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// SPDX-License-Identifier: MIT
/*
* Copyright © 2023-2024 Intel Corporation
*/
#include <linux/errno.h>
#include <linux/perf_event.h>
#include <linux/sysctl.h>
#include <uapi/drm/xe_drm.h>
#include "xe_eu_stall.h"
#include "xe_oa.h"
#include "xe_observation.h"
static u32 xe_observation_paranoid = true;
static struct ctl_table_header *sysctl_header;
/**
* xe_observation_paranoid_check - Gate access to xe observation streams.
*
* When the xe-specific observation_paranoid sysctl is enabled (the
* default), defer to perf_allow_cpu() so that access is governed by the
* same policy as system-wide perf CPU events: kernel.perf_event_paranoid
* plus the security_perf_event_open() LSM hook. When the sysctl has been
* cleared by a privileged user, observation is open to all callers.
*
* Return: 0 if access is permitted, a negative errno otherwise.
*/
int xe_observation_paranoid_check(void)
{
if (!xe_observation_paranoid)
return 0;
return perf_allow_cpu();
}
static int xe_oa_ioctl(struct drm_device *dev, struct drm_xe_observation_param *arg,
struct drm_file *file)
{
switch (arg->observation_op) {
case DRM_XE_OBSERVATION_OP_STREAM_OPEN:
return xe_oa_stream_open_ioctl(dev, arg->param, file);
case DRM_XE_OBSERVATION_OP_ADD_CONFIG:
return xe_oa_add_config_ioctl(dev, arg->param, file);
case DRM_XE_OBSERVATION_OP_REMOVE_CONFIG:
return xe_oa_remove_config_ioctl(dev, arg->param, file);
default:
return -EINVAL;
}
}
static int xe_eu_stall_ioctl(struct drm_device *dev, struct drm_xe_observation_param *arg,
struct drm_file *file)
{
switch (arg->observation_op) {
case DRM_XE_OBSERVATION_OP_STREAM_OPEN:
return xe_eu_stall_stream_open(dev, arg->param, file);
default:
return -EINVAL;
}
}
/**
* xe_observation_ioctl - The top level observation layer ioctl
* @dev: @drm_device
* @data: pointer to struct @drm_xe_observation_param
* @file: @drm_file
*
* The function is called for different observation streams types and
* allows execution of different operations supported by those stream
* types.
*
* Return: 0 on success or a negative error code on failure.
*/
int xe_observation_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
{
struct drm_xe_observation_param *arg = data;
if (arg->extensions)
return -EINVAL;
switch (arg->observation_type) {
case DRM_XE_OBSERVATION_TYPE_OA:
return xe_oa_ioctl(dev, arg, file);
case DRM_XE_OBSERVATION_TYPE_EU_STALL:
return xe_eu_stall_ioctl(dev, arg, file);
default:
return -EINVAL;
}
}
static const struct ctl_table observation_ctl_table[] = {
{
.procname = "observation_paranoid",
.data = &xe_observation_paranoid,
.maxlen = sizeof(xe_observation_paranoid),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
},
};
/**
* xe_observation_sysctl_register - Register the observation_paranoid sysctl
*
* When dev.xe.observation_paranoid is set (the default), access to
* observation streams follows the system-wide perf_allow_cpu() policy:
* kernel.perf_event_paranoid plus the security_perf_event_open() LSM
* hook. A privileged user can clear the sysctl to bypass that gate and
* allow unprivileged access to observation data.
*
* Return: always returns 0
*/
int xe_observation_sysctl_register(void)
{
sysctl_header = register_sysctl("dev/xe", observation_ctl_table);
return 0;
}
/**
* xe_observation_sysctl_unregister - Unregister xe_observation_paranoid sysctl
*/
void xe_observation_sysctl_unregister(void)
{
unregister_sysctl_table(sysctl_header);
}
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