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@xxxxxxxxx>
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
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,
--
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