wireguard-linux/arch/powerpc/kernel/eeh.c, branch jd/unified-crypt-queue

powerpc/eeh: Rework eeh_ops->probe()

2020-03-25T01:09:39Z

With the EEH early probe now being pseries specific there's no need for eeh_ops->probe() to take a pci_dn. Instead, we can make it take a pci_dev and use the probe function to map a pci_dev to an eeh_dev. This allows the platform to implement it's own method for finding (or creating) an eeh_dev for a given pci_dev which also removes a use of pci_dn in generic EEH code. This patch also renames eeh_device_add_late() to eeh_device_probe(). This better reflects what it does does and removes the last vestiges of the early/late EEH probe split. Reviewed-by: Sam Bobroff Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306073904.4737-6-oohall@gmail.com

powerpc/eeh: Make early EEH init pseries specific

2020-03-25T01:09:39Z

The eeh_ops->probe() function is called from two different contexts: 1. On pseries, where we set EEH_PROBE_MODE_DEVTREE, it's called in eeh_add_device_early() which is supposed to run before we create a pci_dev. 2. On PowerNV, where we set EEH_PROBE_MODE_DEV, it's called in eeh_device_add_late() which is supposed to run *after* the pci_dev is created. The "early" probe is required because PAPR requires that we perform an RTAS call to enable EEH support on a device before we start interacting with it via config space or MMIO. This requirement doesn't exist on PowerNV and shoehorning two completely separate initialisation paths into a common interface just results in a convoluted code everywhere. Additionally the early probe requires the probe function to take an pci_dn rather than a pci_dev argument. We'd like to make pci_dn a pseries specific data structure since there's no real requirement for them on PowerNV. To help both goals move the early probe into the pseries containment zone so the platform depedence is more explicit. Reviewed-by: Sam Bobroff Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306073904.4737-5-oohall@gmail.com

powerpc/eeh: Remove PHB check in probe

2020-03-25T01:09:39Z

This check for a missing PHB has existing in various forms since the initial PPC64 port was upstreamed in 2002. The idea seems to be that we need to guard against creating pci-specific data structures for the non-pci children of a PCI device tree node (e.g. USB devices). However, we only create pci_dn structures for DT nodes that correspond to PCI devices so there's not much point in doing this check in the eeh_probe path. Reviewed-by: Sam Bobroff Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306073904.4737-4-oohall@gmail.com

powerpc/eeh: Remove eeh_add_device_tree_late()

2020-03-25T01:09:38Z

On pseries and PowerNV pcibios_bus_add_device() calls eeh_add_device_late() so there's no need to do a separate tree traversal to bind the eeh_dev and pci_dev together setting up the PHB at boot. As a result we can remove eeh_add_device_tree_late(). Reviewed-by: Sam Bobroff Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306073904.4737-2-oohall@gmail.com

powerpc/eeh: Add sysfs files in late probe

2020-03-25T01:09:38Z

Move creating the EEH specific sysfs files into eeh_add_device_late() rather than being open-coded all over the place. Calling the function is generally done immediately after calling eeh_add_device_late() anyway. This is also a correctness fix since currently the sysfs files will be added even if the EEH probe happens to fail. Similarly, on pseries we currently add the sysfs files before calling eeh_add_device_late(). This is flat-out broken since the sysfs files require the pci_dev->dev.archdata.edev pointer to be set, and that is done in eeh_add_device_late(). Reviewed-by: Sam Bobroff Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200306073904.4737-1-oohall@gmail.com

