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From: Xuelin Shi <xuelin.shi@freescale.com>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] librte_lpm: define tbl entry reversely for big endian
Date: Thu, 5 Mar 2015 02:12:12 +0000
Message-ID: <CY1PR0301MB0684CE6F8F332B4F7DD45089861F0@CY1PR0301MB0684.namprd03.prod.outlook.com> (raw)
In-Reply-To: <20150304104815.GF1468@bricha3-MOBL3>

Hi Bruce,

Yes, it needs to swap the fields. The bit field is first identified as the uint8_t and then packed.

Thanks,
Shi xuelin

> -----Original Message-----
> From: Bruce Richardson [mailto:bruce.richardson@intel.com]
> Sent: Wednesday, March 04, 2015 18:48
> To: Shi Xuelin-B29237
> Cc: thomas.monjalon@6wind.com; dev@dpdk.org
> Subject: Re: [PATCH] librte_lpm: define tbl entry reversely for big
> endian
> 
> On Wed, Mar 04, 2015 at 02:34:12PM +0800, xuelin.shi@freescale.com wrote:
> > From: Xuelin Shi <xuelin.shi@freescale.com>
> >
> > This module uses type conversion between struct and int.
> > Also truncation and comparison is used with this int.
> > It is not safe for different endian arch.
> >
> > Add ifdef for big endian struct to fix this issue.
> >
> > Signed-off-by: Xuelin Shi <xuelin.shi@freescale.com>
> > ---
> >  lib/librte_lpm/rte_lpm.h | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/lib/librte_lpm/rte_lpm.h b/lib/librte_lpm/rte_lpm.h index
> > 1af150c..08a2859 100644
> > --- a/lib/librte_lpm/rte_lpm.h
> > +++ b/lib/librte_lpm/rte_lpm.h
> > @@ -96,6 +96,7 @@ extern "C" {
> >  /** Bitmask used to indicate successful lookup */
> >  #define RTE_LPM_LOOKUP_SUCCESS          0x0100
> >
> > +#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
> >  /** @internal Tbl24 entry structure. */  struct rte_lpm_tbl24_entry {
> >  	/* Stores Next hop or group index (i.e. gindex)into tbl8. */ @@
> > -117,6 +118,24 @@ struct rte_lpm_tbl8_entry {
> >  	uint8_t valid_group :1; /**< Group validation flag. */
> >  	uint8_t depth       :6; /**< Rule depth. */
> >  };
> > +#else
> > +struct rte_lpm_tbl24_entry {
> > +	uint8_t depth 	    :6;
> > +	uint8_t ext_entry   :1;
> > +	uint8_t valid	    :1;
> 
> Since endianness only refers to the order of bytes within a word, do the
> bitfields within the uint8_t really need to be swapped around too?
> 
> /Bruce

> 
> > +	union {
> > +		uint8_t tbl8_gindex;
> > +		uint8_t next_hop;
> > +	};
> > +};
> > +
> > +struct rte_lpm_tbl8_entry {
> > +	uint8_t depth 	    :6;
> > +	uint8_t valid_group :1;
> > +	uint8_t valid	    :1;
> > +	uint8_t next_hop;
> > +};
> > +#endif
> >
> >  /** @internal Rule structure. */
> >  struct rte_lpm_rule {
> > --
> > 1.9.1
> >

  reply	other threads:[~2015-03-05  2:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-04  6:34 xuelin.shi
2015-03-04 10:48 ` Bruce Richardson
2015-03-05  2:12   ` Xuelin Shi [this message]
2015-03-06 11:13     ` Bruce Richardson
2015-03-09  1:54       ` Xuelin Shi
2015-03-09  9:12         ` Mcnamara, John
2015-03-09  9:35           ` Xuelin Shi
2015-03-09 14:04           ` Thomas Monjalon
2015-03-09 14:02 ` Bruce Richardson
2015-03-23 14:03   ` Thomas Monjalon
2015-03-24  7:28     ` Xuelin Shi

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