PCI: Don't allow unbinding host controllers that aren't prepared

Many PCI host controller drivers aren't prepared to have their devices
unbound from them forcefully (e.g., through /sys/.../<driver>/unbind), as
they don't provide any driver .remove callback, where they'd detach the
root bus, release resources, etc. Keeping the driver built in (i.e., not a
loadable module) is not enough; and providing no .remove callback just
means we don't do any teardown.

To rule out the possibility of unbinding a device via sysfs, we need to set
the ".suppress_bind_attrs" field.

I found the suspect drivers via the following search:

  git grep -l platform_driver $(git grep -L -e '\.remove' -e suppress_bind_attrs drivers/pci/)

Then I inspected them to ensure that
(a) they set up a PCI bus in their probe() and
(b) they don't have a remove() callback for undoing the setup

Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

6 files changed, 6 insertions, 0 deletions

diff --git a/drivers/pci/host/pci-ftpci100.c b/drivers/pci/host/pci-ftpci100.c
index c0f29d1de341..d26501c4145a 100644
--- a/drivers/pci/host/pci-ftpci100.c
+++ b/drivers/pci/host/pci-ftpci100.c
@@ -556,6 +556,7 @@ static struct platform_driver faraday_pci_driver = {
 	.driver = {
 		.name = "ftpci100",
 		.of_match_table = of_match_ptr(faraday_pci_of_match),
+		.suppress_bind_attrs = true,
 	},
 	.probe  = faraday_pci_probe,
 };
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
index c05ea9d72f69..7d709a7e0aa8 100644
--- a/drivers/pci/host/pci-host-generic.c
+++ b/drivers/pci/host/pci-host-generic.c
@@ -60,6 +60,7 @@ static struct platform_driver gen_pci_driver = {
 	.driver = {
 		.name = "pci-host-generic",
 		.of_match_table = gen_pci_of_match,
+		.suppress_bind_attrs = true,
 	},
 	.probe = gen_pci_probe,
 };
diff --git a/drivers/pci/host/pci-thunder-ecam.c b/drivers/pci/host/pci-thunder-ecam.c
index 3f54a43bbbea..fc0ca03f280e 100644
--- a/drivers/pci/host/pci-thunder-ecam.c
+++ b/drivers/pci/host/pci-thunder-ecam.c
@@ -373,6 +373,7 @@ static struct platform_driver thunder_ecam_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
 		.of_match_table = thunder_ecam_of_match,
+		.suppress_bind_attrs = true,
 	},
 	.probe = thunder_ecam_probe,
 };
diff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c
index 6e031b522529..6e066f8b74df 100644
--- a/drivers/pci/host/pci-thunder-pem.c
+++ b/drivers/pci/host/pci-thunder-pem.c
@@ -474,6 +474,7 @@ static struct platform_driver thunder_pem_driver = {
 	.driver = {
 		.name = KBUILD_MODNAME,
 		.of_match_table = thunder_pem_of_match,
+		.suppress_bind_attrs = true,
 	},
 	.probe = thunder_pem_probe,
 };
diff --git a/drivers/pci/host/pci-versatile.c b/drivers/pci/host/pci-versatile.c
index 85e773661bc8..9281eee2d000 100644
--- a/drivers/pci/host/pci-versatile.c
+++ b/drivers/pci/host/pci-versatile.c
@@ -222,6 +222,7 @@ static struct platform_driver versatile_pci_driver = {
 	.driver = {
 		.name = "versatile-pci",
 		.of_match_table = versatile_pci_of_match,
+		.suppress_bind_attrs = true,
 	},
 	.probe = versatile_pci_probe,
 };
diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c
index de198980432e..8cae013e7188 100644
--- a/drivers/pci/host/pci-xgene.c
+++ b/drivers/pci/host/pci-xgene.c
@@ -697,6 +697,7 @@ static struct platform_driver xgene_pcie_driver = {
 	.driver = {
 		   .name = "xgene-pcie",
 		   .of_match_table = of_match_ptr(xgene_pcie_match_table),
+		   .suppress_bind_attrs = true,
 	},
 	.probe = xgene_pcie_probe_bridge,
 };