DDI_MMAP_GET_MODEL(9F) Kernel Functions for Drivers DDI_MMAP_GET_MODEL(9F)

ddi_mmap_get_model - return data model type of current thread

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

illumos DDI specific (illumos DDI).

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.

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.

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

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 */
       ...
}

mmap(9E), ddi_model_convert_from(9F)

Writing Device Drivers

February 8, 2001 OmniOS