Subject: Re: [PATCH] powerpc/le: enable RTAS events support

From: Laurent Dufour <[email-masked]>
Date: Fri, 28 Mar 2014 09:29:22 +0100

On 28/03/2014 08:33, Greg Kurz wrote:
> The current kernel code assumes big endian and parses RTAS events all
> wrong. The most visible effect is that we cannot honor EPOW events,
> meaning, for example, we cannot shut down a guest properly from the
> hypervisor.
> 
> This patch fixes that.
> 
> Signed-off-by: Greg Kurz <[email-masked]>

Reviewed-by: Laurent Dufour <[email-masked]>

> ---
>  arch/powerpc/include/asm/rtas.h      |   46 ++++++++++++++++++++++++++++++++++
>  arch/powerpc/kernel/rtas.c           |   11 ++++----
>  arch/powerpc/kernel/rtasd.c          |    8 ++++--
>  arch/powerpc/platforms/pseries/ras.c |    3 +-
>  4 files changed, 59 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
> index 9bd52c6..8bb99d0 100644
> --- a/arch/powerpc/include/asm/rtas.h
> +++ b/arch/powerpc/include/asm/rtas.h
> @@ -150,15 +150,37 @@ struct rtas_suspend_me_data {
>  #define RTAS_VECTOR_EXTERNAL_INTERRUPT	0x500
>  
>  struct rtas_error_log {
> +#ifdef __BIG_ENDIAN__
> +	/* Byte 0 */
>  	unsigned long version:8;		/* Architectural version */
> +	/* Byte 1 */
>  	unsigned long severity:3;		/* Severity level of error */
>  	unsigned long disposition:2;		/* Degree of recovery */
>  	unsigned long extended:1;		/* extended log present? */
>  	unsigned long /* reserved */ :2;	/* Reserved for future use */
> +	/* Byte 2 */
>  	unsigned long initiator:4;		/* Initiator of event */
>  	unsigned long target:4;			/* Target of failed operation */
> +	/* Byte 3 */
>  	unsigned long type:8;			/* General event or error*/
> +	/* Byte 4 */
>  	unsigned long extended_log_length:32;	/* length in bytes */
> +#else
> +	/* Byte 0 */
> +	unsigned long version:8;
> +	/* Byte 1 */
> +	unsigned long :2;
> +	unsigned long extended:1;
> +	unsigned long disposition:2;
> +	unsigned long severity:3;
> +	unsigned long target:4;

Hi Greg,

A cosmetic detail: 'target' is in the 'Byte 2'.

Laurent.

