Re: [PATCH 2/2] trace, RAS: Add eMCA trace event interface

[Borislav Petkov <bp@alien8.de>]

On Tue, Mar 04, 2014 at 04:23:17AM -0500, Chen, Gong wrote:
> Add trace interface to elaborate all H/W error related information.
> 
> Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
> ---
>  drivers/acpi/Kconfig        |   3 +-
>  drivers/acpi/Makefile       |   1 +
>  drivers/acpi/acpi_extlog.c  | 131 +++++++++++++++++++++++++++++++++++++++++++-
>  drivers/firmware/efi/cper.c |  13 ++++-
>  include/linux/cper.h        |   2 +
>  include/ras/ras_event.h     |  62 +++++++++++++++++++++
>  kernel/trace/ras-traces.c   |   1 +
>  7 files changed, 208 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 4770de5..3e569d4 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -363,6 +363,7 @@ config ACPI_EXTLOG
>  
>  	  Enhanced MCA Logging allows firmware to provide additional error
>  	  information to system software, synchronous with MCE or CMCI. This
> -	  driver adds support for that functionality.
> +	  driver adds support for that functionality with corresponding
> +	  tracepoint which carries that information to userspace.
>  
>  endif	# ACPI
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 0331f91..f6abc4a 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -82,4 +82,5 @@ obj-$(CONFIG_ACPI_PROCESSOR_AGGREGATOR) += acpi_pad.o
>  
>  obj-$(CONFIG_ACPI_APEI)		+= apei/
>  
> +CFLAGS_acpi_extlog.o := -I$(src)
>  obj-$(CONFIG_ACPI_EXTLOG)	+= acpi_extlog.o
> diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
> index c4a5d87..fbdebad 100644
> --- a/drivers/acpi/acpi_extlog.c
> +++ b/drivers/acpi/acpi_extlog.c
> @@ -14,8 +14,10 @@
>  #include <linux/edac.h>
>  #include <asm/cpu.h>
>  #include <asm/mce.h>
> +#include <linux/dmi.h>
>  
>  #include "apei/apei-internal.h"
> +#include <ras/ras_event.h>
>  
>  #define EXT_ELOG_ENTRY_MASK	GENMASK_ULL(51, 0) /* elog entry address mask */
>  
> @@ -44,6 +46,11 @@ struct extlog_l1_head {
>  static int old_edac_report_status;
>  
>  static u8 extlog_dsm_uuid[] __initdata = "663E35AF-CC10-41A4-88EA-5470AF055295";
> +static const uuid_le invalid_uuid = NULL_UUID_LE;
> +
> +static DEFINE_RAW_SPINLOCK(trace_lock);
> +static char mem_location[LOC_LEN];
> +static char dimm_location[LOC_LEN];
>  
>  /* L1 table related physical address */
>  static u64 elog_base;
> @@ -69,6 +76,106 @@ static u32 l1_percpu_entry;
>  #define ELOG_ENTRY_ADDR(phyaddr) \
>  	(phyaddr - elog_base + (u8 *)elog_addr)
>  
> +static void mem_err_location(struct cper_sec_mem_err *mem)
> +{
> +	char *p;
> +	u32 n = 0;
> +
> +	memset(mem_location, 0, LOC_LEN);
> +	p = mem_location;
> +	if (mem->validation_bits & CPER_MEM_VALID_NODE)
> +		n += sprintf(p + n, " node: %d", mem->node);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_CARD)
> +		n += sprintf(p + n, " card: %d", mem->card);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_MODULE)
> +		n += sprintf(p + n, " module: %d", mem->module);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_RANK_NUMBER)
> +		n += sprintf(p + n, " rank: %d", mem->rank);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_BANK)
> +		n += sprintf(p + n, " bank: %d", mem->bank);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_DEVICE)
> +		n += sprintf(p + n, " device: %d", mem->device);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_ROW)
> +		n += sprintf(p + n, " row: %d", mem->row);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_COLUMN)
> +		n += sprintf(p + n, " column: %d", mem->column);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_BIT_POSITION)
> +		n += sprintf(p + n, " bit_position: %d", mem->bit_pos);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_REQUESTOR_ID)
> +		n += sprintf(p + n, " requestor_id: 0x%016llx",
> +				mem->requestor_id);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_RESPONDER_ID)
> +		n += sprintf(p + n, " responder_id: 0x%016llx",
> +				mem->responder_id);
> +	if (n >= LOC_LEN)
> +		goto end;
> +	if (mem->validation_bits & CPER_MEM_VALID_TARGET_ID)
> +		n += sprintf(p + n, " target_id: 0x%016llx", mem->target_id);
> +end:
> +	return;
> +}

Looks like this wants to share with cper_print_mem() - definitely a lot
of duplication there.

