241 lines
6.4 KiB
C
241 lines
6.4 KiB
C
/*
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* Copyright(c) 2015 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#ifndef __PMEM_H__
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#define __PMEM_H__
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#include <linux/io.h>
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#include <linux/uio.h>
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#ifdef CONFIG_ARCH_HAS_PMEM_API
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#define ARCH_MEMREMAP_PMEM MEMREMAP_WB
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#include <asm/pmem.h>
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#else
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#define ARCH_MEMREMAP_PMEM MEMREMAP_WT
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/*
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* These are simply here to enable compilation, all call sites gate
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* calling these symbols with arch_has_pmem_api() and redirect to the
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* implementation in asm/pmem.h.
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*/
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static inline bool __arch_has_wmb_pmem(void)
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{
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return false;
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}
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static inline void arch_wmb_pmem(void)
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{
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BUG();
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}
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static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src,
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size_t n)
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{
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BUG();
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}
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static inline int arch_memcpy_from_pmem(void *dst, const void __pmem *src,
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size_t n)
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{
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BUG();
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return -EFAULT;
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}
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static inline size_t arch_copy_from_iter_pmem(void __pmem *addr, size_t bytes,
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struct iov_iter *i)
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{
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BUG();
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return 0;
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}
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static inline void arch_clear_pmem(void __pmem *addr, size_t size)
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{
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BUG();
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}
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static inline void arch_wb_cache_pmem(void __pmem *addr, size_t size)
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{
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BUG();
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}
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static inline void arch_invalidate_pmem(void __pmem *addr, size_t size)
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{
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BUG();
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}
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#endif
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static inline bool arch_has_pmem_api(void)
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{
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return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
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}
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static inline int default_memcpy_from_pmem(void *dst, void __pmem const *src,
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size_t size)
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{
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memcpy(dst, (void __force *) src, size);
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return 0;
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}
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/*
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* memcpy_from_pmem - read from persistent memory with error handling
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* @dst: destination buffer
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* @src: source buffer
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* @size: transfer length
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*
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* Returns 0 on success negative error code on failure.
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*/
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static inline int memcpy_from_pmem(void *dst, void __pmem const *src,
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size_t size)
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{
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if (arch_has_pmem_api())
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return arch_memcpy_from_pmem(dst, src, size);
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else
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return default_memcpy_from_pmem(dst, src, size);
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}
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/**
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* arch_has_wmb_pmem - true if wmb_pmem() ensures durability
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*
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* For a given cpu implementation within an architecture it is possible
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* that wmb_pmem() resolves to a nop. In the case this returns
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* false, pmem api users are unable to ensure durability and may want to
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* fall back to a different data consistency model, or otherwise notify
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* the user.
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*/
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static inline bool arch_has_wmb_pmem(void)
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{
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return arch_has_pmem_api() && __arch_has_wmb_pmem();
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}
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/*
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* These defaults seek to offer decent performance and minimize the
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* window between i/o completion and writes being durable on media.
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* However, it is undefined / architecture specific whether
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* ARCH_MEMREMAP_PMEM + default_memcpy_to_pmem is sufficient for
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* making data durable relative to i/o completion.
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*/
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static inline void default_memcpy_to_pmem(void __pmem *dst, const void *src,
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size_t size)
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{
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memcpy((void __force *) dst, src, size);
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}
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static inline size_t default_copy_from_iter_pmem(void __pmem *addr,
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size_t bytes, struct iov_iter *i)
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{
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return copy_from_iter_nocache((void __force *)addr, bytes, i);
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}
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static inline void default_clear_pmem(void __pmem *addr, size_t size)
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{
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if (size == PAGE_SIZE && ((unsigned long)addr & ~PAGE_MASK) == 0)
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clear_page((void __force *)addr);
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else
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memset((void __force *)addr, 0, size);
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}
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/**
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* memcpy_to_pmem - copy data to persistent memory
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* @dst: destination buffer for the copy
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* @src: source buffer for the copy
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* @n: length of the copy in bytes
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*
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* Perform a memory copy that results in the destination of the copy
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* being effectively evicted from, or never written to, the processor
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* cache hierarchy after the copy completes. After memcpy_to_pmem()
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* data may still reside in cpu or platform buffers, so this operation
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* must be followed by a wmb_pmem().
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*/
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static inline void memcpy_to_pmem(void __pmem *dst, const void *src, size_t n)
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{
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if (arch_has_pmem_api())
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arch_memcpy_to_pmem(dst, src, n);
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else
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default_memcpy_to_pmem(dst, src, n);
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}
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/**
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* wmb_pmem - synchronize writes to persistent memory
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*
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* After a series of memcpy_to_pmem() operations this drains data from
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* cpu write buffers and any platform (memory controller) buffers to
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* ensure that written data is durable on persistent memory media.
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*/
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static inline void wmb_pmem(void)
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{
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if (arch_has_wmb_pmem())
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arch_wmb_pmem();
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else
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wmb();
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}
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/**
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* copy_from_iter_pmem - copy data from an iterator to PMEM
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* @addr: PMEM destination address
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* @bytes: number of bytes to copy
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* @i: iterator with source data
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*
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* Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'.
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* This function requires explicit ordering with a wmb_pmem() call.
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*/
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static inline size_t copy_from_iter_pmem(void __pmem *addr, size_t bytes,
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struct iov_iter *i)
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{
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if (arch_has_pmem_api())
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return arch_copy_from_iter_pmem(addr, bytes, i);
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return default_copy_from_iter_pmem(addr, bytes, i);
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}
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/**
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* clear_pmem - zero a PMEM memory range
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* @addr: virtual start address
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* @size: number of bytes to zero
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*
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* Write zeros into the memory range starting at 'addr' for 'size' bytes.
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* This function requires explicit ordering with a wmb_pmem() call.
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*/
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static inline void clear_pmem(void __pmem *addr, size_t size)
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{
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if (arch_has_pmem_api())
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arch_clear_pmem(addr, size);
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else
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default_clear_pmem(addr, size);
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}
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/**
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* invalidate_pmem - flush a pmem range from the cache hierarchy
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* @addr: virtual start address
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* @size: bytes to invalidate (internally aligned to cache line size)
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*
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* For platforms that support clearing poison this flushes any poisoned
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* ranges out of the cache
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*/
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static inline void invalidate_pmem(void __pmem *addr, size_t size)
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{
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if (arch_has_pmem_api())
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arch_invalidate_pmem(addr, size);
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}
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/**
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* wb_cache_pmem - write back processor cache for PMEM memory range
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* @addr: virtual start address
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* @size: number of bytes to write back
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*
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* Write back the processor cache range starting at 'addr' for 'size' bytes.
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* This function requires explicit ordering with a wmb_pmem() call.
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*/
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static inline void wb_cache_pmem(void __pmem *addr, size_t size)
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{
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if (arch_has_pmem_api())
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arch_wb_cache_pmem(addr, size);
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}
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#endif /* __PMEM_H__ */
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