/* * 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 */ /** * 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 #include #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) { lockdep_assert_held(&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; }