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OpenCloudOS-Kernel/drivers/gpu/drm/i915/i915_perf.c

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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 <linux/uuid.h>
#include "i915_drv.h"
#include "i915_oa_hsw.h"
#include "i915_oa_bdw.h"
#include "i915_oa_chv.h"
#include "i915_oa_sklgt2.h"
#include "i915_oa_sklgt3.h"
#include "i915_oa_sklgt4.h"
#include "i915_oa_bxt.h"
#include "i915_oa_kblgt2.h"
#include "i915_oa_kblgt3.h"
#include "i915_oa_glk.h"
#include "i915_oa_cflgt2.h"
#include "i915_oa_cflgt3.h"
#include "i915_oa_cnl.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))
/**
* DOC: OA Tail Pointer Race
*
* 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 (in terms of what's visible to the
* CPU).
*
* Although this can be observed explicitly while copying reports to userspace
* by checking for a zeroed report-id field in tail reports, we want to account
* for this earlier, as part of the oa_buffer_check to avoid lots of redundant
* read() attempts.
*
* In effect we define a tail pointer for reading that lags the real tail
* pointer by at least %OA_TAIL_MARGIN_NSEC nanoseconds, which gives enough
* time for the corresponding reports to become visible to the CPU.
*
* To manage this we actually track two tail pointers:
* 1) An 'aging' tail with an associated timestamp that is tracked until we
* can trust the corresponding data is visible to the CPU; at which point
* it is considered 'aged'.
* 2) An 'aged' tail that can be used for read()ing.
*
* The two separate pointers let us decouple read()s from tail pointer aging.
*
* The tail pointers are checked and updated at a limited rate within a hrtimer
* callback (the same callback that is used for delivering EPOLLIN events)
*
* Initially the tails are marked invalid with %INVALID_TAIL_PTR which
* indicates that an updated tail pointer is needed.
*
* Most of the implementation details for this workaround are in
* oa_buffer_check_unlocked() and _append_oa_reports()
*
* Note for posterity: previously the driver used to define an effective tail
* pointer that lagged the real pointer by a 'tail margin' measured in bytes
* derived from %OA_TAIL_MARGIN_NSEC and the configured sampling frequency.
* This was flawed considering that the OA unit may also automatically generate
* non-periodic reports (such as on context switch) or the OA unit may be
* enabled without any periodic sampling.
*/
#define OA_TAIL_MARGIN_NSEC 100000ULL
#define INVALID_TAIL_PTR 0xffffffff
/* 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
/* On Gen8+ automatically triggered OA reports include a 'reason' field... */
#define OAREPORT_REASON_MASK 0x3f
#define OAREPORT_REASON_SHIFT 19
#define OAREPORT_REASON_TIMER (1<<0)
#define OAREPORT_REASON_CTX_SWITCH (1<<3)
#define OAREPORT_REASON_CLK_RATIO (1<<5)
/* For sysctl proc_dointvec_minmax of i915_oa_max_sample_rate
*
* The highest sampling frequency we can theoretically program the OA unit
* with is always half the timestamp frequency: E.g. 6.25Mhz for Haswell.
*
* Initialized just before we register the sysctl parameter.
*/
static int oa_sample_rate_hard_limit;
/* 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 },
};
static struct i915_oa_format gen8_plus_oa_formats[I915_OA_FORMAT_MAX] = {
[I915_OA_FORMAT_A12] = { 0, 64 },
[I915_OA_FORMAT_A12_B8_C8] = { 2, 128 },
[I915_OA_FORMAT_A32u40_A4u32_B8_C8] = { 5, 256 },
[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;
};
static void free_oa_config(struct drm_i915_private *dev_priv,
struct i915_oa_config *oa_config)
{
if (!PTR_ERR(oa_config->flex_regs))
kfree(oa_config->flex_regs);
if (!PTR_ERR(oa_config->b_counter_regs))
kfree(oa_config->b_counter_regs);
if (!PTR_ERR(oa_config->mux_regs))
kfree(oa_config->mux_regs);
kfree(oa_config);
}
static void put_oa_config(struct drm_i915_private *dev_priv,
struct i915_oa_config *oa_config)
{
if (!atomic_dec_and_test(&oa_config->ref_count))
return;
free_oa_config(dev_priv, oa_config);
}
static int get_oa_config(struct drm_i915_private *dev_priv,
int metrics_set,
struct i915_oa_config **out_config)
{
int ret;
if (metrics_set == 1) {
*out_config = &dev_priv->perf.oa.test_config;
atomic_inc(&dev_priv->perf.oa.test_config.ref_count);
return 0;
}
ret = mutex_lock_interruptible(&dev_priv->perf.metrics_lock);
if (ret)
return ret;
*out_config = idr_find(&dev_priv->perf.metrics_idr, metrics_set);
if (!*out_config)
ret = -EINVAL;
else
atomic_inc(&(*out_config)->ref_count);
mutex_unlock(&dev_priv->perf.metrics_lock);
return ret;
}
static u32 gen8_oa_hw_tail_read(struct drm_i915_private *dev_priv)
{
return I915_READ(GEN8_OATAILPTR) & GEN8_OATAILPTR_MASK;
}
static u32 gen7_oa_hw_tail_read(struct drm_i915_private *dev_priv)
{
u32 oastatus1 = I915_READ(GEN7_OASTATUS1);
return oastatus1 & GEN7_OASTATUS1_TAIL_MASK;
}
/**
* oa_buffer_check_unlocked - check for data and update tail ptr state
* @dev_priv: i915 device instance
*
* This is either called via fops (for blocking reads in user ctx) or the poll
* check hrtimer (atomic ctx) to check the OA buffer tail pointer and check
* if there is data available for userspace to read.
*
* This function is central to providing a workaround for the OA unit tail
* pointer having a race with respect to what data is visible to the CPU.
* It is responsible for reading tail pointers from the hardware and giving
* the pointers time to 'age' before they are made available for reading.
* (See description of OA_TAIL_MARGIN_NSEC above for further details.)
*
* Besides returning true when there is data available to read() this function
* also has the side effect of updating the oa_buffer.tails[], .aging_timestamp
* and .aged_tail_idx state used for reading.
*
* Note: 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.
*
* Returns: %true if the OA buffer contains data, else %false
*/
static bool oa_buffer_check_unlocked(struct drm_i915_private *dev_priv)
{
int report_size = dev_priv->perf.oa.oa_buffer.format_size;
unsigned long flags;
unsigned int aged_idx;
u32 head, hw_tail, aged_tail, aging_tail;
u64 now;
/* We have to consider the (unlikely) possibility that read() errors
* could result in an OA buffer reset which might reset the head,
* tails[] and aged_tail state.
*/
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/* NB: The head we observe here might effectively be a little out of
* date (between head and tails[aged_idx].offset if there is currently
* a read() in progress.
*/
head = dev_priv->perf.oa.oa_buffer.head;
aged_idx = dev_priv->perf.oa.oa_buffer.aged_tail_idx;
aged_tail = dev_priv->perf.oa.oa_buffer.tails[aged_idx].offset;
aging_tail = dev_priv->perf.oa.oa_buffer.tails[!aged_idx].offset;
hw_tail = dev_priv->perf.oa.ops.oa_hw_tail_read(dev_priv);
/* The tail pointer increases in 64 byte increments,
* not in report_size steps...
*/
hw_tail &= ~(report_size - 1);
now = ktime_get_mono_fast_ns();
/* Update the aged tail
*
* Flip the tail pointer available for read()s once the aging tail is
* old enough to trust that the corresponding data will be visible to
* the CPU...
