From 0aed55af88345b5d673240f90e671d79662fb01e Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 29 May 2017 12:22:50 -0700 Subject: x86, uaccess: introduce copy_from_iter_flushcache for pmem / cache-bypass operations The pmem driver has a need to transfer data with a persistent memory destination and be able to rely on the fact that the destination writes are not cached. It is sufficient for the writes to be flushed to a cpu-store-buffer (non-temporal / "movnt" in x86 terms), as we expect userspace to call fsync() to ensure data-writes have reached a power-fail-safe zone in the platform. The fsync() triggers a REQ_FUA or REQ_FLUSH to the pmem driver which will turn around and fence previous writes with an "sfence". Implement a __copy_from_user_inatomic_flushcache, memcpy_page_flushcache, and memcpy_flushcache, that guarantee that the destination buffer is not dirty in the cpu cache on completion. The new copy_from_iter_flushcache and sub-routines will be used to replace the "pmem api" (include/linux/pmem.h + arch/x86/include/asm/pmem.h). The availability of copy_from_iter_flushcache() and memcpy_flushcache() are gated by the CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE config symbol, and fallback to copy_from_iter_nocache() and plain memcpy() otherwise. This is meant to satisfy the concern from Linus that if a driver wants to do something beyond the normal nocache semantics it should be something private to that driver [1], and Al's concern that anything uaccess related belongs with the rest of the uaccess code [2]. The first consumer of this interface is a new 'copy_from_iter' dax operation so that pmem can inject cache maintenance operations without imposing this overhead on other dax-capable drivers. [1]: https://lists.01.org/pipermail/linux-nvdimm/2017-January/008364.html [2]: https://lists.01.org/pipermail/linux-nvdimm/2017-April/009942.html Cc: Cc: Jan Kara Cc: Jeff Moyer Cc: Ingo Molnar Cc: Christoph Hellwig Cc: Toshi Kani Cc: "H. Peter Anvin" Cc: Al Viro Cc: Thomas Gleixner Cc: Matthew Wilcox Reviewed-by: Ross Zwisler Signed-off-by: Dan Williams --- drivers/nvdimm/claim.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/nvdimm/claim.c') diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c index 7ceb5fa4f2a1..b8b9c8ca7862 100644 --- a/drivers/nvdimm/claim.c +++ b/drivers/nvdimm/claim.c @@ -277,7 +277,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns, rc = -EIO; } - memcpy_to_pmem(nsio->addr + offset, buf, size); + memcpy_flushcache(nsio->addr + offset, buf, size); nvdimm_flush(to_nd_region(ndns->dev.parent)); return rc; -- cgit v1.2.3 From f2b612578e163b49661ece2fe01dfafb0e78f545 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 29 May 2017 23:00:34 -0700 Subject: x86, libnvdimm, pmem: move arch_invalidate_pmem() to libnvdimm Kill this globally defined wrapper and move to libnvdimm so that we can ultimately remove include/linux/pmem.h and asm/pmem.h. Cc: Cc: Jeff Moyer Cc: Ingo Molnar Cc: Christoph Hellwig Cc: "H. Peter Anvin" Cc: Thomas Gleixner Cc: Matthew Wilcox Cc: Ross Zwisler Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- drivers/nvdimm/claim.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/nvdimm/claim.c') diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c index b8b9c8ca7862..d2e16c0401df 100644 --- a/drivers/nvdimm/claim.c +++ b/drivers/nvdimm/claim.c @@ -14,6 +14,7 @@ #include #include #include "nd-core.h" +#include "pmem.h" #include "pfn.h" #include "btt.h" #include "nd.h" @@ -272,7 +273,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns, cleared /= 512; badblocks_clear(&nsio->bb, sector, cleared); } - invalidate_pmem(nsio->addr + offset, size); + arch_invalidate_pmem(nsio->addr + offset, size); } else rc = -EIO; } -- cgit v1.2.3 From ca6a4657e5420dec727256717e905ebc3c751352 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 13 Jan 2017 20:36:58 -0800 Subject: x86, libnvdimm, pmem: remove global pmem api Now that all callers of the pmem api have been converted to dax helpers that call back to the pmem driver, we can remove include/linux/pmem.h and asm/pmem.h. Cc: Cc: Jeff Moyer Cc: Ingo Molnar Cc: Christoph Hellwig Cc: Toshi Kani Cc: Oliver O'Halloran Cc: Ross Zwisler Reviewed-by: Jan Kara Signed-off-by: Dan Williams --- drivers/nvdimm/claim.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/nvdimm/claim.c') diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c index d2e16c0401df..3beedf173902 100644 --- a/drivers/nvdimm/claim.c +++ b/drivers/nvdimm/claim.c @@ -12,7 +12,6 @@ */ #include #include -#include #include "nd-core.h" #include "pmem.h" #include "pfn.h" -- cgit v1.2.3