[PATCH v4 0/4] add support for platform persistence capabilities

[PATCH v4 0/4] add support for platform persistence capabilities

[Dave Jiang]

ACPI 6.2a provides an NFIT sub-table that informs if the platform has
auto CPU flush and memory flush on unexpected power loss events. This series
propogates those attributes to nd_region and add sysfs attribute to show
those capabilities.

v4:
Fixed typos and added Reviewed-by tags from Ross.

v3:
Addressed Ross's comments
- fixed mask calculation for platform cap
- fixed nfit_test nfit_buf size calcuation
- fixed offset for test data structure

v2:
Per Dan's comments
- Added ADR cap flags propogation
- Added sysfs attribute

---

Dave Jiang (4):
      acpi: nfit: Add support for detect platform CPU cache flush on power loss
      acpi: nfit: add persistent memory control flag for nd_region
      libnvdimm: expose platform persistence attribute for nd_region
      nfit-test: Add platform cap support from ACPI 6.2a to test


 drivers/acpi/nfit/core.c         |   23 +++++++++++++++++++++++
 drivers/acpi/nfit/nfit.h         |    1 +
 drivers/nvdimm/pmem.c            |    4 +++-
 drivers/nvdimm/region_devs.c     |   13 +++++++++++++
 include/linux/libnvdimm.h        |   11 +++++++++++
 tools/testing/nvdimm/test/nfit.c |   14 ++++++++++++--
 6 files changed, 63 insertions(+), 3 deletions(-)

--
Signature

[PATCH v4 1/4] acpi: nfit: Add support for detect platform CPU cache flush on power loss

[Dave Jiang]

In ACPI 6.2a the platform capability structure has been added to the NFIT
tables. That provides software the ability to determine whether a system
supports the auto flushing of CPU caches on power loss. If the capability
is supported, we do not need to do dax_flush(). Plumbing the path to set the
property on per region from the NFIT tables.

This patch depends on the ACPI NFIT 6.2a platform capabilities support code
in include/acpi/actbl1.h.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
 drivers/acpi/nfit/core.c  |   20 ++++++++++++++++++++
 drivers/acpi/nfit/nfit.h  |    1 +
 drivers/nvdimm/pmem.c     |    4 +++-
 include/linux/libnvdimm.h |    5 +++++
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index ff2580e7611d..bcf52bb93b65 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -838,6 +838,18 @@ static bool add_flush(struct acpi_nfit_desc *acpi_desc,
 	return true;
 }
 
+static bool add_platform_cap(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_capabilities *pcap)
+{
+	struct device *dev = acpi_desc->dev;
+	u32 mask;
+
+	mask = (1 << (pcap->highest_capability + 1)) - 1;
+	acpi_desc->platform_cap = pcap->capabilities & mask;
+	dev_dbg(dev, "%s: cap: %#x\n", __func__, acpi_desc->platform_cap);
+	return true;
+}
+
 static void *add_table(struct acpi_nfit_desc *acpi_desc,
 		struct nfit_table_prev *prev, void *table, const void *end)
 {
@@ -883,6 +895,10 @@ static void *add_table(struct acpi_nfit_desc *acpi_desc,
 	case ACPI_NFIT_TYPE_SMBIOS:
 		dev_dbg(dev, "%s: smbios\n", __func__);
 		break;
+	case ACPI_NFIT_TYPE_CAPABILITIES:
+		if (!add_platform_cap(acpi_desc, table))
+			return err;
+		break;
 	default:
 		dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
 		break;
@@ -2649,6 +2665,9 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 	else
 		ndr_desc->numa_node = NUMA_NO_NODE;
 
+	if(acpi_desc->platform_cap & ACPI_NFIT_CAPABILITY_CACHE_FLUSH)
+		set_bit(ND_REGION_PERSIST_CACHE, &ndr_desc->flags);
+
 	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
 		struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
 		struct nd_mapping_desc *mapping;
@@ -3457,6 +3476,7 @@ static __init int nfit_init(void)
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 9);
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_control_region) != 80);
 	BUILD_BUG_ON(sizeof(struct acpi_nfit_data_region) != 40);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_capabilities) != 16);
 
 	guid_parse(UUID_VOLATILE_MEMORY, &nfit_uuid[NFIT_SPA_VOLATILE]);
 	guid_parse(UUID_PERSISTENT_MEMORY, &nfit_uuid[NFIT_SPA_PM]);
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index f0cf18b2da8b..50d36e166d70 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -202,6 +202,7 @@ struct acpi_nfit_desc {
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
 	unsigned long bus_nfit_cmd_force_en;
+	unsigned int platform_cap;
 	int (*blk_do_io)(struct nd_blk_region *ndbr, resource_size_t dpa,
 			void *iobuf, u64 len, int rw);
 };
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 7fbc5c5dc8e1..8aa542398db4 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -35,6 +35,7 @@
 #include "pmem.h"
 #include "pfn.h"
 #include "nd.h"
+#include "nd-core.h"
 