powerpc/eeh: Only dump stack once if an MMIO loop is detected

2020-01-23T10:31:20Z

Many drivers don't check for errors when they get a 0xFFs response from an MMIO load. As a result after an EEH event occurs a driver can get stuck in a polling loop unless it some kind of internal timeout logic. Currently EEH tries to detect and report stuck drivers by dumping a stack trace after eeh_dev_check_failure() is called EEH_MAX_FAILS times on an already frozen PE. The value of EEH_MAX_FAILS was chosen so that a dump would occur every few seconds if the driver was spinning in a loop. This results in a lot of spurious stack traces in the kernel log. Fix this by limiting it to printing one stack trace for each PE freeze. If the driver is truely stuck the kernel's hung task detector is better suited to reporting the probelm anyway. Signed-off-by: Oliver O'Halloran Reviewed-by: Sam Bobroff Tested-by: Sam Bobroff Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191016012536.22588-1-oohall@gmail.com

powerpc/eeh_sysfs: Make clearing EEH_DEV_SYSFS saner

2020-01-23T10:31:19Z

The eeh_sysfs_remove_device() function is supposed to clear the EEH_DEV_SYSFS flag since it indicates the EEH sysfs entries have been added for a pci_dev. When the sysfs files are removed eeh_remove_device() the eeh_dev and the pci_dev have already been de-associated. This then causes the pci_dev_to_eeh_dev() call in eeh_sysfs_remove_device() to return NULL so the flag can't be cleared from the still-live eeh_dev. This problem is worked around in the caller by clearing the flag manually. However, this behaviour doesn't make a whole lot of sense, so this patch fixes it by: a) Re-ordering eeh_remove_device() so that eeh_sysfs_remove_device() is called before de-associating the pci_dev and eeh_dev. b) Making eeh_sysfs_remove_device() emit a warning if there's no corresponding eeh_dev for a pci_dev. The paths where the sysfs files are only reachable if EEH was setup for the device for the device in the first place so hitting this warning indicates a programming error. Signed-off-by: Oliver O'Halloran Reviewed-by: Sam Bobroff Tested-by: Sam Bobroff Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190715085612.8802-6-oohall@gmail.com

powerpc/eeh: Fix eeh eeh_debugfs_break_device() with SRIOV devices

2019-09-26T23:04:17Z

s/CONFIG_IOV/CONFIG_PCI_IOV/ Whoops. Fixes: bd6461cc7b3c ("powerpc/eeh: Add a eeh_dev_break debugfs interface") Signed-off-by: Oliver O'Halloran [mpe: Fixup the #endif comment as well] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190926122502.14826-1-oohall@gmail.com

powerpc/eeh: Add a eeh_dev_break debugfs interface

2019-09-05T04:22:39Z

Add an interface to debugfs for generating an EEH event on a given device. This works by disabling memory accesses to and from the device by setting the PCI_COMMAND register (or the VF Memory Space Enable on the parent PF). This is a somewhat portable alternative to using the platform specific error injection mechanisms since those tend to be either hard to use, or straight up broken. For pseries the interfaces also requires the use of /dev/mem which is probably going to go away in a post-LOCKDOWN world (and it's a horrific hack to begin with) so moving to a kernel-provided interface makes sense and provides a sane, cross-platform interface for userspace so we can write more generic testing scripts. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190903101605.2890-14-oohall@gmail.com

powerpc/eeh: Add debugfs interface to run an EEH check

2019-09-05T04:22:39Z

Detecting an frozen EEH PE usually occurs when an MMIO load returns a 0xFFs response. When performing EEH testing using the EEH error injection feature available on some platforms there is no simple way to kick-off the kernel's recovery process since any accesses from userspace (usually /dev/mem) will bypass the MMIO helpers in the kernel which check if a 0xFF response is due to an EEH freeze or not. If a device contains a 0xFF byte in it's config space it's possible to trigger the recovery process via config space read from userspace, but this is not a reliable method. If a driver is bound to the device an in use it will frequently trigger the MMIO check, but this is also inconsistent. To solve these problems this patch adds a debugfs file called "eeh_dev_check" which accepts a ::. string and runs eeh_dev_check_failure() on it. This is the same check that's done when the kernel gets a 0xFF result from an config or MMIO read with the added benifit that it can be reliably triggered from userspace. Signed-off-by: Oliver O'Halloran Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190903101605.2890-13-oohall@gmail.com