*
* Do this before updating the aging pointer in case we may be able to
* immediately start aging a new pointer too (if new data has become
* available) without needing to wait for a later hrtimer callback.
*/
if (aging_tail != INVALID_TAIL_PTR &&
((now - dev_priv->perf.oa.oa_buffer.aging_timestamp) >
OA_TAIL_MARGIN_NSEC)) {
aged_idx ^= 1;
dev_priv->perf.oa.oa_buffer.aged_tail_idx = aged_idx;
aged_tail = aging_tail;
/* Mark that we need a new pointer to start aging... */
dev_priv->perf.oa.oa_buffer.tails[!aged_idx].offset = INVALID_TAIL_PTR;
aging_tail = INVALID_TAIL_PTR;
}
/* Update the aging tail
*
* We throttle aging tail updates until we have a new tail that
* represents >= one report more data than is already available for
* reading. This ensures there will be enough data for a successful
* read once this new pointer has aged and ensures we will give the new
* pointer time to age.
*/
if (aging_tail == INVALID_TAIL_PTR &&
(aged_tail == INVALID_TAIL_PTR ||
OA_TAKEN(hw_tail, aged_tail) >= report_size)) {
struct i915_vma *vma = dev_priv->perf.oa.oa_buffer.vma;
u32 gtt_offset = i915_ggtt_offset(vma);
/* Be paranoid and do a bounds check on the pointer read back
* from hardware, just in case some spurious hardware condition
* could put the tail out of bounds...
*/
if (hw_tail >= gtt_offset &&
hw_tail < (gtt_offset + OA_BUFFER_SIZE)) {
dev_priv->perf.oa.oa_buffer.tails[!aged_idx].offset =
aging_tail = hw_tail;
dev_priv->perf.oa.oa_buffer.aging_timestamp = now;
} else {
DRM_ERROR("Ignoring spurious out of range OA buffer tail pointer = %u\n",
hw_tail);
}
}
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
return aged_tail == INVALID_TAIL_PTR ?
false : OA_TAKEN(aged_tail, head) >= 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
*
* 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 tail chases the head?... 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 gen8_append_oa_reports(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;
u8 *oa_buf_base = dev_priv->perf.oa.oa_buffer.vaddr;
u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
u32 mask = (OA_BUFFER_SIZE - 1);
size_t start_offset = *offset;
unsigned long flags;
unsigned int aged_tail_idx;
u32 head, tail;
u32 taken;
int ret = 0;
if (WARN_ON(!stream->enabled))
return -EIO;
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
head = dev_priv->perf.oa.oa_buffer.head;
aged_tail_idx = dev_priv->perf.oa.oa_buffer.aged_tail_idx;
tail = dev_priv->perf.oa.oa_buffer.tails[aged_tail_idx].offset;
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/*
* An invalid tail pointer here means we're still waiting for the poll
* hrtimer callback to give us a pointer
*/
if (tail == INVALID_TAIL_PTR)
return -EAGAIN;
/*
* NB: oa_buffer.head/tail include the gtt_offset which we don't want
* while indexing relative to oa_buf_base.
*/
head -= gtt_offset;
tail -= gtt_offset;
/*
* An out of bounds or misaligned head or tail pointer implies a driver
* bug since we validate + align the tail pointers we read from the
* hardware and we are in full control of the head pointer which should
* only be incremented by multiples of the report size (notably also
* all a power of two).
*/
if (WARN_ONCE(head > OA_BUFFER_SIZE || head % report_size ||
tail > OA_BUFFER_SIZE || tail % report_size,
"Inconsistent OA buffer pointers: head = %u, tail = %u\n",
head, tail))
return -EIO;
for (/* none */;
(taken = OA_TAKEN(tail, head));
head = (head + report_size) & mask) {
u8 *report = oa_buf_base + head;
u32 *report32 = (void *)report;
u32 ctx_id;
u32 reason;
/*
* 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 reason field includes flags identifying what
* triggered this specific report (mostly timer
* triggered or e.g. due to a context switch).
*
* This field is never expected to be zero so we can
* check that the report isn't invalid before copying
* it to userspace...
*/
reason = ((report32[0] >> OAREPORT_REASON_SHIFT) &
OAREPORT_REASON_MASK);
if (reason == 0) {
if (__ratelimit(&dev_priv->perf.oa.spurious_report_rs))
DRM_NOTE("Skipping spurious, invalid OA report\n");
continue;
}
/*
* XXX: Just keep the lower 21 bits for now since I'm not
* entirely sure if the HW touches any of the higher bits in
* this field
*/
ctx_id = report32[2] & 0x1fffff;
/*
* Squash whatever is in the CTX_ID field if it's marked as
* invalid to be sure we avoid false-positive, single-context
* filtering below...
*
* Note: that we don't clear the valid_ctx_bit so userspace can
* understand that the ID has been squashed by the kernel.
*/
if (!(report32[0] & dev_priv->perf.oa.gen8_valid_ctx_bit))
ctx_id = report32[2] = INVALID_CTX_ID;
/*
* NB: For Gen 8 the OA unit no longer supports clock gating
* off for a specific context and the kernel can't securely
* stop the counters from updating as system-wide / global
* values.
*
* Automatic reports now include a context ID so reports can be
* filtered on the cpu but it's not worth trying to
* automatically subtract/hide counter progress for other
* contexts while filtering since we can't stop userspace
* issuing MI_REPORT_PERF_COUNT commands which would still
* provide a side-band view of the real values.
*
* To allow userspace (such as Mesa/GL_INTEL_performance_query)
* to normalize counters for a single filtered context then it
* needs be forwarded bookend context-switch reports so that it
* can track switches in between MI_REPORT_PERF_COUNT commands
* and can itself subtract/ignore the progress of counters
* associated with other contexts. Note that the hardware
* automatically triggers reports when switching to a new
* context which are tagged with the ID of the newly active
* context. To avoid the complexity (and likely fragility) of
* reading ahead while parsing reports to try and minimize
* forwarding redundant context switch reports (i.e. between
* other, unrelated contexts) we simply elect to forward them
* all.
*
* We don't rely solely on the reason field to identify context
* switches since it's not-uncommon for periodic samples to
* identify a switch before any 'context switch' report.
*/
if (!dev_priv->perf.oa.exclusive_stream->ctx ||
dev_priv->perf.oa.specific_ctx_id == ctx_id ||
(dev_priv->perf.oa.oa_buffer.last_ctx_id ==
dev_priv->perf.oa.specific_ctx_id) ||
reason & OAREPORT_REASON_CTX_SWITCH) {
/*
* While filtering for a single context we avoid
* leaking the IDs of other contexts.
*/
if (dev_priv->perf.oa.exclusive_stream->ctx &&
dev_priv->perf.oa.specific_ctx_id != ctx_id) {
report32[2] = INVALID_CTX_ID;
}
ret = append_oa_sample(stream, buf, count, offset,
report);
if (ret)
break;
dev_priv->perf.oa.oa_buffer.last_ctx_id = ctx_id;
}
/*
* The above reason 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;
}
if (start_offset != *offset) {
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/*
* We removed the gtt_offset for the copy loop above, indexing
* relative to oa_buf_base so put back here...
*/
head += gtt_offset;
I915_WRITE(GEN8_OAHEADPTR, head & GEN8_OAHEADPTR_MASK);
dev_priv->perf.oa.oa_buffer.head = head;
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
}
return ret;
}
/**
* gen8_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 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.
*
* NB: some data may be successfully copied to the userspace buffer
* even if an error is returned, and this is reflected in the
* updated @offset.