 static struct device *to_dev(struct pmem_device *pmem)
 {
@@ -334,7 +335,8 @@ static int pmem_attach_disk(struct device *dev,
 		dev_warn(dev, "unable to guarantee persistence of writes\n");
 		fua = 0;
 	}
-	wbc = nvdimm_has_cache(nd_region);
+	wbc = nvdimm_has_cache(nd_region) &&
+		!test_bit(ND_REGION_PERSIST_CACHE, &nd_region->flags);
 
 	if (!devm_request_mem_region(dev, res->start, resource_size(res),
 				dev_name(&ndns->dev))) {
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index f8109ddb5ef1..f2fc0da4da04 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -47,6 +47,11 @@ enum {
 
 	/* region flag indicating to direct-map persistent memory by default */
 	ND_REGION_PAGEMAP = 0,
+	/*
+	 * Platform ensures entire CPU store data path is flushed to pmem on
+	 * system power loss.
+	 */
+	ND_REGION_PERSIST_CACHE = 1,
 
 	/* mark newly adjusted resources as requiring a label update */
 	DPA_RESOURCE_ADJUSTED = 1 << 0,

[PATCH v4 2/4] acpi: nfit: add persistent memory control flag for nd_region

[Dave Jiang]

Propagate the ADR attribute flag from the NFIT platform capabilities
sub-table to nd_region.

Signed-off-by: Dave Jiang <dave.jiang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Ross Zwisler <ross.zwisler-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 drivers/acpi/nfit/core.c  |    3 +++
 include/linux/libnvdimm.h |    6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index bcf52bb93b65..b1616120ca57 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2668,6 +2668,9 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 	if(acpi_desc->platform_cap & ACPI_NFIT_CAPABILITY_CACHE_FLUSH)
 		set_bit(ND_REGION_PERSIST_CACHE, &ndr_desc->flags);
 
+	if (acpi_desc->platform_cap & ACPI_NFIT_CAPABILITY_MEM_FLUSH)
+		set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc->flags);
+
 	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
 		struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
 		struct nd_mapping_desc *mapping;
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index f2fc0da4da04..ff855ed965fb 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -52,6 +52,12 @@ enum {
 	 * system power loss.
 	 */
 	ND_REGION_PERSIST_CACHE = 1,
+	/*
+	 * Platform provides mechanisms to automatically flush outstanding
+	 * write data from memory controler to pmem on system power loss.
+	 * (ADR)
+	 */
+	ND_REGION_PERSIST_MEMCTRL = 2,
 
 	/* mark newly adjusted resources as requiring a label update */
 	DPA_RESOURCE_ADJUSTED = 1 << 0,

[PATCH v4 3/4] libnvdimm: expose platform persistence attribute for nd_region

[Dave Jiang]

Providing a sysfs attribute for nd_region that shows the persistence
capabilities for the platform.

Signed-off-by: Dave Jiang <dave.jiang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Ross Zwisler <ross.zwisler-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 drivers/nvdimm/region_devs.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index abaf38c61220..e6d01911e092 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -528,6 +528,18 @@ static ssize_t resource_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(resource);
 
+static ssize_t persistence_domain_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nd_region *nd_region = to_nd_region(dev);
+	unsigned long flags = nd_region->flags;
+
+	return sprintf(buf, "%s%s\n",
+			flags & BIT(ND_REGION_PERSIST_CACHE) ? "cpu_cache " : "",
+			flags & BIT(ND_REGION_PERSIST_MEMCTRL) ? "memory_controller " : "");
+}
+static DEVICE_ATTR_RO(persistence_domain);
+
 static struct attribute *nd_region_attributes[] = {
 	&dev_attr_size.attr,
 	&dev_attr_nstype.attr,
@@ -543,6 +555,7 @@ static struct attribute *nd_region_attributes[] = {
 	&dev_attr_init_namespaces.attr,
 	&dev_attr_badblocks.attr,
 	&dev_attr_resource.attr,
+	&dev_attr_persistence_domain.attr,
 	NULL,
 };

[PATCH v4 4/4] nfit-test: Add platform cap support from ACPI 6.2a to test

[Dave Jiang]

