Some BIOSen do not handle 0-byte transfer lengths for the _LSR and _LSW (label storage read/write) methods. This causes Linux to fallback to the deprecated _DSM path, or otherwise disable label support.

Introduce acpi_nvdimm_has_method() to detect whether a method is available rather than calling the method, require _LSI and _LSR to be paired, and require read support before enabling write support.

Cc: stable@vger.kernel.org Fixes: 4b27db7e26cd ("acpi, nfit: add support for the _LS...") Suggested-by: Erik Schmauss erik.schmauss@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com --- drivers/acpi/nfit/core.c | 41 +++++++++++++++++++++-------------------- drivers/acpi/nfit/nfit.h | 5 ++--- 2 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 4530d89044db..12fb414fa678 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -196,7 +196,7 @@ static int xlat_nvdimm_status(struct nvdimm *nvdimm, void *buf, unsigned int cmd * In the _LSI, _LSR, _LSW case the locked status is * communicated via the read/write commands */ - if (nfit_mem->has_lsi) + if (nfit_mem->has_lsr) break;

if (status >> 16 & ND_CONFIG_LOCKED) @@ -483,7 +483,7 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm, min_t(u32, 256, in_buf.buffer.length), true);

/* call the BIOS, prefer the named methods over _DSM if available */ - if (nvdimm && cmd == ND_CMD_GET_CONFIG_SIZE && nfit_mem->has_lsi) + if (nvdimm && cmd == ND_CMD_GET_CONFIG_SIZE && nfit_mem->has_lsr) out_obj = acpi_label_info(handle); else if (nvdimm && cmd == ND_CMD_GET_CONFIG_DATA && nfit_mem->has_lsr) { struct nd_cmd_get_config_data_hdr *p = buf; @@ -1653,12 +1653,23 @@ static void acpi_nvdimm_notify(acpi_handle handle, u32 event, void *data) device_unlock(dev->parent); }

+static bool acpi_nvdimm_has_method(struct acpi_device *adev, char *method) +{ + acpi_handle handle; + acpi_status status; + + status = acpi_get_handle(adev->handle, method, &handle); + + if (ACPI_SUCCESS(status)) + return true; + return false; +} + static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc, struct nfit_mem *nfit_mem, u32 device_handle) { struct acpi_device *adev, *adev_dimm; struct device *dev = acpi_desc->dev; - union acpi_object *obj; unsigned long dsm_mask; const guid_t *guid; int i; @@ -1731,25 +1742,15 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc, 1ULL << i)) set_bit(i, &nfit_mem->dsm_mask);

- obj = acpi_label_info(adev_dimm->handle); - if (obj) { - ACPI_FREE(obj); - nfit_mem->has_lsi = 1; - dev_dbg(dev, "%s: has _LSI\n", dev_name(&adev_dimm->dev)); - } - - obj = acpi_label_read(adev_dimm->handle, 0, 0); - if (obj) { - ACPI_FREE(obj); - nfit_mem->has_lsr = 1; + if (acpi_nvdimm_has_method(adev_dimm, "_LSI") + && acpi_nvdimm_has_method(adev_dimm, "_LSR")) { dev_dbg(dev, "%s: has _LSR\n", dev_name(&adev_dimm->dev)); + nfit_mem->has_lsr = true; }

- obj = acpi_label_write(adev_dimm->handle, 0, 0, NULL); - if (obj) { - ACPI_FREE(obj); - nfit_mem->has_lsw = 1; + if (nfit_mem->has_lsr && acpi_nvdimm_has_method(adev_dimm, "_LSW")) { dev_dbg(dev, "%s: has _LSW\n", dev_name(&adev_dimm->dev)); + nfit_mem->has_lsw = true; }

return 0; @@ -1838,10 +1839,10 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc) cmd_mask |= nfit_mem->dsm_mask & NVDIMM_STANDARD_CMDMASK; }

- if (nfit_mem->has_lsi) + if (nfit_mem->has_lsr) { set_bit(ND_CMD_GET_CONFIG_SIZE, &cmd_mask); - if (nfit_mem->has_lsr) set_bit(ND_CMD_GET_CONFIG_DATA, &cmd_mask); + } if (nfit_mem->has_lsw) set_bit(ND_CMD_SET_CONFIG_DATA, &cmd_mask);

diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h index 50d36e166d70..ac9c49463731 100644 --- a/drivers/acpi/nfit/nfit.h +++ b/drivers/acpi/nfit/nfit.h @@ -171,9 +171,8 @@ struct nfit_mem { struct resource *flush_wpq; unsigned long dsm_mask; int family; - u32 has_lsi:1; - u32 has_lsr:1; - u32 has_lsw:1; + bool has_lsr; + bool has_lsw; };

struct acpi_nfit_desc {