
+ dev_priv->perf.oa.pollin = false;
+ }
+
+ return ret;
+}
+
+static enum hrtimer_restart oa_poll_check_timer_cb(struct hrtimer *hrtimer)
+{
+ struct drm_i915_private *dev_priv =
+ container_of(hrtimer, typeof(*dev_priv),
+ perf.oa.poll_check_timer);
+
+ if (!dev_priv->perf.oa.ops.oa_buffer_is_empty(dev_priv)) {
+ dev_priv->perf.oa.pollin = true;
+ wake_up(&dev_priv->perf.oa.poll_wq);
+ }
+
+ hrtimer_forward_now(hrtimer, ns_to_ktime(POLL_PERIOD));
+
+ return HRTIMER_RESTART;
+}
+
+/**
+ * i915_perf_poll_locked - poll_wait() with a suitable wait queue for stream
+ * @dev_priv: i915 device instance
+ * @stream: An i915 perf stream
+ * @file: An i915 perf stream file
+ * @wait: poll() state table
+ *
+ * For handling userspace polling on an i915 perf stream, this calls through to
+ * &i915_perf_stream_ops->poll_wait to call poll_wait() with a wait queue that
+ * will be woken for new stream data.
+ *
+ * Note: The &drm_i915_private->perf.lock mutex has been taken to serialize
+ * with any non-file-operation driver hooks.
+ *
+ * Returns: any poll events that are ready without sleeping
+ */
+static unsigned int i915_perf_poll_locked(struct drm_i915_private *dev_priv,
+ struct i915_perf_stream *stream,
+ struct file *file,
+ poll_table *wait)
+{
+ unsigned int events = 0;
+
+ stream->ops->poll_wait(stream, file, wait);
+
+ /* Note: we don't explicitly check whether there's something to read
+ * here since this path may be very hot depending on what else
+ * userspace is polling, or on the timeout in use. We rely solely on
+ * the hrtimer/oa_poll_check_timer_cb to notify us when there are
+ * samples to read.
+ */
+ if (dev_priv->perf.oa.pollin)
+ events |= POLLIN;
+
+ return events;
+}
+
+/**
+ * i915_perf_poll - call poll_wait() with a suitable wait queue for stream
+ * @file: An i915 perf stream file
+ * @wait: poll() state table
+ *
+ * For handling userspace polling on an i915 perf stream, this ensures
+ * poll_wait() gets called with a wait queue that will be woken for new stream
+ * data.
+ *
+ * Note: Implementation deferred to i915_perf_poll_locked()
+ *
+ * Returns: any poll events that are ready without sleeping
+ */
+static unsigned int i915_perf_poll(struct file *file, poll_table *wait)
+{
+ struct i915_perf_stream *stream = file->private_data;
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ int ret;
+
+ mutex_lock(&dev_priv->perf.lock);
+ ret = i915_perf_poll_locked(dev_priv, stream, file, wait);
+ mutex_unlock(&dev_priv->perf.lock);
+
+ return ret;
+}
+
+/**
+ * i915_perf_enable_locked - handle `I915_PERF_IOCTL_ENABLE` ioctl
+ * @stream: A disabled i915 perf stream
+ *
+ * [Re]enables the associated capture of data for this stream.
+ *
+ * If a stream was previously enabled then there's currently no intention
+ * to provide userspace any guarantee about the preservation of previously
+ * buffered data.
+ */
+static void i915_perf_enable_locked(struct i915_perf_stream *stream)
+{
+ if (stream->enabled)
+ return;
+
+ /* Allow stream->ops->enable() to refer to this */
+ stream->enabled = true;
+
+ if (stream->ops->enable)
+ stream->ops->enable(stream);
+}
+
+/**
+ * i915_perf_disable_locked - handle `I915_PERF_IOCTL_DISABLE` ioctl
+ * @stream: An enabled i915 perf stream
+ *
+ * Disables the associated capture of data for this stream.
+ *
+ * The intention is that disabling an re-enabling a stream will ideally be
+ * cheaper than destroying and re-opening a stream with the same configuration,
+ * though there are no formal guarantees about what state or buffered data
+ * must be retained between disabling and re-enabling a stream.
+ *
+ * Note: while a stream is disabled it's considered an error for userspace
+ * to attempt to read from the stream (-EIO).
