Re: [PATCH v3 1/8] trace: ras: add ARM processor error information trace event

[Steven Rostedt]

On Thu, 30 Mar 2017 18:31:01 +0800
Xie XiuQi <xiexiuqi@xxxxxxxxxx> wrote:

> Add a new trace event for ARM processor error information, so that
> the user will know what error occurred. With this information the
> user may take appropriate action.
> 
> These trace events are consistent with the ARM processor error
> information table which defined in UEFI 2.6 spec section N.2.4.4.1.
> 
> ---
> v2: add trace enabled condition as Steven's suggestion.
>     fix a typo.
> ---
> 
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
> Signed-off-by: Xie XiuQi <xiexiuqi@xxxxxxxxxx>
> ---
>  drivers/acpi/apei/ghes.c | 10 ++++++
>  include/linux/cper.h     |  5 +++
>  include/ras/ras_event.h  | 87 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 102 insertions(+)
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 81eabc6..6be0333 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -518,9 +518,19 @@ static void ghes_do_proc(struct ghes *ghes,
>  		else if (!uuid_le_cmp(sec_type, CPER_SEC_PROC_ARM) &&
>  			 trace_arm_event_enabled()) {
>  			struct cper_sec_proc_arm *arm_err;
> +			struct cper_arm_err_info *err_info;
> +			int i;
>  
>  			arm_err = acpi_hest_generic_data_payload(gdata);
>  			trace_arm_event(arm_err);
> +
> +			if (trace_arm_proc_err_enabled()) {
> +				err_info = (struct cper_arm_err_info *)(arm_err + 1);
> +				for (i = 0; i < arm_err->err_info_num; i++) {
> +					trace_arm_proc_err(err_info);
> +					err_info += 1;
> +				}
> +			}
>  		} else if (trace_unknown_sec_event_enabled()) {
>  			void *unknown_err = acpi_hest_generic_data_payload(gdata);
>  			trace_unknown_sec_event(&sec_type,
> diff --git a/include/linux/cper.h b/include/linux/cper.h
> index 85450f3..0cae900 100644
> --- a/include/linux/cper.h
> +++ b/include/linux/cper.h
> @@ -270,6 +270,11 @@ enum {
>  #define CPER_ARM_INFO_VALID_VIRT_ADDR		0x0008
>  #define CPER_ARM_INFO_VALID_PHYSICAL_ADDR	0x0010
>  
> +#define CPER_ARM_INFO_TYPE_CACHE		0
> +#define CPER_ARM_INFO_TYPE_TLB			1
> +#define CPER_ARM_INFO_TYPE_BUS			2
> +#define CPER_ARM_INFO_TYPE_UARCH		3
> +
>  #define CPER_ARM_INFO_FLAGS_FIRST		0x0001
>  #define CPER_ARM_INFO_FLAGS_LAST		0x0002
>  #define CPER_ARM_INFO_FLAGS_PROPAGATED		0x0004
> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
> index 13befad..026b094 100644
> --- a/include/ras/ras_event.h
> +++ b/include/ras/ras_event.h
> @@ -206,6 +206,93 @@
>  		  __entry->running_state, __entry->psci_state)
>  );
>  
> +#define ARM_PROC_ERR_TYPE	\
> +	EM ( CPER_ARM_INFO_TYPE_CACHE, "cache error" )	\
> +	EM ( CPER_ARM_INFO_TYPE_TLB,  "TLB error" )	\
> +	EM ( CPER_ARM_INFO_TYPE_BUS, "bus error" )	\
> +	EMe ( CPER_ARM_INFO_TYPE_UARCH, "micro-architectural error" )
> +
> +#define ARM_PROC_ERR_FLAGS	\
> +	EM ( CPER_ARM_INFO_FLAGS_FIRST, "First error captured" )	\
> +	EM ( CPER_ARM_INFO_FLAGS_LAST,  "Last error captured" )	\
> +	EM ( CPER_ARM_INFO_FLAGS_PROPAGATED, "Propagated" )	\
> +	EMe ( CPER_ARM_INFO_FLAGS_OVERFLOW, "Overflow" )
> +

Can flags have more than one bit set?

> +/*
> + * First define the enums in MM_ACTION_RESULT to be exported to userspace
> + * via TRACE_DEFINE_ENUM().
> + */
> +#undef EM
> +#undef EMe
> +#define EM(a, b) TRACE_DEFINE_ENUM(a);
> +#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
> +
> +ARM_PROC_ERR_TYPE
> +ARM_PROC_ERR_FLAGS
> +
> +/*
> + * Now redefine the EM() and EMe() macros to map the enums to the strings
> + * that will be printed in the output.
> + */
> +#undef EM
> +#undef EMe
> +#define EM(a, b)		{ a, b },
> +#define EMe(a, b)	{ a, b }
> +
> +TRACE_EVENT(arm_proc_err,
> +
> +	TP_PROTO(const struct cper_arm_err_info *err),
> +
> +	TP_ARGS(err),
> +
> +	TP_STRUCT__entry(
> +		__field(u8, type)
> +		__field(u16, multiple_error)
> +		__field(u8, flags)
> +		__field(u64, error_info)
> +		__field(u64, virt_fault_addr)
> +		__field(u64, physical_fault_addr)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->type = err->type;
> +
> +		if (err->validation_bits & CPER_ARM_INFO_VALID_MULTI_ERR)
> +			__entry->multiple_error = err->multiple_error;
> +		else
> +			__entry->multiple_error = ~0;
> +
> +		if (err->validation_bits & CPER_ARM_INFO_VALID_FLAGS)
> +			__entry->flags = err->flags;
> +		else
> +			__entry->flags = ~0;
> +
> +		if (err->validation_bits & CPER_ARM_INFO_VALID_ERR_INFO)
> +			__entry->error_info = err->error_info;
> +		else
> +			__entry->error_info = 0ULL;
> +
> +		if (err->validation_bits & CPER_ARM_INFO_VALID_VIRT_ADDR)
> +			__entry->virt_fault_addr = err->virt_fault_addr;
> +		else
> +			__entry->virt_fault_addr = 0ULL;
> +
> +		if (err->validation_bits & CPER_ARM_INFO_VALID_PHYSICAL_ADDR)
> +			__entry->physical_fault_addr = err->physical_fault_addr;
> +		else
> +			__entry->physical_fault_addr = 0ULL;

else statements add a lot of branch conditions, and kills the branch
prediction. What about setting up default values, and then setting only
if the if statement is true.


	memset(&__entry->error_info, 0,
	       sizeof(__entry) - offsetof(typeof(__entry), error_info)));
	__entry->multiple_error = ~0;
	__entry->flags = ~0;

	if (...)

> +	),
> +
> +	TP_printk("ARM Processor Error: type %s; count: %u; flags: %s;"
> +		  " error info: %016llx; virtual address: %016llx;"
> +		  " physical address: %016llx",
> +		  __print_symbolic(__entry->type, ARCH_PROC_ERR_TYPE),
> +		  __entry->multiple_error,
> +		  __print_symbolic(__entry->flags, ARCH_PROC_ERR_FLAGS),

Again, can flags have more than one bit set? If so, then this wont work.

-- Steve

> +		  __entry->error_info, __entry->virt_fault_addr,
> +		  __entry->physical_fault_addr)
> +);
> +
>  /*
>   * Unknown Section Report
>   *