Patches to allow usefdt mode that works on a 2 socket PowerMac3, 6 example too --and makes more work on 2-socket/1-core-each PowerMac11, 2
Mark Millard
marklmi at yahoo.com
Sat Apr 20 03:19:54 UTC 2019
[I have added an investigatory patch that so far has stopped
the stuck-sleeping problem.]
On 2019-Apr-15, at 00:06, Mark Millard <marklmi at yahoo.com> wrote:
> On 2019-Apr-13, at 11:39, Mark Millard <marklmi at yahoo.com> wrote:
>
>> [My adjustment to fdt_add_subnode_namelen was inept.]
>>
>> On 2019-Apr-12, at 16:17, Mark Millard <marklmi at yahoo.com> wrote:
>>
>>> On 2019-Apr-12, at 14:20, Dennis Clarke <dclarke a t blastwave.org> wrote:
>>>
>>>> On 4/12/19 4:51 PM, Mark Millard wrote:
>>>>> On 2019-Apr-12, at 13:13, Dennis Clarke <dclarke at blastwave.org> wrote:
>>>>>> On 4/12/19 3:19 PM, Mark Millard via freebsd-ppc wrote:
>>>> .
>>>> .
>>>> .
>>>>>>
>>>>>> Would you be so kind as to paste all this into :
>>>>>>
>>>>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233863
>>>>>>
>>>>>> Really I would like to run some tests and follow up in the bug reports.
>>>>> Okay I'll paste them in as attachments. But be warned:
>>>>
>>>> Fair warning received loud and clear :-)
>>>>
>>>>> The 2 files do not deal with threads being stuck sleeping
>>>>> (and, so, the fans going) or other such. The stuck-sleeping
>>>>> problem happens for both multi-socket G5's and multi-socket
>>>>> G4's. (I do not have access to single-socket multi-core
>>>>> powerpc64 or powerpc machines to test.)
>>>>
>>>> I have multiple G5 type boxen and will try them out. At least try
>>>> to.
>>>>
>>>>> So do not expect too much from these patches: They address
>>>>> some necessary issues but are not sufficient for everything.
>>>>>
>>>>
>>>> Of course. No problem.
>>>>
>>>>
>>>>> These patches for the openfirmware->fdt translation are
>>>>> closer to being reasonable for FreeBSD official use
>>>>> than my highly context-specific stuck-sleeping patches for
>>>>> usefdt mode.
>>>>
>>>> Well to be frank we know this is for mac g5 hardware and thus having
>>>> them working at all in any fashion is better than the current situation.
>>>> Apple made a ton of them and they are dirt cheap and available as
>>>> opposed to the IBM Power situation which is expensive and just in
>>>> datacenters.
>>>
>>>
>>> I have added another attachment with patches for having hang-ups
>>> at AP startup happen less often. These are in AIM-specific code
>>> and so has less of a chance of causing other contexts problems.
>>> They are also powerpc64 specific. Again, the patches are
>>> investigatory and not in a form for direct check-in to FreeBSD.
>>>
>>> This pair of patches narrows the time period over which threads
>>> from the stages:
>>>
>>> SI_SUB_KTHREAD_INIT = 0xe000000, /* init process*/
>>> SI_SUB_KTHREAD_PAGE = 0xe400000, /* pageout daemon*/
>>> SI_SUB_KTHREAD_VM = 0xe800000, /* vm daemon*/
>>> SI_SUB_KTHREAD_BUF = 0xea00000, /* buffer daemon*/
>>> SI_SUB_KTHREAD_UPDATE = 0xec00000, /* update daemon*/
>>> SI_SUB_KTHREAD_IDLE = 0xee00000, /* idle procs*/
>>> #ifndef EARLY_AP_STARTUP
>>> SI_SUB_SMP = 0xf000000, /* start the APs*/
>>> #endif
>>>
>>> can conflict with starting an AP via an slb replacement position
>>> picked via expressions like mftb()%n_slbs . It does this by
>>> explicitly picking and setting up a slb slot for its use just
>>> before starting the AP.
>>>
>>> (The AP has to be part way along before it can do its own
>>> automatic-random-slb-slot-replacements from what I can tell.)
>>>
>>> The patches do not remove the race and still do sometimes fail to
>>> prevent getting a hang-up on a AP start. But it greatly decreased
>>> the rate of hangups in my testing. (So it is a good source of
>>> evidence about the original problem.)
>>>
>>> If EARLY_AP_STARTUP was supported and used, the AP startup would
>>> not have hang-up problems from mftb()%n_slbs based slb
>>> replacements for other threads.
>>>
>>> The patches are a hack, rather than a general/complete fix --and
>>> I do not expect to see them in FreeBSD. But they do help set up
>>> a better context for investigating other things.
