Arm64 double PCI ECAM reservations in acpi_resource_consumer()
Lorenzo Pieralisi
lorenzo.pieralisi at arm.com
Thu Jun 3 07:16:41 PDT 2021
On Wed, Jun 02, 2021 at 08:15:20PM -0400, Qian Cai wrote:
>
>
> 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().
This is not the "reservation". AFAICS acpi_resource_consumer() checks
whether the ECAM region is part of _a_ given ACPI device _CRS in the
namespace, it does not "reserve" anything.
IIUC the issue here is that we request the ECAM region in
pci_ecam_create() and later the code in:
drivers/pnp/system.c
tries to request the ECAM region (that lives in the PNP0C02 _CRS) and
fails (see reserve_range() and request_mem_region()).
As the comment in reserve_range() goes, this is harmless, not sure
whether there is anything to do about it.
Lorenzo
> [ 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]
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