Re: [PATCH v15 3/5] PCI/EDR: Export AER, DPC and error recovery functions

Kuppuswamy Sathyanarayanan
2020-02-26T21:28:58Z

Hi Bjorn,

On 2/26/20 1:13 PM, Bjorn Helgaas wrote:
> On Wed, Feb 26, 2020 at 11:30:43AM -0800, Kuppuswamy Sathyanarayanan wrote:
>> On 2/25/20 5:02 PM, Bjorn Helgaas wrote:
>>> On Thu, Feb 13, 2020 at 10:20:15AM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
>>>> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
>>>> ...
>>>> +int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
>>>> +{
>>>> + if (pcie_aer_get_firmware_first(dev))
>>>> + return -EIO;
>>>> +
>>>> + return pci_aer_clear_err_status_regs(dev);
>>>> +}
>>> We started with these:
>>>
>>> pci_cleanup_aer_uncorrect_error_status()
>>> pci_aer_clear_fatal_status()
>>> pci_cleanup_aer_error_status_regs()
>>>
>>> This was already a mess. They do basically similar things, but the
>>> function names are a complete jumble. Let's start with preliminary
>>> patches to name them consistently, e.g.,
>>>
>>> pci_aer_clear_nonfatal_status()
>>> pci_aer_clear_fatal_status()
>>> pci_aer_clear_status()
>>>
>>> Now, for EDR you eventually add this in edr_handle_event():
>>>
>>> edr_handle_event()
>>> {
>>> ...
>>> pci_aer_clear_err_uncor_status(pdev);
>>> pci_aer_clear_err_fatal_status(pdev);
>>> pci_aer_clear_err_status_regs(pdev);
>>>
>>> I see that this path needs to clear the status even in the
>>> firmware-first case, so you do need some change for that. But
>>> pci_aer_clear_err_status_regs() does exactly the same thing as
>>> pci_aer_clear_err_uncor_status() and pci_aer_clear_err_fatal_status()
>>> plus a little more (clearing PCI_ERR_ROOT_STATUS), so it should be
>>> sufficient to just call pci_aer_clear_err_status_regs().
>>>
>>> So I don't think you need to make wrappers for
>>> pci_aer_clear_nonfatal_status() and pci_aer_clear_fatal_status() at
>>> all since they're not needed by the EDR path.
>>>
>>> You *do* need a wrapper for pci_aer_clear_status(), but instead of
>>> just adding random words ("err", "regs") to the name, please name it
>>> something like pci_aer_raw_clear_status() as a hint that it skips
>>> some sort of check.
> What do you think about the above?
I agree with your comments.. I will use your recommendation in
naming the wrappers I need.
>
>>> I would split this into a separate patch. This patch contains a bunch
>>> of things that aren't really related except that they're needed for
>>> EDR. I think it will be more readable if each patch just does one
>>> piece of it.
>> Ok. I will split it into multiple patches. I just grouped them together
>> as a preparatory patch for adding EDR support.
> Sounds good.
>
>>>> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
>>>> index 99fca8400956..acae12dbf9ff 100644
>>>> --- a/drivers/pci/pcie/dpc.c
>>>> +++ b/drivers/pci/pcie/dpc.c
>>>> @@ -15,15 +15,9 @@
>>>> #include <linux/pci.h>
>>>> #include "portdrv.h"
>>>> +#include "dpc.h"
>>>> #include "../pci.h"
>>>> -struct dpc_dev {
>>>> - struct pci_dev *pdev;
>>>> - u16 cap_pos;
>>>> - bool rp_extensions;
>>>> - u8 rp_log_size;
>>>> -};
>>> Adding dpc.h shouldn't be in this patch because there's no need for a
>>> separate dpc.h file yet -- it's only included this one place. I'm not
>>> positive a dpc.h is needed at all -- see comments on patch [4/5].
>> Yes, if we use pdev in dpc functions used by EDR code, we should
>> not need it.
