Arm64 double PCI ECAM reservations in acpi_resource_consumer()

[Qian Cai]

On 6/2/2021 6:09 PM, Bjorn Helgaas wrote:
> [+cc linux-pci]
> 
> On Wed, Jun 2, 2021 at 4:49 PM Qian Cai <quic_qiancai at quicinc.com> wrote:
>>
>> Bjorn, I noticed PCI ECAM could be reserved twice on arm64. Firs time through,
>>
>> [   19.087790][    T1]  acpi_ns_walk_namespace+0xc0/0x390
>> [   19.092927][    T1]  acpi_get_devices+0x160/0x1a4
>> [   19.097629][    T1]  acpi_resource_consumer+0x8c/0xc0
>> [   19.102680][    T1]  pci_acpi_scan_root+0x158/0x4c8
>> [   19.107555][    T1]  acpi_pci_root_add+0x450/0x8e8
>> [   19.112345][    T1]  acpi_bus_attach+0x300/0x7d0
>> [   19.116960][    T1]  acpi_bus_attach+0x178/0x7d0
>> [   19.121576][    T1]  acpi_bus_attach+0x178/0x7d0
>> [   19.126190][    T1]  acpi_bus_scan+0xa8/0x170
>> [   19.130545][    T1]  acpi_scan_init+0x220/0x558
>> [   19.135074][    T1]  acpi_init+0x1f4/0x270
>>
>> where pci_acpi_setup_ecam_mapping() confirmed all reservations are succeed. Then,
>>
>> [   19.880588][    T1]  acpi_ns_walk_namespace+0xc0/0x390
>> [   19.885725][    T1]  acpi_get_devices+0x160/0x1a4
>> [   19.890426][    T1]  pnpacpi_init+0xa0/0x10
>>
>> As the results, those messages are showed up during the boot in pnpacpi_init().
>>
>> [ 17.763968] system 00:00: [mem 0x10000000000-0x1000fffffff window] could not be reserved
>> [ 17.772900] system 00:00: [mem 0x7800000000-0x780fffffff window] could not be reserved
>> [ 17.781627] system 00:00: [mem 0x7000000000-0x700fffffff window] could not be reserved
>> [ 17.790350] system 00:00: [mem 0x6000000000-0x600fffffff window] could not be reserved
>> [ 17.799073] system 00:00: [mem 0x5800000000-0x580fffffff window] could not be reserved
>> [ 17.808155] system 00:00: [mem 0x1000000000-0x100fffffff window] could not be reserved
>> [ 17.816862] system 00:00: [mem 0x600000000-0x60fffffff window] could not be reserved
>> [ 17.825417] system 00:00: [mem 0x400000000-0x40fffffff window] could not be reserved
>>
>> Looking through the x86's version of pci_acpi_scan_root(), it won't call acpi_resource_consumer(), so I suppose this bug is only affecting arm64?
> 
> This might be related to
> https://lore.kernel.org/linux-acpi/20210510234020.1330087-1-luzmaximilian@gmail.com/T/#u
> 
> Can you try applying that patch to see if it is related?

Unfortunately, that revert patch does not help. FYI, here is the first reservation from acpi_resource_consumer().

[   16.224306] acpi PNP0A08:00: ECAM area [mem 0x10000000000-0x1000fffffff] reserved by PNP0C02:00
[   16.241027] acpi PNP0A08:00: ECAM at [mem 0x10000000000-0x1000fffffff] for [bus 00-ff]
[   16.810172] acpi PNP0A08:01: ECAM area [mem 0x7800000000-0x780fffffff] reserved by PNP0C02:00
[   16.826701] acpi PNP0A08:01: ECAM at [mem 0x7800000000-0x780fffffff] for [bus 00-ff]
[   17.289302] acpi PNP0A08:02: ECAM area [mem 0x1000000000-0x100fffffff] reserved by PNP0C02:00
[   17.305840] acpi PNP0A08:02: ECAM at [mem 0x1000000000-0x100fffffff] for [bus 00-ff]
[   17.641917] acpi PNP0A08:03: ECAM area [mem 0x5800000000-0x580fffffff] reserved by PNP0C02:00
[   17.658445] acpi PNP0A08:03: ECAM at [mem 0x5800000000-0x580fffffff] for [bus 00-ff]
[   18.059837] acpi PNP0A08:04: ECAM area [mem 0x6000000000-0x600fffffff] reserved by PNP0C02:00
[   18.076368] acpi PNP0A08:04: ECAM at [mem 0x6000000000-0x600fffffff] for [bus 00-ff]
[   18.413220] acpi PNP0A08:05: ECAM area [mem 0x7000000000-0x700fffffff] reserved by PNP0C02:00
[   18.429745] acpi PNP0A08:05: ECAM at [mem 0x7000000000-0x700fffffff] for [bus 00-ff]
[   18.767189] acpi PNP0A08:06: ECAM area [mem 0x600000000-0x60fffffff] reserved by PNP0C02:00
[   18.783559] acpi PNP0A08:06: ECAM at [mem 0x600000000-0x60fffffff] for [bus 00-ff]
[   19.201613] acpi PNP0A08:07: ECAM area [mem 0x400000000-0x40fffffff] reserved by PNP0C02:00
[   19.217965] acpi PNP0A08:07: ECAM at [mem 0x400000000-0x40fffffff] for [bus 00-ff]