*
* Returns: zero on success or a negative error code
*/
static int gen8_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;
u32 oastatus;
int ret;
if (WARN_ON(!dev_priv->perf.oa.oa_buffer.vaddr))
return -EIO;
oastatus = I915_READ(GEN8_OASTATUS);
/*
* We treat OABUFFER_OVERFLOW as a significant error:
*
* Although theoretically we could handle this more gracefully
* sometimes, some Gens don't correctly suppress certain
* automatically triggered reports in this condition and so we
* have to assume that old reports are now being trampled
* over.
*
* Considering how we don't currently give userspace control
* over the OA buffer size and always configure a large 16MB
* buffer, then a buffer overflow does anyway likely indicate
* that something has gone quite badly wrong.
*/
if (oastatus & GEN8_OASTATUS_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 (exponent = %d): force restart\n",
dev_priv->perf.oa.period_exponent);
dev_priv->perf.oa.ops.oa_disable(dev_priv);
dev_priv->perf.oa.ops.oa_enable(dev_priv);
/*
* Note: .oa_enable() is expected to re-init the oabuffer and
* reset GEN8_OASTATUS for us
*/
oastatus = I915_READ(GEN8_OASTATUS);
}
if (oastatus & GEN8_OASTATUS_REPORT_LOST) {
ret = append_oa_status(stream, buf, count, offset,
DRM_I915_PERF_RECORD_OA_REPORT_LOST);
if (ret)
return ret;
I915_WRITE(GEN8_OASTATUS,
oastatus & ~GEN8_OASTATUS_REPORT_LOST);
}
return gen8_append_oa_reports(stream, buf, count, offset);
}
/**
* 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
*
* 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 tail chases the head?... 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)
{
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;
u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
u32 mask = (OA_BUFFER_SIZE - 1);
size_t start_offset = *offset;
unsigned long flags;
unsigned int aged_tail_idx;
u32 head, tail;
u32 taken;
int ret = 0;
if (WARN_ON(!stream->enabled))
return -EIO;
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
head = dev_priv->perf.oa.oa_buffer.head;
aged_tail_idx = dev_priv->perf.oa.oa_buffer.aged_tail_idx;
tail = dev_priv->perf.oa.oa_buffer.tails[aged_tail_idx].offset;
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/* An invalid tail pointer here means we're still waiting for the poll
* hrtimer callback to give us a pointer
*/
if (tail == INVALID_TAIL_PTR)
return -EAGAIN;
/* NB: oa_buffer.head/tail include the gtt_offset which we don't want
* while indexing relative to oa_buf_base.
*/
head -= gtt_offset;
tail -= gtt_offset;
/* An out of bounds or misaligned head or tail pointer implies a driver
* bug since we validate + align the tail pointers we read from the
* hardware and we are in full control of the head pointer which should
* only be incremented by multiples of the report size (notably also
* all a power of two).
*/
if (WARN_ONCE(head > OA_BUFFER_SIZE || head % report_size ||
tail > OA_BUFFER_SIZE || tail % report_size,
"Inconsistent OA buffer pointers: head = %u, tail = %u\n",
head, tail))
return -EIO;
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) {
if (__ratelimit(&dev_priv->perf.oa.spurious_report_rs))
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;
}
if (start_offset != *offset) {
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/* We removed the gtt_offset for the copy loop above, indexing
* relative to oa_buf_base so put back here...
*/
head += gtt_offset;
I915_WRITE(GEN7_OASTATUS2,
((head & GEN7_OASTATUS2_HEAD_MASK) |
OA_MEM_SELECT_GGTT));
dev_priv->perf.oa.oa_buffer.head = head;
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
}
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;
u32 oastatus1;
int ret;
if (WARN_ON(!dev_priv->perf.oa.oa_buffer.vaddr))
return -EIO;
oastatus1 = I915_READ(GEN7_OASTATUS1);
/* 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 (exponent = %d): force restart\n",
dev_priv->perf.oa.period_exponent);
dev_priv->perf.oa.ops.oa_disable(dev_priv);
dev_priv->perf.oa.ops.oa_enable(dev_priv);
oastatus1 = I915_READ(GEN7_OASTATUS1);
}
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;
}
return gen7_append_oa_reports(stream, buf, count, offset);
}
/**
* 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;
return wait_event_interruptible(dev_priv->perf.oa.poll_wq,
oa_buffer_check_unlocked(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;
if (HAS_LOGICAL_RING_CONTEXTS(dev_priv)) {
dev_priv->perf.oa.specific_ctx_id = stream->ctx->hw_id;
} else {
struct intel_engine_cs *engine = dev_priv->engine[RCS];
struct intel_ring *ring;
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...
*/
ring = engine->context_pin(engine, stream->ctx);
mutex_unlock(&dev_priv->drm.struct_mutex);
if (IS_ERR(ring))
return PTR_ERR(ring);
/*
* 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);
}
return 0;
}
/**
* 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;
if (HAS_LOGICAL_RING_CONTEXTS(dev_priv)) {
dev_priv->perf.oa.specific_ctx_id = INVALID_CTX_ID;
} else {
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);
/*
* Unset exclusive_stream first, it will be checked while disabling
* the metric set on gen8+.
*/
mutex_lock(&dev_priv->drm.struct_mutex);
dev_priv->perf.oa.exclusive_stream = NULL;
dev_priv->perf.oa.ops.disable_metric_set(dev_priv);
mutex_unlock(&dev_priv->drm.struct_mutex);
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);
put_oa_config(dev_priv, stream->oa_config);
if (dev_priv->perf.oa.spurious_report_rs.missed) {
DRM_NOTE("%d spurious OA report notices suppressed due to ratelimiting\n",
dev_priv->perf.oa.spurious_report_rs.missed);
}
}
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);
unsigned long flags;
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/* 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 */
dev_priv->perf.oa.oa_buffer.head = gtt_offset;
I915_WRITE(GEN7_OABUFFER, gtt_offset);
I915_WRITE(GEN7_OASTATUS1, gtt_offset | OABUFFER_SIZE_16M); /* tail */
/* Mark that we need updated tail pointers to read from... */
dev_priv->perf.oa.oa_buffer.tails[0].offset = INVALID_TAIL_PTR;
dev_priv->perf.oa.oa_buffer.tails[1].offset = INVALID_TAIL_PTR;
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/* 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 void gen8_init_oa_buffer(struct drm_i915_private *dev_priv)
{
u32 gtt_offset = i915_ggtt_offset(dev_priv->perf.oa.oa_buffer.vma);
unsigned long flags;
spin_lock_irqsave(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
I915_WRITE(GEN8_OASTATUS, 0);
I915_WRITE(GEN8_OAHEADPTR, gtt_offset);
dev_priv->perf.oa.oa_buffer.head = gtt_offset;
I915_WRITE(GEN8_OABUFFER_UDW, 0);
/*
* PRM says:
*
* "This MMIO must be set before the OATAILPTR
* register and after the OAHEADPTR register. This is
* to enable proper functionality of the overflow
* bit."
*/
I915_WRITE(GEN8_OABUFFER, gtt_offset |
OABUFFER_SIZE_16M | OA_MEM_SELECT_GGTT);
I915_WRITE(GEN8_OATAILPTR, gtt_offset & GEN8_OATAILPTR_MASK);
/* Mark that we need updated tail pointers to read from... */
dev_priv->perf.oa.oa_buffer.tails[0].offset = INVALID_TAIL_PTR;
dev_priv->perf.oa.oa_buffer.tails[1].offset = INVALID_TAIL_PTR;
/*
* Reset state used to recognise context switches, affecting which
* reports we will forward to userspace while filtering for a single
* context.
