| Message ID | 20190615002359.29577-4-benh@kernel.crashing.org (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | [1/4] arm64: pci: acpi: Use pci_assign_unassigned_root_bus_resources() | expand |
On Sat, Jun 15, 2019 at 10:23:59AM +1000, Benjamin Herrenschmidt wrote: > When _DSM #5 returns 0 for a host bridge, we need to claim the existing Nit: technically we do not know whether it is a _DSM #5 setting hb->preserve_config or not, it is just a matter of rewording the log. > resources rather than reassign everything. > > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> > --- > arch/arm64/kernel/pci.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index 1419b1b4e9b9..a2c608a3fc41 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -168,6 +168,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) > struct acpi_pci_generic_root_info *ri; > struct pci_bus *bus, *child; > struct acpi_pci_root_ops *root_ops; > + struct pci_host_bridge *hb; > > ri = kzalloc(sizeof(*ri), GFP_KERNEL); > if (!ri) > @@ -193,6 +194,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) > if (!bus) > return NULL; > > + hb = pci_find_host_bridge(bus); to_pci_host_bridge(bus->bridge) would do but it is probably better to leave it as-is. > + > + /* If ACPI tells us to preserve the resource configuration, claim now */ > + if (hb->preserve_config) > + pci_bus_claim_resources(bus); > + > + /* > + * Assign whatever was left unassigned. If we didn't claim above, this will > + * reassign everything. > + */ > pci_assign_unassigned_root_bus_resources(bus); > > list_for_each_entry(child, &bus->children, node) This is fine as far as we acknowledge that claiming resources on a bus is what should be done to make them immutable. Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
On Sat, 15 Jun 2019 at 02:30, Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote: > > When _DSM #5 returns 0 for a host bridge, we need to claim the existing > resources rather than reassign everything. > > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/arm64/kernel/pci.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index 1419b1b4e9b9..a2c608a3fc41 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -168,6 +168,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) > struct acpi_pci_generic_root_info *ri; > struct pci_bus *bus, *child; > struct acpi_pci_root_ops *root_ops; > + struct pci_host_bridge *hb; > > ri = kzalloc(sizeof(*ri), GFP_KERNEL); > if (!ri) > @@ -193,6 +194,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) > if (!bus) > return NULL; > > + hb = pci_find_host_bridge(bus); > + > + /* If ACPI tells us to preserve the resource configuration, claim now */ > + if (hb->preserve_config) > + pci_bus_claim_resources(bus); > + > + /* > + * Assign whatever was left unassigned. If we didn't claim above, this will > + * reassign everything. > + */ > pci_assign_unassigned_root_bus_resources(bus); > > list_for_each_entry(child, &bus->children, node) > -- > 2.17.1 >
arm64: PCI: Preserve firmware configuration when necessary On Sat, Jun 15, 2019 at 10:23:59AM +1000, Benjamin Herrenschmidt wrote: > When _DSM #5 returns 0 for a host bridge, we need to claim the existing > resources rather than reassign everything. Use imperative mood. I'd remove the reference to _DSM #5. This patch does not directly reference _DSM, and it's conceivable a kernel command line parameter or other mechanism could set host->preserve_config. > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> > --- > arch/arm64/kernel/pci.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > index 1419b1b4e9b9..a2c608a3fc41 100644 > --- a/arch/arm64/kernel/pci.c > +++ b/arch/arm64/kernel/pci.c > @@ -168,6 +168,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) > struct acpi_pci_generic_root_info *ri; > struct pci_bus *bus, *child; > struct acpi_pci_root_ops *root_ops; > + struct pci_host_bridge *hb; > > ri = kzalloc(sizeof(*ri), GFP_KERNEL); > if (!ri) > @@ -193,6 +194,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) > if (!bus) > return NULL; > > + hb = pci_find_host_bridge(bus); > + > + /* If ACPI tells us to preserve the resource configuration, claim now */ > + if (hb->preserve_config) > + pci_bus_claim_resources(bus); > + > + /* > + * Assign whatever was left unassigned. If we didn't claim above, this will > + * reassign everything. Wrap the comment so it fits in 80 columns (unless local arch/arm64 style allows wider lines, but I don't see any other wide lines in the file). This series generally looks good to me. > + */ > pci_assign_unassigned_root_bus_resources(bus); > > list_for_each_entry(child, &bus->children, node) > -- > 2.17.1 >
On Fri, 2019-06-21 at 15:57 +0100, Lorenzo Pieralisi wrote: > > pci_assign_unassigned_root_bus_resources(bus); > > > > list_for_each_entry(child, &bus->children, node) > > This is fine as far as we acknowledge that claiming resources > on a bus is what should be done to make them immutable. Well, as immuatable as it gets today. It's not perfect but it's a step in the right direction. With the previous change in the series that prevents auto-realloc when preserve_config is set, it will be equivalent, in the current state of the code. As part of my ongoing rework, I plan to look at making IORESOURCE_PCI_FIXED more generally useful/robust, in which case we could add that on top as well. That said, if we go down that path, I'm keen on also adding a cmdline arg to ignore _DSM #5, if anything as a test/diag tool when chasing problems caused by buggy BIOSes. Cheers, Ben.
diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 1419b1b4e9b9..a2c608a3fc41 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -168,6 +168,7 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) struct acpi_pci_generic_root_info *ri; struct pci_bus *bus, *child; struct acpi_pci_root_ops *root_ops; + struct pci_host_bridge *hb; ri = kzalloc(sizeof(*ri), GFP_KERNEL); if (!ri) @@ -193,6 +194,16 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) if (!bus) return NULL; + hb = pci_find_host_bridge(bus); + + /* If ACPI tells us to preserve the resource configuration, claim now */ + if (hb->preserve_config) + pci_bus_claim_resources(bus); + + /* + * Assign whatever was left unassigned. If we didn't claim above, this will + * reassign everything. + */ pci_assign_unassigned_root_bus_resources(bus); list_for_each_entry(child, &bus->children, node)
When _DSM #5 returns 0 for a host bridge, we need to claim the existing resources rather than reassign everything. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> --- arch/arm64/kernel/pci.c | 11 +++++++++++ 1 file changed, 11 insertions(+)