> +
> +static void dimm_err_location(struct cper_sec_mem_err *mem)
> +{
> +	const char *bank = NULL, *device = NULL;
> +
> +	memset(dimm_location, 0, LOC_LEN);
> +	if (!(mem->validation_bits & CPER_MEM_VALID_MODULE_HANDLE))
> +		return;
> +
> +	dmi_memdev_name(mem->mem_dev_handle, &bank, &device);
> +	if (bank != NULL && device != NULL)
> +		snprintf(dimm_location, LOC_LEN - 1, "%s %s", bank, device);
> +	else
> +		snprintf(dimm_location, LOC_LEN - 1, "DMI handle: 0x%.4x",
> +			 mem->mem_dev_handle);
> +}

This one too.

> +
> +static void trace_mem_error(const uuid_le *fru_id, char *fru_text,
> +			    u64 err_count, u32 severity,
> +			    struct cper_sec_mem_err *mem)
> +{
> +	u32 etype = ~0U;
> +	u64 phy_addr = ~0ull;

I'm assuming userspace knows that all 1s means field value is invalid?

> +	unsigned long flags;
> +
> +	if (mem->validation_bits & CPER_MEM_VALID_ERROR_TYPE)
> +		etype = mem->error_type;

newline.

> +	if (mem->validation_bits & CPER_MEM_VALID_PA) {
> +		phy_addr = mem->physical_addr;
> +		if (mem->validation_bits & CPER_MEM_VALID_PA_MASK)
> +			phy_addr &= mem->physical_addr_mask;
> +	}
> +
> +	raw_spin_lock_irqsave(&trace_lock, flags);
> +	mem_err_location(mem);
> +	dimm_err_location(mem);
> +
> +	trace_extlog_mem_event(etype, dimm_location, fru_id, fru_text,
> +			       err_count, severity, phy_addr, mem_location);
> +	raw_spin_unlock_irqrestore(&trace_lock, flags);
> +}
> +
>  static struct acpi_generic_status *extlog_elog_entry_check(int cpu, int bank)
>  {
>  	int idx;
> @@ -137,7 +244,12 @@ static int extlog_print(struct notifier_block *nb, unsigned long val,
>  	struct mce *mce = (struct mce *)data;
>  	int	bank = mce->bank;
>  	int	cpu = mce->extcpu;
> -	struct acpi_generic_status *estatus;
> +	struct acpi_generic_status *estatus, *tmp;
> +	struct acpi_generic_data *gdata;
> +	const uuid_le *fru_id = &invalid_uuid;
> +	char *fru_text = "";
> +	uuid_le *sec_type;
> +	static u64 err_count;
>  	int rc;
>  
>  	estatus = extlog_elog_entry_check(cpu, bank);
> @@ -149,6 +261,23 @@ static int extlog_print(struct notifier_block *nb, unsigned long val,
>  	estatus->block_status = 0;
>  
>  	rc = print_extlog_rcd(NULL, (struct acpi_generic_status *)elog_buf, cpu);
> +	tmp = (struct acpi_generic_status *)elog_buf;
> +	gdata = (struct acpi_generic_data *)(tmp + 1);
> +	rc = print_extlog_rcd(NULL, tmp, cpu);

We probably need a mechanism to disable printking to dmesg once
userspace has opened the tracepoint.

> +	/* trace extended error log */
> +	err_count++;
> +	if (gdata->validation_bits & CPER_SEC_VALID_FRU_ID)
> +		fru_id = (uuid_le *)gdata->fru_id;
> +	if (gdata->validation_bits & CPER_SEC_VALID_FRU_TEXT)
> +		fru_text = gdata->fru_text;
> +	sec_type = (uuid_le *)gdata->section_type;
> +	if (!uuid_le_cmp(*sec_type, CPER_SEC_PLATFORM_MEM)) {
> +		struct cper_sec_mem_err *mem_err = (void *)(gdata + 1);
> +		if (gdata->error_data_length >= sizeof(*mem_err))
> +			trace_mem_error(fru_id, fru_text, err_count,
> +					gdata->error_severity, mem_err);
> +	}
>  
>  	return NOTIFY_STOP;
>  }
> diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
> index 1491dd4..9d3e2c4 100644
> --- a/drivers/firmware/efi/cper.c
> +++ b/drivers/firmware/efi/cper.c
> @@ -57,11 +57,12 @@ static const char *cper_severity_strs[] = {
>  	"info",
>  };
>  
> -static const char *cper_severity_str(unsigned int severity)
> +const char *cper_severity_str(unsigned int severity)
>  {
>  	return severity < ARRAY_SIZE(cper_severity_strs) ?
>  		cper_severity_strs[severity] : "unknown";
>  }
> +EXPORT_SYMBOL_GPL(cper_severity_str);

Yes, this calls for a common file sharin cper and extlog functionality.

