| Message ID | 20200519055502.128318-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v3,1/7] powerpc/pmem: Restrict papr_scm to P8 and above. | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (7b06fb8795ffea9d12be45a172197c3307955479) |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 1 warnings, 0 checks, 12 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
diff --git a/arch/powerpc/platforms/pseries/pmem.c b/arch/powerpc/platforms/pseries/pmem.c index f860a897a9e0..2347e1038f58 100644 --- a/arch/powerpc/platforms/pseries/pmem.c +++ b/arch/powerpc/platforms/pseries/pmem.c @@ -147,6 +147,12 @@ const struct of_device_id drc_pmem_match[] = { static int pseries_pmem_init(void) { + /* + * Only supported on POWER8 and above. + */ + if (!cpu_has_feature(CPU_FTR_ARCH_207S)) + return 0; + pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory"); if (!pmem_node) return 0;
The PAPR based virtualized persistent memory devices are only supported on POWER9 and above. In the followup patch, the kernel will switch the persistent memory cache flush functions to use a new `dcbf` variant instruction. The new instructions even though added in ISA 3.1 works even on P8 and P9 because these are implemented as a variant of existing `dcbf` and `hwsync` and on P8 and above behaves as such. Considering these devices are only supported on P8 and above, update the driver to prevent a P7-compat guest from using persistent memory devices. We don't update of_pmem driver with the same condition, because, on bare-metal, the firmware enables pmem support only on P9 and above. There the kernel depends on OPAL firmware to restrict exposing persistent memory related device tree entries on older hardware. of_pmem.ko is written without any arch dependency and we don't want to add ppc64 specific cpu feature check in of_pmem driver. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- arch/powerpc/platforms/pseries/pmem.c | 6 ++++++ 1 file changed, 6 insertions(+)