Re: [PATCH v4 11/32] drm/xe/log: Index all SIGID printk messages

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 8/13/2026 2:31 PM, Mallesh, Koujalagi wrote:
> 
> On 13-08-2026 12:44 am, Michal Wajdeczko wrote:
>> When CONFIG_PRINTK_INDEX is enabled, it is expected that all device
>> level printk messages are indexed for audit. While usually this is
>> done automatically behind the scenes when code is using regular
>> dev_printk macros, since we are generating different dmesg messages
>> inside xe_log_emit() based on the severity, component and location,
>> we only get those entries in /sys/kernel/debug/printk/index/xe:
>>
>>    <3> drivers/gpu/drm/xe/xe_log.c:142 log_dmesg_vprintk "%s %s: [drm] *ERROR* %pV"
>>    <6> drivers/gpu/drm/xe/xe_log.c:140 log_dmesg_vprintk "%s %s: [drm] %pV"
>>
>> Explicitly generate printk index using dev_printk_index_emit() with
>> some generic prefix that includes the SIGID tag.
>>
>> Suggested-by: Jani Nikula <jani.nikula@intel.com>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
>> Cc: Jani Nikula <jani.nikula@intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_log.c |  8 ++++----
>>   drivers/gpu/drm/xe/xe_log.h | 14 +++++++++++---
>>   2 files changed, 15 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_log.c b/drivers/gpu/drm/xe/xe_log.c
>> index 0b423ed121cd..50a9b35e5b3e 100644
>> --- a/drivers/gpu/drm/xe/xe_log.c
>> +++ b/drivers/gpu/drm/xe/xe_log.c
>> @@ -177,7 +177,7 @@ static void log_emit_dmesg(struct pci_dev *pdev, int cper_sev, enum xe_sigid sig
>>   }
>>     /**
>> - * xe_log_emit() - Emit a structured SIGID log entry
>> + * __xe_log_emit() - Emit a structured SIGID log entry
>>    * @pdev: the &pci_dev device
>>    * @cper_sev: CPER severity (CPER_SEV_FATAL, CPER_SEV_RECOVERABLE, ...)
>>    * @sigid: signature identifier, see &enum xe_sigid
>> @@ -206,9 +206,9 @@ static void log_emit_dmesg(struct pci_dev *pdev, int cper_sev, enum xe_sigid sig
>>    *   <3> xe 0000:03:00.0: [drm] *ERROR* SIGID=106 (-ETIMEDOUT) Engine 'rcs0' hung
>>    *   <6> xe 0000:03:00.0: [drm] SIGID=103 In survivability mode
>>    */
>> -void xe_log_emit(struct pci_dev *pdev, int cper_sev, enum xe_sigid sigid,
>> -         u32 component, u32 location, const void *data, size_t len,
>> -         const char *fmt, ...)
>> +void __xe_log_emit(struct pci_dev *pdev, int cper_sev, enum xe_sigid sigid,
>> +           u32 component, u32 location, const void *data, size_t len,
>> +           const char *fmt, ...)
>>   {
>>       struct va_format vaf;
>>       va_list args;
>> diff --git a/drivers/gpu/drm/xe/xe_log.h b/drivers/gpu/drm/xe/xe_log.h
>> index 0928b0866617..53fe2bb7ddd3 100644
>> --- a/drivers/gpu/drm/xe/xe_log.h
>> +++ b/drivers/gpu/drm/xe/xe_log.h
>> @@ -16,9 +16,17 @@
>>   struct pci_dev;
>>     __printf(8, 9)
>> -void xe_log_emit(struct pci_dev *pdev, int cper_sev, enum xe_sigid sigid,
>> -         u32 component, u32 location, const void *data, size_t len,
>> -         const char *fmt, ...);
>> +void __xe_log_emit(struct pci_dev *pdev, int cper_sev, enum xe_sigid sigid,
>> +           u32 component, u32 location, const void *data, size_t len,
>> +           const char *fmt, ...);
>> +
>> +#define __xe_log_emit_printk_index(fmt) \
>> +    dev_printk_index_emit(NULL, "[drm]%s SIGID=%u %s(%s)%s%s%s: " fmt);
> We need to change format for a. error path b. blob path c. plain or info path right?

well, that's not doable as final format/output depends on the
severity and data value, which could be non-const at compile
time, while printk-index requires this to emit right entry

I can change that to a something more generic (and unfriendly), like:

    dev_printk_index_emit(NULL, "%sSIGID=%u %s" fmt);

but that will catch and match all our outputs.

@Jani, are you OK with that?

>> +
>> +#define xe_log_emit(pdev, sev, sig, comp, loc, data, len, fmt, args...) ({        \
>> +    __xe_log_emit_printk_index(fmt);                        \
>> +    __xe_log_emit((pdev), (sev), (sig), (comp), (loc), (data), (len), fmt, ##args); \
>> +})
> 
> nit: use do{} while (0)
> 
> Reviewed-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
> 
>>     #define xe_log_emit_fatal(pdev, sig, comp, loc, data, len, fmt, args...) \
>>       xe_log_emit((pdev), CPER_SEV_FATAL, (sig), (comp), (loc), \