> I think struct dpc_dev might be more trouble than it's worth. I
> attached a possible patch at the end that folds the 25 bits of
> DPC-related info into the struct pci_dev and gets rid of struct
> dpc_dev completely. I compiled it but haven't tested it.
That would solve most of my export issues. Do you want me
to add it to my patch list or merge it separately.
>
>>>> -static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
>>>> +pci_ers_result_t dpc_reset_link_common(struct dpc_dev *dpc)
>>>> {
>>> I don't see why you need to split this into dpc_reset_link_common()
>>> and dpc_reset_link(). IIUC, you split it so the DPC driver path can
>>> supply a pci_dev * via
>>>
>>> dpc_handler
>>> pcie_do_recovery
>>> pcie_do_recovery_common(..., NULL, NULL)
>>> reset_link(..., NULL, NULL)
>>> driver->reset_link(pdev)
>>> dpc_reset_link(pdev)
>>> dpc = to_dpc_dev(pdev)
>> I have split it mainly because of dpc_dev dependency. If we use
>> dpc_reset_link(pdev) directly it will try to find related dpc_dev using
>> to_dpc_dev() function. But this will not work in FF mode where DPC
>> is handled by firmware and hence we will not have DPC pcie_port
>> service driver enumerated for this device.
> The patch below might help this case.
Yes.
>
>>>> +void dpc_dev_init(struct pci_dev *pdev, struct dpc_dev *dpc)
>>>> +{
>>> Can you include the kzalloc() here so we don't have to do the alloc in
>>> pci_acpi_add_edr_notifier()?
>> Currently dpc driver allocates dpc_dev structure using pcie_port->device
>> reference in its devm_alloc* calls. But if we allocate dpc_dev inside
>> this function we should use pci_dev->dev reference for it. Is it OK to us
>> pci_dev->dev reference for DPC driver allocations ?
> I think the patch below would solve this issue too because we don't
> need the alloc at all.
Agree.
>
>>> I think there's also a leak there: pci_acpi_add_edr_notifier()
>>> kzallocs a struct dpc_dev, but I don't see a corresponding kfree().
>> since we are using devm_allocs, It should be freed when removing
>> the PCI device right?
> Oh, right, sorry.
>
>
> commit 7fb9f4495711 ("PCI/DPC: Move data to struct pci_dev")
> Author: Bjorn Helgaas <bhelgaas@google.com>
> Date: Wed Feb 26 08:00:55 2020 -0600
>
> PCI/DPC: Move data to struct pci_dev
>
>
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index e06f42f58d3d..6b116d7fdb89 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -17,13 +17,6 @@
> #include "portdrv.h"
> #include "../pci.h"
>
> -struct dpc_dev {
> - struct pcie_device *dev;
> - u16 cap_pos;
> - bool rp_extensions;
> - u8 rp_log_size;
> -};
> -
> static const char * const rp_pio_error_string[] = {
> "Configuration Request received UR Completion", /* Bit Position 0 */
> "Configuration Request received CA Completion", /* Bit Position 1 */
> @@ -46,63 +39,42 @@ static const char * const rp_pio_error_string[] = {
> "Memory Request Completion Timeout", /* Bit Position 18 */
> };
>
> -static struct dpc_dev *to_dpc_dev(struct pci_dev *dev)
> -{
> - struct device *device;
> -
> - device = pcie_port_find_device(dev, PCIE_PORT_SERVICE_DPC);
> - if (!device)
> - return NULL;
> - return get_service_data(to_pcie_device(device));
> -}
> -
> void pci_save_dpc_state(struct pci_dev *dev)
> {
> - struct dpc_dev *dpc;
> struct pci_cap_saved_state *save_state;
> u16 *cap;
>
> if (!pci_is_pcie(dev))
> return;
>
> - dpc = to_dpc_dev(dev);
> - if (!dpc)
> - return;
> -
> save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
> if (!save_state)
> return;
>
> cap = (u16 *)&save_state->cap.data[0];
> - pci_read_config_word(dev, dpc->cap_pos + PCI_EXP_DPC_CTL, cap);
> + pci_read_config_word(dev, dev->dpc_cap + PCI_EXP_DPC_CTL, cap);
> }
>
> void pci_restore_dpc_state(struct pci_dev *dev)
> {
> - struct dpc_dev *dpc;
> struct pci_cap_saved_state *save_state;
> u16 *cap;
>
> if (!pci_is_pcie(dev))
> return;
>
> - dpc = to_dpc_dev(dev);
> - if (!dpc)
