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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i915_gem_ww.c (1430B)

      1// SPDX-License-Identifier: MIT
      2/*
      3 * Copyright © 2020 Intel Corporation
      4 */
      5#include <linux/dma-resv.h>
      6#include "i915_gem_ww.h"
      7#include "gem/i915_gem_object.h"
      8
      9void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ww, bool intr)
     10{
     11	ww_acquire_init(&ww->ctx, &reservation_ww_class);
     12	INIT_LIST_HEAD(&ww->obj_list);
     13	ww->intr = intr;
     14	ww->contended = NULL;
     15}
     16
     17static void i915_gem_ww_ctx_unlock_all(struct i915_gem_ww_ctx *ww)
     18{
     19	struct drm_i915_gem_object *obj;
     20
     21	while ((obj = list_first_entry_or_null(&ww->obj_list, struct drm_i915_gem_object, obj_link))) {
     22		list_del(&obj->obj_link);
     23		i915_gem_object_unlock(obj);
     24		i915_gem_object_put(obj);
     25	}
     26}
     27
     28void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj)
     29{
     30	list_del(&obj->obj_link);
     31	i915_gem_object_unlock(obj);
     32	i915_gem_object_put(obj);
     33}
     34
     35void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ww)
     36{
     37	i915_gem_ww_ctx_unlock_all(ww);
     38	WARN_ON(ww->contended);
     39	ww_acquire_fini(&ww->ctx);
     40}
     41
     42int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ww)
     43{
     44	int ret = 0;
     45
     46	if (WARN_ON(!ww->contended))
     47		return -EINVAL;
     48
     49	i915_gem_ww_ctx_unlock_all(ww);
     50	if (ww->intr)
     51		ret = dma_resv_lock_slow_interruptible(ww->contended->base.resv, &ww->ctx);
     52	else
     53		dma_resv_lock_slow(ww->contended->base.resv, &ww->ctx);
     54
     55	if (!ret)
     56		list_add_tail(&ww->contended->obj_link, &ww->obj_list);
     57	else
     58		i915_gem_object_put(ww->contended);
     59
     60	ww->contended = NULL;
     61
     62	return ret;
     63}