linux-kernel - [PATCH v1 2/9] PCI/PM: Clear PCIe PME Status bit in core, not PCIe port driver

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 07 Mar 2018 00:13:34 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     linux-pci@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org,
        Keith Busch <keith.busch@...el.com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Lukas Wunner <lukas@...ner.de>
Subject: [PATCH v1 2/9] PCI/PM: Clear PCIe PME Status bit in core,
 not PCIe port driver

From: Bjorn Helgaas <bhelgaas@...gle.com>

fe31e69740ed ("PCI/PCIe: Clear Root PME Status bits early during system
resume") added a .resume_noirq() callback to the PCIe port driver to clear
the PME Status bit during resume to work around a BIOS issue.

The BIOS evidently enabled PME interrupts for ACPI-based runtime wakeups
but did not clear the PME Status bit during resume, which meant PMEs after
resume did not trigger interrupts because PME Status did not transition
from cleared to set.

The fix was in the PCIe port driver, so it worked when CONFIG_PCIEPORTBUS
was set.  But I think we *always* want the fix because the platform may use
PME interrupts even if Linux is built without the PCIe port driver.

Move the fix from the port driver to the PCI core so we can work around
this "PME doesn't work after waking from a sleep state" issue regardless of
CONFIG_PCIEPORTBUS.

Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
 drivers/pci/pci-driver.c       |   14 ++++++++++++++
 drivers/pci/pcie/portdrv_pci.c |   15 ---------------
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 3bed6beda051..bf0704b75f79 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -525,6 +525,18 @@ static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
 	pci_fixup_device(pci_fixup_resume_early, pci_dev);
 }
 
+static void pcie_resume_early(struct pci_dev *pci_dev)
+{
+	/*
+	 * Some BIOSes forget to clear Root PME Status bits after system wakeup
+	 * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
+	 * bits now just in case (shouldn't hurt).
+	 */
+	if (pci_is_pcie(pci_dev) &&
+	    pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT)
+		pcie_clear_root_pme_status(pci_dev);
+}
+
 /*
  * Default "suspend" method for devices that have no driver provided suspend,
  * or not even a driver at all (second part).
@@ -873,6 +885,8 @@ static int pci_pm_resume_noirq(struct device *dev)
 	if (pci_has_legacy_pm_support(pci_dev))
 		return pci_legacy_resume_early(dev);
 
+	pcie_resume_early(pci_dev);
+
 	if (drv && drv->pm && drv->pm->resume_noirq)
 		error = drv->pm->resume_noirq(dev);
 
diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index 4413dd85e923..f91afd09e356 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -62,20 +62,6 @@ static int pcie_portdrv_restore_config(struct pci_dev *dev)
 }
 
 #ifdef CONFIG_PM
-static int pcie_port_resume_noirq(struct device *dev)
-{
-	struct pci_dev *pdev = to_pci_dev(dev);
-
-	/*
-	 * Some BIOSes forget to clear Root PME Status bits after system wakeup
-	 * which breaks ACPI-based runtime wakeup on PCI Express, so clear those
-	 * bits now just in case (shouldn't hurt).
-	 */
-	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT)
-		pcie_clear_root_pme_status(pdev);
-	return 0;
-}
-
 static int pcie_port_runtime_suspend(struct device *dev)
 {
 	return to_pci_dev(dev)->bridge_d3 ? 0 : -EBUSY;
@@ -103,7 +89,6 @@ static const struct dev_pm_ops pcie_portdrv_pm_ops = {
 	.thaw		= pcie_port_device_resume,
 	.poweroff	= pcie_port_device_suspend,
 	.restore	= pcie_port_device_resume,
-	.resume_noirq	= pcie_port_resume_noirq,
 	.runtime_suspend = pcie_port_runtime_suspend,
 	.runtime_resume	= pcie_port_runtime_resume,
 	.runtime_idle	= pcie_port_runtime_idle,