+ */
+static void i915_perf_disable_locked(struct i915_perf_stream *stream)
+{
+ if (!stream->enabled)
+ return;
+
+ /* Allow stream->ops->disable() to refer to this */
+ stream->enabled = false;
+
+ if (stream->ops->disable)
+ stream->ops->disable(stream);
+}
+
+/**
+ * i915_perf_ioctl - support ioctl() usage with i915 perf stream FDs
+ * @stream: An i915 perf stream
+ * @cmd: the ioctl request
+ * @arg: the ioctl data
+ *
+ * Note: The &drm_i915_private->perf.lock mutex has been taken to serialize
+ * with any non-file-operation driver hooks.
+ *
+ * Returns: zero on success or a negative error code. Returns -EINVAL for
+ * an unknown ioctl request.
+ */
+static long i915_perf_ioctl_locked(struct i915_perf_stream *stream,
+ unsigned int cmd,
+ unsigned long arg)
+{
+ switch (cmd) {
+ case I915_PERF_IOCTL_ENABLE:
+ i915_perf_enable_locked(stream);
+ return 0;
+ case I915_PERF_IOCTL_DISABLE:
+ i915_perf_disable_locked(stream);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+/**
+ * i915_perf_ioctl - support ioctl() usage with i915 perf stream FDs
+ * @file: An i915 perf stream file
+ * @cmd: the ioctl request
+ * @arg: the ioctl data
+ *
+ * Implementation deferred to i915_perf_ioctl_locked().
+ *
+ * Returns: zero on success or a negative error code. Returns -EINVAL for
+ * an unknown ioctl request.
+ */
+static long i915_perf_ioctl(struct file *file,
+ unsigned int cmd,
+ unsigned long arg)
+{
+ struct i915_perf_stream *stream = file->private_data;
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+ long ret;
+
+ mutex_lock(&dev_priv->perf.lock);
+ ret = i915_perf_ioctl_locked(stream, cmd, arg);
+ mutex_unlock(&dev_priv->perf.lock);
+
+ return ret;
+}
+
+/**
+ * i915_perf_destroy_locked - destroy an i915 perf stream
+ * @stream: An i915 perf stream
+ *
+ * Frees all resources associated with the given i915 perf @stream, disabling
+ * any associated data capture in the process.
+ *
+ * Note: The &drm_i915_private->perf.lock mutex has been taken to serialize
+ * with any non-file-operation driver hooks.
+ */
+static void i915_perf_destroy_locked(struct i915_perf_stream *stream)
+{
+ if (stream->enabled)
+ i915_perf_disable_locked(stream);
+
+ if (stream->ops->destroy)
+ stream->ops->destroy(stream);
+
+ list_del(&stream->link);
+
+ if (stream->ctx)
+ i915_gem_context_put_unlocked(stream->ctx);
+
+ kfree(stream);
+}
+
+/**
+ * i915_perf_release - handles userspace close() of a stream file
+ * @inode: anonymous inode associated with file
+ * @file: An i915 perf stream file
+ *
+ * Cleans up any resources associated with an open i915 perf stream file.
+ *
+ * NB: close() can't really fail from the userspace point of view.
+ *
+ * Returns: zero on success or a negative error code.
+ */
+static int i915_perf_release(struct inode *inode, struct file *file)
+{
+ struct i915_perf_stream *stream = file->private_data;
+ struct drm_i915_private *dev_priv = stream->dev_priv;
+
+ mutex_lock(&dev_priv->perf.lock);
+ i915_perf_destroy_locked(stream);
+ mutex_unlock(&dev_priv->perf.lock);
+
+ return 0;
+}
+
+
+static const struct file_operations fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .release = i915_perf_release,
+ .poll = i915_perf_poll,
+ .read = i915_perf_read,
+ .unlocked_ioctl = i915_perf_ioctl,
+};
+
+
+static struct i915_gem_context *
+lookup_context(struct drm_i915_private *dev_priv,
+ struct drm_i915_file_private *file_priv,
+ u32 ctx_user_handle)
+{
+ struct i915_gem_context *ctx;
+ int ret;
+
+ ret = i915_mutex_lock_interruptible(&dev_priv->drm);
+ if (ret)
+ return ERR_PTR(ret);
+
+ ctx = i915_gem_context_lookup(file_priv, ctx_user_handle);
+ if (!IS_ERR(ctx))
+ i915_gem_context_get(ctx);
+
+ mutex_unlock(&dev_priv->drm.struct_mutex);
+
+ return ctx;
+}
+
+/**
+ * i915_perf_open_ioctl_locked - DRM ioctl() for userspace to open a stream FD
+ * @dev_priv: i915 device instance
+ * @param: The open parameters passed to 'DRM_I915_PERF_OPEN`
+ * @props: individually validated u64 property value pairs
+ * @file: drm file
+ *
+ * See i915_perf_ioctl_open() for interface details.
