2018-03-22 04:52:47

by Dan Williams

Subject: [PATCH] nfit: skip region registration for incomplete control regions

Per the ACPI specification the only functional purpose for a DIMM
Control Region to be mapped into the system physical address space, from
an OSPM perspective, is to support block-apertures. However, there are
some BIOSen that publish DIMM Control Region SPA entries for pre-boot
environment consumption. Undo the kernel policy of generating disabled
'ndblk' regions when this configuration is detected.

Signed-off-by: Dan Williams <[email protected]>
---
drivers/acpi/nfit/core.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 39ad06143e78..4530d89044db 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -2578,7 +2578,7 @@ static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
struct acpi_nfit_system_address *spa = nfit_spa->spa;
struct nd_blk_region_desc *ndbr_desc;
struct nfit_mem *nfit_mem;
- int blk_valid = 0, rc;
+ int rc;

if (!nvdimm) {
dev_err(acpi_desc->dev, "spa%d dimm: %#x not found\n",
@@ -2598,15 +2598,14 @@ static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
if (!nfit_mem || !nfit_mem->bdw) {
dev_dbg(acpi_desc->dev, "spa%d %s missing bdw\n",
spa->range_index, nvdimm_name(nvdimm));
- } else {
- mapping->size = nfit_mem->bdw->capacity;
- mapping->start = nfit_mem->bdw->start_address;
- ndr_desc->num_lanes = nfit_mem->bdw->windows;
- blk_valid = 1;
+ break;
}

+ mapping->size = nfit_mem->bdw->capacity;
+ mapping->start = nfit_mem->bdw->start_address;
+ ndr_desc->num_lanes = nfit_mem->bdw->windows;
ndr_desc->mapping = mapping;
- ndr_desc->num_mappings = blk_valid;
+ ndr_desc->num_mappings = 1;
ndbr_desc = to_blk_region_desc(ndr_desc);
ndbr_desc->enable = acpi_nfit_blk_region_enable;
ndbr_desc->do_io = acpi_desc->blk_do_io;

2018-03-22 20:00:09

by Kani, Toshimitsu

Subject: Re: [PATCH] nfit: skip region registration for incomplete control regions

On Wed, 2018-03-21 at 21:42 -0700, Dan Williams wrote:
> Per the ACPI specification the only functional purpose for a DIMM
> Control Region to be mapped into the system physical address space, from
> an OSPM perspective, is to support block-apertures. However, there are
> some BIOSen that publish DIMM Control Region SPA entries for pre-boot
> environment consumption. Undo the kernel policy of generating disabled
> 'ndblk' regions when this configuration is detected.
>
> Signed-off-by: Dan Williams <[email protected]>

The change looks good.

Reviewed-by: Toshi Kani <[email protected]>

Thanks!
-Toshi