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_write_cache(). Plumbing the path to set the property on per region from the NFTI 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(a)intel.com&gt; --- drivers/acpi/nfit/core.c | 20 ++++++++++++++++++++ drivers/acpi/nfit/nfit.h | 1 + drivers/nvdimm/pmem.c | 4 +++- drivers/nvdimm/region_devs.c | 1 + include/linux/libnvdimm.h | 5 +++++ 5 files changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index ff2580e7611d..c08b3da61b93 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; + u8 mask; + + mask = pcap->highest_capability - 1 + pcap->highest_capability; + acpi_desc->platform_cap = pcap->capabilities & (u32)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..13f2ed80899e 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/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c index abaf38c61220..87e8cd10de05 100644 --- a/drivers/nvdimm/region_devs.c +++ b/drivers/nvdimm/region_devs.c @@ -994,6 +994,7 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus, dev->groups = ndr_desc->attr_groups; nd_region->ndr_size = resource_size(ndr_desc->res); nd_region->ndr_start = ndr_desc->res->start; + nd_device_register(dev); return nd_region; 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,

Propogate the ADR attribute flag from the NFIT platform capabilities sub-table to nd_region. Signed-off-by: Dave Jiang <dave.jiang(a)intel.com&gt; --- 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 c08b3da61b93..435222944950 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,

Providing a sysfs attribute for nd_region that shows the persistence capabilities for the platform. Signed-off-by: Dave Jiang <dave.jiang(a)intel.com&gt; --- 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 87e8cd10de05..211639d836c8 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, };

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(a)intel.com&gt; --- tools/testing/nvdimm/test/nfit.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c index 7217b2b953b5..8a16f90a9573 100644 --- a/tools/testing/nvdimm/test/nfit.c +++ b/tools/testing/nvdimm/test/nfit.c @@ -993,6 +993,7 @@ 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 +1501,16 @@ 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 + sizeof(*pcap); /* dcr-descriptor4: blk */ dcr = nfit_buf + offset; dcr->header.type = ACPI_NFIT_TYPE_CONTROL_REGION;