Quoting Benjamin Herrenschmidt (benh@kernel.crashing.org):

quoted

+struct cr_hdr_cpu {
+	struct pt_regs pt_regs;
+	/* relevant fields from thread_struct */
+	double fpr[32][TS_FPRWIDTH];
+	unsigned int fpscr;
+	int fpexc_mode;
+	/* unsigned int align_ctl; this is never updated? */
+	unsigned long dabr;
+};

Is there some version or other identification somewhere ? If not there
should be. ie, we're going to add things here. For example, what about
the vector registers ? Also, some CPUs will have more HW debug registers
than just the DABR (we plan to add support for all the BookE architected
IACs and DACs for example), etc...

The arch-independent checkpoint header does have kernel
maj:min:rev:patch info.  We expect to have to do more,
assuming that the .config can change the arch-dependent
cpu header (i.e. perhaps TS_FPRWIDTH could be changed).

-serge