NAME

ddi_mmap_get_model - return data model type of current thread

SYNOPSIS

#include <sys/ddi.h>
#include <sys/sunddi.h>
uint_t ddi_mmap_get_model(void);

INTERFACE LEVEL

illumos DDI specific (illumos DDI).

DESCRIPTION

ddi_mmap_get_model() returns the C Language Type Model which the current thread expects. ddi_mmap_get_model() is used in combination with ddi_model_convert_from(9F) in the mmap(9E) driver entry point to determine whether there is a data model mismatch between the current thread and the device driver. The device driver might have to adjust the shape of data structures before exporting them to a user thread which supports a different data model.

RETURN VALUES

DDI_MODEL_ILP32

Current thread expects 32-bit (ILP32) semantics.

DDI_MODEL_LP64

Current thread expects 64-bit (LP64) semantics.

DDI_FAILURE

The ddi_mmap_get_model() function was not called from the mmap(9E) entry point.

CONTEXT

The ddi_mmap_get_model() function can only be called from the mmap(9E) driver entry point.

EXAMPLES

Example 1 : Using ddi_mmap_get_model()

The following is an example of the mmap(9E) entry point and how to support 32-bit and 64-bit applications with the same device driver.

struct data32 {


        int len;


        caddr32_t addr;
};
struct data {


        int len;


        caddr_t addr;
};
xxmmap(dev_t dev, off_t off, int prot) {


        struct data dtc; /* a local copy for clash resolution */


        struct data *dp = (struct data *)shared_area;


        switch (ddi_model_convert_from(ddi_mmap_get_model())) {


        case DDI_MODEL_ILP32:


        {


                struct data32 *da32p;


                da32p = (struct data32 *)shared_area;


                dp = &dtc;


                dp->len = da32p->len;


                dp->address = da32->address;


                break;


        }


        case DDI_MODEL_NONE:


                break;


        }


        /* continues along using dp */


       ...
}