> - return;
> -
> save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC);
> if (!save_state)
> return;
>
> cap = (u16 *)&save_state->cap.data[0];
> - pci_write_config_word(dev, dpc->cap_pos + PCI_EXP_DPC_CTL, *cap);
> + pci_write_config_word(dev, dev->dpc_cap + PCI_EXP_DPC_CTL, *cap);
> }
>
> -static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
> +static int dpc_wait_rp_inactive(struct pci_dev *pdev)
> {
> unsigned long timeout = jiffies + HZ;
> - struct pci_dev *pdev = dpc->dev->port;
> - u16 cap = dpc->cap_pos, status;
> + u16 cap = pdev->dpc_cap, status;
>
> pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> while (status & PCI_EXP_DPC_RP_BUSY &&
> @@ -119,15 +91,13 @@ static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
>
> static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
> {
> - struct dpc_dev *dpc;
> u16 cap;
>
> /*
> * DPC disables the Link automatically in hardware, so it has
> * already been reset by the time we get here.
> */
> - dpc = to_dpc_dev(pdev);
> - cap = dpc->cap_pos;
> + cap = pdev->dpc_cap;
>
> /*
> * Wait until the Link is inactive, then clear DPC Trigger Status
> @@ -135,7 +105,7 @@ static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
> */
> pcie_wait_for_link(pdev, false);
>
> - if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
> + if (pdev->dpc_rp_extensions && dpc_wait_rp_inactive(pdev))
> return PCI_ERS_RESULT_DISCONNECT;
>
> pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
> @@ -147,10 +117,9 @@ static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
> return PCI_ERS_RESULT_RECOVERED;
> }
>
> -static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
> +static void dpc_process_rp_pio_error(struct pci_dev *pdev)
> {
> - struct pci_dev *pdev = dpc->dev->port;
> - u16 cap = dpc->cap_pos, dpc_status, first_error;
> + u16 cap = pdev->dpc_cap, dpc_status, first_error;
> u32 status, mask, sev, syserr, exc, dw0, dw1, dw2, dw3, log, prefix;
> int i;
>
> @@ -175,7 +144,7 @@ static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
> first_error == i ? " (First)" : "");
> }
>
> - if (dpc->rp_log_size < 4)
> + if (pdev->dpc_rp_log_size < 4)
> goto clear_status;
> pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG,
> &dw0);
> @@ -188,12 +157,12 @@ static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
> pci_err(pdev, "TLP Header: %#010x %#010x %#010x %#010x\n",
> dw0, dw1, dw2, dw3);
>
> - if (dpc->rp_log_size < 5)
> + if (pdev->dpc_rp_log_size < 5)
> goto clear_status;
> pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_IMPSPEC_LOG, &log);
> pci_err(pdev, "RP PIO ImpSpec Log %#010x\n", log);
>
> - for (i = 0; i < dpc->rp_log_size - 5; i++) {
> + for (i = 0; i < pdev->dpc_rp_log_size - 5; i++) {
> pci_read_config_dword(pdev,
> cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG, &prefix);
> pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, prefix);
> @@ -226,10 +195,9 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
>
> static irqreturn_t dpc_handler(int irq, void *context)
> {
> + struct pci_dev *pdev = context;
> + u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
> struct aer_err_info info;
> - struct dpc_dev *dpc = context;
> - struct pci_dev *pdev = dpc->dev->port;
> - u16 cap = dpc->cap_pos, status, source, reason, ext_reason;
>
> pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
> @@ -248,8 +216,8 @@ static irqreturn_t dpc_handler(int irq, void *context)
> "reserved error");
>
> /* show RP PIO error detail information */
> - if (dpc->rp_extensions && reason == 3 && ext_reason == 0)
> - dpc_process_rp_pio_error(dpc);
> + if (pdev->dpc_rp_extensions && reason == 3 && ext_reason == 0)
> + dpc_process_rp_pio_error(pdev);
> else if (reason == 0 &&
> dpc_get_aer_uncorrect_severity(pdev, &info) &&
> aer_get_device_error_info(pdev, &info)) {
> @@ -266,9 +234,8 @@ static irqreturn_t dpc_handler(int irq, void *context)
