RE: [PATCH v1] kdd: remove zero-length arrays

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Christopher Clark <christopher.w.clark@xxxxxxxxx>
> Sent: 16 June 2020 21:50
> To: Olaf Hering <olaf@xxxxxxxxx>
> Cc: Tim Deegan <tim@xxxxxxx>; xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>; Ian 
> Jackson
> <ian.jackson@xxxxxxxxxxxxx>; Wei Liu <wl@xxxxxxx>; paul@xxxxxxx
> Subject: Re: [PATCH v1] kdd: remove zero-length arrays
> 
> On Thu, Jun 11, 2020 at 12:12 PM Olaf Hering <olaf@xxxxxxxxx> wrote:
> >
> > Am Wed, 10 Jun 2020 20:16:57 +0100
> > schrieb Tim Deegan <tim@xxxxxxx>:
> >
> > > How tedious.
> >
> > Indeed. This compiles for me as well:
> 
> just a nudge on this; it would be nice to get a patch into the tree
> since the build failure affects master builds of Xen in OpenEmbedded
> now.
> 

I'd be happy to take a patch into 4.14 if someone can provide one with a 
suitable maintainer ack.

  Paul

> Christopher
> 
> >
> > --- orig/kdd.h  2020-06-08 17:40:05.000000000 +0000
> > +++ kdd.h       2020-06-11 19:00:44.234364040 +0000
> > @@ -68,7 +68,6 @@
> >      uint16_t len;     /* Payload length, excl. header and trailing byte */
> >      uint32_t id;      /* Echoed in responses */
> >      uint32_t sum;     /* Unsigned sum of all payload bytes */
> > -    uint8_t payload[0];
> >  } PACKED kdd_hdr;
> >
> >  #define KDD_PKT_CMD 0x0002      /* Debugger commands (and replies to them) 
> > */
> > @@ -323,7 +322,7 @@
> >          kdd_msg msg;
> >          kdd_reg reg;
> >          kdd_stc stc;
> > -        uint8_t payload[0];
> > +        uint8_t payload[65536];
> >      };
> >  } PACKED kdd_pkt;
> >
> > --- orig/kdd.c  2020-06-08 17:40:05.000000000 +0000
> > +++ kdd.c       2020-06-11 19:08:36.775724640 +0000
> > @@ -79,11 +79,11 @@
> >  /* State of the debugger stub */
> >  typedef struct {
> >      union {
> > -        uint8_t txb[sizeof (kdd_hdr) + 65536];   /* Marshalling area for 
> > tx */
> > +        uint8_t txb[sizeof (kdd_hdr) + 0xffff];   /* Marshalling area for 
> > tx */
> >          kdd_pkt txp;                 /* Also readable as a packet 
> > structure */
> >      };
> >      union {
> > -        uint8_t rxb[sizeof (kdd_hdr) + 65536];   /* Marshalling area for 
> > rx */
> > +        uint8_t rxb[sizeof (kdd_hdr)];   /* Marshalling area for rx */
> >          kdd_pkt rxp;                 /* Also readable as a packet 
> > structure */
> >      };
> >      unsigned int cur;       /* Offset into rx where we'll put the next 
> > byte */
> >
> > Olaf