ddi_model_convert_from(9F)

NAME

     ddi_model_convert_from - determine data model type mismatch

SYNOPSIS

     #include <sys/ddi.h>
     #include <sys/sunddi.h>

      uint_tddi_model_convert_from(uint_t model);

INTERFACE LEVEL

     Solaris DDI specific (Solaris DDI).

PARAMETERS

     model The data model type of the current thread.

DESCRIPTION

     ddi_model_convert_from() is used to determine if the current
     thread  uses a different C Language Type Model than the dev-
     ice driver. The 64-bit version of  Solaris  will  require  a
     64-bit  kernel  to  support both 64-bit and 32-bit user mode
     programs. The difference between a 32-bit program and a  64-
     bit  program  is in its C Language Type Model: a 32-bit pro-
     gram is ILP32 (integer, longs, and pointers are 32-bit)  and
     a  64-bit  program  is LP64 (longs and pointers are 64-bit).
     There are a number of driver entry points such as  ioctl(9E)
     and  mmap(9E)  where  it  is  necessary  to  identify  the C
     Language Type Model of the user-mode originator of an kernel
     event. For example any data which flows between programs and
     the device driver or vice versa need to be identical in for-
     mat. A 64-bit device driver may need to modify the format of
     the  data  before  sending  it  to  a  32-bit   application.
     ddi_model_convert_from()  is  used to determine if data that
     is passed between the  device  driver  and  the  application
     requires reformatting to any non-native data model.

RETURN VALUES

     DDI_MODEL_ILP32
           A conversion to/from ILP32 is necessary.

     DDI_MODEL_NONE
           No conversion is necessary. Current thread and  driver
           use the same data model.

CONTEXT

     ddi_model_convert_from() can be called from any context.

EXAMPLES

     Example 1: : Using ddi_model_convert_from() in  the  ioctl()
     entry point to support both 32-bit and 64-bit applications.

     The    following    is    an    example    how    to     use
     ddi_model_convert_from()  in  the  ioctl()  entry  point  to
     support both 32-bit and 64-bit applications.

     struct passargs32 {
             int len;
             caddr32_t addr;
     };

     struct passargs {
             int len;
             caddr_t addr;
     };
     xxioctl(dev_t dev, int cmd, intptr_t arg, int mode,
         cred_t *credp, int *rvalp) {
             struct passargs pa;

             switch (ddi_model_convert_from(mode & FMODELS)) {
                 case DDI_MODEL_ILP32:
                 {
                     struct passargs32 pa32;

                     ddi_copyin(arg, &pa32, sizeof (struct passargs32), mode);
                     pa.len = pa32.len;
                     pa.address = pa32.address;
                     break;
                 }
                 case DDI_MODEL_NONE:
                     ddi_copyin(arg, &pa, sizeof (struct passargs), mode);
                     break;
             }

             do_ioctl(&pa);
             ....
     }

SEE ALSO

     ioctl(9E), mmap(9E), ddi_mmap_get_model(9F)

     Writing Device Drivers