>
> static irqreturn_t dpc_irq(int irq, void *context)
> {
> - struct dpc_dev *dpc = (struct dpc_dev *)context;
> - struct pci_dev *pdev = dpc->dev->port;
> - u16 cap = dpc->cap_pos, status;
> + struct pci_dev *pdev = context;
> + u16 cap = pdev->dpc_cap, status;
>
> pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
>
> @@ -285,7 +252,6 @@ static irqreturn_t dpc_irq(int irq, void *context)
> #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
> static int dpc_probe(struct pcie_device *dev)
> {
> - struct dpc_dev *dpc;
> struct pci_dev *pdev = dev->port;
> struct device *device = &dev->device;
> int status;
> @@ -294,43 +260,37 @@ static int dpc_probe(struct pcie_device *dev)
> if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native)
> return -ENOTSUPP;
>
> - dpc = devm_kzalloc(device, sizeof(*dpc), GFP_KERNEL);
> - if (!dpc)
> - return -ENOMEM;
> -
> - dpc->cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
> - dpc->dev = dev;
> - set_service_data(dev, dpc);
> + pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
>
> status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
> dpc_handler, IRQF_SHARED,
> - "pcie-dpc", dpc);
> + "pcie-dpc", pdev);
> if (status) {
> pci_warn(pdev, "request IRQ%d failed: %d\n", dev->irq,
> status);
> return status;
> }
>
> - pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap);
> - pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
> + pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
> + pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
>
> - dpc->rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT);
> - if (dpc->rp_extensions) {
> - dpc->rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
> - if (dpc->rp_log_size < 4 || dpc->rp_log_size > 9) {
> + pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
> + if (pdev->dpc_rp_extensions) {
> + pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
> + if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
> pci_err(pdev, "RP PIO log size %u is invalid\n",
> - dpc->rp_log_size);
> - dpc->rp_log_size = 0;
> + pdev->dpc_rp_log_size);
> + pdev->dpc_rp_log_size = 0;
> }
> }
>
> ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
> - pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
> + pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
>
> pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n",
> cap & PCI_EXP_DPC_IRQ, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
> FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
> - FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), dpc->rp_log_size,
> + FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), pdev->dpc_rp_log_size,
> FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE));
>
> pci_add_ext_cap_save_buffer(pdev, PCI_EXT_CAP_ID_DPC, sizeof(u16));
> @@ -339,13 +299,12 @@ static int dpc_probe(struct pcie_device *dev)
>
> static void dpc_remove(struct pcie_device *dev)
> {
> - struct dpc_dev *dpc = get_service_data(dev);
> struct pci_dev *pdev = dev->port;
> u16 ctl;
>
> - pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
> + pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
> ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN);
> - pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
> + pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
> }
>
> static struct pcie_port_service_driver dpcdriver = {
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 3840a541a9de..a0b7e7a53741 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -444,6 +444,11 @@ struct pci_dev {
> const struct attribute_group **msi_irq_groups;
> #endif
> struct pci_vpd *vpd;
> +#ifdef CONFIG_PCIE_DPC
> + u16 dpc_cap;
> + unsigned int dpc_rp_extensions:1;
> + u8 dpc_rp_log_size;
> +#endif
> #ifdef CONFIG_PCI_ATS
> union {
> struct pci_sriov *sriov; /* PF: SR-IOV info */
>
--
Sathyanarayanan Kuppuswamy
Linux kernel developer