Kernel v6.17-rc4 with STATIC_CALL_SELFTEST=y enabled fails to boot at early stage (PowerMac G4 DP)

[Christophe Leroy]

Le 04/09/2025 à 10:40, Madhavan Srinivasan a écrit :
> 
> 
> On 9/4/25 1:01 PM, Christophe Leroy wrote:
>> Hi Erhard,
>>
>> Le 04/09/2025 à 00:44, Erhard Furtner a écrit :
>>> Greetings!
>>>
>>> In a conversation with Andrew about his page table check code for PowerPC he found out there seems to be a general problem of the code patching code on ppc:
>>>
>>>   > I note that STATIC_CALL_SELFTEST seems to fail, which could be but isn't
>>>   > necessarily related.
>>>
>>>   > Specifically, it looks like code patching fails if the instruction being patched
>>>   > is in an __init function, and in this case, that occurs due to
>>>   > page_table_check_pte_clear() being inlined into ptep_clear(), which is in turn
>>>   > inlined into pte_clear_tests() in debug_vm_pgtable.c which is marked __init.
>>>   > Very curious!
>>>
>>> Indeed, when I enable STATIC_CALL_SELFTEST=y on my G4 the kernel fails to boot at an early stage, the OpenFirmware console showing only:
>>>
>>> done
>>> found display   : /pci at f0000000/ATY,AlteracParent at 10/ATY,Alterac_B at 1, opening...
>>>
>>> Without STATIC_CALL_SELFTEST the kernel boots just fine.
>>>
>>> Kernel .config attached.
>>
>> With your .config, on QEMU I get the following. I will investigate.
>>
>> [    0.000000] Kernel panic - not syncing: arch_static_call_transform: patching failed func_a+0x0/0x10 at 0x0
>> [    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.17.0-rc4-PMacG4+ #1628 PREEMPTLAZY
>> [    0.000000] Hardware name: PowerMac3,1 7400 0xc0209 PowerMac
>> [    0.000000] Call Trace:
> 
> I am using qemu with -M mac99 and it boots
> 
> Hardware name: PowerMac3,1 7400 0xc0209 PowerMac
> printk: legacy bootconsole [udbg0] enabled
> -----------------------------------------------------
> phys_mem_size     = 0x8000000
> dcache_bsize      = 0x20
> 
> I am missing something here. Digging some more


Did you use the .config provided by Erhard ?

Christophe