+ *
+ * Implements further stream config validation and stream initialization on
+ * behalf of i915_perf_open_ioctl() with the &drm_i915_private->perf.lock mutex
+ * taken to serialize with any non-file-operation driver hooks.
+ *
+ * Note: at this point the @props have only been validated in isolation and
+ * it's still necessary to validate that the combination of properties makes
+ * sense.
+ *
+ * In the case where userspace is interested in OA unit metrics then further
+ * config validation and stream initialization details will be handled by
+ * i915_oa_stream_init(). The code here should only validate config state that
+ * will be relevant to all stream types / backends.
+ *
+ * Returns: zero on success or a negative error code.
+ */
+static int
+i915_perf_open_ioctl_locked(struct drm_i915_private *dev_priv,
+ struct drm_i915_perf_open_param *param,
+ struct perf_open_properties *props,
+ struct drm_file *file)
+{
+ struct i915_gem_context *specific_ctx = NULL;
+ struct i915_perf_stream *stream = NULL;
+ unsigned long f_flags = 0;
+ int stream_fd;
+ int ret;
+
+ if (props->single_context) {
+ u32 ctx_handle = props->ctx_handle;
+ struct drm_i915_file_private *file_priv = file->driver_priv;
+
+ specific_ctx = lookup_context(dev_priv, file_priv, ctx_handle);
+ if (IS_ERR(specific_ctx)) {
+ ret = PTR_ERR(specific_ctx);
+ if (ret != -EINTR)
+ DRM_DEBUG("Failed to look up context with ID %u for opening perf stream\n",
+ ctx_handle);
+ goto err;
+ }
+ }
+
+ /* Similar to perf's kernel.perf_paranoid_cpu sysctl option
+ * we check a dev.i915.perf_stream_paranoid sysctl option
+ * to determine if it's ok to access system wide OA counters
+ * without CAP_SYS_ADMIN privileges.
+ */
+ if (!specific_ctx &&
+ i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
+ DRM_DEBUG("Insufficient privileges to open system-wide i915 perf stream\n");
+ ret = -EACCES;
+ goto err_ctx;
+ }
+
+ stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+ if (!stream) {
+ ret = -ENOMEM;
+ goto err_ctx;
+ }
+
+ stream->dev_priv = dev_priv;
+ stream->ctx = specific_ctx;
+
+ ret = i915_oa_stream_init(stream, param, props);
+ if (ret)
+ goto err_alloc;
+
+ /* we avoid simply assigning stream->sample_flags = props->sample_flags
+ * to have _stream_init check the combination of sample flags more
+ * thoroughly, but still this is the expected result at this point.
+ */
+ if (WARN_ON(stream->sample_flags != props->sample_flags)) {
+ ret = -ENODEV;
+ goto err_alloc;
+ }
+
+ list_add(&stream->link, &dev_priv->perf.streams);
+
+ if (param->flags & I915_PERF_FLAG_FD_CLOEXEC)
+ f_flags |= O_CLOEXEC;
+ if (param->flags & I915_PERF_FLAG_FD_NONBLOCK)
+ f_flags |= O_NONBLOCK;
+
+ stream_fd = anon_inode_getfd("[i915_perf]", &fops, stream, f_flags);
+ if (stream_fd < 0) {
+ ret = stream_fd;
+ goto err_open;
+ }
+
+ if (!(param->flags & I915_PERF_FLAG_DISABLED))
+ i915_perf_enable_locked(stream);
+
+ return stream_fd;
+
+err_open:
+ list_del(&stream->link);
+ if (stream->ops->destroy)
+ stream->ops->destroy(stream);
+err_alloc:
+ kfree(stream);
+err_ctx:
+ if (specific_ctx)
+ i915_gem_context_put_unlocked(specific_ctx);
+err:
+ return ret;
+}
+
+/**
+ * read_properties_unlocked - validate + copy userspace stream open properties
+ * @dev_priv: i915 device instance
+ * @uprops: The array of u64 key value pairs given by userspace
+ * @n_props: The number of key value pairs expected in @uprops
+ * @props: The stream configuration built up while validating properties
+ *
+ * Note this function only validates properties in isolation it doesn't
+ * validate that the combination of properties makes sense or that all
+ * properties necessary for a particular kind of stream have been set.