*/
dev_priv->perf.oa.oa_buffer.last_ctx_id = INVALID_CTX_ID;
spin_unlock_irqrestore(&dev_priv->perf.oa.oa_buffer.ptr_lock, flags);
/*
* 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 gen8_append_oa_reports() that looks at the
* reason 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,
u32 n_regs)
{
u32 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,
const struct i915_oa_config *oa_config)
{
/* 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, oa_config->mux_regs, oa_config->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, oa_config->b_counter_regs,
oa_config->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));
}
/*
* NB: It must always remain pointer safe to run this even if the OA unit
* has been disabled.
*
* It's fine to put out-of-date values into these per-context registers
* in the case that the OA unit has been disabled.
*/
static void gen8_update_reg_state_unlocked(struct i915_gem_context *ctx,
u32 *reg_state,
const struct i915_oa_config *oa_config)
{
struct drm_i915_private *dev_priv = ctx->i915;
u32 ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset;
u32 ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset;
/* The MMIO offsets for Flex EU registers aren't contiguous */
u32 flex_mmio[] = {
i915_mmio_reg_offset(EU_PERF_CNTL0),
i915_mmio_reg_offset(EU_PERF_CNTL1),
i915_mmio_reg_offset(EU_PERF_CNTL2),
i915_mmio_reg_offset(EU_PERF_CNTL3),
i915_mmio_reg_offset(EU_PERF_CNTL4),
i915_mmio_reg_offset(EU_PERF_CNTL5),
i915_mmio_reg_offset(EU_PERF_CNTL6),
};
int i;
reg_state[ctx_oactxctrl] = i915_mmio_reg_offset(GEN8_OACTXCONTROL);
reg_state[ctx_oactxctrl+1] = (dev_priv->perf.oa.period_exponent <<
GEN8_OA_TIMER_PERIOD_SHIFT) |
(dev_priv->perf.oa.periodic ?
GEN8_OA_TIMER_ENABLE : 0) |
GEN8_OA_COUNTER_RESUME;
for (i = 0; i < ARRAY_SIZE(flex_mmio); i++) {
u32 state_offset = ctx_flexeu0 + i * 2;
u32 mmio = flex_mmio[i];
/*
* This arbitrary default will select the 'EU FPU0 Pipeline
* Active' event. In the future it's anticipated that there
* will be an explicit 'No Event' we can select, but not yet...
*/
u32 value = 0;
if (oa_config) {
u32 j;
for (j = 0; j < oa_config->flex_regs_len; j++) {
if (i915_mmio_reg_offset(oa_config->flex_regs[j].addr) == mmio) {
value = oa_config->flex_regs[j].value;
break;
}
}
}
reg_state[state_offset] = mmio;
reg_state[state_offset+1] = value;
}
}
/*
* Same as gen8_update_reg_state_unlocked only through the batchbuffer. This
* is only used by the kernel context.
*/
static int gen8_emit_oa_config(struct i915_request *rq,
const struct i915_oa_config *oa_config)
{
struct drm_i915_private *dev_priv = rq->i915;
/* The MMIO offsets for Flex EU registers aren't contiguous */
u32 flex_mmio[] = {
i915_mmio_reg_offset(EU_PERF_CNTL0),
i915_mmio_reg_offset(EU_PERF_CNTL1),
i915_mmio_reg_offset(EU_PERF_CNTL2),
i915_mmio_reg_offset(EU_PERF_CNTL3),
i915_mmio_reg_offset(EU_PERF_CNTL4),
i915_mmio_reg_offset(EU_PERF_CNTL5),
i915_mmio_reg_offset(EU_PERF_CNTL6),
};
u32 *cs;
int i;
cs = intel_ring_begin(rq, ARRAY_SIZE(flex_mmio) * 2 + 4);
if (IS_ERR(cs))
return PTR_ERR(cs);
*cs++ = MI_LOAD_REGISTER_IMM(ARRAY_SIZE(flex_mmio) + 1);
*cs++ = i915_mmio_reg_offset(GEN8_OACTXCONTROL);
*cs++ = (dev_priv->perf.oa.period_exponent << GEN8_OA_TIMER_PERIOD_SHIFT) |
(dev_priv->perf.oa.periodic ? GEN8_OA_TIMER_ENABLE : 0) |
GEN8_OA_COUNTER_RESUME;
for (i = 0; i < ARRAY_SIZE(flex_mmio); i++) {
u32 mmio = flex_mmio[i];
/*
* This arbitrary default will select the 'EU FPU0 Pipeline
* Active' event. In the future it's anticipated that there
* will be an explicit 'No Event' we can select, but not
* yet...
*/
u32 value = 0;
if (oa_config) {
u32 j;
for (j = 0; j < oa_config->flex_regs_len; j++) {
if (i915_mmio_reg_offset(oa_config->flex_regs[j].addr) == mmio) {
value = oa_config->flex_regs[j].value;
break;
}
}
}
*cs++ = mmio;
*cs++ = value;
}
*cs++ = MI_NOOP;
intel_ring_advance(rq, cs);
return 0;
}
static int gen8_switch_to_updated_kernel_context(struct drm_i915_private *dev_priv,
const struct i915_oa_config *oa_config)
{
struct intel_engine_cs *engine = dev_priv->engine[RCS];
struct i915_gem_timeline *timeline;
struct i915_request *rq;
int ret;
lockdep_assert_held(&dev_priv->drm.struct_mutex);
i915_retire_requests(dev_priv);
rq = i915_request_alloc(engine, dev_priv->kernel_context);
if (IS_ERR(rq))
return PTR_ERR(rq);
ret = gen8_emit_oa_config(rq, oa_config);
if (ret) {
i915_request_add(rq);
return ret;
}
/* Queue this switch after all other activity */
list_for_each_entry(timeline, &dev_priv->gt.timelines, link) {
struct i915_request *prev;
struct intel_timeline *tl;
tl = &timeline->engine[engine->id];
prev = i915_gem_active_raw(&tl->last_request,
&dev_priv->drm.struct_mutex);
if (prev)
i915_sw_fence_await_sw_fence_gfp(&rq->submit,
&prev->submit,
GFP_KERNEL);
}
i915_request_add(rq);
return 0;
}
/*
* Manages updating the per-context aspects of the OA stream
* configuration across all contexts.
*
* The awkward consideration here is that OACTXCONTROL controls the
* exponent for periodic sampling which is primarily used for system
* wide profiling where we'd like a consistent sampling period even in
* the face of context switches.
*
* Our approach of updating the register state context (as opposed to
* say using a workaround batch buffer) ensures that the hardware
* won't automatically reload an out-of-date timer exponent even
* transiently before a WA BB could be parsed.
*
* This function needs to:
* - Ensure the currently running context's per-context OA state is
* updated
* - Ensure that all existing contexts will have the correct per-context
* OA state if they are scheduled for use.
* - Ensure any new contexts will be initialized with the correct
* per-context OA state.
*
* Note: it's only the RCS/Render context that has any OA state.
*/
static int gen8_configure_all_contexts(struct drm_i915_private *dev_priv,
const struct i915_oa_config *oa_config)
{
struct i915_gem_context *ctx;
int ret;
unsigned int wait_flags = I915_WAIT_LOCKED;
lockdep_assert_held(&dev_priv->drm.struct_mutex);
/* Switch away from any user context. */
ret = gen8_switch_to_updated_kernel_context(dev_priv, oa_config);
if (ret)
goto out;
/*
* The OA register config is setup through the context image. This image
* might be written to by the GPU on context switch (in particular on
* lite-restore). This means we can't safely update a context's image,
* if this context is scheduled/submitted to run on the GPU.
