UFM(4D) 4D UFM(4D)


ufm - Upgradeable Firmware Module driver



#include <sys/ddi_ufm.h>


The ufm device is a character special file that provides access to
Upgradeable Firmware Image information, as described in ddi_ufm(9E) via a
private ioctl interface.

The UFM interfaces described below are used in the implementation of the
system through tools such as fwflash(8) or as part of the fault management


/kernel/drv/amd64/ufm 64-bit AMD64 ELF kernel driver

/kernel/drv/sparcv9/ufm 64-bit SPARC ELF kernel driver


The ufm driver implements a versioned ioctl interface for accessing UFM
facilities. The ioctl interfaces are defined in sys/ddi_ufm.h. The
following ioctl cmds are supported by DDI_UFM_VERSION_ONE:

The UFM_IOC_GETCAPS ioctl is used to retrieve the set of DDI
UFM capabilities supported by this device instance.

The ddi_ufm_cap_t type defines a bitfield enumerating the
full set of DDI UFM capabilities.

typedef enum {
} ddi_ufm_cap_t;

The capabilities mean:

Indicates that the device is capable of
reporting UFM information and supports the

Indicates that the device is capable of
retrieving a firmware image from a slot and
transferring it back to the caller. The
UFM_IOC_READIMG ioctl is supported.

The ufm_ioc_getcaps_t structure defines the input/output data
for the UFM_IOC_GETCAPS ioctl. Callers should specify the
ufmg_version and ufmg_devpath fields. On success the
ufmg_caps field will be filled in with a value indicating the
supported UFM capabilities of the device specified in

typedef struct ufm_ioc_getcaps {
uint_t ufmg_version; /* DDI_UFM_VERSION_ONE */
uint_t ufmg_caps; /* UFM Caps */
char ufmg_devpath[MAXPATHLEN];
} ufm_ioc_getcaps_t;

The UFM_IOC_REPORTSZ ioctl is used to retrieve the amount of
space (in bytes) required to hold the UFM data for this
device instance. This should be used to allocate a
sufficiently sized buffer for the UFM_IOC_REPORT ioctl.

The ufm_ioc_bufsz_t structure defines the input/output data
for the UFM_IOC_REPORTSZ ioctl. Callers should specify the
ufbz_version and ufbz_devpath fields. On success the
ufbz_size field will be filled in with the required buffer

typedef struct ufm_ioc_bufsz {
uint_t ufbz_version; /* DDI_UFM_VERSION_ONE */
size_t ufbz_size; /* sz of buf to be returned by ioctl */
char ufbz_devpath[MAXPATHLEN];
} ufm_ioc_bufsz_t;

The UFM_IOC_REPORT ioctl returns UFM image and slot data in
the form of a packed nvlist. The ufm_ioc_report_t structure
defines the input/output data for the UFM_IOC_REPORT ioctl.
Callers should specify the ufmr_version, ufmr_bufsz and
ufmr_devpath fields. On success, the ufmr_buf field will
point to a packed nvlist containing the UFM data for the
specified device instance. This data can be unpacked and
decoded into an nvlist using nvlist_unpack(3NVPAIR).

typedef struct ufm_ioc_report {
uint_t ufmr_version; /* DDI_UFM_VERSIONONE */
size_t ufmr_bufsz; /* size of caller-supplied buffer */
caddr_t ufmr_buf; /* buf to hold packed output nvl */
char ufmr_devpath[MAXPATHLEN];
} ufm_ioc_report_t;

Due to the asynchronous nature of the system, it's possible
for a device to undergo a configuration change in between a
UFM_IOC_REPORTSZ ioctl and a subsequent UFM_IOC_REPORT ioctl
that would alter the size of the buffer required to hold the
UFM data.

If the size of buffer supplied in the UFM_IOC_REPORT ioctl is
greater than is required to hold the UFM data, then the ioctl
will succeed and the ufmr_bufsz field will be updated to
reflect the actual size of the returned UFM data. If the
size of buffer supplied in the UFM_IOC_REPORT ioctl is less
than what is required to hold the UFM data, the ioctl will
fail with errno set to EOVERFLOW.

The UFM_IOC_READIMG ioctl retrieves a firmware image and slot
from a device. The ufm_ioc_readimg_t structure defines the
input and output data for the ioctl. Devices may have their
own alignment and size constraints which may be enforced upon
issuing this ioctl. The structure has the following form:

typedef struct ufm_ioc_readimg {
uint_t ufri_version;
uint_t ufri_imageno;
uint_t ufri_slotno;
uint64_t ufri_offset;
uint64_t ufri_len;
uint64_t ufri_nread;
void *ufri_buf;
char ufri_devpath[MAXPATHLEN];
} ufm_ioc_readimg_t;

The ufri_imageno and ufri_slotno values are used to indicate
the image and slot to read. These indexes correspond to the
same indices that are returned in the nvlist from the
UFM_IOC_REPORT ioctl. The ufri_offset and ufri_len members
are used to indicate how many bytes to read from the image
and where in the image to begin. The ufri_buf member must be
set to a valid pointer. Data read from the device will be
placed in that pointer. The pointer must be at least
ufri_len bytes long. Upon successful completion, the
ufri_nread member will be filled in with the number of bytes
that have been placed in ufri_buf. Finally, the ufri_version
and ufri_devpath fields must be filled in with the version
number, DDI_UFM_VERSION_ONE, and the corresponding /devices


This example demonstrates how to use the UFM_IOC_GETCAPS ioctl to determine
the UFM capabilities of a given device instance.

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <sys/ddi_ufm.h>
#include <sys/types.h>

static const char devname[] = "/pci@ce,0/pci8086,2030@0/pci15d9,808@0";

main(int argc, char **argv)
int fd;
ufm_ioc_getcaps_t ioc = { 0 };

if ((fd = open(DDI_UFM_DEV, O_RDWR)) < 0) {
(void) fprintf(stderr, "failed to open %s (%s)0, DDI_UFM_DEV,
return (1);

ioc.ufmg_version = DDI_UFM_CURRENT_VERSION;
(void) strcpy(ioc.ufmg_devpath, devname);

if (ioctl(fd, UFM_IOC_GETCAPS, &ioc) < 0) {
(void) fprintf(stderr, "getcaps ioctl failed (%s)0,
(void) close(fd);
return (1);
if ((ioc.ufmg_caps & DDI_UFM_CAP_REPORT) == 0) {
(void) printf("Driver does not support DDI_UFM_CAP_REPORT0);
} else {
(void) printf("Driver supports DDI_UFM_CAP_REPORT0);
(void) close(fd);
return (0);


On failure to open or perform ioctls to the ufm driver, errno will be set
to indicate the type of error. A subset of the more common errors are
detailed below. For a full list of error numbers, see Intro(2)

EAGAIN The device driver is not currently ready to accept calls
to it's DDI UFM entry points. This may be because the
driver is not fully initialized or because the driver is
in the process of detaching.

EFAULT The ufm driver encountered a failure while copying data
either from or to the address space of the calling

EINVAL The offset or length of an image would have resulted in
a read outside of the image's valid range or with
improper alignment.

EIO A failure occurred while executing a DDI UFM entry

ENOTSUP Either the requested ioctl is not supported by the
target device, the device does not exist or the device
does not support the UFM interfaces.




ddi_ufm(9E), ddi_ufm(9F), ddi_ufm_image(9F), ddi_ufm_slot(9F)

OmniOS May 23, 2021 OmniOS