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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rcu_segcblist.h (5095B)

      1/* SPDX-License-Identifier: GPL-2.0+ */
      2/*
      3 * RCU segmented callback lists, internal-to-rcu header file
      4 *
      5 * Copyright IBM Corporation, 2017
      6 *
      7 * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
      8 */
      9
     10#include <linux/rcu_segcblist.h>
     11
     12/* Return number of callbacks in the specified callback list. */
     13static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
     14{
     15	return READ_ONCE(rclp->len);
     16}
     17
     18/* Return number of callbacks in segmented callback list by summing seglen. */
     19long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp);
     20
     21void rcu_cblist_init(struct rcu_cblist *rclp);
     22void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
     23void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
     24			      struct rcu_cblist *srclp,
     25			      struct rcu_head *rhp);
     26struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
     27
     28/*
     29 * Is the specified rcu_segcblist structure empty?
     30 *
     31 * But careful!  The fact that the ->head field is NULL does not
     32 * necessarily imply that there are no callbacks associated with
     33 * this structure.  When callbacks are being invoked, they are
     34 * removed as a group.  If callback invocation must be preempted,
     35 * the remaining callbacks will be added back to the list.  Either
     36 * way, the counts are updated later.
     37 *
     38 * So it is often the case that rcu_segcblist_n_cbs() should be used
     39 * instead.
     40 */
     41static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
     42{
     43	return !READ_ONCE(rsclp->head);
     44}
     45
     46/* Return number of callbacks in segmented callback list. */
     47static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
     48{
     49#ifdef CONFIG_RCU_NOCB_CPU
     50	return atomic_long_read(&rsclp->len);
     51#else
     52	return READ_ONCE(rsclp->len);
     53#endif
     54}
     55
     56static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
     57					   int flags)
     58{
     59	WRITE_ONCE(rsclp->flags, rsclp->flags | flags);
     60}
     61
     62static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
     63					     int flags)
     64{
     65	WRITE_ONCE(rsclp->flags, rsclp->flags & ~flags);
     66}
     67
     68static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
     69					    int flags)
     70{
     71	return READ_ONCE(rsclp->flags) & flags;
     72}
     73
     74/*
     75 * Is the specified rcu_segcblist enabled, for example, not corresponding
     76 * to an offline CPU?
     77 */
     78static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
     79{
     80	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
     81}
     82
     83/*
     84 * Is the specified rcu_segcblist NOCB offloaded (or in the middle of the
     85 * [de]offloading process)?
     86 */
     87static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
     88{
     89	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
     90	    rcu_segcblist_test_flags(rsclp, SEGCBLIST_LOCKING))
     91		return true;
     92
     93	return false;
     94}
     95
     96static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rsclp)
     97{
     98	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
     99	    !rcu_segcblist_test_flags(rsclp, SEGCBLIST_RCU_CORE))
    100		return true;
    101
    102	return false;
    103}
    104
    105/*
    106 * Are all segments following the specified segment of the specified
    107 * rcu_segcblist structure empty of callbacks?  (The specified
    108 * segment might well contain callbacks.)
    109 */
    110static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
    111{
    112	return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
    113}
    114
    115/*
    116 * Is the specified segment of the specified rcu_segcblist structure
    117 * empty of callbacks?
    118 */
    119static inline bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
    120{
    121	if (seg == RCU_DONE_TAIL)
    122		return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
    123	return rsclp->tails[seg - 1] == rsclp->tails[seg];
    124}
    125
    126void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
    127void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v);
    128void rcu_segcblist_init(struct rcu_segcblist *rsclp);
    129void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
    130void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload);
    131bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
    132bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
    133struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
    134struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
    135bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
    136void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
    137			   struct rcu_head *rhp);
    138bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
    139			   struct rcu_head *rhp);
    140void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
    141				    struct rcu_cblist *rclp);
    142void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
    143				    struct rcu_cblist *rclp);
    144void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
    145				struct rcu_cblist *rclp);
    146void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
    147				   struct rcu_cblist *rclp);
    148void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
    149				   struct rcu_cblist *rclp);
    150void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
    151bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
    152void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
    153			 struct rcu_segcblist *src_rsclp);