[PATCH v2 1/3] drm/xe: Add functions and sysfs for boot survivability
Riana Tauro
riana.tauro at intel.com
Wed Jan 15 16:17:53 UTC 2025
Hi Rodrigo
On 1/10/2025 8:51 PM, Rodrigo Vivi wrote:
> On Wed, Jan 08, 2025 at 04:09:57PM +0530, Riana Tauro wrote:
>> Boot Survivability is a software based workflow for recovering a system
>> in a failed boot state. Here system recoverability is concerned with
>> recovering the firmware responsible for boot.
>>
>> This is implemented by loading the driver with bare minimum (no drm card)
>> to allow the firmware to be flashed through mei-gsc and collect telemetry.
>> The driver's probe flow is modified such that it enters survivability mode
>> when pcode initialization is incomplete and boot status denotes a failure.
>> In this mode, drm card is not exposed and presence of survivability_mode
>> entry in PCI sysfs is used to indicate survivability mode and
>> provide additional information required for debug
>>
>> This patch adds initialization functions and exposes admin
>> readable sysfs entries
>>
>> The new sysfs will have the below layout
>>
>> /sys/bus/.../bdf
>> ├── survivability_mode
>>
>> v2: reorder headers
>> fix doc
>> remove survivability info and use mode to display information
>> use separate function for logging survivability information
>> for critical error (Rodrigo)
>>
>> Signed-off-by: Riana Tauro <riana.tauro at intel.com>
>> ---
>> drivers/gpu/drm/xe/Makefile | 1 +
>> drivers/gpu/drm/xe/xe_device_types.h | 4 +
>> drivers/gpu/drm/xe/xe_pcode_api.h | 14 ++
>> drivers/gpu/drm/xe/xe_survivability_mode.c | 231 ++++++++++++++++++
>> drivers/gpu/drm/xe/xe_survivability_mode.h | 17 ++
>> .../gpu/drm/xe/xe_survivability_mode_types.h | 35 +++
>> 6 files changed, 302 insertions(+)
>> create mode 100644 drivers/gpu/drm/xe/xe_survivability_mode.c
>> create mode 100644 drivers/gpu/drm/xe/xe_survivability_mode.h
>> create mode 100644 drivers/gpu/drm/xe/xe_survivability_mode_types.h
>>
>> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
>> index 5c97ad6ed738..fb1cb98ce891 100644
>> --- a/drivers/gpu/drm/xe/Makefile
>> +++ b/drivers/gpu/drm/xe/Makefile
>> @@ -95,6 +95,7 @@ xe-y += xe_bb.o \
>> xe_sa.o \
>> xe_sched_job.o \
>> xe_step.o \
>> + xe_survivability_mode.o \
>> xe_sync.o \
>> xe_tile.o \
>> xe_tile_sysfs.o \
>> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
>> index 8a7b15972413..0f5a052150c9 100644
>> --- a/drivers/gpu/drm/xe/xe_device_types.h
>> +++ b/drivers/gpu/drm/xe/xe_device_types.h
>> @@ -21,6 +21,7 @@
>> #include "xe_pt_types.h"
>> #include "xe_sriov_types.h"
>> #include "xe_step_types.h"
>> +#include "xe_survivability_mode_types.h"
>>
>> #if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
>> #define TEST_VM_OPS_ERROR
>> @@ -341,6 +342,9 @@ struct xe_device {
>> u8 skip_pcode:1;
>> } info;
>>
>> + /** @survivability: survivability information for device */
>> + struct xe_survivability survivability;
>> +
>> /** @irq: device interrupt state */
>> struct {
>> /** @irq.lock: lock for processing irq's on this device */
>> diff --git a/drivers/gpu/drm/xe/xe_pcode_api.h b/drivers/gpu/drm/xe/xe_pcode_api.h
>> index f153ce96f69a..4e373b8199ca 100644
>> --- a/drivers/gpu/drm/xe/xe_pcode_api.h
>> +++ b/drivers/gpu/drm/xe/xe_pcode_api.h
>> @@ -49,6 +49,20 @@
>> /* Domain IDs (param2) */
>> #define PCODE_MBOX_DOMAIN_HBM 0x2
>>
>> +#define PCODE_SCRATCH_ADDR(x) XE_REG(0x138320 + ((x) * 4))
>> +/* PCODE_SCRATCH0 */
>> +#define AUXINFO_REG_OFFSET REG_GENMASK(17, 15)
>> +#define OVERFLOW_REG_OFFSET REG_GENMASK(14, 12)
>> +#define HISTORY_TRACKING REG_BIT(11)
>> +#define OVERFLOW_SUPPORT REG_BIT(10)
>> +#define AUXINFO_SUPPORT REG_BIT(9)
>> +#define BOOT_STATUS REG_GENMASK(3, 1)
>> +#define CRITICAL_FAILURE 4
>> +#define NON_CRITICAL_FAILURE 7
>> +
>> +/* Auxillary info bits */
>> +#define AUXINFO_HISTORY_OFFSET REG_GENMASK(31, 29)
