This adds a kernel config option that controls whether MAP_SYNC is enabled by
default. With POWER10, architecture is adding new pmem flush and sync
instructions. The kernel should prevent the usage of MAP_SYNC if applications
are not using the new instructions on newer hardware.
This config allows user to control whether MAP_SYNC should be enabled by
default or not.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/powerpc/platforms/Kconfig.cputype | 9 +++++++++
arch/powerpc/platforms/pseries/papr_scm.c | 17 ++++++++++++++++-
drivers/nvdimm/of_pmem.c | 7 +++++++
3 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/Kconfig.cputype
b/arch/powerpc/platforms/Kconfig.cputype
index d349603fb889..abcc163b8dc6 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -383,6 +383,15 @@ config PPC_KUEP
If you're unsure, say Y.
+config ARCH_MAP_SYNC_DISABLE
+ bool "Disable synchronous fault support (MAP_SYNC)"
+ default y
+ help
+ Disable support for synchronous fault with nvdimm namespaces.
+
+ If you're unsure, say Y.
+
+
config PPC_HAVE_KUAP
bool
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
b/arch/powerpc/platforms/pseries/papr_scm.c
index ad506e7003c9..b970d2dbe589 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -30,6 +30,7 @@ struct papr_scm_priv {
uint64_t block_size;
int metadata_size;
bool is_volatile;
+ bool disable_map_sync;
uint64_t bound_addr;
@@ -353,11 +354,18 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
ndr_desc.num_mappings = 1;
ndr_desc.nd_set = &p->nd_set;
ndr_desc.flush = papr_scm_flush_sync;
+ set_bit(ND_REGION_SYNC_ENABLED, &ndr_desc.flags);
if (p->is_volatile)
p->region = nvdimm_volatile_region_create(p->bus, &ndr_desc);
else {
set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
+ /*
+ * for a persistent region, check if the platform needs to
+ * force MAP_SYNC disable.
+ */
+ if (p->disable_map_sync)
+ clear_bit(ND_REGION_SYNC_ENABLED, &ndr_desc.flags);
p->region = nvdimm_pmem_region_create(p->bus, &ndr_desc);
}
if (!p->region) {
@@ -378,7 +386,7 @@ err: nvdimm_bus_unregister(p->bus);
static int papr_scm_probe(struct platform_device *pdev)
{
- struct device_node *dn = pdev->dev.of_node;
+ struct device_node *dn;
u32 drc_index, metadata_size;
u64 blocks, block_size;
struct papr_scm_priv *p;
@@ -386,6 +394,10 @@ static int papr_scm_probe(struct platform_device *pdev)
u64 uuid[2];
int rc;
+ dn = dev_of_node(&pdev->dev);
+ if (!dn)
+ return -ENXIO;
+
/* check we have all the required DT properties */
if (of_property_read_u32(dn, "ibm,my-drc-index", &drc_index)) {
dev_err(&pdev->dev, "%pOF: missing drc-index!\n", dn);
@@ -415,6 +427,9 @@ static int papr_scm_probe(struct platform_device *pdev)
/* optional DT properties */
of_property_read_u32(dn, "ibm,metadata-size", &metadata_size);
+ if (of_device_is_compatible(dn, "ibm,pmemory-v2"))
+ p->disable_map_sync = true;
+
p->dn = dn;
p->drc_index = drc_index;
p->block_size = block_size;
diff --git a/drivers/nvdimm/of_pmem.c b/drivers/nvdimm/of_pmem.c
index 6826a274a1f1..a6cc3488e552 100644
--- a/drivers/nvdimm/of_pmem.c
+++ b/drivers/nvdimm/of_pmem.c
@@ -59,12 +59,19 @@ static int of_pmem_region_probe(struct platform_device
*pdev)
ndr_desc.res = &pdev->resource[i];
ndr_desc.of_node = np;
set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
+ set_bit(ND_REGION_SYNC_ENABLED, &ndr_desc.flags);
if (is_volatile)
region = nvdimm_volatile_region_create(bus, &ndr_desc);
else {
set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
+ /*
+ * for a persistent region, check for newer device
+ */
+ if (of_device_is_compatible(np, "pmem-region-v2"))
+ clear_bit(ND_REGION_SYNC_ENABLED,
&ndr_desc.flags);
region = nvdimm_pmem_region_create(bus, &ndr_desc);
+
}
if (!region)
--
2.26.2