>  /*
>   * cper_print_bits - print strings for set bits
> @@ -196,6 +197,13 @@ static const char *cper_mem_err_type_strs[] = {
>  	"physical memory map-out event",
>  };
>  
> +const char *cper_mem_err_type_str(unsigned int etype)
> +{
> +	return etype < ARRAY_SIZE(cper_mem_err_type_strs) ?
> +		cper_mem_err_type_strs[etype] : "unknown";
> +}
> +EXPORT_SYMBOL_GPL(cper_mem_err_type_str);
> +
>  static void cper_print_mem(const char *pfx, const struct cper_sec_mem_err *mem)
>  {
>  	if (mem->validation_bits & CPER_MEM_VALID_ERROR_STATUS)
> @@ -233,8 +241,7 @@ static void cper_print_mem(const char *pfx, const struct cper_sec_mem_err *mem)
>  	if (mem->validation_bits & CPER_MEM_VALID_ERROR_TYPE) {
>  		u8 etype = mem->error_type;
>  		printk("%s""error_type: %d, %s\n", pfx, etype,
> -		       etype < ARRAY_SIZE(cper_mem_err_type_strs) ?
> -		       cper_mem_err_type_strs[etype] : "unknown");
> +			cper_mem_err_type_str(etype));
>  	}
>  	if (mem->validation_bits & CPER_MEM_VALID_MODULE_HANDLE) {
>  		const char *bank = NULL, *device = NULL;

Ditto.

> diff --git a/include/linux/cper.h b/include/linux/cper.h
> index 2fc0ec3..c6d87fc 100644
> --- a/include/linux/cper.h
> +++ b/include/linux/cper.h
> @@ -395,6 +395,8 @@ struct cper_sec_pcie {
>  #pragma pack()
>  
>  u64 cper_next_record_id(void);
> +const char *cper_severity_str(unsigned int);
> +const char *cper_mem_err_type_str(unsigned int);
>  void cper_print_bits(const char *prefix, unsigned int bits,
>  		     const char * const strs[], unsigned int strs_size);
>  
> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
> index 21cdb0b..97f2192 100644
> --- a/include/ras/ras_event.h
> +++ b/include/ras/ras_event.h
> @@ -8,6 +8,68 @@
>  #include <linux/tracepoint.h>
>  #include <linux/edac.h>
>  #include <linux/ktime.h>
> +#include <linux/cper.h>
> +
> +/*
> + * MCE Extended Error Log trace event
> + *
> + * These events are generated when hardware detects a corrected or
> + * uncorrected event.
> + *
> + */
> +
> +/* memory trace event */
> +
> +#define LOC_LEN		512
> +
> +TRACE_EVENT(extlog_mem_event,

So this is a mem thing so we're defining a tracepoint for memory events,
specifically.

However, if extlog carries all kinds of errors outside, not only DRAM
errors, we should do a TRACE_EVENT_CLASS which contains the shared args
to every error type and then make a mem event ontop of it.

> +	TP_PROTO(u32 etype,
> +		 char *dimm_info,
> +		 const uuid_le *fru_id,
> +		 char *fru_text,
> +		 u64 error_count,
> +		 u32 severity,
> +		 u64 phy_addr,
> +		 char *mem_loc),
> +
> +	TP_ARGS(etype, dimm_info, fru_id, fru_text, error_count, severity,
> +		phy_addr, mem_loc),
> +
> +	TP_STRUCT__entry(
> +		__field(u32, etype)
> +		__dynamic_array(char, dimm_info, LOC_LEN)
> +		__field(u64, error_count)
> +		__field(u32, severity)
> +		__field(u64, paddr)
> +		__string(mem_loc, mem_loc)
> +		__dynamic_array(char, fru, LOC_LEN)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->error_count = error_count;
> +		__entry->severity = severity;
> +		__entry->etype = etype;
> +		if (dimm_info[0] != '\0')
> +			snprintf(__get_dynamic_array(dimm_info), LOC_LEN - 1,
> +				 "%s", dimm_info);
> +		else
> +			__assign_str(dimm_info, "");
> +		__entry->paddr = phy_addr;
> +		__assign_str(mem_loc, mem_loc);
> +		snprintf(__get_dynamic_array(fru), LOC_LEN - 1,
> +			 "FRU: %pUl %.20s", fru_id, fru_text);
> +	),
> +
> +	TP_printk("%llu %s error%s: %s %s physical addr: 0x%016llx%s %s",
> +		  __entry->error_count,
> +		  cper_severity_str(__entry->severity),
> +		  __entry->error_count > 1 ? "s" : "",
> +		  cper_mem_err_type_str(__entry->etype),
> +		  __get_str(dimm_info),
> +		  __entry->paddr,
> +		  __get_str(mem_loc),
> +		  __get_str(fru))
> +);
>  
>  /*
>   * Hardware Events Report
> diff --git a/kernel/trace/ras-traces.c b/kernel/trace/ras-traces.c
> index b0c6ed1..197b1ea 100644
> --- a/kernel/trace/ras-traces.c
> +++ b/kernel/trace/ras-traces.c
> @@ -9,4 +9,5 @@
>  #define TRACE_INCLUDE_PATH ../../include/ras
>  #include <ras/ras_event.h>
>  
> +EXPORT_TRACEPOINT_SYMBOL_GPL(extlog_mem_event);
>  EXPORT_TRACEPOINT_SYMBOL_GPL(mc_event);
> -- 
> 1.8.4.3
> 
> 

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--