[PATCH 1/3] powerpc: bare minimum checkpoint/restart implementation

[Oren Laadan]

Benjamin Herrenschmidt wrote:
> On Wed, 2009-02-04 at 09:54 -0600, Serge E. Hallyn wrote:
>> Quoting Benjamin Herrenschmidt (benh at kernel.crashing.org):
>>>> +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).
> 
> It could to a certain extent... things like VSX, VSR, or freescale SPE,
> or even the Cell SPU state etc....
> 
> I wonder if we want a tagged structure so we can easily add things...