Add a new PMEM API to x86, and allow for architectures that do not implement this API. Architectures that implement the PMEM API should define ARCH_HAS_PMEM_API in their kernel configuration and must provide implementations for persistent_copy(), persistent_flush() and persistent_sync(). Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: x86@xxxxxxxxxx Cc: linux-nvdimm@xxxxxxxxxxxx --- MAINTAINERS | 1 + arch/x86/Kconfig | 3 ++ arch/x86/include/asm/cacheflush.h | 23 ++++++++++++ include/linux/pmem.h | 79 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 106 insertions(+) create mode 100644 include/linux/pmem.h diff --git a/MAINTAINERS b/MAINTAINERS index 0448fec8e44a..ca1f3d99618d 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5944,6 +5944,7 @@ L: linux-nvdimm@xxxxxxxxxxxx Q: https://patchwork.kernel.org/project/linux-nvdimm/list/ S: Supported F: drivers/block/nd/pmem.c +F: include/linux/pmem.h LINUX FOR IBM pSERIES (RS/6000) M: Paul Mackerras <paulus@xxxxxxxxxx> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 23c587938804..eb8f12e715af 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -215,6 +215,9 @@ config ARCH_HAS_CPU_RELAX config ARCH_HAS_CACHE_LINE_SIZE def_bool y +config ARCH_HAS_PMEM_API + def_bool y + config HAVE_SETUP_PER_CPU_AREA def_bool y diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h index 47c8e32f621a..ffd5ccdc86f0 100644 --- a/arch/x86/include/asm/cacheflush.h +++ b/arch/x86/include/asm/cacheflush.h @@ -4,6 +4,7 @@ /* Caches aren't brain-dead on the intel. */ #include <asm-generic/cacheflush.h> #include <asm/special_insns.h> +#include <asm/uaccess.h> /* * The set_memory_* API can be used to change various attributes of a virtual @@ -84,6 +85,28 @@ int set_pages_rw(struct page *page, int numpages); void clflush_cache_range(void *addr, unsigned int size); +static inline void arch_persistent_copy(void *dst, const void *src, size_t n) +{ + /* + * We are copying between two kernel buffers, so it should be + * impossible for us to hit this BUG_ON() because we should never need + * to take a page fault. + */ + BUG_ON(__copy_from_user_inatomic_nocache(dst, + (__user const void *)src, n)); +} + +static inline void arch_persistent_flush(void *vaddr, size_t size) +{ + clflush_cache_range(vaddr, size); +} + +static inline void arch_persistent_sync(void) +{ + wmb(); + pcommit_sfence(); +} + #ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void); extern const int rodata_test_data; diff --git a/include/linux/pmem.h b/include/linux/pmem.h new file mode 100644 index 000000000000..88ade7376632 --- /dev/null +++ b/include/linux/pmem.h @@ -0,0 +1,79 @@ +/* + * 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 __PMEM_H__ +#define __PMEM_H__ + +#include <asm/cacheflush.h> + +/* + * Architectures that define ARCH_HAS_PMEM_API must provide implementations + * for persistent_copy(), persistent_flush() and persistent_sync(). + */ + +#ifdef CONFIG_ARCH_HAS_PMEM_API +/** + * persistent_copy - copy data to persistent memory + * @dst: destination buffer for the copy + * @src: source buffer for the copy + * @n: length of the copy in bytes + * + * Perform a memory copy that results in the destination of the copy being + * evicted from the processor cache hierarchy ("accepted to memory"). This + * can typically be accomplished with non-temporal stores or by regular stores + * followed by cache flush commands via persistent_flush(). + */ +static inline void persistent_copy(void *dst, const void *src, size_t n) +{ + arch_persistent_copy(dst, src, n); +} + +/** + * persistent_flush - flush a memory range from the processor cache + * @vaddr: virtual address to begin flushing + * @size: number of bytes to flush + * + * This call needs to include fencing so that the flushing will be ordered + * with respect to both reads and writes. + */ +static inline void persistent_flush(void *vaddr, size_t size) +{ + arch_persistent_flush(vaddr, size); +} + +/** + * persistent_sync - synchronize writes to persistent memory + * + * To be used after a series of copies and/or flushes, this should perform any + * necessary fencing to order writes/flushes and then ensure that writes that + * have been "accepted to memory", i.e. previously flushed from the cache + * hierarchy, are actually written to the appropriate DIMMs. This typically + * involves making sure they are flushed from any platform buffers not covered + * by the cache flushes performed by persistent_flush(). + */ +static inline void persistent_sync(void) +{ + arch_persistent_sync(); +} + +#else /* ! CONFIG_ARCH_HAS_PMEM_API */ + +static inline void persistent_copy(void *dst, const void *src, size_t n) +{ + memcpy(dst, src, n); +} +static inline void persistent_flush(void *vaddr, size_t size) {} +static inline void persistent_sync(void) {} + +#endif /* CONFIG_ARCH_HAS_PMEM_API */ + +#endif /* __PMEM_H__ */ -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