+ *
+ * Note that there currently aren't any ordering requirements for properties so
+ * we shouldn't validate or assume anything about ordering here. This doesn't
+ * rule out defining new properties with ordering requirements in the future.
+ */
+static int read_properties_unlocked(struct drm_i915_private *dev_priv,
+ u64 __user *uprops,
+ u32 n_props,
+ struct perf_open_properties *props)
+{
+ u64 __user *uprop = uprops;
+ int i;
+
+ memset(props, 0, sizeof(struct perf_open_properties));
+
+ if (!n_props) {
+ DRM_DEBUG("No i915 perf properties given\n");
+ return -EINVAL;
+ }
+
+ /* Considering that ID = 0 is reserved and assuming that we don't
+ * (currently) expect any configurations to ever specify duplicate
+ * values for a particular property ID then the last _PROP_MAX value is
+ * one greater than the maximum number of properties we expect to get
+ * from userspace.
+ */
+ if (n_props >= DRM_I915_PERF_PROP_MAX) {
+ DRM_DEBUG("More i915 perf properties specified than exist\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < n_props; i++) {
+ u64 oa_period, oa_freq_hz;
+ u64 id, value;
+ int ret;
+
+ ret = get_user(id, uprop);
+ if (ret)
+ return ret;
+
+ ret = get_user(value, uprop + 1);
+ if (ret)
+ return ret;
+
+ switch ((enum drm_i915_perf_property_id)id) {
+ case DRM_I915_PERF_PROP_CTX_HANDLE:
+ props->single_context = 1;
+ props->ctx_handle = value;
+ break;
+ case DRM_I915_PERF_PROP_SAMPLE_OA:
+ props->sample_flags |= SAMPLE_OA_REPORT;
+ break;
+ case DRM_I915_PERF_PROP_OA_METRICS_SET:
+ if (value == 0 ||
+ value > dev_priv->perf.oa.n_builtin_sets) {
+ DRM_DEBUG("Unknown OA metric set ID\n");
+ return -EINVAL;
+ }
+ props->metrics_set = value;
+ break;
+ case DRM_I915_PERF_PROP_OA_FORMAT:
+ if (value == 0 || value >= I915_OA_FORMAT_MAX) {
+ DRM_DEBUG("Invalid OA report format\n");
+ return -EINVAL;
+ }
+ if (!dev_priv->perf.oa.oa_formats[value].size) {
+ DRM_DEBUG("Invalid OA report format\n");
+ return -EINVAL;
+ }
+ props->oa_format = value;
+ break;
+ case DRM_I915_PERF_PROP_OA_EXPONENT:
+ if (value > OA_EXPONENT_MAX) {
+ DRM_DEBUG("OA timer exponent too high (> %u)\n",
+ OA_EXPONENT_MAX);
+ return -EINVAL;
+ }
+
+ /* Theoretically we can program the OA unit to sample
+ * every 160ns but don't allow that by default unless
+ * root.
+ *
+ * On Haswell the period is derived from the exponent
+ * as:
+ *
+ * period = 80ns * 2^(exponent + 1)
+ */
+ BUILD_BUG_ON(sizeof(oa_period) != 8);
+ oa_period = 80ull * (2ull << value);
+
+ /* This check is primarily to ensure that oa_period <=
+ * UINT32_MAX (before passing to do_div which only
+ * accepts a u32 denominator), but we can also skip
+ * checking anything < 1Hz which implicitly can't be
+ * limited via an integer oa_max_sample_rate.