>>
>> The disabling of blocking duplicate paths in fdt_add_subnode_namelen
>> was done incorrectly. I'll replace the attachment after building
>> and testing. I think this is the explanation for the PowerMac11,2
>> shutdown -r or -p problems.
>>
>> The code should have just disabled the return, more like:
>>
>> if (offset >= 0)
>> #if 0
>> // Some Macintoshes have identical package-to-pathname results for
>> // multiple nodes of the same type and unit under the parent node.
>> // Avoid blocking this for fdt.
>> return -FDT_ERR_EXISTS;
>> #else
>> ;
>> #endif
>> else if (offset != -FDT_ERR_NOTFOUND)
>> return offset;
>>
>> Instead the messed up change did the "return offset;" and
>> so did not do the addition of the node, instead returning
>> the pre-existing one to be manipulated.
>
>
> I've managed to boot the 2-socket/1-core-each G5 PowerMac7,2 in
> usefdt mode. I've added another attachment for patching 3 more
> files, also shown below:
>
> Index: /usr/src/sys/powerpc/powermac/hrowpic.c
> ===================================================================
> --- /usr/src/sys/powerpc/powermac/hrowpic.c (revision 345758)
> +++ /usr/src/sys/powerpc/powermac/hrowpic.c (working copy)
> @@ -169,7 +169,7 @@
> hrowpic_write_reg(sc, HPIC_ENABLE, HPIC_SECONDARY, 0);
> hrowpic_write_reg(sc, HPIC_CLEAR, HPIC_SECONDARY, 0xffffffff);
>
> - powerpc_register_pic(dev, ofw_bus_get_node(dev), 64, 0, FALSE);
> + powerpc_register_pic(dev, OF_xref_from_node(ofw_bus_get_node(dev)), 64, 0, FALSE);
> return (0);
> }
>
> Index: /usr/src/sys/powerpc/powermac/uninorth.c
> ===================================================================
> --- /usr/src/sys/powerpc/powermac/uninorth.c (revision 345758)
> +++ /usr/src/sys/powerpc/powermac/uninorth.c (working copy)
> @@ -181,7 +181,7 @@
> <= 0)
> panic("Interrupt but no interrupt parent!\n");
>
> - if (OF_searchprop(iparent, "#interrupt-cells", &icells, sizeof(icells))
> + if (OF_searchprop(OF_node_from_xref(iparent), "#interrupt-cells", &icells, sizeof(icells))
> <= 0)
> icells = 1;
>
> Index: /usr/src/sys/powerpc/powerpc/openpic.c
> ===================================================================
> --- /usr/src/sys/powerpc/powerpc/openpic.c (revision 345758)
> +++ /usr/src/sys/powerpc/powerpc/openpic.c (working copy)
> @@ -37,6 +37,8 @@
> #include <sys/sched.h>
> #include <sys/smp.h>
>
> +#include <dev/ofw/openfirm.h>
> +
> #include <machine/bus.h>
> #include <machine/intr_machdep.h>
> #include <machine/md_var.h>
> @@ -220,7 +222,7 @@
> for (cpu = 0; cpu < sc->sc_ncpu; cpu++)
> openpic_write(sc, OPENPIC_PCPU_TPR(cpu), 0);
>
> - powerpc_register_pic(dev, node, sc->sc_nirq, 4, FALSE);
> + powerpc_register_pic(dev, OF_xref_from_node(node), sc->sc_nirq, 4, FALSE);
>
> /* If this is not a cascaded PIC, it must be the root PIC */
> if (sc->sc_intr == NULL)
The patch is:
# svnlite diff /usr/src/sys/powerpc/powerpc/mp_machdep.c | more
Index: /usr/src/sys/powerpc/powerpc/mp_machdep.c
===================================================================
--- /usr/src/sys/powerpc/powerpc/mp_machdep.c (revision 345758)
+++ /usr/src/sys/powerpc/powerpc/mp_machdep.c (working copy)
@@ -77,9 +77,10 @@
PCPU_SET(awake, 1);
__asm __volatile("msync; isync");
+ powerpc_sync();
while (ap_letgo == 0)
- __asm __volatile("or 31,31,31");
- __asm __volatile("or 6,6,6");
+ powerpc_sync();
+ isync();
/*
* Set timebase as soon as possible to meet an implicit rendezvous
@@ -262,8 +263,11 @@
__asm __volatile("msync; isync");
/* Let APs continue */
- atomic_store_rel_int(&ap_letgo, 1);
+ ap_letgo= 1; // depend on prior sync, no need to lwsync first
+ powerpc_sync(); // analogous to what the ap's do (more similar time frame?)
+ if (ap_letgo) isync();
+
platform_smp_timebase_sync(ap_timebase, 0);
while (ap_awake < smp_cpus)
===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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