On Sat, Jul 1, 2017 at 1:38 PM, Jerry Hoemann <jerry.hoem...@hpe.com> wrote: > On Sat, Jul 01, 2017 at 01:10:31PM -0700, Dan Williams wrote: >> 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. > > I don't understand this comment, but I think your next comment > essentially says to disregard this comment?
Yes, sorry. >> Actually, just the discovery portion does not lead to this leak, but >> it's redundant when we have the 'dsm_mask' sysfs attribute. > > No. The generation of the mask in sysfs is not done by > executing the code in acpi_nfit_ctl. One of the reasons I call > function 0 to test changes I am making to the ioctl path itself. > The sysfs has nothing to do with that path and cannot be used > to serve this purpose. > > And since the content of sysfs has been edited it also can not be > used as a basic test of firmware. > > What is the downside to allowing the calling of function 0? It needlessly expands the kernel ABI. I would suggest, if you want to test acpi_nfit_ctl() path changes, expand the existing test infrastructure we have in nfit_ctl_test(). If you want to test firmware you don't need the upstream kernel to carry firmware debug enabling in the production path, but I would support expanding tools/testing/nvdimm/ to make it easier to test firmware.
