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;
};


Member	Type	Description
`type`	_Uint16t	One of the startup_info_types enumerated values (see startup_info_types below)
`size`	_Uint16t	Size of the current startup_info_* structure, in bytes

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.

The startup_info_mem structure is defined as follows:

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


Member	Type	Description
startup_info_hdr	struct	Standard `info` array header structure
`addr`	_Uint32t	Memory block start address
`size`	_Uint32t	Memory block size, in bytes

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;
};


Member	Type	Description
startup_info_mem	struct	The structure for memory blocks that are less than 4 GB
`addr_hi`	_Uint32t	High portion of the memory address (see below)
`size_hi`	_Uint32t	High portion of the memory size (see below)

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

Note:

More than one startup_info_mem or startup_info_mem_extended structure may be present to accommodate systems that have free memory located in various blocks throughout the address space. Both structures are identified by a type member of STARTUP_INFO_MEM in the startup_info_hdr structure; use the size field in the header to tell them apart.

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;
};


Member	Type	Description
startup_info_hdr	struct	Standard `info` array header structure
`drive`	_Uint8t	Drive number
`zero`	_Uint8t	Reserved; must be zero
`heads`	_Uint16t	Number of heads present
`cylinders`	_Uint16t	Number of cylinders present
`sectors`	_Uint16t	Number of sectors present
`blocks`	_Uint32t	Total block size of device. Assuming 512 bytes per block, the total size is calculated as `heads` × `cylinders` × `sectors`.

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;
};


Member	Type	Description
startup_info_hdr	struct	Standard `info` array header structure
`time`	_Uint32t	Current time as the number of seconds since 1970 01 01 00:00:00 GMT.

startup_info_box

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


Member	Type	Description
startup_info_hdr	struct	Standard `info` array header structure
`boxtype`	_Uint8t
`bustype`	_Uint8t
`spare[2]`	_Uint8t	Reserved, must be zero

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 */
};


Member	Type	Description
`size_lo`	_Uint8t
`size_hi`	_Uint8t
`argc`	_Int8t
`envc`	_Int8t
`shdr_addr`	_Uint32t
`args[1]`	char

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;
};


Member	Type	Description
`cksum`	_Uint32t	Checksum from start of header to start of trailer