Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Copyright(c) 2015 Intel Corporation. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of version 2 of the GNU General Public License as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13#ifndef __PMEM_H__
14#define __PMEM_H__
15
16#include <linux/io.h>
17#include <linux/uio.h>
18
19#ifdef CONFIG_ARCH_HAS_PMEM_API
20#define ARCH_MEMREMAP_PMEM MEMREMAP_WB
21#include <asm/pmem.h>
22#else
23#define ARCH_MEMREMAP_PMEM MEMREMAP_WT
24/*
25 * These are simply here to enable compilation, all call sites gate
26 * calling these symbols with arch_has_pmem_api() and redirect to the
27 * implementation in asm/pmem.h.
28 */
29static inline bool __arch_has_wmb_pmem(void)
30{
31 return false;
32}
33
34static inline void arch_wmb_pmem(void)
35{
36 BUG();
37}
38
39static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src,
40 size_t n)
41{
42 BUG();
43}
44
45static inline int arch_memcpy_from_pmem(void *dst, const void __pmem *src,
46 size_t n)
47{
48 BUG();
49 return -EFAULT;
50}
51
52static inline size_t arch_copy_from_iter_pmem(void __pmem *addr, size_t bytes,
53 struct iov_iter *i)
54{
55 BUG();
56 return 0;
57}
58
59static inline void arch_clear_pmem(void __pmem *addr, size_t size)
60{
61 BUG();
62}
63
64static inline void arch_wb_cache_pmem(void __pmem *addr, size_t size)
65{
66 BUG();
67}
68
69static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
70{
71 BUG();
72}
73#endif
74
75static inline bool arch_has_pmem_api(void)
76{
77 return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
78}
79
80static inline int default_memcpy_from_pmem(void *dst, void __pmem const *src,
81 size_t size)
82{
83 memcpy(dst, (void __force *) src, size);
84 return 0;
85}
86
87/*
88 * memcpy_from_pmem - read from persistent memory with error handling
89 * @dst: destination buffer
90 * @src: source buffer
91 * @size: transfer length
92 *
93 * Returns 0 on success negative error code on failure.
94 */
95static inline int memcpy_from_pmem(void *dst, void __pmem const *src,
96 size_t size)
97{
98 if (arch_has_pmem_api())
99 return arch_memcpy_from_pmem(dst, src, size);
100 else
101 return default_memcpy_from_pmem(dst, src, size);
102}
103
104/**
105 * arch_has_wmb_pmem - true if wmb_pmem() ensures durability
106 *
107 * For a given cpu implementation within an architecture it is possible
108 * that wmb_pmem() resolves to a nop. In the case this returns
109 * false, pmem api users are unable to ensure durability and may want to
110 * fall back to a different data consistency model, or otherwise notify
111 * the user.
112 */
113static inline bool arch_has_wmb_pmem(void)
114{
115 return arch_has_pmem_api() && __arch_has_wmb_pmem();
116}
117
118/*
119 * These defaults seek to offer decent performance and minimize the
120 * window between i/o completion and writes being durable on media.
121 * However, it is undefined / architecture specific whether
122 * ARCH_MEMREMAP_PMEM + default_memcpy_to_pmem is sufficient for
123 * making data durable relative to i/o completion.
124 */
125static inline void default_memcpy_to_pmem(void __pmem *dst, const void *src,
126 size_t size)
127{
128 memcpy((void __force *) dst, src, size);
129}
130
131static inline size_t default_copy_from_iter_pmem(void __pmem *addr,
132 size_t bytes, struct iov_iter *i)
133{
134 return copy_from_iter_nocache((void __force *)addr, bytes, i);
135}
136
137static inline void default_clear_pmem(void __pmem *addr, size_t size)
138{
139 if (size == PAGE_SIZE && ((unsigned long)addr & ~PAGE_MASK) == 0)
140 clear_page((void __force *)addr);
141 else
142 memset((void __force *)addr, 0, size);
143}
144
145/**
146 * memcpy_to_pmem - copy data to persistent memory
147 * @dst: destination buffer for the copy
148 * @src: source buffer for the copy
149 * @n: length of the copy in bytes
150 *
151 * Perform a memory copy that results in the destination of the copy
152 * being effectively evicted from, or never written to, the processor
153 * cache hierarchy after the copy completes. After memcpy_to_pmem()
154 * data may still reside in cpu or platform buffers, so this operation
155 * must be followed by a wmb_pmem().
156 */
157static inline void memcpy_to_pmem(void __pmem *dst, const void *src, size_t n)
158{
159 if (arch_has_pmem_api())
160 arch_memcpy_to_pmem(dst, src, n);
161 else
162 default_memcpy_to_pmem(dst, src, n);
163}
164
165/**
166 * wmb_pmem - synchronize writes to persistent memory
167 *
168 * After a series of memcpy_to_pmem() operations this drains data from
169 * cpu write buffers and any platform (memory controller) buffers to
170 * ensure that written data is durable on persistent memory media.
171 */
172static inline void wmb_pmem(void)
173{
174 if (arch_has_wmb_pmem())
175 arch_wmb_pmem();
176 else
177 wmb();
178}
179
180/**
181 * copy_from_iter_pmem - copy data from an iterator to PMEM
182 * @addr: PMEM destination address
183 * @bytes: number of bytes to copy
184 * @i: iterator with source data
185 *
186 * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'.
187 * This function requires explicit ordering with a wmb_pmem() call.
188 */
189static inline size_t copy_from_iter_pmem(void __pmem *addr, size_t bytes,
190 struct iov_iter *i)
191{
192 if (arch_has_pmem_api())
193 return arch_copy_from_iter_pmem(addr, bytes, i);
194 return default_copy_from_iter_pmem(addr, bytes, i);
195}
196
197/**
198 * clear_pmem - zero a PMEM memory range
199 * @addr: virtual start address
200 * @size: number of bytes to zero
201 *
202 * Write zeros into the memory range starting at 'addr' for 'size' bytes.
203 * This function requires explicit ordering with a wmb_pmem() call.
204 */
205static inline void clear_pmem(void __pmem *addr, size_t size)
206{
207 if (arch_has_pmem_api())
208 arch_clear_pmem(addr, size);
209 else
210 default_clear_pmem(addr, size);
211}
212
213/**
214 * invalidate_pmem - flush a pmem range from the cache hierarchy
215 * @addr: virtual start address
216 * @size: bytes to invalidate (internally aligned to cache line size)
217 *
218 * For platforms that support clearing poison this flushes any poisoned
219 * ranges out of the cache
220 */
221static inline void invalidate_pmem(void __pmem *addr, size_t size)
222{
223 if (arch_has_pmem_api())
224 arch_invalidate_pmem(addr, size);
225}
226
227/**
228 * wb_cache_pmem - write back processor cache for PMEM memory range
229 * @addr: virtual start address
230 * @size: number of bytes to write back
231 *
232 * Write back the processor cache range starting at 'addr' for 'size' bytes.
233 * This function requires explicit ordering with a wmb_pmem() call.
234 */
235static inline void wb_cache_pmem(void __pmem *addr, size_t size)
236{
237 if (arch_has_pmem_api())
238 arch_wb_cache_pmem(addr, size);
239}
240#endif /* __PMEM_H__ */