From: Sam Bobroff <sbobroff@linux.ibm.com>
To: "Oliver O'Halloran" <oohall@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 12/14] powerpc/eeh: Add debugfs interface to run an EEH check
Date: Tue, 17 Sep 2019 13:15:59 +1000 [thread overview]
Message-ID: <20190917031558.GI21303@tungsten.ozlabs.ibm.com> (raw)
In-Reply-To: <20190903101605.2890-13-oohall@gmail.com>
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On Tue, Sep 03, 2019 at 08:16:03PM +1000, Oliver O'Halloran wrote:
> 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 <domain>:<bus>:<dev>.<fn> 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 <oohall@gmail.com>
Looks good, and I tested it with the next patch and it seems to work.
But I think you should make it clear that this does not work with
the hardware "EEH error injection" facility accessible via debugfs in
err_injct (that doesn't seem clear to me from the commit message).
Tested-by: Sam Bobroff <sbobroff@linux.ibm.com>
Reviewed-by: Sam Bobroff <sbobroff@linux.ibm.com>
> ---
> arch/powerpc/kernel/eeh.c | 61 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
> index 46d17817b438..ace1c5a6b8ed 100644
> --- a/arch/powerpc/kernel/eeh.c
> +++ b/arch/powerpc/kernel/eeh.c
> @@ -1873,6 +1873,64 @@ static const struct file_operations eeh_force_recover_fops = {
> .llseek = no_llseek,
> .write = eeh_force_recover_write,
> };
> +
> +static ssize_t eeh_debugfs_dev_usage(struct file *filp,
> + char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + static const char usage[] = "input format: <domain>:<bus>:<dev>.<fn>\n";
> +
> + return simple_read_from_buffer(user_buf, count, ppos,
> + usage, sizeof(usage) - 1);
> +}
> +
> +static ssize_t eeh_dev_check_write(struct file *filp,
> + const char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + uint32_t domain, bus, dev, fn;
> + struct pci_dev *pdev;
> + struct eeh_dev *edev;
> + char buf[20];
> + int ret;
> +
> + ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count);
> + if (!ret)
> + return -EFAULT;
> +
> + ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn);
> + if (ret != 4) {
> + pr_err("%s: expected 4 args, got %d\n", __func__, ret);
> + return -EINVAL;
> + }
> +
> + pdev = pci_get_domain_bus_and_slot(domain, bus, (dev << 3) | fn);
> + if (!pdev)
> + return -ENODEV;
> +
> + edev = pci_dev_to_eeh_dev(pdev);
> + if (!edev) {
> + pci_err(pdev, "No eeh_dev for this device!\n");
> + pci_dev_put(pdev);
> + return -ENODEV;
> + }
> +
> + ret = eeh_dev_check_failure(edev);
> + pci_info(pdev, "eeh_dev_check_failure(%04x:%02x:%02x.%01x) = %d\n",
> + domain, bus, dev, fn, ret);
> +
> + pci_dev_put(pdev);
> +
> + return count;
> +}
> +
> +static const struct file_operations eeh_dev_check_fops = {
> + .open = simple_open,
> + .llseek = no_llseek,
> + .write = eeh_dev_check_write,
> + .read = eeh_debugfs_dev_usage,
> +};
> +
> #endif
>
> static int __init eeh_init_proc(void)
> @@ -1888,6 +1946,9 @@ static int __init eeh_init_proc(void)
> debugfs_create_bool("eeh_disable_recovery", 0600,
> powerpc_debugfs_root,
> &eeh_debugfs_no_recover);
> + debugfs_create_file_unsafe("eeh_dev_check", 0600,
> + powerpc_debugfs_root, NULL,
> + &eeh_dev_check_fops);
> debugfs_create_file_unsafe("eeh_force_recover", 0600,
> powerpc_debugfs_root, NULL,
> &eeh_force_recover_fops);
> --
> 2.21.0
>
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next prev parent reply other threads:[~2019-09-17 3:18 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 10:15 EEH + hotplug fixes Oliver O'Halloran
2019-09-03 10:15 ` [PATCH 01/14] powerpc/eeh: Clean up EEH PEs after recovery finishes Oliver O'Halloran
2019-09-17 0:43 ` Sam Bobroff
2019-09-19 10:25 ` Michael Ellerman
2019-09-03 10:15 ` [PATCH 02/14] powerpc/eeh: Fix race when freeing PDNs Oliver O'Halloran
2019-09-17 0:50 ` Sam Bobroff
2019-09-03 10:15 ` [PATCH 03/14] powerpc/eeh: Make permanently failed devices non-actionable Oliver O'Halloran
2019-09-17 0:51 ` Sam Bobroff
2019-09-03 10:15 ` [PATCH 04/14] powerpc/eeh: Check slot presence state in eeh_handle_normal_event() Oliver O'Halloran
2019-09-17 1:00 ` Sam Bobroff
2019-09-17 4:20 ` Oliver O'Halloran
2019-09-03 10:15 ` [PATCH 05/14] powerpc/eeh: Defer printing stack trace Oliver O'Halloran
2019-09-17 1:04 ` Sam Bobroff
2019-09-17 1:45 ` Oliver O'Halloran
2019-09-17 3:35 ` Sam Bobroff
2019-09-17 3:38 ` Oliver O'Halloran
2019-09-03 10:15 ` [PATCH 06/14] powerpc/eeh: Remove stale CAPI comment Oliver O'Halloran
2019-09-03 14:09 ` Andrew Donnellan
2019-09-17 1:04 ` Sam Bobroff
2019-09-03 10:15 ` [PATCH 07/14] powernv/eeh: Use generic code to handle hot resets Oliver O'Halloran
2019-09-17 1:15 ` Sam Bobroff
2019-09-17 7:30 ` Oliver O'Halloran
2019-09-03 10:15 ` [PATCH 08/14] pci-hotplug/pnv_php: Add a reset_slot() callback Oliver O'Halloran
2019-09-03 10:16 ` [PATCH 09/14] pci-hotplug/pnv_php: Add support for IODA3 Power9 PHBs Oliver O'Halloran
2019-09-03 10:16 ` [PATCH 10/14] pci-hotplug/pnv_php: Add attention indicator support Oliver O'Halloran
2019-09-03 10:16 ` [PATCH 11/14] powerpc/eeh: Set attention indicator while recovering Oliver O'Halloran
2019-09-17 1:23 ` Sam Bobroff
2019-09-03 10:16 ` [PATCH 12/14] powerpc/eeh: Add debugfs interface to run an EEH check Oliver O'Halloran
2019-09-17 3:15 ` Sam Bobroff [this message]
2019-09-17 3:36 ` Oliver O'Halloran
2019-09-17 4:23 ` Oliver O'Halloran
2019-09-03 10:16 ` [PATCH 13/14] powerpc/eeh: Add a eeh_dev_break debugfs interface Oliver O'Halloran
2019-09-17 3:19 ` Sam Bobroff
2019-09-03 10:16 ` [PATCH 14/14] selftests/powerpc: Add basic EEH selftest Oliver O'Halloran
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