[PATCH AUTOSEL 4.9 19/45] PCI: sysfs: Ignore lockdep for remove attribute

[PATCH AUTOSEL 4.9 19/45] PCI: sysfs: Ignore lockdep for remove attribute

[Sasha Levin]

From: Marek Vasut <marek.vasut+renesas@gmail.com>

[ Upstream commit dc6b698a86fe40a50525433eb8e92a267847f6f9 ]

With CONFIG_PROVE_LOCKING=y, using sysfs to remove a bridge with a device
below it causes a lockdep warning, e.g.,

  # echo 1 > /sys/class/pci_bus/0000:00/device/0000:00:00.0/remove
  ============================================
  WARNING: possible recursive locking detected
  ...
  pci_bus 0000:01: busn_res: [bus 01] is released

The remove recursively removes the subtree below the bridge.  Each call
uses a different lock so there's no deadlock, but the locks were all
created with the same lockdep key so the lockdep checker can't tell them
apart.

Mark the "remove" sysfs attribute with __ATTR_IGNORE_LOCKDEP() as it is
safe to ignore the lockdep check between different "remove" kernfs
instances.

There's discussion about a similar issue in USB at [1], which resulted in
356c05d58af0 ("sysfs: get rid of some lockdep false positives") and
e9b526fe7048 ("i2c: suppress lockdep warning on delete_device"), which do
basically the same thing for USB "remove" and i2c "delete_device" files.

[1] https://lore.kernel.org/r/Pine.LNX.4.44L0.1204251436140.1206-100000@iolanthe.rowland.org
Link: https://lore.kernel.org/r/20190526225151.3865-1-marek.vasut@gmail.com
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
[bhelgaas: trim commit log, details at above links]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/pci-sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index e5d8e2e2bd30..717540161223 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -371,7 +371,7 @@ static ssize_t remove_store(struct device *dev, struct device_attribute *attr,
 		pci_stop_and_remove_bus_device_locked(to_pci_dev(dev));
 	return count;
 }
-static struct device_attribute dev_remove_attr = __ATTR(remove,
+static struct device_attribute dev_remove_attr = __ATTR_IGNORE_LOCKDEP(remove,
 							(S_IWUSR|S_IWGRP),
 							NULL, remove_store);
 
-- 
2.20.1

[PATCH AUTOSEL 4.9 22/45] PCI: xilinx-nwl: Fix Multi MSI data programming

[Sasha Levin]

From: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>

[ Upstream commit 181fa434d0514e40ebf6e9721f2b72700287b6e2 ]

According to the PCI Local Bus specification Revision 3.0,
section 6.8.1.3 (Message Control for MSI), endpoints that
are Multiple Message Capable as defined by bits [3:1] in
the Message Control for MSI can request a number of vectors
that is power of two aligned.

As specified in section 6.8.1.6 "Message data for MSI", the Multiple
Message Enable field (bits [6:4] of the Message Control register)
defines the number of low order message data bits the function is
permitted to modify to generate its system software allocated
vectors.

The MSI controller in the Xilinx NWL PCIe controller supports a number
of MSI vectors specified through a bitmap and the hwirq number for an
MSI, that is the value written in the MSI data TLP is determined by
the bitmap allocation.

For instance, in a situation where two endpoints sitting on
the PCI bus request the following MSI configuration, with
the current PCI Xilinx bitmap allocation code (that does not
align MSI vector allocation on a power of two boundary):

Endpoint #1: Requesting 1 MSI vector - allocated bitmap bits 0
Endpoint #2: Requesting 2 MSI vectors - allocated bitmap bits [1,2]

The bitmap value(s) corresponds to the hwirq number that is programmed
into the Message Data for MSI field in the endpoint MSI capability
and is detected by the root complex to fire the corresponding
MSI irqs. The value written in Message Data for MSI field corresponds
to the first bit allocated in the bitmap for Multi MSI vectors.

The current Xilinx NWL MSI allocation code allows a bitmap allocation
that is not a power of two boundaries, so endpoint #2, is allowed to
toggle Message Data bit[0] to differentiate between its two vectors
(meaning that the MSI data will be respectively 0x0 and 0x1 for the two
vectors allocated to endpoint #2).

This clearly aliases with the Endpoint #1 vector allocation, resulting
in a broken Multi MSI implementation.

Update the code to allocate MSI bitmap ranges with a power of two
alignment, fixing the bug.

