@@ -20,6 +20,7 @@
#define PFN_SIG_LEN 16
#define PFN_SIG "NVDIMM_PFN_INFO\0"
#define DAX_SIG "NVDIMM_DAX_INFO\0"
+#define PFN_VERSION_SUPPORT 2
struct nd_pfn_sb {
u8 signature[PFN_SIG_LEN];
@@ -36,7 +37,8 @@ struct nd_pfn_sb {
__le32 end_trunc;
/* minor-version-2 record the base alignment of the mapping */
__le32 align;
- u8 padding[4000];
+ __le16 min_version;
+ u8 padding[3998];
__le64 checksum;
};
@@ -459,6 +459,12 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
if (__le16_to_cpu(pfn_sb->version_minor) < 2)
pfn_sb->align = 0;
+ if (__le16_to_cpu(pfn_sb->version_major) != 1)
+ return -EINVAL;
+
+ if (__le16_to_cpu(pfn_sb->min_version) > PFN_VERSION_SUPPORT)
+ return -EINVAL;
+
switch (le32_to_cpu(pfn_sb->mode)) {
case PFN_MODE_RAM:
case PFN_MODE_PMEM:
@@ -771,6 +777,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
pfn_sb->version_major = cpu_to_le16(1);
pfn_sb->version_minor = cpu_to_le16(2);
+ pfn_sb->min_version = cpu_to_le16(2);
pfn_sb->start_pad = cpu_to_le32(start_pad);
pfn_sb->end_trunc = cpu_to_le32(end_trunc);
pfn_sb->align = cpu_to_le32(nd_pfn->align);
In support of fixing a pfn info-block interpretation problem that requires a backwards incompatible format change introduce a mechanism to indicate a minimum support level to the parsing agent. Hopefully this mechanism never needs to be used, but it otherwise prevents the need to hunt for a state that causes old implementations to bail out. For now, the method chosen to make implementations prior to this introduction fail is to use new PFN3_MODE_* values. The use of 'mode' ensures that older Linux fails, but agents like the EFI driver that only care about 'data_offset' can continue to ignore the requirement. That is to say 'data_offset' should always be valid, but the interpretation of values that older Linux kernels use to setup the dev_pagemap and perform sector-to-pfn translations is going to change. Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/nvdimm/pfn.h | 4 +++- drivers/nvdimm/pfn_devs.c | 7 +++++++ 2 files changed, 10 insertions(+), 1 deletion(-)