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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dma-fence-chain.h (3576B)

      1/* SPDX-License-Identifier: GPL-2.0-only */
      2/*
      3 * fence-chain: chain fences together in a timeline
      4 *
      5 * Copyright (C) 2018 Advanced Micro Devices, Inc.
      6 * Authors:
      7 *	Christian König <christian.koenig@amd.com>
      8 */
      9
     10#ifndef __LINUX_DMA_FENCE_CHAIN_H
     11#define __LINUX_DMA_FENCE_CHAIN_H
     12
     13#include <linux/dma-fence.h>
     14#include <linux/irq_work.h>
     15#include <linux/slab.h>
     16
     17/**
     18 * struct dma_fence_chain - fence to represent an node of a fence chain
     19 * @base: fence base class
     20 * @prev: previous fence of the chain
     21 * @prev_seqno: original previous seqno before garbage collection
     22 * @fence: encapsulated fence
     23 * @lock: spinlock for fence handling
     24 */
     25struct dma_fence_chain {
     26	struct dma_fence base;
     27	struct dma_fence __rcu *prev;
     28	u64 prev_seqno;
     29	struct dma_fence *fence;
     30	union {
     31		/**
     32		 * @cb: callback for signaling
     33		 *
     34		 * This is used to add the callback for signaling the
     35		 * complection of the fence chain. Never used at the same time
     36		 * as the irq work.
     37		 */
     38		struct dma_fence_cb cb;
     39
     40		/**
     41		 * @work: irq work item for signaling
     42		 *
     43		 * Irq work structure to allow us to add the callback without
     44		 * running into lock inversion. Never used at the same time as
     45		 * the callback.
     46		 */
     47		struct irq_work work;
     48	};
     49	spinlock_t lock;
     50};
     51
     52
     53/**
     54 * to_dma_fence_chain - cast a fence to a dma_fence_chain
     55 * @fence: fence to cast to a dma_fence_array
     56 *
     57 * Returns NULL if the fence is not a dma_fence_chain,
     58 * or the dma_fence_chain otherwise.
     59 */
     60static inline struct dma_fence_chain *
     61to_dma_fence_chain(struct dma_fence *fence)
     62{
     63	if (!fence || !dma_fence_is_chain(fence))
     64		return NULL;
     65
     66	return container_of(fence, struct dma_fence_chain, base);
     67}
     68
     69/**
     70 * dma_fence_chain_contained - return the contained fence
     71 * @fence: the fence to test
     72 *
     73 * If the fence is a dma_fence_chain the function returns the fence contained
     74 * inside the chain object, otherwise it returns the fence itself.
     75 */
     76static inline struct dma_fence *
     77dma_fence_chain_contained(struct dma_fence *fence)
     78{
     79	struct dma_fence_chain *chain = to_dma_fence_chain(fence);
     80
     81	return chain ? chain->fence : fence;
     82}
     83
     84/**
     85 * dma_fence_chain_alloc
     86 *
     87 * Returns a new struct dma_fence_chain object or NULL on failure.
     88 */
     89static inline struct dma_fence_chain *dma_fence_chain_alloc(void)
     90{
     91	return kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL);
     92};
     93
     94/**
     95 * dma_fence_chain_free
     96 * @chain: chain node to free
     97 *
     98 * Frees up an allocated but not used struct dma_fence_chain object. This
     99 * doesn't need an RCU grace period since the fence was never initialized nor
    100 * published. After dma_fence_chain_init() has been called the fence must be
    101 * released by calling dma_fence_put(), and not through this function.
    102 */
    103static inline void dma_fence_chain_free(struct dma_fence_chain *chain)
    104{
    105	kfree(chain);
    106};
    107
    108/**
    109 * dma_fence_chain_for_each - iterate over all fences in chain
    110 * @iter: current fence
    111 * @head: starting point
    112 *
    113 * Iterate over all fences in the chain. We keep a reference to the current
    114 * fence while inside the loop which must be dropped when breaking out.
    115 *
    116 * For a deep dive iterator see dma_fence_unwrap_for_each().
    117 */
    118#define dma_fence_chain_for_each(iter, head)	\
    119	for (iter = dma_fence_get(head); iter; \
    120	     iter = dma_fence_chain_walk(iter))
    121
    122struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence);
    123int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno);
    124void dma_fence_chain_init(struct dma_fence_chain *chain,
    125			  struct dma_fence *prev,
    126			  struct dma_fence *fence,
    127			  uint64_t seqno);
    128
    129#endif /* __LINUX_DMA_FENCE_CHAIN_H */