>> +
>> struct pcode_err_decode {
>> int errno;
>> const char *str;
>> diff --git a/drivers/gpu/drm/xe/xe_survivability_mode.c b/drivers/gpu/drm/xe/xe_survivability_mode.c
>> new file mode 100644
>> index 000000000000..077422ae009d
>> --- /dev/null
>> +++ b/drivers/gpu/drm/xe/xe_survivability_mode.c
>> @@ -0,0 +1,231 @@
>> +// SPDX-License-Identifier: MIT
>> +/*
>> + * Copyright © 2025 Intel Corporation
>> + */
>> +
>> +#include "xe_survivability_mode.h"
>> +#include "xe_survivability_mode_types.h"
>> +
>> +#include <drm/drm_managed.h>
>> +#include <linux/kobject.h>
>> +#include <linux/pci.h>
>> +#include <linux/sysfs.h>
>> +
>> +#include "xe_device.h"
>> +#include "xe_gt.h"
>> +#include "xe_mmio.h"
>> +#include "xe_pcode_api.h"
>> +
>> +#define MAX_SCRATCH_MMIO 8
>> +
>> +/**
>> + * DOC: Xe Boot Survivability
>> + *
>> + * Boot Survivability is a software based workflow for recovering a system in a failed boot state
>> + * Here system recoverability is concerned with recovering the firmware responsible for boot.
>> + *
>> + * This is implemented by loading the driver with bare minimum (no drm card) to allow the firmware
>> + * to be flashed through mei and collect telemetry. The driver's probe flow is modified
>> + * such that it enters survivability mode when pcode initialization is incomplete and boot status
>> + * denotes a failure. The driver then populates the survivability_mode PCI sysfs indicating
>> + * survivability mode and provides additional information required for debug
>> + *
>> + * KMD exposes below admin-only readable sysfs in survivability mode
>> + *
>> + * device/survivability_mode: The presence of this file indicates that the card is in survivability
>> + * mode. Also, provides additional information on why the driver entered
>> + * survivability mode.
>> + *
>> + * Capability Information - Provides boot status
>> + * Postcode Information - Provides information about the failure
>> + * Overflow Information - Provides history of previous failures
>> + * Auxillary Information - Certain failures may have information in
>> + * addition to postcode information
>> + */
>> +
>> +static void set_survivability_info(struct xe_device *xe, struct xe_survivability_info *info,
>> + int id, char *name)
>> +{
>> + struct xe_mmio *mmio = xe_root_tile_mmio(xe);
>> +
>> + strscpy(info[id].name, name, sizeof(info[id].name));
>> + info[id].reg = PCODE_SCRATCH_ADDR(id).raw;
>> + info[id].value = xe_mmio_read32(mmio, PCODE_SCRATCH_ADDR(id));
>> +}
>> +
>> +static int populate_survivability_info(struct xe_device *xe)
>> +{
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct xe_survivability_info *info = survivability->info;
>> + u32 capability_info;
>> + int id = 0;
>> +
>> + set_survivability_info(xe, info, id, "Capability Info");
>> + capability_info = info[id].value;
>> +
>> + if (capability_info & HISTORY_TRACKING) {
>> + id++;
>> + set_survivability_info(xe, info, id, "Postcode Info");
>> +
>> + if (capability_info & OVERFLOW_SUPPORT) {
>> + id = REG_FIELD_GET(OVERFLOW_REG_OFFSET, capability_info);
>> + /* ID should be within MAX_SCRATCH_MMIO */
>> + if (id >= MAX_SCRATCH_MMIO)
>> + return -EINVAL;
>> + set_survivability_info(xe, info, id, "Overflow Info");
>> + }
>> + }
>> +
>> + if (capability_info & AUXINFO_SUPPORT) {
>> + u32 aux_info;
>> + int index = 0;
>> + char name[NAME_MAX];
>> +
>> + id = REG_FIELD_GET(AUXINFO_REG_OFFSET, capability_info);
>> + if (id >= MAX_SCRATCH_MMIO)
>> + return -EINVAL;
>> +
>> + snprintf(name, NAME_MAX, "Auxiliary Info %d", index);
>> + set_survivability_info(xe, info, id, name);
>> + aux_info = info[id].value;
>> +
>> + while ((id = REG_FIELD_GET(AUXINFO_HISTORY_OFFSET, aux_info)) &&
>> + (id < MAX_SCRATCH_MMIO)) {
>
> This is a clear case where 'for' is better. But also, generally here we
> try to limit while usages...
