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/*
* Copyright(c) 2015 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#ifndef __ASM_X86_PMEM_H__
#define __ASM_X86_PMEM_H__
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/cpufeature.h>
#include <asm/special_insns.h>
#ifdef CONFIG_ARCH_HAS_PMEM_API
/**
* arch_memcpy_to_pmem - copy data to persistent memory
* @dst: destination buffer for the copy
* @src: source buffer for the copy
* @n: length of the copy in bytes
*
* Copy data to persistent memory media via non-temporal stores so that
* a subsequent arch_wmb_pmem() can flush cpu and memory controller
* write buffers to guarantee durability.
*/
static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src,
size_t n)
{
int unwritten;
/*
* We are copying between two kernel buffers, if
* __copy_from_user_inatomic_nocache() returns an error (page
* fault) we would have already reported a general protection fault
* before the WARN+BUG.
*/
unwritten = __copy_from_user_inatomic_nocache((void __force *) dst,
(void __user *) src, n);
if (WARN(unwritten, "%s: fault copying %p <- %p unwritten: %d\n",
__func__, dst, src, unwritten))
BUG();
}
/**
* arch_wmb_pmem - synchronize writes to persistent memory
*
* After a series of arch_memcpy_to_pmem() operations this drains data
* from cpu write buffers and any platform (memory controller) buffers
* to ensure that written data is durable on persistent memory media.
*/
static inline void arch_wmb_pmem(void)
{
/*
* wmb() to 'sfence' all previous writes such that they are
* architecturally visible to 'pcommit'. Note, that we've
* already arranged for pmem writes to avoid the cache via
* arch_memcpy_to_pmem().
*/
wmb();
pcommit_sfence();
}
static inline bool arch_has_wmb_pmem(void)
{
#ifdef CONFIG_X86_64
/*
* We require that wmb() be an 'sfence', that is only guaranteed on
* 64-bit builds
*/
return static_cpu_has(X86_FEATURE_PCOMMIT);
#else
return false;
#endif
}
#endif /* CONFIG_ARCH_HAS_PMEM_API */
#endif /* __ASM_X86_PMEM_H__ */
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