On Tue, Jun 02, 2015 at 12:56:44AM -0400, Joshua Kinard wrote:
> >>> I'll submit the final fix, properly annotated, if your testing confirms
> >>> my diagnosis.
> >>
> >> That got it to boot again. I added CPU ID to the printk as well, and got some
> >> odd output from one of the CPUs:
> >>
> >> # dmesg | grep FCSR
> >> [ 0.000000] CPU0: FCSR is: 00000000
> >> [ 0.319158] CPU1: FCSR is: 00000000
> >> [ 0.364971] CPU2: FCSR is: ffffffffa8000000
> >> [ 0.404854] CPU3: FCSR is: 00000000
> >
> > The value reported for CPU2 merely shows FCC[7,5,3] bits set, nothing
> > really odd about that, the CPU may well have come out of reset like this.
> > Neither of the values reported though actually corresponds to the symptom
> > you saw, can you double-check you didn't make a typo in your modification
> > to `printk'?
>
> I commented on it being odd because out of four CPUs, #2 was coming up with a
> sign-extended value, twice (I tested two reboot cycles, same both times). I'm
> not fully knowledgable of IP27 hardware, and am probably one of the few on the
> planet in possession of R14K node boards, so this might be a quirk of these
> specific nodes. Would need others to test to verify, I guess.
>
> Could always turn on heavy diags and poke through the verbose MSC reporting if
> needed.
>
> As for a typo, nope:
>
> __enable_fpu(FPU_AS_IS);
>
> fcsr = read_32bit_cp1_register(CP1_STATUS);
> -> pr_info("CPU%d: FCSR is: %08lx\n", smp_processor_id(), fcsr);
> fcsr &= ~mask;
Maciej, I think the variables sr, mask, fcsr, fcsr0 and fcsr1 should
become unsigned ints; they all represent 32 bit CPU registers. Also
read_32bit_cp1_register() return a signed int. A signed int probably
would make more sense here.
Ralf