This is similar to linked list with the address of prev aux registers in
the AUXINFO_HISTORY_OFFSET. So used while.
Using for would be like below
for (id = REG_FIELD_GET(AUXINFO_HISTORY_OFFSET, aux_info);
aux_info && id < MAX_SCRATCH_MMIO; id
=REG_FIELD_GET(AUXINFO_HISTORY_OFFSET, aux_info))
Isn't while better?
>
>> + index++;
>> + snprintf(name, NAME_MAX, "Prev Auxiliary Info %d", index);
>> + set_survivability_info(xe, info, id, name);
>> + aux_info = info[id].value;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void log_survivability_info(struct xe_device *xe)
>> +{
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct xe_survivability_info *info = survivability->info;
>> + int id;
>> +
>> + drm_info(&xe->drm, "Survivability Boot Status : Critical Failure (%d)\n",
>> + survivability->boot_status);
>
> hmm, since we are avoiding the drm, should we really use drm variants here?
> or the pci/dev ones?!
drm variants use the dev ones and prints the prefix if drm is not null.
Will change the drm_info in this file but the logs in mei and vsec
initialization would have to be retained.
>
>> + for (id = 0; id < MAX_SCRATCH_MMIO; id++) {
>> + if (info[id].reg)
>> + drm_info(&xe->drm, "%s: 0x%x - 0x%x\n", info[id].name,
>> + info[id].reg, info[id].value);
>> + }
>> +}
>> +
>> +static ssize_t survivability_mode_show(struct device *dev,
>> + struct device_attribute *attr, char *buff)
>> +{
>> + struct pci_dev *pdev = to_pci_dev(dev);
>> + struct xe_device *xe = pdev_to_xe_device(pdev);
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct xe_survivability_info *info = survivability->info;
>> + int index = 0, count = 0;
>> +
>> + for (index = 0; index < MAX_SCRATCH_MMIO; index++) {
>> + if (info[index].reg)
>> + count += sysfs_emit_at(buff, count, "%s: 0x%x - 0x%x\n", info[index].name,
>> + info[index].reg, info[index].value);
>> + }
>> +
>> + return count;
>> +}
>> +
>> +static DEVICE_ATTR_ADMIN_RO(survivability_mode);
>> +
>> +static void enable_survivability_mode(struct xe_device *xe)
>> +{
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct device *dev = xe->drm.dev;
>
> do we really have this pointer valid at this point?!
This is allocated in xe_device_create. Registration is done later in
xe_device_probe so the prints and xe->drm.dev will be valid
Thanks
Riana
>
>> + int ret = 0;
>> +
>> + /* set survivability mode */
>> + survivability->mode = true;
>> + drm_info(&xe->drm, "In Survivability Mode\n");
>
> same here...
