Commit 466d1493 authored by Dan Williams's avatar Dan Williams
Browse files

acpi, nfit: rework NVDIMM leaf method detection 



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: 4b27db7e ("acpi, nfit: add support for the _LS...")
Suggested-by: default avatarErik Schmauss <erik.schmauss@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 0731de47

drivers/acpi/nfit/core.c

+21 −20
Original line number Diff line number Diff line
@@ -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);

drivers/acpi/nfit/nfit.h

+2 −3
Original line number Diff line number Diff line
@@ -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 {

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