Re: [PATCH v2 2/2] RAS: Report all ARM processor CPER information to userspace

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Thu, 27 Jun 2024 12:36:08 +0200
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:

> From: Shengwei Luo <luoshengwei@huawei.com>
> 
> The ARM processor CPER record was added at UEFI 2.6, and hasn't
> any changes up to UEFI 2.10 on its struct.
> 
> Yet, the original arm_event trace code added on changeset
> e9279e83ad1f ("trace, ras: add ARM processor error trace event") is
> incomplete, as it only traces some fields of UAPI 2.6 table N.16,
> not exporting at all any information from tables N.17 to N.29 of
> the record.
> 
> This is not enough for user to take appropriate action or to log
> what exactly happened.
> 
> According to UEFI_2_9 specification chapter N2.4.4, the ARM processor
> error section includes:
> 
> - several (ERR_INFO_NUM) ARM processor error information structures
>   (Tables N.17 to N.20);
> - several (CONTEXT_INFO_NUM) ARM processor context information
>   structures (Tables N.21 to N.29);
> - several vendor specific error information structures. The
>   size is given by Section Length minus the size of the other
>   fields.
> 
> In addition to those data, it also exports two fields that are
> parsed by the GHES driver when firmware reports it, e. g.:
> 
> - error severity
> - cpu logical index
> 
> Report all of these information to userspace via trace uAPI, So that

so (no capital S)

> userspace can properly record the error and take decisions related
> to cpu core isolation according to error severity and other info.
> 
> After this patch, all the data from ARM Processor record from table
> N.16 are directly or indirectly visible on userspace:
> 
> ======================================	=============================
> UEFI field on table N.16		ARM Processor trace fields
> ======================================	=============================
> Validation				handled when filling data for
> 					affinity MPIDR and running
> 					state.
> ERR_INFO_NUM				pei_len
> CONTEXT_INFO_NUM			ctx_len
> Section Length				indirectly reported by
> 					pei_len, ctx_len and oem_len
> Error affinity level			affinity
> MPIDR_EL1				mpidr
> MIDR_EL1				midr
> Running State				running_state
> PSCI State				psci_state
> Processor Error Information Structure	pei_err - count at pei_len
> Processor Context			ctx_err- count at ctx_len
> Vendor Specific Error Info		oem - count at oem_len
> ======================================	=============================
> 
> It should be noticed that decoding of tables N.17 to N.29, if needed,
> will be handled on userspace. That gives more flexibility, as there

in userspace

> won't be any need to flood the Kernel with micro-architecture specific
> error decoding).

architecture specific (this isn't specific to an implementation of the
arm architecture - if it were it wouldn't be in the uefi spec).

> Also, decoding the other fields require a complex logic, and should

require complex logic.  (the next bit seems unnecessary detail to me).

> be done for each of the several values inside the record field.
> So, let userspace daemons like rasdaemon decode them, parsing such
> tables and having vendor-specific micro-architecture-specific decoders.
> 
> [mchehab: modified patch description and fix coding style]
> Fixes: e9279e83ad1f ("trace, ras: add ARM processor error trace event")
> Signed-off-by: Shengwei Luo <luoshengwei@huawei.com>
> Signed-off-by: Jason Tian <jason@os.amperecomputing.com>
> Signed-off-by: Daniel Ferguson <danielf@os.amperecomputing.com>
> Tested-by: Shiju Jose <shiju.jose@huawei.com>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Link: https://uefi.org/specs/UEFI/2.10/Apx_N_Common_Platform_Error_Record.html#arm-processor-error-section
A few minor things inline.

