linux-kernel - [PATCH -v3 3/3] PCI,pciehp: use PCIe DSN to identify device change during suspend

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]

Message-ID: <1373621543-54836-4-git-send-email-wangyijing@huawei.com>
Date:	Fri, 12 Jul 2013 17:32:23 +0800
From:	Yijing Wang <wangyijing@...wei.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
CC:	<linux-kernel@...r.kernel.org>, Don Dutile <ddutile@...hat.com>,
	Paul Bolle <pebolle@...cali.nl>, <linux-pci@...r.kernel.org>,
	Rafael <rjw@...k.pl>, Hanjun Guo <guohanjun@...wei.com>,
	<jiang.liu@...wei.com>, Yijing Wang <wangyijing@...wei.com>,
	Oliver Neukum <oneukum@...e.de>,
	Gu Zheng <guz.fnst@...fujitsu.com>
Subject: [PATCH -v3 3/3] PCI,pciehp: use PCIe DSN to identify device change during suspend

If device was removed from slot and reinsert a new device during
suspend, pciehp can not identify the physical device change now.
So the old driver .resume() method will be called for the new device,
this is bad. If device support device serial number capability,
we can identify this by DSN. So the reasonable way is first remove
the old device, then enable the new device.

Signed-off-by: Yijing Wang <wangyijing@...wei.com>
Cc: Paul Bolle <pebolle@...cali.nl>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Oliver Neukum <oneukum@...e.de>
Cc: Gu Zheng <guz.fnst@...fujitsu.com>
Cc: linux-pci@...r.kernel.org
---
 drivers/pci/hotplug/pciehp_core.c |   45 +++++++++++++++++++++++++++++++++++++
 1 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 7fe9dbd..bc47f8e 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -296,11 +296,38 @@ static int pciehp_suspend (struct pcie_device *dev)
 	return 0;
 }
 
+/*
+ * check the func 0 device serial number is changed,
+ * if device does not support device serial number,
+ * return false.
+ */
+static bool device_serial_number_changed(struct pci_bus *pbus)
+{
+	u64 old_dsn, new_dsn;
+	struct pci_dev *pdev;
+
+	pdev = pci_get_slot(pbus, PCI_DEVFN(0, 0));
+	if (!pdev)
+		return false;
+
+	old_dsn = pdev->sn;
+
+	/* get func 0 device serial number */
+	new_dsn = pci_device_serial_number(pdev);
+	pci_dev_put(pdev);
+
+	if (old_dsn != new_dsn)
+		return true;
+
+	return false;
+}
+
 static int pciehp_resume (struct pcie_device *dev)
 {
 	struct controller *ctrl;
 	struct slot *slot;
 	struct pci_bus *pbus = dev->port->subordinate;
+	int retval = 0;
 	u8 status;
 
 	ctrl = get_service_data(dev);
@@ -315,6 +342,24 @@ static int pciehp_resume (struct pcie_device *dev)
 	if (status) {
 		if (list_empty(&pbus->devices))
 			pciehp_enable_slot(slot);
+
+		if (device_serial_number_changed(pbus)) {
+			/*
+			 * first power off slot, avoid the old driver
+			 * .remove() method touch the new hardware
+			 */
+			if (POWER_CTRL(ctrl)) {
+				retval = pciehp_power_off_slot(slot);
+				if (retval) {
+					ctrl_err(ctrl,
+						"Issue of Slot Disable command failed\n");
+					return 0;
+				}
+				msleep(1000);
+				pciehp_unconfigure_device(slot);
+				pciehp_enable_slot(slot);
+			}
+		}
 	} else if (!list_empty(&pbus->devices)) {
 		pciehp_disable_slot(slot);
 	}
-- 
1.7.1


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/