Fixes: ab597d35ef11 ("PCI: xilinx-nwl: Add support for Xilinx NWL PCIe Host Controller")
Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
[lorenzo.pieralisi@arm.com: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/host/pcie-xilinx-nwl.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/host/pcie-xilinx-nwl.c b/drivers/pci/host/pcie-xilinx-nwl.c
index 94fdd295aae2..3bba87af0b6b 100644
--- a/drivers/pci/host/pcie-xilinx-nwl.c
+++ b/drivers/pci/host/pcie-xilinx-nwl.c
@@ -456,15 +456,13 @@ static int nwl_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
 	int i;
 
 	mutex_lock(&msi->lock);
-	bit = bitmap_find_next_zero_area(msi->bitmap, INT_PCI_MSI_NR, 0,
-					 nr_irqs, 0);
-	if (bit >= INT_PCI_MSI_NR) {
+	bit = bitmap_find_free_region(msi->bitmap, INT_PCI_MSI_NR,
+				      get_count_order(nr_irqs));
+	if (bit < 0) {
 		mutex_unlock(&msi->lock);
 		return -ENOSPC;
 	}
 
-	bitmap_set(msi->bitmap, bit, nr_irqs);
-
 	for (i = 0; i < nr_irqs; i++) {
 		irq_domain_set_info(domain, virq + i, bit + i, &nwl_irq_chip,
 				domain->host_data, handle_simple_irq,
@@ -482,7 +480,8 @@ static void nwl_irq_domain_free(struct irq_domain *domain, unsigned int virq,
 	struct nwl_msi *msi = &pcie->msi;
 
 	mutex_lock(&msi->lock);
-	bitmap_clear(msi->bitmap, data->hwirq, nr_irqs);
+	bitmap_release_region(msi->bitmap, data->hwirq,
+			      get_count_order(nr_irqs));
 	mutex_unlock(&msi->lock);
 }
 
-- 
2.20.1

[PATCH AUTOSEL 4.9 33/45] PCI: tegra: Enable Relaxed Ordering only for Tegra20 & Tegra30

[Sasha Levin]

From: Vidya Sagar <vidyas@nvidia.com>

[ Upstream commit 7be142caabc4780b13a522c485abc806de5c4114 ]

The PCI Tegra controller conversion to a device tree configurable
driver in commit d1523b52bff3 ("PCI: tegra: Move PCIe driver
to drivers/pci/host") implied that code for the driver can be
compiled in for a kernel supporting multiple platforms.

Unfortunately, a blind move of the code did not check that some of the
quirks that were applied in arch/arm (eg enabling Relaxed Ordering on
all PCI devices - since the quirk hook erroneously matches PCI_ANY_ID
for both Vendor-ID and Device-ID) are now applied in all kernels that
compile the PCI Tegra controlled driver, DT and ACPI alike.

This is completely wrong, in that enablement of Relaxed Ordering is only
required by default in Tegra20 platforms as described in the Tegra20
Technical Reference Manual (available at
https://developer.nvidia.com/embedded/downloads#?search=tegra%202 in
Section 34.1, where it is mentioned that Relaxed Ordering bit needs to
be enabled in its root ports to avoid deadlock in hardware) and in the
Tegra30 platforms for the same reasons (unfortunately not documented
in the TRM).

There is no other strict requirement on PCI devices Relaxed Ordering
enablement on any other Tegra platforms or PCI host bridge driver.

Fix this quite upsetting situation by limiting the vendor and device IDs
to which the Relaxed Ordering quirk applies to the root ports in
question, reported above.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
[lorenzo.pieralisi@arm.com: completely rewrote the commit log/fixes tag]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/host/pci-tegra.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 8dfccf733241..6985102a4ae3 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -603,12 +603,15 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf1, tegra_pcie_fixup_class);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1c, tegra_pcie_fixup_class);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0e1d, tegra_pcie_fixup_class);
 
-/* Tegra PCIE requires relaxed ordering */
+/* Tegra20 and Tegra30 PCIE requires relaxed ordering */
 static void tegra_pcie_relax_enable(struct pci_dev *dev)
 {
 	pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_RELAX_EN);
 }
-DECLARE_PCI_FIXUP_FINAL(PCI_ANY_ID, PCI_ANY_ID, tegra_pcie_relax_enable);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, 0x0bf0, tegra_pcie_relax_enable);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, 0x0bf1, tegra_pcie_relax_enable);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, 0x0e1c, tegra_pcie_relax_enable);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, 0x0e1d, tegra_pcie_relax_enable);
 
 static int tegra_pcie_setup(int nr, struct pci_sys_data *sys)
 {
-- 
2.20.1