*
* We could emit the OA register config through the batch buffer but
* this might leave small interval of time where the OA unit is
* configured at an invalid sampling period.
*
* So far the best way to work around this issue seems to be draining
* the GPU from any submitted work.
*/
ret = i915_gem_wait_for_idle(dev_priv, wait_flags);
if (ret)
goto out;
/* Update all contexts now that we've stalled the submission. */
list_for_each_entry(ctx, &dev_priv->contexts.list, link) {
struct intel_context *ce = &ctx->engine[RCS];
u32 *regs;
/* OA settings will be set upon first use */
if (!ce->state)
continue;
regs = i915_gem_object_pin_map(ce->state->obj, I915_MAP_WB);
if (IS_ERR(regs)) {
ret = PTR_ERR(regs);
goto out;
}
ce->state->obj->mm.dirty = true;
regs += LRC_STATE_PN * PAGE_SIZE / sizeof(*regs);
gen8_update_reg_state_unlocked(ctx, regs, oa_config);
i915_gem_object_unpin_map(ce->state->obj);
}
out:
return ret;
}
static int gen8_enable_metric_set(struct drm_i915_private *dev_priv,
const struct i915_oa_config *oa_config)
{
int ret;
/*
* We disable slice/unslice clock ratio change reports on SKL since
* they are too noisy. The HW generates a lot of redundant reports
* where the ratio hasn't really changed causing a lot of redundant
* work to processes and increasing the chances we'll hit buffer
* overruns.
*
* Although we don't currently use the 'disable overrun' OABUFFER
* feature it's worth noting that clock ratio reports have to be
* disabled before considering to use that feature since the HW doesn't
* correctly block these reports.
*
* Currently none of the high-level metrics we have depend on knowing
* this ratio to normalize.
*
* Note: This register is not power context saved and restored, but
* that's OK considering that we disable RC6 while the OA unit is
* enabled.
*
* The _INCLUDE_CLK_RATIO bit allows the slice/unslice frequency to
* be read back from automatically triggered reports, as part of the
* RPT_ID field.
*/
if (IS_GEN9(dev_priv) || IS_GEN10(dev_priv)) {
I915_WRITE(GEN8_OA_DEBUG,
_MASKED_BIT_ENABLE(GEN9_OA_DEBUG_DISABLE_CLK_RATIO_REPORTS |
GEN9_OA_DEBUG_INCLUDE_CLK_RATIO));
}
/*
* Update all contexts prior writing the mux configurations as we need
* to make sure all slices/subslices are ON before writing to NOA
* registers.
*/
ret = gen8_configure_all_contexts(dev_priv, oa_config);
if (ret)
return ret;
config_oa_regs(dev_priv, oa_config->mux_regs, oa_config->mux_regs_len);
config_oa_regs(dev_priv, oa_config->b_counter_regs,
oa_config->b_counter_regs_len);
return 0;
}
static void gen8_disable_metric_set(struct drm_i915_private *dev_priv)
{
/* Reset all contexts' slices/subslices configurations. */
gen8_configure_all_contexts(dev_priv, NULL);
I915_WRITE(GDT_CHICKEN_BITS, (I915_READ(GDT_CHICKEN_BITS) &
~GT_NOA_ENABLE));
}
static void gen10_disable_metric_set(struct drm_i915_private *dev_priv)
{
/* Reset all contexts' slices/subslices configurations. */
gen8_configure_all_contexts(dev_priv, NULL);
/* Make sure we disable noa to save power. */
I915_WRITE(RPM_CONFIG1,
I915_READ(RPM_CONFIG1) & ~GEN10_GT_NOA_ENABLE);
}
static void gen7_oa_enable(struct drm_i915_private *dev_priv)
{
/*
* 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);
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 gen8_oa_enable(struct drm_i915_private *dev_priv)
{
u32 report_format = dev_priv->perf.oa.oa_buffer.format;
/*
* 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.
*/
gen8_init_oa_buffer(dev_priv);
/*
* Note: we don't rely on the hardware to perform single context
* filtering and instead filter on the cpu based on the context-id
* field of reports
*/
I915_WRITE(GEN8_OACONTROL, (report_format <<
GEN8_OA_REPORT_FORMAT_SHIFT) |
GEN8_OA_COUNTER_ENABLE);
}
/**
* 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);
}
static void gen8_oa_disable(struct drm_i915_private *dev_priv)
{
I915_WRITE(GEN8_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 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->oa_format) {
DRM_DEBUG("OA report format not specified\n");
return -EINVAL;
}
/* We set up some ratelimit state to potentially throttle any _NOTES
* about spurious, invalid OA reports which we don't forward to
* userspace.
*
* The initialization is associated with opening the stream (not driver
* init) considering we print a _NOTE about any throttling when closing
* the stream instead of waiting until driver _fini which no one would
* ever see.
*
* Using the same limiting factors as printk_ratelimit()
*/
ratelimit_state_init(&dev_priv->perf.oa.spurious_report_rs,
5 * HZ, 10);
/* Since we use a DRM_NOTE for spurious reports it would be
* inconsistent to let __ratelimit() automatically print a warning for
* throttling.
*/
ratelimit_set_flags(&dev_priv->perf.oa.spurious_report_rs,
RATELIMIT_MSG_ON_RELEASE);
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.periodic = props->oa_periodic;
if (dev_priv->perf.oa.periodic)
dev_priv->perf.oa.period_exponent = props->oa_period_exponent;
if (stream->ctx) {
ret = oa_get_render_ctx_id(stream);
if (ret)
return ret;
}
ret = get_oa_config(dev_priv, props->metrics_set, &stream->oa_config);
if (ret)
goto err_config;
/* 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 = alloc_oa_buffer(dev_priv);
if (ret)
goto err_oa_buf_alloc;
ret = i915_mutex_lock_interruptible(&dev_priv->drm);
if (ret)
goto err_lock;
ret = dev_priv->perf.oa.ops.enable_metric_set(dev_priv,
stream->oa_config);
if (ret)
goto err_enable;
stream->ops = &i915_oa_stream_ops;
dev_priv->perf.oa.exclusive_stream = stream;
mutex_unlock(&dev_priv->drm.struct_mutex);
return 0;
err_enable:
dev_priv->perf.oa.ops.disable_metric_set(dev_priv);
mutex_unlock(&dev_priv->drm.struct_mutex);
err_lock:
free_oa_buffer(dev_priv);
err_oa_buf_alloc:
put_oa_config(dev_priv, stream->oa_config);
intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
intel_runtime_pm_put(dev_priv);
err_config:
if (stream->ctx)
oa_put_render_ctx_id(stream);
return ret;
}
void i915_oa_init_reg_state(struct intel_engine_cs *engine,
struct i915_gem_context *ctx,
u32 *reg_state)
{
struct i915_perf_stream *stream;
if (engine->id != RCS)
return;
stream = engine->i915->perf.oa.exclusive_stream;
if (stream)
gen8_update_reg_state_unlocked(ctx, reg_state, stream->oa_config);
}
/**
* 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);
}
/* We allow the poll checking to sometimes report false positive EPOLLIN
* events where we might actually report EAGAIN on read() if there's
* not really any data available. In this situation though we don't
* want to enter a busy loop between poll() reporting a EPOLLIN event
* and read() returning -EAGAIN. Clearing the oa.pollin state here
* effectively ensures we back off until the next hrtimer callback
* before reporting another EPOLLIN event.
