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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Generic support for Memory System Cache Maintenance operations.
4 *
5 * Coherency maintenance drivers register with this simple framework that will
6 * iterate over each registered instance to first kick off invalidation and
7 * then to wait until it is complete.
8 *
9 * If no implementations are registered yet cpu_cache_has_invalidate_memregion()
10 * will return false. If this runs concurrently with unregistration then a
11 * race exists but this is no worse than the case where the operations instance
12 * responsible for a given memory region has not yet registered.
13 */
14#include <linux/cache_coherency.h>
15#include <linux/cleanup.h>
16#include <linux/container_of.h>
17#include <linux/export.h>
18#include <linux/kref.h>
19#include <linux/list.h>
20#include <linux/memregion.h>
21#include <linux/module.h>
22#include <linux/rwsem.h>
23#include <linux/slab.h>
24
25static LIST_HEAD(cache_ops_instance_list);
26static DECLARE_RWSEM(cache_ops_instance_list_lock);
27
28static void __cache_coherency_ops_instance_free(struct kref *kref)
29{
30 struct cache_coherency_ops_inst *cci =
31 container_of(kref, struct cache_coherency_ops_inst, kref);
32 kfree(objp: cci);
33}
34
35void cache_coherency_ops_instance_put(struct cache_coherency_ops_inst *cci)
36{
37 kref_put(kref: &cci->kref, release: __cache_coherency_ops_instance_free);
38}
39EXPORT_SYMBOL_GPL(cache_coherency_ops_instance_put);
40
41static int cache_inval_one(struct cache_coherency_ops_inst *cci, void *data)
42{
43 if (!cci->ops)
44 return -EINVAL;
45
46 return cci->ops->wbinv(cci, data);
47}
48
49static int cache_inval_done_one(struct cache_coherency_ops_inst *cci)
50{
51 if (!cci->ops)
52 return -EINVAL;
53
54 if (!cci->ops->done)
55 return 0;
56
57 return cci->ops->done(cci);
58}
59
60static int cache_invalidate_memregion(phys_addr_t addr, size_t size)
61{
62 int ret;
63 struct cache_coherency_ops_inst *cci;
64 struct cc_inval_params params = {
65 .addr = addr,
66 .size = size,
67 };
68
69 guard(rwsem_read)(T: &cache_ops_instance_list_lock);
70 list_for_each_entry(cci, &cache_ops_instance_list, node) {
71 ret = cache_inval_one(cci, data: &params);
72 if (ret)
73 return ret;
74 }
75 list_for_each_entry(cci, &cache_ops_instance_list, node) {
76 ret = cache_inval_done_one(cci);
77 if (ret)
78 return ret;
79 }
80
81 return 0;
82}
83
84struct cache_coherency_ops_inst *
85_cache_coherency_ops_instance_alloc(const struct cache_coherency_ops *ops,
86 size_t size)
87{
88 struct cache_coherency_ops_inst *cci;
89
90 if (!ops || !ops->wbinv)
91 return NULL;
92
93 cci = kzalloc(size, GFP_KERNEL);
94 if (!cci)
95 return NULL;
96
97 cci->ops = ops;
98 INIT_LIST_HEAD(list: &cci->node);
99 kref_init(kref: &cci->kref);
100
101 return cci;
102}
103EXPORT_SYMBOL_NS_GPL(_cache_coherency_ops_instance_alloc, "CACHE_COHERENCY");
104
105int cache_coherency_ops_instance_register(struct cache_coherency_ops_inst *cci)
106{
107 guard(rwsem_write)(T: &cache_ops_instance_list_lock);
108 list_add(new: &cci->node, head: &cache_ops_instance_list);
109
110 return 0;
111}
112EXPORT_SYMBOL_NS_GPL(cache_coherency_ops_instance_register, "CACHE_COHERENCY");
113
114void cache_coherency_ops_instance_unregister(struct cache_coherency_ops_inst *cci)
115{
116 guard(rwsem_write)(T: &cache_ops_instance_list_lock);
117 list_del(entry: &cci->node);
118}
119EXPORT_SYMBOL_NS_GPL(cache_coherency_ops_instance_unregister, "CACHE_COHERENCY");
120
121int cpu_cache_invalidate_memregion(phys_addr_t start, size_t len)
122{
123 return cache_invalidate_memregion(addr: start, size: len);
124}
125EXPORT_SYMBOL_NS_GPL(cpu_cache_invalidate_memregion, "DEVMEM");
126
127/*
128 * Used for optimization / debug purposes only as removal can race
129 *
130 * Machines that do not support invalidation, e.g. VMs, will not have any
131 * operations instance to register and so this will always return false.
132 */
133bool cpu_cache_has_invalidate_memregion(void)
134{
135 guard(rwsem_read)(T: &cache_ops_instance_list_lock);
136 return !list_empty(head: &cache_ops_instance_list);
137}
138EXPORT_SYMBOL_NS_GPL(cpu_cache_has_invalidate_memregion, "DEVMEM");
139

source code of linux/lib/cache_maint.c