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authorDan Williams <dan.j.williams@intel.com>2016-04-29 01:23:43 +0200
committerDan Williams <dan.j.williams@intel.com>2016-04-29 01:59:06 +0200
commit31eca76ba2fc988bf88f16fcf763a0ec4068cd30 (patch)
tree7b7f359ac8340576842350708cd4de5b84bbf53a /drivers/nvdimm
parentnfit, libnvdimm: clarify "commands" vs "_DSMs" (diff)
downloadlinux-31eca76ba2fc988bf88f16fcf763a0ec4068cd30.tar.xz
linux-31eca76ba2fc988bf88f16fcf763a0ec4068cd30.zip
nfit, libnvdimm: limited/whitelisted dimm command marshaling mechanism
There are currently 4 known similar but incompatible definitions of the command sets that can be sent to an NVDIMM through ACPI. It is also clear that future platform generations (ACPI or not) will continue to revise and extend the DIMM command set as new devices and use cases arrive. It is obviously untenable to continue to proliferate divergence of these command definitions, and to that end a standardization process has begun to provide for a unified specification. However, that leaves a problem about what to do with this first generation where vendors are already shipping divergence. The Linux kernel can support these initial diverged platforms without giving platform-firmware free reign to continue to diverge and compound kernel maintenance overhead. The kernel implementation can encourage standardization in two ways: 1/ Require that any function code that userspace wants to send be explicitly white-listed in the implementation. For ACPI this means function codes marked as supported by acpi_check_dsm() may only be invoked if they appear in the white-list. A function must be publicly documented before it is added to the white-list. 2/ The above restrictions can be trivially bypassed by using the "vendor-specific" payload command. However, since vendor-specific commands are by definition not publicly documented and have the potential to corrupt the kernel's view of the dimm state, we provide a toggle to disable vendor-specific operations. Enabling undefined behavior is a policy decision that can be made by the platform owner and encourages firmware implementations to choose public over private command implementations. Based on an initial patch from Jerry Hoemann Cc: Jerry Hoemann <jerry.hoemann@hpe.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm')
-rw-r--r--drivers/nvdimm/bus.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index cb2042a12b76..395a9fbbc69d 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -439,6 +439,12 @@ static const struct nd_cmd_desc __nd_cmd_dimm_descs[] = {
.out_num = 3,
.out_sizes = { 4, 4, UINT_MAX, },
},
+ [ND_CMD_CALL] = {
+ .in_num = 2,
+ .in_sizes = { sizeof(struct nd_cmd_pkg), UINT_MAX, },
+ .out_num = 1,
+ .out_sizes = { UINT_MAX, },
+ },
};
const struct nd_cmd_desc *nd_cmd_dimm_desc(int cmd)
@@ -473,6 +479,12 @@ static const struct nd_cmd_desc __nd_cmd_bus_descs[] = {
.out_num = 3,
.out_sizes = { 4, 4, 8, },
},
+ [ND_CMD_CALL] = {
+ .in_num = 2,
+ .in_sizes = { sizeof(struct nd_cmd_pkg), UINT_MAX, },
+ .out_num = 1,
+ .out_sizes = { UINT_MAX, },
+ },
};
const struct nd_cmd_desc *nd_cmd_bus_desc(int cmd)
@@ -500,6 +512,10 @@ u32 nd_cmd_in_size(struct nvdimm *nvdimm, int cmd,
struct nd_cmd_vendor_hdr *hdr = buf;
return hdr->in_length;
+ } else if (cmd == ND_CMD_CALL) {
+ struct nd_cmd_pkg *pkg = buf;
+
+ return pkg->nd_size_in;
}
return UINT_MAX;
@@ -522,6 +538,12 @@ u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
return out_field[1];
else if (!nvdimm && cmd == ND_CMD_ARS_STATUS && idx == 2)
return out_field[1] - 8;
+ else if (cmd == ND_CMD_CALL) {
+ struct nd_cmd_pkg *pkg = (struct nd_cmd_pkg *) in_field;
+
+ return pkg->nd_size_out;
+ }
+
return UINT_MAX;
}
@@ -588,6 +610,7 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
unsigned int cmd = _IOC_NR(ioctl_cmd);
void __user *p = (void __user *) arg;
struct device *dev = &nvdimm_bus->dev;
+ struct nd_cmd_pkg pkg;
const char *cmd_name, *dimm_name;
unsigned long cmd_mask;
void *buf;
@@ -605,6 +628,11 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
dimm_name = "bus";
}
+ if (cmd == ND_CMD_CALL) {
+ if (copy_from_user(&pkg, p, sizeof(pkg)))
+ return -EFAULT;
+ }
+
if (!desc || (desc->out_num + desc->in_num == 0) ||
!test_bit(cmd, &cmd_mask))
return -ENOTTY;
@@ -616,6 +644,7 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
case ND_CMD_SET_CONFIG_DATA:
case ND_CMD_ARS_START:
case ND_CMD_CLEAR_ERROR:
+ case ND_CMD_CALL:
dev_dbg(&nvdimm_bus->dev, "'%s' command while read-only.\n",
nvdimm ? nvdimm_cmd_name(cmd)
: nvdimm_bus_cmd_name(cmd));
@@ -643,6 +672,16 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
in_len += in_size;
}
+ if (cmd == ND_CMD_CALL) {
+ dev_dbg(dev, "%s:%s, idx: %llu, in: %zu, out: %zu, len %zu\n",
+ __func__, dimm_name, pkg.nd_command,
+ in_len, out_len, buf_len);
+
+ for (i = 0; i < ARRAY_SIZE(pkg.nd_reserved2); i++)
+ if (pkg.nd_reserved2[i])
+ return -EINVAL;
+ }
+
/* process an output envelope */
for (i = 0; i < desc->out_num; i++) {
u32 out_size = nd_cmd_out_size(nvdimm, cmd, desc, i,