man pages section 9: DDI and DKI Kernel Functions

ddi_mmap_get_model(9F)

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

Solaris DDI specific (Solaris 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 */
       …
}