Adding NFIT platform capabilities sub table in nfit_test simulated ACPI
NFIT table. Only the first NFIT table is added with the capability
sub-table.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
 tools/testing/nvdimm/test/nfit.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index 7217b2b953b5..f4791e6e70cf 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -881,7 +881,8 @@ static int nfit_test0_alloc(struct nfit_test *t)
 					window_size) * NUM_DCR
 			+ sizeof(struct acpi_nfit_data_region) * NUM_BDW
 			+ (sizeof(struct acpi_nfit_flush_address)
-					+ sizeof(u64) * NUM_HINTS) * NUM_DCR;
+					+ sizeof(u64) * NUM_HINTS) * NUM_DCR
+			+ sizeof(struct acpi_nfit_capabilities);
 	int i;
 
 	t->nfit_buf = test_alloc(t, nfit_size, &t->nfit_dma);
@@ -993,6 +994,7 @@ static void nfit_test0_setup(struct nfit_test *t)
 	struct acpi_nfit_control_region *dcr;
 	struct acpi_nfit_data_region *bdw;
 	struct acpi_nfit_flush_address *flush;
+	struct acpi_nfit_capabilities *pcap;
 	unsigned int offset, i;
 
 	/*
@@ -1500,8 +1502,16 @@ static void nfit_test0_setup(struct nfit_test *t)
 	for (i = 0; i < NUM_HINTS; i++)
 		flush->hint_address[i] = t->flush_dma[3] + i * sizeof(u64);
 
+	/* platform capabilities */
+	pcap = nfit_buf + offset + flush_hint_size * 4;
+	pcap->header.type = ACPI_NFIT_TYPE_CAPABILITIES;
+	pcap->header.length = sizeof(*pcap);
+	pcap->highest_capability = BIT(2);
+	pcap->capabilities = ACPI_NFIT_CAPABILITY_CACHE_FLUSH |
+		ACPI_NFIT_CAPABILITY_MEM_FLUSH;
+
 	if (t->setup_hotplug) {
-		offset = offset + flush_hint_size * 4;
+		offset = offset + flush_hint_size * 4 + sizeof(*pcap);
 		/* dcr-descriptor4: blk */
 		dcr = nfit_buf + offset;
 		dcr->header.type = ACPI_NFIT_TYPE_CONTROL_REGION;

Re: [PATCH v4 4/4] nfit-test: Add platform cap support from ACPI 6.2a to test

[Ross Zwisler]

On Tue, Jan 30, 2018 at 05:21:39PM -0700, Dave Jiang wrote:
> Adding NFIT platform capabilities sub table in nfit_test simulated ACPI
> NFIT table. Only the first NFIT table is added with the capability
> sub-table.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> ---
>  tools/testing/nvdimm/test/nfit.c |   14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
> index 7217b2b953b5..f4791e6e70cf 100644
> --- a/tools/testing/nvdimm/test/nfit.c
> +++ b/tools/testing/nvdimm/test/nfit.c
> @@ -881,7 +881,8 @@ static int nfit_test0_alloc(struct nfit_test *t)
>  					window_size) * NUM_DCR
>  			+ sizeof(struct acpi_nfit_data_region) * NUM_BDW
>  			+ (sizeof(struct acpi_nfit_flush_address)
> -					+ sizeof(u64) * NUM_HINTS) * NUM_DCR;
> +					+ sizeof(u64) * NUM_HINTS) * NUM_DCR
> +			+ sizeof(struct acpi_nfit_capabilities);
>  	int i;
>  
>  	t->nfit_buf = test_alloc(t, nfit_size, &t->nfit_dma);
> @@ -993,6 +994,7 @@ static void nfit_test0_setup(struct nfit_test *t)
>  	struct acpi_nfit_control_region *dcr;
>  	struct acpi_nfit_data_region *bdw;
>  	struct acpi_nfit_flush_address *flush;
> +	struct acpi_nfit_capabilities *pcap;
>  	unsigned int offset, i;
>  
>  	/*
> @@ -1500,8 +1502,16 @@ static void nfit_test0_setup(struct nfit_test *t)
>  	for (i = 0; i < NUM_HINTS; i++)
>  		flush->hint_address[i] = t->flush_dma[3] + i * sizeof(u64);
>  
> +	/* platform capabilities */
> +	pcap = nfit_buf + offset + flush_hint_size * 4;
> +	pcap->header.type = ACPI_NFIT_TYPE_CAPABILITIES;
> +	pcap->header.length = sizeof(*pcap);
> +	pcap->highest_capability = BIT(2);

One last thing I noticed: I'm pretty sure this needs to be 
	pcap->highest_capability = 1;

The way I read the spec, this is the value of the highest bit index which is
valid.  We define bits 0 and 1, so this should be 1.  BIT(2) = 0x4, which
gives us a mask of 0x1f for bits 0, 1, 2, 3, and 4.