*/
if (ret >= 0 || ret == -EAGAIN) {
/* 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 (oa_buffer_check_unlocked(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 __poll_t i915_perf_poll_locked(struct drm_i915_private *dev_priv,
struct i915_perf_stream *stream,
struct file *file,
poll_table *wait)
{
__poll_t 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 |= EPOLLIN;
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 __poll_t 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;
__poll_t 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(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,
/* Our ioctl have no arguments, so it's safe to use the same function
* to handle 32bits compatibility.
*/
.compat_ioctl = i915_perf_ioctl,
};
/**
* 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;
bool privileged_op = true;
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 = i915_gem_context_lookup(file_priv, ctx_handle);
if (!specific_ctx) {
DRM_DEBUG("Failed to look up context with ID %u for opening perf stream\n",
ctx_handle);
ret = -ENOENT;
goto err;
}
}
/*
* On Haswell the OA unit supports clock gating off for a specific
* context and in this mode there's no visibility of metrics for the
* rest of the system, which we consider acceptable for a
* non-privileged client.
*
* For Gen8+ the OA unit no longer supports clock gating off for a
* specific context and the kernel can't securely stop the counters
* from updating as system-wide / global values. Even though we can
* filter reports based on the included context ID we can't block
* clients from seeing the raw / global counter values via
* MI_REPORT_PERF_COUNT commands and so consider it a privileged op to
* enable the OA unit by default.
*/
if (IS_HASWELL(dev_priv) && specific_ctx)
privileged_op = false;
/* 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 (privileged_op &&
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_flags;
}
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);
err_flags:
if (stream->ops->destroy)
stream->ops->destroy(stream);
err_alloc:
kfree(stream);
err_ctx:
if (specific_ctx)
i915_gem_context_put(specific_ctx);
err:
return ret;
}
static u64 oa_exponent_to_ns(struct drm_i915_private *dev_priv, int exponent)
{
return div64_u64(1000000000ULL * (2ULL << exponent),
1000ULL * INTEL_INFO(dev_priv)->cs_timestamp_frequency_khz);
}
/**
* 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;
u32 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;
if (id == 0 || id >= DRM_I915_PERF_PROP_MAX) {
DRM_DEBUG("Unknown i915 perf property ID\n");
return -EINVAL;
}
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) {
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("Out-of-range OA report format %llu\n",
value);
return -EINVAL;
}
if (!dev_priv->perf.oa.oa_formats[value].size) {
DRM_DEBUG("Unsupported OA report format %llu\n",
value);
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
* e.g. every 160ns for HSW, 167ns for BDW/SKL or 104ns
* for BXT. We don't allow such high sampling
* frequencies by default unless root.
*/
BUILD_BUG_ON(sizeof(oa_period) != 8);
oa_period = oa_exponent_to_ns(dev_priv, 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;
case DRM_I915_PERF_PROP_MAX:
MISSING_CASE(id);
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)
{
int ret;
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;
sysfs_attr_init(&dev_priv->perf.oa.test_config.sysfs_metric_id.attr);
if (IS_HASWELL(dev_priv)) {
i915_perf_load_test_config_hsw(dev_priv);
} else if (IS_BROADWELL(dev_priv)) {
i915_perf_load_test_config_bdw(dev_priv);
} else if (IS_CHERRYVIEW(dev_priv)) {
i915_perf_load_test_config_chv(dev_priv);
} else if (IS_SKYLAKE(dev_priv)) {
if (IS_SKL_GT2(dev_priv))
i915_perf_load_test_config_sklgt2(dev_priv);
else if (IS_SKL_GT3(dev_priv))
i915_perf_load_test_config_sklgt3(dev_priv);
else if (IS_SKL_GT4(dev_priv))
i915_perf_load_test_config_sklgt4(dev_priv);
} else if (IS_BROXTON(dev_priv)) {
i915_perf_load_test_config_bxt(dev_priv);
} else if (IS_KABYLAKE(dev_priv)) {
if (IS_KBL_GT2(dev_priv))
i915_perf_load_test_config_kblgt2(dev_priv);
else if (IS_KBL_GT3(dev_priv))
i915_perf_load_test_config_kblgt3(dev_priv);
} else if (IS_GEMINILAKE(dev_priv)) {
i915_perf_load_test_config_glk(dev_priv);
} else if (IS_COFFEELAKE(dev_priv)) {
if (IS_CFL_GT2(dev_priv))
i915_perf_load_test_config_cflgt2(dev_priv);
if (IS_CFL_GT3(dev_priv))
i915_perf_load_test_config_cflgt3(dev_priv);
} else if (IS_CANNONLAKE(dev_priv)) {
i915_perf_load_test_config_cnl(dev_priv);
}
if (dev_priv->perf.oa.test_config.id == 0)
goto sysfs_error;
ret = sysfs_create_group(dev_priv->perf.metrics_kobj,
&dev_priv->perf.oa.test_config.sysfs_metric);
if (ret)
goto sysfs_error;
atomic_set(&dev_priv->perf.oa.test_config.ref_count, 1);
goto exit;
sysfs_error:
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 (!dev_priv->perf.metrics_kobj)
return;
sysfs_remove_group(dev_priv->perf.metrics_kobj,
&dev_priv->perf.oa.test_config.sysfs_metric);
kobject_put(dev_priv->perf.metrics_kobj);
dev_priv->perf.metrics_kobj = NULL;
}
static bool gen8_is_valid_flex_addr(struct drm_i915_private *dev_priv, u32 addr)
{
static const i915_reg_t flex_eu_regs[] = {
EU_PERF_CNTL0,
EU_PERF_CNTL1,
EU_PERF_CNTL2,
EU_PERF_CNTL3,
EU_PERF_CNTL4,
EU_PERF_CNTL5,
EU_PERF_CNTL6,
};
int i;
for (i = 0; i < ARRAY_SIZE(flex_eu_regs); i++) {
if (i915_mmio_reg_offset(flex_eu_regs[i]) == addr)
return true;
}
return false;
}
static bool gen7_is_valid_b_counter_addr(struct drm_i915_private *dev_priv, u32 addr)
{
return (addr >= i915_mmio_reg_offset(OASTARTTRIG1) &&
addr <= i915_mmio_reg_offset(OASTARTTRIG8)) ||
(addr >= i915_mmio_reg_offset(OAREPORTTRIG1) &&
addr <= i915_mmio_reg_offset(OAREPORTTRIG8)) ||
(addr >= i915_mmio_reg_offset(OACEC0_0) &&
addr <= i915_mmio_reg_offset(OACEC7_1));
}
static bool gen7_is_valid_mux_addr(struct drm_i915_private *dev_priv, u32 addr)
{
return addr == i915_mmio_reg_offset(HALF_SLICE_CHICKEN2) ||
(addr >= i915_mmio_reg_offset(MICRO_BP0_0) &&
addr <= i915_mmio_reg_offset(NOA_WRITE)) ||
(addr >= i915_mmio_reg_offset(OA_PERFCNT1_LO) &&
addr <= i915_mmio_reg_offset(OA_PERFCNT2_HI)) ||
(addr >= i915_mmio_reg_offset(OA_PERFMATRIX_LO) &&
addr <= i915_mmio_reg_offset(OA_PERFMATRIX_HI));
}
static bool gen8_is_valid_mux_addr(struct drm_i915_private *dev_priv, u32 addr)
{
return gen7_is_valid_mux_addr(dev_priv, addr) ||
addr == i915_mmio_reg_offset(WAIT_FOR_RC6_EXIT) ||
(addr >= i915_mmio_reg_offset(RPM_CONFIG0) &&
addr <= i915_mmio_reg_offset(NOA_CONFIG(8)));
}
static bool gen10_is_valid_mux_addr(struct drm_i915_private *dev_priv, u32 addr)
{
return gen8_is_valid_mux_addr(dev_priv, addr) ||
(addr >= i915_mmio_reg_offset(OA_PERFCNT3_LO) &&
addr <= i915_mmio_reg_offset(OA_PERFCNT4_HI));
}
static bool hsw_is_valid_mux_addr(struct drm_i915_private *dev_priv, u32 addr)
{
return gen7_is_valid_mux_addr(dev_priv, addr) ||
(addr >= 0x25100 && addr <= 0x2FF90) ||
(addr >= i915_mmio_reg_offset(HSW_MBVID2_NOA0) &&
addr <= i915_mmio_reg_offset(HSW_MBVID2_NOA9)) ||
addr == i915_mmio_reg_offset(HSW_MBVID2_MISR0);
}
static bool chv_is_valid_mux_addr(struct drm_i915_private *dev_priv, u32 addr)
{
return gen7_is_valid_mux_addr(dev_priv, addr) ||
(addr >= 0x182300 && addr <= 0x1823A4);
}
static uint32_t mask_reg_value(u32 reg, u32 val)
{
/* HALF_SLICE_CHICKEN2 is programmed with a the
* WaDisableSTUnitPowerOptimization workaround. Make sure the value
* programmed by userspace doesn't change this.
