cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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panfrost_gem_shrinker.c (3044B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (C) 2019 Arm Ltd.
      3 *
      4 * Based on msm_gem_freedreno.c:
      5 * Copyright (C) 2016 Red Hat
      6 * Author: Rob Clark <robdclark@gmail.com>
      7 */
      8
      9#include <linux/list.h>
     10
     11#include <drm/drm_device.h>
     12#include <drm/drm_gem_shmem_helper.h>
     13
     14#include "panfrost_device.h"
     15#include "panfrost_gem.h"
     16#include "panfrost_mmu.h"
     17
     18static unsigned long
     19panfrost_gem_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc)
     20{
     21	struct panfrost_device *pfdev =
     22		container_of(shrinker, struct panfrost_device, shrinker);
     23	struct drm_gem_shmem_object *shmem;
     24	unsigned long count = 0;
     25
     26	if (!mutex_trylock(&pfdev->shrinker_lock))
     27		return 0;
     28
     29	list_for_each_entry(shmem, &pfdev->shrinker_list, madv_list) {
     30		if (drm_gem_shmem_is_purgeable(shmem))
     31			count += shmem->base.size >> PAGE_SHIFT;
     32	}
     33
     34	mutex_unlock(&pfdev->shrinker_lock);
     35
     36	return count;
     37}
     38
     39static bool panfrost_gem_purge(struct drm_gem_object *obj)
     40{
     41	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
     42	struct panfrost_gem_object *bo = to_panfrost_bo(obj);
     43	bool ret = false;
     44
     45	if (atomic_read(&bo->gpu_usecount))
     46		return false;
     47
     48	if (!mutex_trylock(&bo->mappings.lock))
     49		return false;
     50
     51	if (!mutex_trylock(&shmem->pages_lock))
     52		goto unlock_mappings;
     53
     54	panfrost_gem_teardown_mappings_locked(bo);
     55	drm_gem_shmem_purge_locked(&bo->base);
     56	ret = true;
     57
     58	mutex_unlock(&shmem->pages_lock);
     59
     60unlock_mappings:
     61	mutex_unlock(&bo->mappings.lock);
     62	return ret;
     63}
     64
     65static unsigned long
     66panfrost_gem_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc)
     67{
     68	struct panfrost_device *pfdev =
     69		container_of(shrinker, struct panfrost_device, shrinker);
     70	struct drm_gem_shmem_object *shmem, *tmp;
     71	unsigned long freed = 0;
     72
     73	if (!mutex_trylock(&pfdev->shrinker_lock))
     74		return SHRINK_STOP;
     75
     76	list_for_each_entry_safe(shmem, tmp, &pfdev->shrinker_list, madv_list) {
     77		if (freed >= sc->nr_to_scan)
     78			break;
     79		if (drm_gem_shmem_is_purgeable(shmem) &&
     80		    panfrost_gem_purge(&shmem->base)) {
     81			freed += shmem->base.size >> PAGE_SHIFT;
     82			list_del_init(&shmem->madv_list);
     83		}
     84	}
     85
     86	mutex_unlock(&pfdev->shrinker_lock);
     87
     88	if (freed > 0)
     89		pr_info_ratelimited("Purging %lu bytes\n", freed << PAGE_SHIFT);
     90
     91	return freed;
     92}
     93
     94/**
     95 * panfrost_gem_shrinker_init - Initialize panfrost shrinker
     96 * @dev: DRM device
     97 *
     98 * This function registers and sets up the panfrost shrinker.
     99 */
    100void panfrost_gem_shrinker_init(struct drm_device *dev)
    101{
    102	struct panfrost_device *pfdev = dev->dev_private;
    103	pfdev->shrinker.count_objects = panfrost_gem_shrinker_count;
    104	pfdev->shrinker.scan_objects = panfrost_gem_shrinker_scan;
    105	pfdev->shrinker.seeks = DEFAULT_SEEKS;
    106	WARN_ON(register_shrinker(&pfdev->shrinker));
    107}
    108
    109/**
    110 * panfrost_gem_shrinker_cleanup - Clean up panfrost shrinker
    111 * @dev: DRM device
    112 *
    113 * This function unregisters the panfrost shrinker.
    114 */
    115void panfrost_gem_shrinker_cleanup(struct drm_device *dev)
    116{
    117	struct panfrost_device *pfdev = dev->dev_private;
    118
    119	if (pfdev->shrinker.nr_deferred) {
    120		unregister_shrinker(&pfdev->shrinker);
    121	}
    122}