Narayana Murty N <nnmli...@linux.ibm.com> writes:
> Makes pseries_eeh_err_inject() available even when debugfs
> is disabled (CONFIG_DEBUG_FS=n). It moves eeh_debugfs_break_device()
> and eeh_pe_inject_mmio_error() out of the CONFIG_DEBUG_FS block
> and renames it as eeh_break_device().
>
> Reported-by: kernel test robot <l...@intel.com>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/202409170509.vwc6jadc-...@intel.com/
> Fixes: b0e2b828dfca ("powerpc/pseries/eeh: Fix pseries_eeh_err_inject")
> Signed-off-by: Narayana Murty N <nnmli...@linux.ibm.com>
> ---
> arch/powerpc/kernel/eeh.c | 198 +++++++++++++++++++-------------------
> 1 file changed, 99 insertions(+), 99 deletions(-)
Ok, so in your original patch you implemented eeh_inject ops for pseries
using mmio based eeh error injection (eeh_pe_inject_mmio_error()), which
uses the functions defined under debugfs -> eeh_debugfs_break_device().
This was failing when CONFIG_DEBUGFS is not defined, thus referring to
undefined function definition.
Minor nit below.
>
> diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
> index 49ab11a287a3..0fe25e907ea6 100644
> --- a/arch/powerpc/kernel/eeh.c
> +++ b/arch/powerpc/kernel/eeh.c
> @@ -1574,6 +1574,104 @@ static int proc_eeh_show(struct seq_file *m, void *v)
> }
> #endif /* CONFIG_PROC_FS */
>
> +static int eeh_break_device(struct pci_dev *pdev)
> +{
> + struct resource *bar = NULL;
> + void __iomem *mapped;
> + u16 old, bit;
> + int i, pos;
> +
> + /* Do we have an MMIO BAR to disable? */
> + for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
> + struct resource *r = &pdev->resource[i];
> +
> + if (!r->flags || !r->start)
> + continue;
> + if (r->flags & IORESOURCE_IO)
> + continue;
> + if (r->flags & IORESOURCE_UNSET)
> + continue;
> +
> + bar = r;
> + break;
> + }
> +
> + if (!bar) {
> + pci_err(pdev, "Unable to find Memory BAR to cause EEH with\n");
> + return -ENXIO;
> + }
> +
> + pci_err(pdev, "Going to break: %pR\n", bar);
> +
> + if (pdev->is_virtfn) {
> +#ifndef CONFIG_PCI_IOV
> + return -ENXIO;
> +#else
> + /*
> + * VFs don't have a per-function COMMAND register, so the best
> + * we can do is clear the Memory Space Enable bit in the PF's
> + * SRIOV control reg.
> + *
> + * Unfortunately, this requires that we have a PF (i.e doesn't
> + * work for a passed-through VF) and it has the potential side
> + * effect of also causing an EEH on every other VF under the
> + * PF. Oh well.
> + */
> + pdev = pdev->physfn;
> + if (!pdev)
> + return -ENXIO; /* passed through VFs have no PF */
> +
> + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_SRIOV);
> + pos += PCI_SRIOV_CTRL;
> + bit = PCI_SRIOV_CTRL_MSE;
> +#endif /* !CONFIG_PCI_IOV */
> + } else {
> + bit = PCI_COMMAND_MEMORY;
> + pos = PCI_COMMAND;
> + }
> +
> + /*
> + * Process here is:
> + *
> + * 1. Disable Memory space.
> + *
> + * 2. Perform an MMIO to the device. This should result in an error
> + * (CA / UR) being raised by the device which results in an EEH
> + * PE freeze. Using the in_8() accessor skips the eeh detection hook
> + * so the freeze hook so the EEH Detection machinery won't be
> + * triggered here. This is to match the usual behaviour of EEH
> + * where the HW will asynchronously freeze a PE and it's up to
> + * the kernel to notice and deal with it.
> + *
> + * 3. Turn Memory space back on. This is more important for VFs
> + * since recovery will probably fail if we don't. For normal
> + * the COMMAND register is reset as a part of re-initialising
> + * the device.
> + *
> + * Breaking stuff is the point so who cares if it's racy ;)
> + */
> + pci_read_config_word(pdev, pos, &old);
> +
> + mapped = ioremap(bar->start, PAGE_SIZE);
> + if (!mapped) {
> + pci_err(pdev, "Unable to map MMIO BAR %pR\n", bar);
> + return -ENXIO;
> + }
> +
> + pci_write_config_word(pdev, pos, old & ~bit);
> + in_8(mapped);
> + pci_write_config_word(pdev, pos, old);
> +
> + iounmap(mapped);
> +
> + return 0;
> +}
> +
> +int eeh_pe_inject_mmio_error(struct pci_dev *pdev)
> +{
> + return eeh_break_device(pdev);
> +}
> +
Why have an extra eeh_pe_inject_mmio_error() function which only calls
eeh_break_device()?
Maybe we can rename eeh_break_device() to eeh_mmio_break_device() and use
this function itself at both call sites?
-ritesh