Jonathan


> diff --git a/drivers/ras/ras.c b/drivers/ras/ras.c
> index 5d94ab79c8c3..b515659cc8cc 100644
> --- a/drivers/ras/ras.c
> +++ b/drivers/ras/ras.c
> @@ -52,10 +52,51 @@ void log_non_standard_event(const guid_t *sec_type, const guid_t *fru_id,
>  	trace_non_standard_event(sec_type, fru_id, fru_text, sev, err, len);
>  }
>  
> -void log_arm_hw_error(struct cper_sec_proc_arm *err)
> +void log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev)
>  {
>  #if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
> -	trace_arm_event(err);
> +	struct cper_arm_err_info *err_info;
> +	struct cper_arm_ctx_info *ctx_info;
> +	u8 *ven_err_data;
> +	u32 ctx_len = 0;
> +	int n, sz, cpu;
> +	s32 vsei_len;
> +	u32 pei_len;
> +	u8 *pei_err;
> +	u8 *ctx_err;
> +
> +	pei_len = sizeof(struct cper_arm_err_info) * err->err_info_num;
> +	pei_err = (u8 *)err + sizeof(struct cper_sec_proc_arm);
> +
> +	err_info = (struct cper_arm_err_info *)(err + 1);

After some staring... Isn't pei_err == err_info here?
The err_info assignment is nicer, so I'd just use that.


> +	ctx_info = (struct cper_arm_ctx_info *)(err_info + err->err_info_num);
> +	ctx_err = ctx_info;
> +	for (n = 0; n < err->context_info_num; n++) {
> +		sz = sizeof(struct cper_arm_ctx_info) + ctx_info->size;

You 'could' add a variable length array on end of struct cper_arm_ctx_info
just to be able to use struct size here, but probably not worth it.

> +		ctx_info = (struct cper_arm_ctx_info *)((long)ctx_info + sz);

I'd cast to a (u8 *) rather than a long so it's clear this is byte sized
arithmetic

> +		ctx_len += sz;
> +	}
> +
> +	vsei_len = err->section_length - (sizeof(struct cper_sec_proc_arm) +
> +					  pei_len + ctx_len);
> +	if (vsei_len < 0) {
> +		pr_warn(FW_BUG
> +			"section length: %d\n", err->section_length);
> +		pr_warn(FW_BUG
> +			"section length is too small\n");
> +		pr_warn(FW_BUG
> +			"firmware-generated error record is incorrect\n");
> +		vsei_len = 0;
> +	}
> +	ven_err_data = (u8 *)ctx_info;
> +
> +	cpu = GET_LOGICAL_INDEX(err->mpidr);
> +	/* when return value is invalid, set cpu index to -1 */
> +	if (cpu < 0)
> +		cpu = -1;
> +
> +	trace_arm_event(err, pei_err, pei_len, ctx_err, ctx_len,
> +			ven_err_data, (u32)vsei_len, sev, cpu);
>  #endif
>  }
>  
> diff --git a/include/linux/ras.h b/include/linux/ras.h
> index a64182bc72ad..6025afe5736a 100644
> --- a/include/linux/ras.h
> +++ b/include/linux/ras.h
> @@ -24,8 +24,7 @@ int __init parse_cec_param(char *str);
>  void log_non_standard_event(const guid_t *sec_type,
>  			    const guid_t *fru_id, const char *fru_text,
>  			    const u8 sev, const u8 *err, const u32 len);
> -void log_arm_hw_error(struct cper_sec_proc_arm *err);
> -
> +void log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev);
>  #else
>  static inline void
>  log_non_standard_event(const guid_t *sec_type,
> @@ -33,7 +32,7 @@ log_non_standard_event(const guid_t *sec_type,
>  		       const u8 sev, const u8 *err, const u32 len)
>  { return; }
>  static inline void
> -log_arm_hw_error(struct cper_sec_proc_arm *err) { return; }
> +log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev) { return; }

Silly question and obviously nothing to do with this patch, but why return?

>  #endif
>  
>  struct atl_err {
> @@ -52,5 +51,14 @@ static inline void amd_retire_dram_row(struct atl_err *err) { }
>  static inline unsigned long
>  amd_convert_umc_mca_addr_to_sys_addr(struct atl_err *err) { return -EINVAL; }
>  #endif /* CONFIG_AMD_ATL */
> -

I'd keep a blank line here.

> +#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
...

> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
> index 7c47151d5c72..ce5214f008eb 100644
> --- a/include/ras/ras_event.h
> +++ b/include/ras/ras_event.h
> @@ -168,11 +168,24 @@ TRACE_EVENT(mc_event,
>   * This event is generated when hardware detects an ARM processor error
>   * has occurred. UEFI 2.6 spec section N.2.4.4.
>   */
> +#define APEIL "ARM Processor Err Info data len"
> +#define APEID "ARM Processor Err Info raw data"
> +#define APECIL "ARM Processor Err Context Info data len"
> +#define APECID "ARM Processor Err Context Info raw data"
> +#define VSEIL "Vendor Specific Err Info data len"
> +#define VSEID "Vendor Specific Err Info raw data"
>  TRACE_EVENT(arm_event,
>  
> -	TP_PROTO(const struct cper_sec_proc_arm *proc),
> +	TP_PROTO(const struct cper_sec_proc_arm *proc, const u8 *pei_err,
> +			const u32 pei_len,
> +			const u8 *ctx_err,

Weird wrapping choice...  Either pull pei_err down, or wrap the
remaining lines to 80 chars as well.
Or maybe pair pointer and length as appropriate.

> +			const u32 ctx_len,
> +			const u8 *oem,
> +			const u32 oem_len,
> +			u8 sev,
> +			int cpu),
>  
> -	TP_ARGS(proc),
> +	TP_ARGS(proc, pei_err, pei_len, ctx_err, ctx_len, oem, oem_len, sev, cpu),
>  
>  	TP_STRUCT__entry(
>  		__field(u64, mpidr)
> @@ -180,6 +193,14 @@ TRACE_EVENT(arm_event,
>  		__field(u32, running_state)
>  		__field(u32, psci_state)
>  		__field(u8, affinity)
> +		__field(u32, pei_len)
> +		__dynamic_array(u8, buf, pei_len)
> +		__field(u32, ctx_len)
> +		__dynamic_array(u8, buf1, ctx_len)
> +		__field(u32, oem_len)
> +		__dynamic_array(u8, buf2, oem_len)
> +		__field(u8, sev)
> +		__field(int, cpu)
>  	),
>  
>  	TP_fast_assign(
> @@ -199,12 +220,29 @@ TRACE_EVENT(arm_event,
>  			__entry->running_state = ~0;
>  			__entry->psci_state = ~0;
>  		}
> +		__entry->pei_len = pei_len;
> +		memcpy(__get_dynamic_array(buf), pei_err, pei_len);
> +		__entry->ctx_len = ctx_len;
> +		memcpy(__get_dynamic_array(buf1), ctx_err, ctx_len);
> +		__entry->oem_len = oem_len;
> +		memcpy(__get_dynamic_array(buf2), oem, oem_len);
> +		__entry->sev = sev;
> +		__entry->cpu = cpu;
>  	),
>  
> -	TP_printk("affinity level: %d; MPIDR: %016llx; MIDR: %016llx; "
> -		  "running state: %d; PSCI state: %d",
> +	TP_printk("cpu: %d; error: %d; affinity level: %d; MPIDR: %016llx; MIDR: %016llx; "
> +		  "running state: %d; PSCI state: %d; "

Given the string is broken up already, why have a long first line?

> +		  "%s: %d; %s: %s; %s: %d; %s: %s; %s: %d; %s: %s",
> +		  __entry->cpu,
> +		  __entry->sev,
>  		  __entry->affinity, __entry->mpidr, __entry->midr,
> -		  __entry->running_state, __entry->psci_state)
> +		  __entry->running_state, __entry->psci_state,
> +		  APEIL, __entry->pei_len, APEID,
> +		  __print_hex(__get_dynamic_array(buf), __entry->pei_len),
> +		  APECIL, __entry->ctx_len, APECID,
> +		  __print_hex(__get_dynamic_array(buf1), __entry->ctx_len),
> +		  VSEIL, __entry->oem_len, VSEID,
> +		  __print_hex(__get_dynamic_array(buf2), __entry->oem_len))
>  );
>  
>  /*