*/
if (i915_mmio_reg_offset(HALF_SLICE_CHICKEN2) == reg)
val = val & ~_MASKED_BIT_ENABLE(GEN8_ST_PO_DISABLE);
/* WAIT_FOR_RC6_EXIT has only one bit fullfilling the function
* indicated by its name and a bunch of selection fields used by OA
* configs.
*/
if (i915_mmio_reg_offset(WAIT_FOR_RC6_EXIT) == reg)
val = val & ~_MASKED_BIT_ENABLE(HSW_WAIT_FOR_RC6_EXIT_ENABLE);
return val;
}
static struct i915_oa_reg *alloc_oa_regs(struct drm_i915_private *dev_priv,
bool (*is_valid)(struct drm_i915_private *dev_priv, u32 addr),
u32 __user *regs,
u32 n_regs)
{
struct i915_oa_reg *oa_regs;
int err;
u32 i;
if (!n_regs)
return NULL;
if (!access_ok(VERIFY_READ, regs, n_regs * sizeof(u32) * 2))
return ERR_PTR(-EFAULT);
/* No is_valid function means we're not allowing any register to be programmed. */
GEM_BUG_ON(!is_valid);
if (!is_valid)
return ERR_PTR(-EINVAL);
oa_regs = kmalloc_array(n_regs, sizeof(*oa_regs), GFP_KERNEL);
if (!oa_regs)
return ERR_PTR(-ENOMEM);
for (i = 0; i < n_regs; i++) {
u32 addr, value;
err = get_user(addr, regs);
if (err)
goto addr_err;
if (!is_valid(dev_priv, addr)) {
DRM_DEBUG("Invalid oa_reg address: %X\n", addr);
err = -EINVAL;
goto addr_err;
}
err = get_user(value, regs + 1);
if (err)
goto addr_err;
oa_regs[i].addr = _MMIO(addr);
oa_regs[i].value = mask_reg_value(addr, value);
regs += 2;
}
return oa_regs;
addr_err:
kfree(oa_regs);
return ERR_PTR(err);
}
static ssize_t show_dynamic_id(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct i915_oa_config *oa_config =
container_of(attr, typeof(*oa_config), sysfs_metric_id);
return sprintf(buf, "%d\n", oa_config->id);
}
static int create_dynamic_oa_sysfs_entry(struct drm_i915_private *dev_priv,
struct i915_oa_config *oa_config)
{
sysfs_attr_init(&oa_config->sysfs_metric_id.attr);
oa_config->sysfs_metric_id.attr.name = "id";
oa_config->sysfs_metric_id.attr.mode = S_IRUGO;
oa_config->sysfs_metric_id.show = show_dynamic_id;
oa_config->sysfs_metric_id.store = NULL;
oa_config->attrs[0] = &oa_config->sysfs_metric_id.attr;
oa_config->attrs[1] = NULL;
oa_config->sysfs_metric.name = oa_config->uuid;
oa_config->sysfs_metric.attrs = oa_config->attrs;
return sysfs_create_group(dev_priv->perf.metrics_kobj,
&oa_config->sysfs_metric);
}
/**
* i915_perf_add_config_ioctl - DRM ioctl() for userspace to add a new OA config
* @dev: drm device
* @data: ioctl data (pointer to struct drm_i915_perf_oa_config) copied from
* userspace (unvalidated)
* @file: drm file
*
* Validates the submitted OA register to be saved into a new OA config that
* can then be used for programming the OA unit and its NOA network.
*
* Returns: A new allocated config number to be used with the perf open ioctl
* or a negative error code on failure.
*/
int i915_perf_add_config_ioctl(struct drm_device *dev, void *data,
struct drm_file *file)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_perf_oa_config *args = data;
struct i915_oa_config *oa_config, *tmp;
int err, id;
if (!dev_priv->perf.initialized) {
DRM_DEBUG("i915 perf interface not available for this system\n");
return -ENOTSUPP;
}
if (!dev_priv->perf.metrics_kobj) {
DRM_DEBUG("OA metrics weren't advertised via sysfs\n");
return -EINVAL;
}
if (i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
DRM_DEBUG("Insufficient privileges to add i915 OA config\n");
return -EACCES;
}
if ((!args->mux_regs_ptr || !args->n_mux_regs) &&
(!args->boolean_regs_ptr || !args->n_boolean_regs) &&
(!args->flex_regs_ptr || !args->n_flex_regs)) {
DRM_DEBUG("No OA registers given\n");
return -EINVAL;
}
oa_config = kzalloc(sizeof(*oa_config), GFP_KERNEL);
if (!oa_config) {
DRM_DEBUG("Failed to allocate memory for the OA config\n");
return -ENOMEM;
}
atomic_set(&oa_config->ref_count, 1);
if (!uuid_is_valid(args->uuid)) {
DRM_DEBUG("Invalid uuid format for OA config\n");
err = -EINVAL;
goto reg_err;
}
/* Last character in oa_config->uuid will be 0 because oa_config is
* kzalloc.
*/
memcpy(oa_config->uuid, args->uuid, sizeof(args->uuid));
oa_config->mux_regs_len = args->n_mux_regs;
oa_config->mux_regs =
alloc_oa_regs(dev_priv,
dev_priv->perf.oa.ops.is_valid_mux_reg,
u64_to_user_ptr(args->mux_regs_ptr),
args->n_mux_regs);
if (IS_ERR(oa_config->mux_regs)) {
DRM_DEBUG("Failed to create OA config for mux_regs\n");
err = PTR_ERR(oa_config->mux_regs);
goto reg_err;
}
oa_config->b_counter_regs_len = args->n_boolean_regs;
oa_config->b_counter_regs =
alloc_oa_regs(dev_priv,
dev_priv->perf.oa.ops.is_valid_b_counter_reg,
u64_to_user_ptr(args->boolean_regs_ptr),
args->n_boolean_regs);
if (IS_ERR(oa_config->b_counter_regs)) {
DRM_DEBUG("Failed to create OA config for b_counter_regs\n");
err = PTR_ERR(oa_config->b_counter_regs);
goto reg_err;
}
if (INTEL_GEN(dev_priv) < 8) {
if (args->n_flex_regs != 0) {
err = -EINVAL;
goto reg_err;
}
} else {
oa_config->flex_regs_len = args->n_flex_regs;
oa_config->flex_regs =
alloc_oa_regs(dev_priv,
dev_priv->perf.oa.ops.is_valid_flex_reg,
u64_to_user_ptr(args->flex_regs_ptr),
args->n_flex_regs);
if (IS_ERR(oa_config->flex_regs)) {
DRM_DEBUG("Failed to create OA config for flex_regs\n");
err = PTR_ERR(oa_config->flex_regs);
goto reg_err;
}
}
err = mutex_lock_interruptible(&dev_priv->perf.metrics_lock);
if (err)
goto reg_err;
/* We shouldn't have too many configs, so this iteration shouldn't be
* too costly.