>
>> +
>> + /* create survivability mode sysfs */
>> + ret = sysfs_create_file(&dev->kobj, &dev_attr_survivability_mode.attr);
>> + if (ret) {
>> + drm_warn(&xe->drm, "Failed to create survivability sysfs files\n");
>> + return;
>> + }
>> +}
>> +
>> +/**
>> + * xe_survivability_mode_required- checks if survivability mode is required
>> + * @xe: xe device instance
>> + *
>> + * This function reads the boot status of Pcode capability register
>> + *
>> + * Return: true if boot status indicates failure, false otherwise
>> + */
>> +bool xe_survivability_mode_required(struct xe_device *xe)
>> +{
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct xe_mmio *mmio = xe_root_tile_mmio(xe);
>> + u32 data;
>> +
>> + data = xe_mmio_read32(mmio, PCODE_SCRATCH_ADDR(0));
>> + survivability->boot_status = REG_FIELD_GET(BOOT_STATUS, data);
>> +
>> + return (survivability->boot_status == NON_CRITICAL_FAILURE ||
>> + survivability->boot_status == CRITICAL_FAILURE);
>> +}
>> +
>> +/**
>> + * xe_survivability_mode_remove - remove survivability mode
>> + * @xe: xe device instance
>> + *
>> + * clean up sysfs entries of survivability mode
>> + */
>> +void xe_survivability_mode_remove(struct xe_device *xe)
>> +{
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
>> +
>> + sysfs_remove_file(&xe->drm.dev->kobj, &dev_attr_survivability_mode.attr);
>> + kfree(survivability->info);
>> + pci_set_drvdata(pdev, NULL);
>> +}
>> +
>> +/**
>> + * xe_survivability_mode_init - Initialize the survivability mode
>> + * @xe: xe device instance
>> + *
>> + * Initializes the sysfs and required actions to enter survivability mode
>> + */
>> +void xe_survivability_mode_init(struct xe_device *xe)
>> +{
>> + struct xe_survivability *survivability = &xe->survivability;
>> + struct xe_survivability_info *info;
>> + int ret = 0;
>> +
>> + survivability->size = MAX_SCRATCH_MMIO;
>> +
>> + info = kcalloc(survivability->size, sizeof(*info), GFP_KERNEL);
>> + if (!info) {
>> + ret = -ENOMEM;
>> + goto err;
>> + }
>> +
>> + survivability->info = info;
>> +
>> + ret = populate_survivability_info(xe);
>> + if (ret)
>> + goto err;
>> +
>> + /* Only log debug information and exit if it is a critical failure */
>> + if (survivability->boot_status == CRITICAL_FAILURE) {
>> + log_survivability_info(xe);
>> + kfree(survivability->info);
>> + return;
>> + }
>> +
>> + enable_survivability_mode(xe);
>> +err:
>> + if (ret)
>> + drm_warn(&xe->drm, "%s failed, err: %d\n", __func__, ret);
>
> same...
>
>> +}
>> diff --git a/drivers/gpu/drm/xe/xe_survivability_mode.h b/drivers/gpu/drm/xe/xe_survivability_mode.h
>> new file mode 100644
>> index 000000000000..410e3ee5f5d1
>> --- /dev/null
>> +++ b/drivers/gpu/drm/xe/xe_survivability_mode.h
>> @@ -0,0 +1,17 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright © 2025 Intel Corporation
>> + */
>> +
>> +#ifndef _XE_SURVIVABILITY_MODE_H_
>> +#define _XE_SURVIVABILITY_MODE_H_
>> +
>> +#include <linux/types.h>
>> +
>> +struct xe_device;
>> +
>> +void xe_survivability_mode_init(struct xe_device *xe);
>> +void xe_survivability_mode_remove(struct xe_device *xe);
>> +bool xe_survivability_mode_required(struct xe_device *xe);
>> +
>> +#endif /* _XE_SURVIVABILITY_MODE_H_ */
>> diff --git a/drivers/gpu/drm/xe/xe_survivability_mode_types.h b/drivers/gpu/drm/xe/xe_survivability_mode_types.h
>> new file mode 100644
>> index 000000000000..19d433e253df
>> --- /dev/null
>> +++ b/drivers/gpu/drm/xe/xe_survivability_mode_types.h
>> @@ -0,0 +1,35 @@
>> +/* SPDX-License-Identifier: MIT */
>> +/*
>> + * Copyright © 2025 Intel Corporation
>> + */
>> +
>> +#ifndef _XE_SURVIVABILITY_MODE_TYPES_H_
>> +#define _XE_SURVIVABILITY_MODE_TYPES_H_
>> +
>> +#include <linux/limits.h>
>> +#include <linux/types.h>
>> +
>> +struct xe_survivability_info {
>> + char name[NAME_MAX];
>> + u32 reg;
>> + u32 value;
>> +};
>> +
>> +/**
>> + * struct xe_survivability: Contains survivability mode information
>> + */
>> +struct xe_survivability {
>> + /** @info: struct that holds survivability info from scratch registers */
>> + struct xe_survivability_info *info;
>> +
>> + /** @size: number of scratch registers */
>> + u32 size;
>> +
>> + /** @boot_status: indicates critical/non critical boot failure */
>> + u8 boot_status;
>> +
>> + /** @mode: boolean to indicate survivability mode */
>> + bool mode;
>> +};
>> +
>
> I believe the only blocker is the while-vs-for loop. I believe the 'drm'
> could be avoided, but not a big deal if it is really working...
>
>> +#endif /* _XE_SURVIVABILITY_MODE_TYPES_H_ */
>> --
>> 2.47.1
>>
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