> +	/* Byte 2 */
> +	unsigned long initiator:4;
> +	/* Byte 3 */
> +	unsigned long type:8;
> +	/* Byte 4 */
> +	unsigned long extended_log_length:32;
> +#endif
>  	unsigned char buffer[1];		/* Start of extended log */
>  						/* Variable length.      */
>  };
> @@ -171,6 +193,7 @@ struct rtas_error_log {
>   * from "buffer" field of struct rtas_error_log defined above.
>   */
>  struct rtas_ext_event_log_v6 {
> +#ifdef __BIG_ENDIAN__
>  	/* Byte 0 */
>  	uint32_t log_valid:1;		/* 1:Log valid */
>  	uint32_t unrecoverable_error:1;	/* 1:Unrecoverable error */
> @@ -200,6 +223,29 @@ struct rtas_ext_event_log_v6 {
>  	uint32_t company_id;		/* Company ID of the company	*/
>  					/* that defines the format for	*/
>  					/* the vendor specific log type	*/
> +#else
> +	/* Byte 0 */
> +	uint32_t :1;
> +	uint32_t big_endian:1;
> +	uint32_t new_log:1;
> +	uint32_t predictive_error:1;
> +	uint32_t degraded_operation:1;
> +	uint32_t recoverable_error:1;
> +	uint32_t unrecoverable_error:1;
> +	uint32_t log_valid:1;
> +	/* Byte 1 */
> +	uint32_t :8;
> +	/* Byte 2 */
> +	uint32_t log_format:4;
> +	uint32_t :3;
> +	uint32_t powerpc_format:1;
> +	/* Byte 3 */
> +	uint32_t :8;
> +	/* Byte 4-11 */
> +	uint8_t reserved[8];
> +	/* Byte 12-15 */
> +	uint32_t company_id;
> +#endif
>  	/* Byte 16-end of log */
>  	uint8_t vendor_log[1];		/* Start of vendor specific log	*/
>  					/* Variable length.		*/
> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> index f386296..e18ab12 100644
> --- a/arch/powerpc/kernel/rtas.c
> +++ b/arch/powerpc/kernel/rtas.c
> @@ -993,21 +993,22 @@ struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
>  		(struct rtas_ext_event_log_v6 *)log->buffer;
>  	struct pseries_errorlog *sect;
>  	unsigned char *p, *log_end;
> +	uint32_t extended_log_length = be32_to_cpu(log->extended_log_length);
>  
>  	/* Check that we understand the format */
> -	if (log->extended_log_length < sizeof(struct rtas_ext_event_log_v6) ||
> +	if (extended_log_length < sizeof(struct rtas_ext_event_log_v6) ||
>  	    ext_log->log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
> -	    ext_log->company_id != RTAS_V6EXT_COMPANY_ID_IBM)
> +	    be32_to_cpu(ext_log->company_id) != RTAS_V6EXT_COMPANY_ID_IBM)
>  		return NULL;
>  
> -	log_end = log->buffer + log->extended_log_length;
> +	log_end = log->buffer + extended_log_length;
>  	p = ext_log->vendor_log;
>  
>  	while (p < log_end) {
>  		sect = (struct pseries_errorlog *)p;
> -		if (sect->id == section_id)
> +		if (be16_to_cpu(sect->id) == section_id)
>  			return sect;
> -		p += sect->length;
> +		p += be16_to_cpu(sect->length);
>  	}
>  
>  	return NULL;
> diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c
> index 1130c53..1987825 100644
> --- a/arch/powerpc/kernel/rtasd.c
> +++ b/arch/powerpc/kernel/rtasd.c
> @@ -159,14 +159,16 @@ static int log_rtas_len(char * buf)
>  {
>  	int len;
>  	struct rtas_error_log *err;
> +	uint32_t extended_log_length;
>  
>  	/* rtas fixed header */
>  	len = 8;
>  	err = (struct rtas_error_log *)buf;
> -	if (err->extended && err->extended_log_length) {
> +	extended_log_length = be32_to_cpu(err->extended_log_length);
> +	if (err->extended && extended_log_length) {
>  
>  		/* extended header */
> -		len += err->extended_log_length;
> +		len += extended_log_length;
>  	}
>  
>  	if (rtas_error_log_max == 0)
> @@ -298,7 +300,7 @@ static void handle_rtas_event(const struct rtas_error_log *log)
>  		 * the scope for calling rtas update-nodes.
>  		 */
>  		if (prrn_is_enabled())
> -			prrn_schedule_update(log->extended_log_length);
> +			prrn_schedule_update(be32_to_cpu(log->extended_log_length));
>  	}
>  
>  	return;
> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
> index 721c058..39e7557 100644
> --- a/arch/powerpc/platforms/pseries/ras.c
> +++ b/arch/powerpc/platforms/pseries/ras.c
> @@ -306,7 +306,8 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
>  	} else {
>  		int len;
>  
> -		len = max_t(int, 8+h->extended_log_length, RTAS_ERROR_LOG_MAX);
> +		len = max_t(int, 8+be32_to_cpu(h->extended_log_length),
> +			    RTAS_ERROR_LOG_MAX);
>  		memset(global_mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
>  		memcpy(global_mce_data_buf, h, len);
>  		errhdr = (struct rtas_error_log *)global_mce_data_buf;
> 
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