At this time, a generic EEH recovery mechanism has been implemented,
so that individual device drivers do not need to be modified to support
EEH recovery. This generic mechanism piggy-backs on the PCI hotplug
-infrastructure, and percolates events up through the hotplug/udev
+infrastructure, and percolates events up through the userspace/udev
infrastructure. Followiing is a detailed description of how this is
accomplished.
EEH must be enabled in the PHB's very early during the boot process,
and if a PCI slot is hot-plugged. The former is performed by
-eeh_init() in arch/ppc64/kernel/eeh.c, and the later by
+eeh_init() in arch/powerpc/platforms/pseries/eeh.c, and the later by
drivers/pci/hotplug/pSeries_pci.c calling in to the eeh.c code.
EEH must be enabled before a PCI scan of the device can proceed.
Current Power5 hardware will not work unless EEH is enabled;
pci_get_device_by_addr() will find the pci device associated
with that address (if any).
-The default include/asm-ppc64/io.h macros readb(), inb(), insb(),
+The default include/asm-powerpc/io.h macros readb(), inb(), insb(),
etc. include a check to see if the i/o read returned all-0xff's.
If so, these make a call to eeh_dn_check_failure(), which in turn
asks the firmware if the all-ff's value is the sign of a true EEH
all of these occur during boot, when the PCI bus is scanned, where
a large number of 0xff reads are part of the bus scan procedure.
-If a frozen slot is detected, code in arch/ppc64/kernel/eeh.c will
-print a stack trace to syslog (/var/log/messages). This stack trace
-has proven to be very useful to device-driver authors for finding
-out at what point the EEH error was detected, as the error itself
-usually occurs slightly beforehand.
+If a frozen slot is detected, code in
+arch/powerpc/platforms/pseries/eeh.c will print a stack trace to
+syslog (/var/log/messages). This stack trace has proven to be very
+useful to device-driver authors for finding out at what point the EEH
+error was detected, as the error itself usually occurs slightly
+beforehand.
Next, it uses the Linux kernel notifier chain/work queue mechanism to
allow any interested parties to find out about the failure. Device
drivers/pci/hotplug/pSeries_pci.c, called handle_eeh_events().
It saves the device BAR's and then calls rpaphp_unconfig_pci_adapter().
This last call causes the device driver for the card to be stopped,
-which causes hotplug events to go out to user space. This triggers
+which causes uevents to go out to user space. This triggers
user-space scripts that might issue commands such as "ifdown eth0"
for ethernet cards, and so on. This handler then sleeps for 5 seconds,
hoping to give the user-space scripts enough time to complete.
calls
pci_destroy_dev (struct pci_dev *) {
calls
- device_unregister (&dev->dev) { // in /drivers/base/core.c
+ device_unregister (&dev->dev) { // in /drivers/base/core.c
calls
- device_del(struct device * dev) { // in /drivers/base/core.c
+ device_del(struct device * dev) { // in /drivers/base/core.c
calls
- kobject_del() { //in /libs/kobject.c
+ kobject_del() { //in /libs/kobject.c
calls
- kobject_hotplug() { // in /libs/kobject.c
+ kobject_uevent() { // in /libs/kobject.c
calls
- kset_hotplug() { // in /lib/kobject.c
+ kset_uevent() { // in /lib/kobject.c
calls
- kset->hotplug_ops->hotplug() which is really just
+ kset->uevent_ops->uevent() // which is really just
a call to
- dev_hotplug() { // in /drivers/base/core.c
+ dev_uevent() { // in /drivers/base/core.c
calls
- dev->bus->hotplug() which is really just a call to
- pci_hotplug () { // in drivers/pci/hotplug.c
+ dev->bus->uevent() which is really just a call to
+ pci_uevent () { // in drivers/pci/hotplug.c
which prints device name, etc....
}
}
- then kset_hotplug() calls
- call_usermodehelper () with
- argv[0]=hotplug_path[] which is "/sbin/hotplug"
- --> event to userspace,
+ then kobject_uevent() sends a netlink uevent to userspace
+ --> userspace uevent
+ (during early boot, nobody listens to netlink events and
+ kobject_uevent() executes uevent_helper[], which runs the
+ event process /sbin/hotplug)
}
}
kobject_del() then calls sysfs_remove_dir(), which would