[PATCH v2 26/33] x86, dax, libnvdimm: move wb_cache_pmem() to libnvdimm

From: Dan Williams
Date: Fri Apr 14 2017 - 22:41:22 EST


With all calls to this routine re-directed through the pmem driver, we
can kill the pmem api indirection. arch_wb_cache_pmem() is now
optionally supplied by an arch specific extension to libnvdimm. Same as
before, pmem flushing is only defined for x86_64, but it is
straightforward to add other archs in the future.

Cc: <x86@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Oliver O'Halloran <oohall@xxxxxxxxx>
Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
arch/x86/include/asm/pmem.h | 21 ---------------------
drivers/nvdimm/Makefile | 1 +
drivers/nvdimm/pmem.c | 14 +++++---------
drivers/nvdimm/pmem.h | 8 ++++++++
drivers/nvdimm/x86.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/pmem.h | 19 -------------------
tools/testing/nvdimm/Kbuild | 1 +
7 files changed, 51 insertions(+), 49 deletions(-)
create mode 100644 drivers/nvdimm/x86.c

diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
index f4c119d253f3..4759a179aa52 100644
--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -44,27 +44,6 @@ static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
BUG();
}

-/**
- * arch_wb_cache_pmem - write back a cache range with CLWB
- * @vaddr: virtual start address
- * @size: number of bytes to write back
- *
- * Write back a cache range using the CLWB (cache line write back)
- * instruction. Note that @size is internally rounded up to be cache
- * line size aligned.
- */
-static inline void arch_wb_cache_pmem(void *addr, size_t size)
-{
- u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
- unsigned long clflush_mask = x86_clflush_size - 1;
- void *vend = addr + size;
- void *p;
-
- for (p = (void *)((unsigned long)addr & ~clflush_mask);
- p < vend; p += x86_clflush_size)
- clwb(p);
-}
-
static inline void arch_invalidate_pmem(void *addr, size_t size)
{
clflush_cache_range(addr, size);
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
index 909554c3f955..9eafb1dd2876 100644
--- a/drivers/nvdimm/Makefile
+++ b/drivers/nvdimm/Makefile
@@ -24,3 +24,4 @@ libnvdimm-$(CONFIG_ND_CLAIM) += claim.o
libnvdimm-$(CONFIG_BTT) += btt_devs.o
libnvdimm-$(CONFIG_NVDIMM_PFN) += pfn_devs.o
libnvdimm-$(CONFIG_NVDIMM_DAX) += dax_devs.o
+libnvdimm-$(CONFIG_X86_64) += x86.o
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 822b85fb3365..c77a3a757729 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -245,19 +245,19 @@ static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,

if (bytes < 8) {
if (!IS_ALIGNED(dest, 4) || (bytes != 4))
- wb_cache_pmem(addr, 1);
+ arch_wb_cache_pmem(addr, 1);
} else {
if (!IS_ALIGNED(dest, 8)) {
dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
- wb_cache_pmem(addr, 1);
+ arch_wb_cache_pmem(addr, 1);
}

flushed = dest - (unsigned long) addr;
if (bytes > flushed && !IS_ALIGNED(bytes - flushed, 8))
- wb_cache_pmem(addr + bytes - 1, 1);
+ arch_wb_cache_pmem(addr + bytes - 1, 1);
}
} else
- wb_cache_pmem(addr, bytes);
+ arch_wb_cache_pmem(addr, bytes);

return len;
}
@@ -279,11 +279,7 @@ static long pmem_dax_direct_access(struct dax_device *dax_dev,
static void pmem_dax_flush(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t size)
{
- /*
- * TODO: move arch specific cache management into the driver
- * directly.
- */
- wb_cache_pmem(addr, size);
+ arch_wb_cache_pmem(addr, size);
}

static const struct dax_operations pmem_dax_ops = {
diff --git a/drivers/nvdimm/pmem.h b/drivers/nvdimm/pmem.h
index 7f4dbd72a90a..c4b3371c7f88 100644
--- a/drivers/nvdimm/pmem.h
+++ b/drivers/nvdimm/pmem.h
@@ -5,6 +5,14 @@
#include <linux/pfn_t.h>
#include <linux/fs.h>

+#ifdef CONFIG_ARCH_HAS_PMEM_API
+void arch_wb_cache_pmem(void *addr, size_t size);
+#else
+static inline void arch_wb_cache_pmem(void *addr, size_t size)
+{
+}
+#endif
+
/* this definition is in it's own header for tools/testing/nvdimm to consume */
struct pmem_device {
/* One contiguous memory region per device */
diff --git a/drivers/nvdimm/x86.c b/drivers/nvdimm/x86.c
new file mode 100644
index 000000000000..79d7267da4d2
--- /dev/null
+++ b/drivers/nvdimm/x86.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright(c) 2015 - 2017 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.
+ */
+#include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
+#include <asm/special_insns.h>
+
+/**
+ * arch_wb_cache_pmem - write back a cache range with CLWB
+ * @vaddr: virtual start address
+ * @size: number of bytes to write back
+ *
+ * Write back a cache range using the CLWB (cache line write back)
+ * instruction.
+ */
+void arch_wb_cache_pmem(void *addr, size_t size)
+{
+ u16 x86_clflush_size = boot_cpu_data.x86_clflush_size;
+ unsigned long clflush_mask = x86_clflush_size - 1;
+ void *vend = addr + size;
+ void *p;
+
+ for (p = (void *)((unsigned long)addr & ~clflush_mask);
+ p < vend; p += x86_clflush_size)
+ clwb(p);
+}
+EXPORT_SYMBOL_GPL(arch_wb_cache_pmem);
diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index 772bd02a5b52..33ae761f010a 100644
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -31,11 +31,6 @@ static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
BUG();
}

-static inline void arch_wb_cache_pmem(void *addr, size_t size)
-{
- BUG();
-}
-
static inline void arch_invalidate_pmem(void *addr, size_t size)
{
BUG();
@@ -80,18 +75,4 @@ static inline void invalidate_pmem(void *addr, size_t size)
if (arch_has_pmem_api())
arch_invalidate_pmem(addr, size);
}
-
-/**
- * wb_cache_pmem - write back processor cache for PMEM memory range
- * @addr: virtual start address
- * @size: number of bytes to write back
- *
- * Write back the processor cache range starting at 'addr' for 'size' bytes.
- * See blkdev_issue_flush() note for memcpy_to_pmem().
- */
-static inline void wb_cache_pmem(void *addr, size_t size)
-{
- if (arch_has_pmem_api())
- arch_wb_cache_pmem(addr, size);
-}
#endif /* __PMEM_H__ */
diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild
index 2033ad03b8cd..0e0c444737e9 100644
--- a/tools/testing/nvdimm/Kbuild
+++ b/tools/testing/nvdimm/Kbuild
@@ -72,6 +72,7 @@ libnvdimm-$(CONFIG_ND_CLAIM) += $(NVDIMM_SRC)/claim.o
libnvdimm-$(CONFIG_BTT) += $(NVDIMM_SRC)/btt_devs.o
libnvdimm-$(CONFIG_NVDIMM_PFN) += $(NVDIMM_SRC)/pfn_devs.o
libnvdimm-$(CONFIG_NVDIMM_DAX) += $(NVDIMM_SRC)/dax_devs.o
+libnvdimm-$(CONFIG_X86_64) += $(NVDIMM_SRC)/x86.o
libnvdimm-y += config_check.o

obj-m += test/