*/
idr_for_each_entry(&dev_priv->perf.metrics_idr, tmp, id) {
if (!strcmp(tmp->uuid, oa_config->uuid)) {
DRM_DEBUG("OA config already exists with this uuid\n");
err = -EADDRINUSE;
goto sysfs_err;
}
}
err = create_dynamic_oa_sysfs_entry(dev_priv, oa_config);
if (err) {
DRM_DEBUG("Failed to create sysfs entry for OA config\n");
goto sysfs_err;
}
/* Config id 0 is invalid, id 1 for kernel stored test config. */
oa_config->id = idr_alloc(&dev_priv->perf.metrics_idr,
oa_config, 2,
0, GFP_KERNEL);
if (oa_config->id < 0) {
DRM_DEBUG("Failed to create sysfs entry for OA config\n");
err = oa_config->id;
goto sysfs_err;
}
mutex_unlock(&dev_priv->perf.metrics_lock);
return oa_config->id;
sysfs_err:
mutex_unlock(&dev_priv->perf.metrics_lock);
reg_err:
put_oa_config(dev_priv, oa_config);
DRM_DEBUG("Failed to add new OA config\n");
return err;
}
/**
* i915_perf_remove_config_ioctl - DRM ioctl() for userspace to remove an OA config
* @dev: drm device
* @data: ioctl data (pointer to u64 integer) copied from userspace
* @file: drm file
*
* Configs can be removed while being used, the will stop appearing in sysfs
* and their content will be freed when the stream using the config is closed.
*
* Returns: 0 on success or a negative error code on failure.
*/
int i915_perf_remove_config_ioctl(struct drm_device *dev, void *data,
struct drm_file *file)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u64 *arg = data;
struct i915_oa_config *oa_config;
int ret;
if (!dev_priv->perf.initialized) {
DRM_DEBUG("i915 perf interface not available for this system\n");
return -ENOTSUPP;
}
if (i915_perf_stream_paranoid && !capable(CAP_SYS_ADMIN)) {
DRM_DEBUG("Insufficient privileges to remove i915 OA config\n");
return -EACCES;
}
ret = mutex_lock_interruptible(&dev_priv->perf.metrics_lock);
if (ret)
goto lock_err;
oa_config = idr_find(&dev_priv->perf.metrics_idr, *arg);
if (!oa_config) {
DRM_DEBUG("Failed to remove unknown OA config\n");
ret = -ENOENT;
goto config_err;
}
GEM_BUG_ON(*arg != oa_config->id);
sysfs_remove_group(dev_priv->perf.metrics_kobj,
&oa_config->sysfs_metric);
idr_remove(&dev_priv->perf.metrics_idr, *arg);
put_oa_config(dev_priv, oa_config);
config_err:
mutex_unlock(&dev_priv->perf.metrics_lock);
lock_err:
return ret;
}
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)) {
dev_priv->perf.oa.ops.is_valid_b_counter_reg =
gen7_is_valid_b_counter_addr;
dev_priv->perf.oa.ops.is_valid_mux_reg =
hsw_is_valid_mux_addr;
dev_priv->perf.oa.ops.is_valid_flex_reg = NULL;
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_hw_tail_read =
gen7_oa_hw_tail_read;
dev_priv->perf.oa.oa_formats = hsw_oa_formats;
} else if (HAS_LOGICAL_RING_CONTEXTS(dev_priv)) {
/* Note: that although we could theoretically also support the
* legacy ringbuffer mode on BDW (and earlier iterations of
* this driver, before upstreaming did this) it didn't seem
* worth the complexity to maintain now that BDW+ enable
* execlist mode by default.
*/
dev_priv->perf.oa.oa_formats = gen8_plus_oa_formats;
dev_priv->perf.oa.ops.init_oa_buffer = gen8_init_oa_buffer;
dev_priv->perf.oa.ops.oa_enable = gen8_oa_enable;
dev_priv->perf.oa.ops.oa_disable = gen8_oa_disable;
dev_priv->perf.oa.ops.read = gen8_oa_read;
dev_priv->perf.oa.ops.oa_hw_tail_read = gen8_oa_hw_tail_read;
if (IS_GEN8(dev_priv) || IS_GEN9(dev_priv)) {
dev_priv->perf.oa.ops.is_valid_b_counter_reg =
gen7_is_valid_b_counter_addr;
dev_priv->perf.oa.ops.is_valid_mux_reg =
gen8_is_valid_mux_addr;
dev_priv->perf.oa.ops.is_valid_flex_reg =
gen8_is_valid_flex_addr;
if (IS_CHERRYVIEW(dev_priv)) {
dev_priv->perf.oa.ops.is_valid_mux_reg =
chv_is_valid_mux_addr;
}
dev_priv->perf.oa.ops.enable_metric_set = gen8_enable_metric_set;
dev_priv->perf.oa.ops.disable_metric_set = gen8_disable_metric_set;
if (IS_GEN8(dev_priv)) {
dev_priv->perf.oa.ctx_oactxctrl_offset = 0x120;
dev_priv->perf.oa.ctx_flexeu0_offset = 0x2ce;
dev_priv->perf.oa.gen8_valid_ctx_bit = (1<<25);
} else {
dev_priv->perf.oa.ctx_oactxctrl_offset = 0x128;
dev_priv->perf.oa.ctx_flexeu0_offset = 0x3de;
dev_priv->perf.oa.gen8_valid_ctx_bit = (1<<16);
}
} else if (IS_GEN10(dev_priv)) {
dev_priv->perf.oa.ops.is_valid_b_counter_reg =
gen7_is_valid_b_counter_addr;
dev_priv->perf.oa.ops.is_valid_mux_reg =
gen10_is_valid_mux_addr;
dev_priv->perf.oa.ops.is_valid_flex_reg =
gen8_is_valid_flex_addr;
dev_priv->perf.oa.ops.enable_metric_set = gen8_enable_metric_set;
dev_priv->perf.oa.ops.disable_metric_set = gen10_disable_metric_set;
dev_priv->perf.oa.ctx_oactxctrl_offset = 0x128;
dev_priv->perf.oa.ctx_flexeu0_offset = 0x3de;
dev_priv->perf.oa.gen8_valid_ctx_bit = (1<<16);
}
}
if (dev_priv->perf.oa.ops.enable_metric_set) {
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.oa.oa_buffer.ptr_lock);
oa_sample_rate_hard_limit = 1000 *
(INTEL_INFO(dev_priv)->cs_timestamp_frequency_khz / 2);
dev_priv->perf.sysctl_header = register_sysctl_table(dev_root);
mutex_init(&dev_priv->perf.metrics_lock);
idr_init(&dev_priv->perf.metrics_idr);
dev_priv->perf.initialized = true;
}
}
static int destroy_config(int id, void *p, void *data)
{
struct drm_i915_private *dev_priv = data;
struct i915_oa_config *oa_config = p;
put_oa_config(dev_priv, oa_config);
return 0;
}
/**
* 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;
idr_for_each(&dev_priv->perf.metrics_idr, destroy_config, dev_priv);
idr_destroy(&dev_priv->perf.metrics_idr);
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;
}
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