The info member

When the IPL code detects system features (e.g., amount of memory installed, current time, information about the bus used on the system, etc.), it stores this information in the info array so that the startup code can retrieve it later. This design saves the startup code from repeating the same detection logic as the IPL. The startup_info* structures and enumerated types include:

startup_info_hdr, startup_info_types, startup_info_skip, startup_info_mem and startup_info_mem_extended, startup_info_disk, startup_info_time, startup_info_box, bootargs_entry, startup_trailer

startup_info_hdr

The info member is declared as an array of _Uint32t fields. This declaration allocates a storage area that contains a set of structures, each beginning with a startup_info_hdr header:

struct startup_info_hdr {
    _Uint16t        type;
    _Uint16t        size;
};

startup_info_types

enum startup_info_types {
    STARTUP_INFO_SKIP = 0,	/* If size 0 then end of list */
    STARTUP_INFO_MEM,
    STARTUP_INFO_DISK,
    STARTUP_INFO_TIME,
    STARTUP_INFO_BOX,
    STARTUP_INFO_USER = 0x8000	/* User reserved numbers start here */
};

The startup_info_hdr enumerated types include:

STARTUP_INFO_SKIP

Ignore this field. If the corresponding size member is 0, this is the end of the info list.

STARTUP_INFO_MEM

A startup_info_mem or startup_info_mem_extended structure is present.

STARTUP_INFO_DISK

A startup_info_disk structure is present.

STARTUP_INFO_TIME

A startup_info_time structure is present.

STARTUP_INFO_BOX

A startup_info_box structure is present.

startup_info_skip

This structure is used to indicate the end of the info list; it stores no extra information.

struct startup_info_skip {
    struct startup_info_hdr hdr;
};

startup_info_mem and startup_info_mem_extended

These structures each contain an address and size pair defining a chunk of memory that should be added to procnto's free memory pool.

struct startup_info_mem {
    struct startup_info_hdr hdr;
    _Uint32t                addr;
    _Uint32t                size;
};

The addr and size fields are 32 bits long, so memory is limited to 4 GB. For larger memory blocks, the startup_info_mem_extended structure is used:

struct startup_info_mem_extended {
    struct startup_info_mem mem;
    _Uint32t            addr_hi;
    _Uint32t            size_hi;
};

For the extended structure, you can determine the address and size from the addr_hi and size_hi members and the encapsulated startup_info_mem structure as follows:

((paddr64_t) addr_hi << 32) | mem.addr
((paddr64_t) size_hi << 32) | mem.size

startup_info_disk

The startup_info_disk structure contains information about any hard disks detected. It is defined as follows:

struct startup_info_disk {
    struct startup_info_hdr hdr;
    _Uint8t                 drive;
    _Uint8t                 zero;
    _Uint16t                heads;
    _Uint16t                cylinders;
    _Uint16t                sectors;
    _Uint32t                blocks;
};

startup_info_time

The startup_info_time structure contains a record of the system's most recent startup time. It is defined as follows:

struct startup_info_time {
    struct startup_info_hdr hdr;
    _Uint32t                time;
};

startup_info_box

struct startup_info_box {
    struct startup_info_hdr hdr;
    _Uint8t                 boxtype;
    _Uint8t                 bustype;
    _Uint8t                 spare[2];
};

bootargs_entry

struct bootargs_entry {
    _Uint8t     size_lo;    /* Includes entire structure */
    _Uint8t     size_hi;
    _Int8t      argc;
    _Int8t      envc;
    _Uint32t    shdr_addr;
    char        args[1];    /* variable length */
};

startup_trailer

The startup_trailer structure contains a checksum for the startup_header structure, calculated from the start of the header to the start of the trailer (this structure). It is defined as follows:

struct startup_trailer {
    unsigned long   cksum;
};