tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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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 __ASM_X86_PMEM_H__
14#define __ASM_X86_PMEM_H__
15
16#include <linux/uaccess.h>
17#include <asm/cacheflush.h>
18#include <asm/cpufeature.h>
19#include <asm/special_insns.h>
20
21#ifdef CONFIG_ARCH_HAS_PMEM_API
22/**
23 * arch_memcpy_to_pmem - copy data to persistent memory
24 * @dst: destination buffer for the copy
25 * @src: source buffer for the copy
26 * @n: length of the copy in bytes
27 *
28 * Copy data to persistent memory media via non-temporal stores so that
29 * a subsequent pmem driver flush operation will drain posted write queues.
30 */
31static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
32{
33 int rem;
34
35 /*
36 * We are copying between two kernel buffers, if
37 * __copy_from_user_inatomic_nocache() returns an error (page
38 * fault) we would have already reported a general protection fault
39 * before the WARN+BUG.
40 */
41 rem = __copy_from_user_inatomic_nocache(dst, (void __user *) src, n);
42 if (WARN(rem, "%s: fault copying %p <- %p unwritten: %d\n",
43 __func__, dst, src, rem))
44 BUG();
45}
46
47static inline int arch_memcpy_from_pmem(void *dst, const void *src, size_t n)
48{
49 if (static_cpu_has(X86_FEATURE_MCE_RECOVERY))
50 return memcpy_mcsafe(dst, src, n);
51 memcpy(dst, src, n);
52 return 0;
53}
54
55/**
56 * arch_wb_cache_pmem - write back a cache range with CLWB
57 * @vaddr: virtual start address
58 * @size: number of bytes to write back
59 *
60 * Write back a cache range using the CLWB (cache line write back)
61 * instruction.
62 */
63static inline void arch_wb_cache_pmem(void *addr, size_t size)
64{
65 u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
66 unsigned long clflush_mask = x86_clflush_size - 1;
67 void *vend = addr + size;
68 void *p;
69
70 for (p = (void *)((unsigned long)addr & ~clflush_mask);
71 p < vend; p += x86_clflush_size)
72 clwb(p);
73}
74
75/*
76 * copy_from_iter_nocache() on x86 only uses non-temporal stores for iovec
77 * iterators, so for other types (bvec & kvec) we must do a cache write-back.
78 */
79static inline bool __iter_needs_pmem_wb(struct iov_iter *i)
80{
81 return iter_is_iovec(i) == false;
82}
83
84/**
85 * arch_copy_from_iter_pmem - copy data from an iterator to PMEM
86 * @addr: PMEM destination address
87 * @bytes: number of bytes to copy
88 * @i: iterator with source data
89 *
90 * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'.
91 */
92static inline size_t arch_copy_from_iter_pmem(void *addr, size_t bytes,
93 struct iov_iter *i)
94{
95 size_t len;
96
97 /* TODO: skip the write-back by always using non-temporal stores */
98 len = copy_from_iter_nocache(addr, bytes, i);
99
100 if (__iter_needs_pmem_wb(i))
101 arch_wb_cache_pmem(addr, bytes);
102
103 return len;
104}
105
106/**
107 * arch_clear_pmem - zero a PMEM memory range
108 * @addr: virtual start address
109 * @size: number of bytes to zero
110 *
111 * Write zeros into the memory range starting at 'addr' for 'size' bytes.
112 */
113static inline void arch_clear_pmem(void *addr, size_t size)
114{
115 memset(addr, 0, size);
116 arch_wb_cache_pmem(addr, size);
117}
118
119static inline void arch_invalidate_pmem(void *addr, size_t size)
120{
121 clflush_cache_range(addr, size);
122}
123#endif /* CONFIG_ARCH_HAS_PMEM_API */
124#endif /* __ASM_X86_PMEM_H__ */