Re: [PATCH v2 07/10] s390x: smp: Use full PSW to bringup new cpu

Janosch Frank
2020-04-24T11:31:09Z

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On 4/24/20 1:23 PM, David Hildenbrand wrote:
> On 24.04.20 13:16, Janosch Frank wrote:
>> On 4/24/20 12:09 PM, David Hildenbrand wrote:
>>> On 23.04.20 11:10, Janosch Frank wrote:
>>>> Up to now we ignored the psw mask and only used the psw address when
>>>> bringing up a new cpu. For DAT we need to also load the mask, so let's
>>>> do that.
>>>>
>>>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>>>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>>>> ---
>>>> lib/s390x/smp.c | 2 ++
>>>> s390x/cstart64.S | 3 ++-
>>>> 2 files changed, 4 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
>>>> index 3f86243..6ef0335 100644
>>>> --- a/lib/s390x/smp.c
>>>> +++ b/lib/s390x/smp.c
>>>> @@ -202,6 +202,8 @@ int smp_cpu_setup(uint16_t addr, struct psw psw)
>>>> cpu->stack = (uint64_t *)alloc_pages(2);
>>>>
>>>> /* Start without DAT and any other mask bits. */
>>>> + cpu->lowcore->sw_int_psw.mask = psw.mask;
>>>> + cpu->lowcore->sw_int_psw.addr = psw.addr;
>>>> cpu->lowcore->sw_int_grs[14] = psw.addr;
>>>
>>> Do we still have to set sw_int_grs[14] ?
>>>
>> r14 is saved to restart_new so we don't go through setup twice.
>> We could instead copy cpu->lowcore->sw_int_psw.addr to restart new, but
>> that means more changes than the removal of one line.
>>
>> Also, what about backtraces or plain old debug?
>> Having r14 is a good backup to have IMHO.
>>
>
> Fine with me
>
> Reviewed-by: David Hildenbrand <david@redhat.com>
>

Thanks!
Also we need that if the cpu returns from its assigned function, so it
drops into the infinite loop.

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