| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20251218113318.774e18c6@fedora>
Date: Thu, 18 Dec 2025 11:33:18 +0100
From: Boris Brezillon <boris.brezillon@...labora.com>
To: Lukas Zapolskas <lukas.zapolskas@....com>
Cc: Liviu Dudau <liviu.dudau@....com>, Maarten Lankhorst
<maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
Simona Vetter <simona@...ll.ch>, Adrián Larumbe
<adrian.larumbe@...labora.com>, nd@....com,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, Mihail
Atanassov <mihail.atanassov@....com>
Subject: Re: [PATCH v6 3/7] drm/panthor: Add panthor perf initialization and
termination
On Mon, 15 Dec 2025 17:14:49 +0000
Lukas Zapolskas <lukas.zapolskas@....com> wrote:
> Added the panthor_perf system initialization and unplug code to allow
> for the handling of userspace sessions to be added in follow-up
> patches.
>
> Signed-off-by: Lukas Zapolskas <lukas.zapolskas@....com>
> Reviewed-by: Adrián Larumbe <adrian.larumbe@...labora.com>
> ---
> drivers/gpu/drm/panthor/panthor_device.c | 2 +
> drivers/gpu/drm/panthor/panthor_device.h | 5 +-
> drivers/gpu/drm/panthor/panthor_perf.c | 63 +++++++++++++++++++++++-
> drivers/gpu/drm/panthor/panthor_perf.h | 1 +
> 4 files changed, 69 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
> index dc237da92340..3063ffbead45 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.c
> +++ b/drivers/gpu/drm/panthor/panthor_device.c
> @@ -120,6 +120,7 @@ void panthor_device_unplug(struct panthor_device *ptdev)
> /* Now, try to cleanly shutdown the GPU before the device resources
> * get reclaimed.
> */
> + panthor_perf_unplug(ptdev);
> panthor_sched_unplug(ptdev);
> panthor_fw_unplug(ptdev);
> panthor_mmu_unplug(ptdev);
> @@ -323,6 +324,7 @@ int panthor_device_init(struct panthor_device *ptdev)
>
> err_disable_autosuspend:
> pm_runtime_dont_use_autosuspend(ptdev->base.dev);
> + panthor_perf_unplug(ptdev);
>
> err_unplug_sched:
> panthor_sched_unplug(ptdev);
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
> index 64b0048de6ac..e1a6250cecc8 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -28,8 +28,8 @@ struct panthor_hw;
> struct panthor_job;
> struct panthor_mmu;
> struct panthor_fw;
> -struct panthor_perfcnt;
> struct panthor_pwr;
> +struct panthor_perf;
> struct panthor_vm;
> struct panthor_vm_pool;
>
> @@ -160,6 +160,9 @@ struct panthor_device {
> /** @devfreq: Device frequency scaling management data. */
> struct panthor_devfreq *devfreq;
>
> + /** @perf: Performance counter management data. */
> + struct panthor_perf *perf;
> +
> /** @unplug: Device unplug related fields. */
> struct {
> /** @lock: Lock used to serialize unplug operations. */
> diff --git a/drivers/gpu/drm/panthor/panthor_perf.c b/drivers/gpu/drm/panthor/panthor_perf.c
> index 842d62826ac3..3a65d6d326e8 100644
> --- a/drivers/gpu/drm/panthor/panthor_perf.c
> +++ b/drivers/gpu/drm/panthor/panthor_perf.c
> @@ -4,6 +4,7 @@
>
> #include <linux/bitops.h>
> #include <drm/panthor_drm.h>
> +#include <drm/drm_print.h>
>
> #include "panthor_device.h"
> #include "panthor_fw.h"
> @@ -22,6 +23,19 @@
> */
> #define PANTHOR_HW_COUNTER_SIZE (sizeof(u32))
>
> +struct panthor_perf {
> + /** @next_session: The ID of the next session. */
> + u32 next_session;
> +
> + /** @session_range: The number of sessions supported at a time. */
> + struct xa_limit session_range;
> +
> + /**
> + * @sessions: Global map of sessions, accessed by their ID.
> + */
> + struct xarray sessions;
Unless there's a need to have global session ID (sessions can be shared
and accessed from different processes), I'd move the xarray to some
panthor_file_perf object and make this session ID per-FD. Actually, I'm
not even sure I see a use case for having more than one session
per-file, so it could even be just a panthor_perf_session pointer and a
lock in panthor_file:
struct panthor_file {
...
struct {
struct mutex lock;
struct panthor_perf_session *session;
} perf;
};
If we want to restrict the total number of sessions, we can have an
atomic_t in panthor_perf, but I think what really matters is the
maximum number of active sessions, and I believe we already have a
counter for that (panthor_perf_sampler::enabled_clients).
> +};
> +
> struct panthor_perf_counter_block {
> struct drm_panthor_perf_block_header header;
> u64 counters[];
> @@ -76,14 +90,61 @@ static void panthor_perf_info_init(struct panthor_device *const ptdev)
> * panthor_perf_init - Initialize the performance counter subsystem.
> * @ptdev: Panthor device
> *
> + * The performance counters require the FW interface to be available to setup the
> + * sampling ringbuffers, so this must be called only after FW is initialized.
> + *
> * Return: 0 on success, negative error code on failure.
> */
> int panthor_perf_init(struct panthor_device *ptdev)
> {
> + struct panthor_perf *perf __free(kfree) = NULL;
> + int ret = 0;
> +
> if (!ptdev)
> return -EINVAL;
>
> panthor_perf_info_init(ptdev);
>
> - return 0;
> + perf = kzalloc(sizeof(*perf), GFP_KERNEL);
> + if (ZERO_OR_NULL_PTR(perf))
> + return -ENOMEM;
> +
> + xa_init_flags(&perf->sessions, XA_FLAGS_ALLOC);
> +
> + perf->session_range = (struct xa_limit) {
> + .min = 0,
> + .max = 1,
> + };
> +
> + drm_info(&ptdev->base, "Performance counter subsystem initialized");
> +
> + ptdev->perf = no_free_ptr(perf);
> +
> + return ret;
> +}
> +
> +/**
> + * panthor_perf_unplug - Terminate the performance counter subsystem.
> + * @ptdev: Panthor device.
> + *
> + * This function will terminate the performance counter control structures and any remaining
> + * sessions, after waiting for any pending interrupts.
> + */
> +void panthor_perf_unplug(struct panthor_device *ptdev)
> +{
> + struct panthor_perf *perf = ptdev->perf;
> +
> + if (!perf)
> + return;
> +
> + if (!xa_empty(&perf->sessions)) {
> + drm_err(&ptdev->base,
> + "Performance counter sessions active when unplugging the driver!");
> + }
> +
> + xa_destroy(&perf->sessions);
> +
> + kfree(ptdev->perf);
> +
> + ptdev->perf = NULL;
> }
> diff --git a/drivers/gpu/drm/panthor/panthor_perf.h b/drivers/gpu/drm/panthor/panthor_perf.h
> index 3c32c24c164c..e4805727b9e7 100644
> --- a/drivers/gpu/drm/panthor/panthor_perf.h
> +++ b/drivers/gpu/drm/panthor/panthor_perf.h
> @@ -10,6 +10,7 @@
> struct panthor_device;
>
> int panthor_perf_init(struct panthor_device *ptdev);
> +void panthor_perf_unplug(struct panthor_device *ptdev);
>
> #endif /* __PANTHOR_PERF_H__ */
>
Powered by blists - more mailing lists