+ */
+ if (oa_period <= NSEC_PER_SEC) {
+ u64 tmp = NSEC_PER_SEC;
+ do_div(tmp, oa_period);
+ oa_freq_hz = tmp;
+ } else
+ oa_freq_hz = 0;
+
+ if (oa_freq_hz > i915_oa_max_sample_rate &&
+ !capable(CAP_SYS_ADMIN)) {
+ DRM_DEBUG("OA exponent would exceed the max sampling frequency (sysctl dev.i915.oa_max_sample_rate) %uHz without root privileges\n",
+ i915_oa_max_sample_rate);
+ return -EACCES;
+ }
+
+ props->oa_periodic = true;
+ props->oa_period_exponent = value;
+ break;
+ default:
+ MISSING_CASE(id);
+ DRM_DEBUG("Unknown i915 perf property ID\n");
+ return -EINVAL;
+ }
+
+ uprop += 2;
+ }
+
+ return 0;
+}
+
+/**
+ * i915_perf_open_ioctl - DRM ioctl() for userspace to open a stream FD
+ * @dev: drm device
+ * @data: ioctl data copied from userspace (unvalidated)
+ * @file: drm file
+ *
+ * Validates the stream open parameters given by userspace including flags
+ * and an array of u64 key, value pair properties.
+ *
+ * Very little is assumed up front about the nature of the stream being
+ * opened (for instance we don't assume it's for periodic OA unit metrics). An
+ * i915-perf stream is expected to be a suitable interface for other forms of
+ * buffered data written by the GPU besides periodic OA metrics.
+ *
+ * Note we copy the properties from userspace outside of the i915 perf
+ * mutex to avoid an awkward lockdep with mmap_sem.
+ *
+ * Most of the implementation details are handled by
+ * i915_perf_open_ioctl_locked() after taking the &drm_i915_private->perf.lock
+ * mutex for serializing with any non-file-operation driver hooks.
+ *
+ * Return: A newly opened i915 Perf stream file descriptor or negative
+ * error code on failure.
+ */
+int i915_perf_open_ioctl(struct drm_device *dev, void *data,
+ struct drm_file *file)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct drm_i915_perf_open_param *param = data;
+ struct perf_open_properties props;
+ u32 known_open_flags;
+ int ret;
+
+ if (!dev_priv->perf.initialized) {
+ DRM_DEBUG("i915 perf interface not available for this system\n");
+ return -ENOTSUPP;
+ }
+
+ known_open_flags = I915_PERF_FLAG_FD_CLOEXEC |
+ I915_PERF_FLAG_FD_NONBLOCK |
+ I915_PERF_FLAG_DISABLED;
+ if (param->flags & ~known_open_flags) {
+ DRM_DEBUG("Unknown drm_i915_perf_open_param flag\n");
+ return -EINVAL;
+ }
+
+ ret = read_properties_unlocked(dev_priv,
+ u64_to_user_ptr(param->properties_ptr),
+ param->num_properties,
+ &props);
+ if (ret)
+ return ret;
+
+ mutex_lock(&dev_priv->perf.lock);
+ ret = i915_perf_open_ioctl_locked(dev_priv, param, &props, file);
+ mutex_unlock(&dev_priv->perf.lock);
+
+ return ret;
+}
+
+/**
+ * i915_perf_register - exposes i915-perf to userspace
+ * @dev_priv: i915 device instance
+ *
+ * In particular OA metric sets are advertised under a sysfs metrics/
+ * directory allowing userspace to enumerate valid IDs that can be
+ * used to open an i915-perf stream.
+ */
+void i915_perf_register(struct drm_i915_private *dev_priv)
+{
+ if (!IS_HASWELL(dev_priv))
+ return;
+
+ if (!dev_priv->perf.initialized)
+ return;
+
+ /* To be sure we're synchronized with an attempted
+ * i915_perf_open_ioctl(); considering that we register after
+ * being exposed to userspace.
+ */
+ mutex_lock(&dev_priv->perf.lock);
+
+ dev_priv->perf.metrics_kobj =
+ kobject_create_and_add("metrics",
+ &dev_priv->drm.primary->kdev->kobj);
+ if (!dev_priv->perf.metrics_kobj)
+ goto exit;
+
+ if (i915_perf_register_sysfs_hsw(dev_priv)) {
+ kobject_put(dev_priv->perf.metrics_kobj);
+ dev_priv->perf.metrics_kobj = NULL;
+ }
+
+exit:
+ mutex_unlock(&dev_priv->perf.lock);
+}
+
+/**
+ * i915_perf_unregister - hide i915-perf from userspace
+ * @dev_priv: i915 device instance
+ *
+ * i915-perf state cleanup is split up into an 'unregister' and
+ * 'deinit' phase where the interface is first hidden from
+ * userspace by i915_perf_unregister() before cleaning up
+ * remaining state in i915_perf_fini().
