On Sat, Jul 1, 2017 at 1:08 PM, Dan Williams <dan.j.willi...@intel.com> wrote: > On Sat, Jul 1, 2017 at 12:58 PM, Jerry Hoemann <jerry.hoem...@hpe.com> wrote: >> On Fri, Jun 30, 2017 at 08:55:22PM -0700, Dan Williams wrote: >> >> ... >> >>> On Fri, Jun 30, 2017 at 9:09 AM, Jerry Hoemann <jerry.hoem...@hpe.com> >>> wrote: >>> > + if (cmd == ND_CMD_CALL) >>> > + dsm_mask = nd_desc->bus_dsm_mask; >>> > desc = nd_cmd_bus_desc(cmd); >>> > uuid = to_nfit_uuid(NFIT_DEV_BUS); >>> > handle = adev->handle; >>> > @@ -1613,6 +1615,7 @@ static void acpi_nfit_init_dsms(struct >>> > acpi_nfit_desc *acpi_desc) >>> > struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc; >>> > const u8 *uuid = to_nfit_uuid(NFIT_DEV_BUS); >>> > struct acpi_device *adev; >>> > + unsigned long dsm_mask; >>> > int i; >>> > >>> > nd_desc->cmd_mask = acpi_desc->bus_cmd_force_en; >>> > @@ -1624,6 +1627,11 @@ static void acpi_nfit_init_dsms(struct >>> > acpi_nfit_desc *acpi_desc) >>> > if (acpi_check_dsm(adev->handle, uuid, 1, 1ULL << i)) >>> > set_bit(i, &nd_desc->cmd_mask); >>> > set_bit(ND_CMD_CALL, &nd_desc->cmd_mask); >>> > + >>> > + dsm_mask = 0x3bf; >>> >>> I went ahead and fixed this up to use dsm_mask defined like this: >>> >>> + dsm_mask = >>> + (1 << ND_CMD_ARS_CAP) | >>> + (1 << ND_CMD_ARS_START) | >>> + (1 << ND_CMD_ARS_STATUS) | >>> + (1 << ND_CMD_CLEAR_ERROR) | >>> + (1 << NFIT_CMD_TRANSLATE_SPA) | >>> + (1 << NFIT_CMD_ARS_INJECT_SET) | >>> + (1 << NFIT_CMD_ARS_INJECT_CLEAR) | >>> + (1 << NFIT_CMD_ARS_INJECT_GET); >>> >>> This drops function number 0 which userspace has no need to call. >> >> Actually I like to call function 0. Its an excellent test when >> modifying the code path as its a no side effects function whose output >> is known in advance and instantly recognizable. I also use it when >> testing new firmware. >> >> What is the downside to allowing it? What bad things happen? > > It allows implementations to bypass the standardization process and > ship new root DSMs. It's always possible to patch the kernel locally > for development, so I see no reason to ship this capability globally.
Actually, just the discovery portion does not lead to this leak, but it's redundant when we have the 'dsm_mask' sysfs attribute.
