acpi/nfit: Fix command-supported detection

The _DSM function number validation only happens to succeed when the
generic Linux command number translation corresponds with a
DSM-family-specific function number. This breaks NVDIMM-N
implementations that correctly implement _LSR, _LSW, and _LSI, but do
not happen to publish support for DSM function numbers 4, 5, and 6.

Recall that the support for _LS{I,R,W} family of methods results in the
DIMM being marked as supporting those command numbers at
acpi_nfit_register_dimms() time. The DSM function mask is only used for
ND_CMD_CALL support of non-NVDIMM_FAMILY_INTEL devices.

Fixes: 31eca76ba2fc ("nfit, libnvdimm: limited/whitelisted dimm command...")
Cc: <stable@vger.kernel.org>
Link: https://github.com/pmem/ndctl/issues/78
Reported-by: Sujith Pandel <sujith_pandel@dell.com>
Tested-by: Sujith Pandel <sujith_pandel@dell.com>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index ed05697a2b38e364fa0f94881b40a59b6d1e6867..e18ade5d74e9ecf38126bce5301f027073779bc3 100644 (file)
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -409,6 +409,32 @@ static bool payload_dumpable(struct nvdimm *nvdimm, unsigned int func)
        return true;
 }
 
+static int cmd_to_func(struct nfit_mem *nfit_mem, unsigned int cmd,
+               struct nd_cmd_pkg *call_pkg)
+{
+       if (call_pkg) {
+               int i;
+
+               if (nfit_mem->family != call_pkg->nd_family)
+                       return -ENOTTY;
+
+               for (i = 0; i < ARRAY_SIZE(call_pkg->nd_reserved2); i++)
+                       if (call_pkg->nd_reserved2[i])
+                               return -EINVAL;
+               return call_pkg->nd_command;
+       }
+
+       /* Linux ND commands == NVDIMM_FAMILY_INTEL function numbers */
+       if (nfit_mem->family == NVDIMM_FAMILY_INTEL)
+               return cmd;
+
+       /*
+        * Force function number validation to fail since 0 is never
+        * published as a valid function in dsm_mask.
+        */
+       return 0;
+}
+
 int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
                unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)
 {
@@ -422,30 +448,23 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
        unsigned long cmd_mask, dsm_mask;
        u32 offset, fw_status = 0;
        acpi_handle handle;
-       unsigned int func;
        const guid_t *guid;
-       int rc, i;
+       int func, rc, i;
 
        if (cmd_rc)
                *cmd_rc = -EINVAL;
-       func = cmd;
-       if (cmd == ND_CMD_CALL) {
-               call_pkg = buf;
-               func = call_pkg->nd_command;
-
-               for (i = 0; i < ARRAY_SIZE(call_pkg->nd_reserved2); i++)
-                       if (call_pkg->nd_reserved2[i])
-                               return -EINVAL;
-       }
 
        if (nvdimm) {
                struct acpi_device *adev = nfit_mem->adev;
 
                if (!adev)
                        return -ENOTTY;
-               if (call_pkg && nfit_mem->family != call_pkg->nd_family)
-                       return -ENOTTY;
 
+               if (cmd == ND_CMD_CALL)
+                       call_pkg = buf;
+               func = cmd_to_func(nfit_mem, cmd, call_pkg);
+               if (func < 0)
+                       return func;
                dimm_name = nvdimm_name(nvdimm);
                cmd_name = nvdimm_cmd_name(cmd);
                cmd_mask = nvdimm_cmd_mask(nvdimm);
@@ -456,6 +475,7 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
        } else {
                struct acpi_device *adev = to_acpi_dev(acpi_desc);
 
+               func = cmd;
                cmd_name = nvdimm_bus_cmd_name(cmd);
                cmd_mask = nd_desc->cmd_mask;
                dsm_mask = cmd_mask;
@@ -470,7 +490,13 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
        if (!desc || (cmd && (desc->out_num + desc->in_num == 0)))
                return -ENOTTY;
 
-       if (!test_bit(cmd, &cmd_mask) || !test_bit(func, &dsm_mask))
+       /*
+        * Check for a valid command.  For ND_CMD_CALL, we also have to
+        * make sure that the DSM function is supported.
+        */
+       if (cmd == ND_CMD_CALL && !test_bit(func, &dsm_mask))
+               return -ENOTTY;
+       else if (!test_bit(cmd, &cmd_mask))
                return -ENOTTY;
 
        in_obj.type = ACPI_TYPE_PACKAGE;