+ */
+void i915_perf_unregister(struct drm_i915_private *dev_priv)
+{
+ if (!IS_HASWELL(dev_priv))
+ return;
+
+ if (!dev_priv->perf.metrics_kobj)
+ return;
+
+ i915_perf_unregister_sysfs_hsw(dev_priv);
+
+ kobject_put(dev_priv->perf.metrics_kobj);
+ dev_priv->perf.metrics_kobj = NULL;
+}
+
+static struct ctl_table oa_table[] = {
+ {
+ .procname = "perf_stream_paranoid",
+ .data = &i915_perf_stream_paranoid,
+ .maxlen = sizeof(i915_perf_stream_paranoid),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &one,
+ },
+ {
+ .procname = "oa_max_sample_rate",
+ .data = &i915_oa_max_sample_rate,
+ .maxlen = sizeof(i915_oa_max_sample_rate),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &zero,
+ .extra2 = &oa_sample_rate_hard_limit,
+ },
+ {}
+};
+
+static struct ctl_table i915_root[] = {
+ {
+ .procname = "i915",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = oa_table,
+ },
+ {}
+};
+
+static struct ctl_table dev_root[] = {
+ {
+ .procname = "dev",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = i915_root,
+ },
+ {}
+};
+
+/**
+ * i915_perf_init - initialize i915-perf state on module load
+ * @dev_priv: i915 device instance
+ *
+ * Initializes i915-perf state without exposing anything to userspace.
+ *
+ * Note: i915-perf initialization is split into an 'init' and 'register'
+ * phase with the i915_perf_register() exposing state to userspace.
+ */
+void i915_perf_init(struct drm_i915_private *dev_priv)
+{
+ if (!IS_HASWELL(dev_priv))
+ return;
+
+ hrtimer_init(&dev_priv->perf.oa.poll_check_timer,
+ CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ dev_priv->perf.oa.poll_check_timer.function = oa_poll_check_timer_cb;
+ init_waitqueue_head(&dev_priv->perf.oa.poll_wq);
+
+ INIT_LIST_HEAD(&dev_priv->perf.streams);
+ mutex_init(&dev_priv->perf.lock);
+ spin_lock_init(&dev_priv->perf.hook_lock);
+
+ dev_priv->perf.oa.ops.init_oa_buffer = gen7_init_oa_buffer;
+ dev_priv->perf.oa.ops.enable_metric_set = hsw_enable_metric_set;
+ dev_priv->perf.oa.ops.disable_metric_set = hsw_disable_metric_set;
+ dev_priv->perf.oa.ops.oa_enable = gen7_oa_enable;
+ dev_priv->perf.oa.ops.oa_disable = gen7_oa_disable;
+ dev_priv->perf.oa.ops.read = gen7_oa_read;
+ dev_priv->perf.oa.ops.oa_buffer_is_empty =
+ gen7_oa_buffer_is_empty_fop_unlocked;
+
+ dev_priv->perf.oa.timestamp_frequency = 12500000;
+
+ dev_priv->perf.oa.oa_formats = hsw_oa_formats;
+
+ dev_priv->perf.oa.n_builtin_sets =
+ i915_oa_n_builtin_metric_sets_hsw;
+
+ dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
+
+ dev_priv->perf.initialized = true;
+}
+
+/**
+ * i915_perf_fini - Counter part to i915_perf_init()
+ * @dev_priv: i915 device instance
+ */
+void i915_perf_fini(struct drm_i915_private *dev_priv)
+{
+ if (!dev_priv->perf.initialized)
+ return;
+
+ unregister_sysctl_table(dev_priv->perf.sysctl_header);
+
+ memset(&dev_priv->perf.oa.ops, 0, sizeof(dev_priv->perf.oa.ops));
+ dev_priv->perf.initialized = false;
+}