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NAME

     bios_sigsearch, bios32_SDlookup, bios32, bios_oem_strings — interact with PC BIOS

SYNOPSIS

     #include <sys/param.h>
     #include <vm/vm.h>
     #include <vm/pmap.h>
     #include <machine/param.h>
     #include <machine/pmap.h>
     #include <machine/pc/bios.h>

     u_int32_t
     bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen, int sigofs);

     int
     bios32_SDlookup(struct bios32_SDentry *ent);

     int
     bios32(struct bios_regs *br, u_int offset, u_short segment);

     BIOS_PADDRTOVADDR(addr);

     BIOS_VADDRTOPADDR(addr);

     extern struct bios32_SDentry PCIbios;
     extern struct SMBIOS_table SMBIOStable;
     extern struct DMI_table DMItable;

     int
     bios_oem_strings(struct bios_oem *oem, u_char *buffer, size_t maxlen);

     struct bios_oem_signature {
             char * anchor;          /* search anchor string in BIOS memory */
             size_t offset;          /* offset from anchor (may be negative) */
             size_t totlen;          /* total length of BIOS string to copy */
     };
     struct bios_oem_range {
             u_int from;             /* shouldn't be below 0xe0000 */
             u_int to;               /* shouldn't be above 0xfffff */
     };
     struct bios_oem {
             struct bios_oem_range range;
             struct bios_oem_signature signature[];
     };

DESCRIPTION

     These functions provide a general-purpose interface for dealing with the BIOS functions and
     data encountered on x86 PC-architecture systems.

     bios_sigsearch()      Searches the BIOS address space for a service signature, usually an
                           uppercase ASCII sequence surrounded by underscores.  The search begins
                           at start, or at the beginning of the BIOS if start is zero.  siglen
                           bytes of the BIOS image and sig are compared at sigofs bytes offset
                           from the current location.  If no match is found, the current location
                           is incremented by paralen bytes and the search repeated.  If the
                           signature is found, its effective physical address is returned.  If no
                           signature is found, zero is returned.

     bios_oem_strings()    Searches a given BIOS memory range for one or more strings, and
                           composes a printable concatenation of those found.  The routine
                           expects a structure describing the BIOS address range (within 0xe0000
                           - 0xfffff), and a { NULL, 0, 0 } -terminated array of
                           bios_oem_signature structures which define the anchor string, an
                           offset from the beginning of the match (which may be negative), and
                           totlen number of bytes to be collected from BIOS memory starting at
                           that offset.  Unmatched anchors are ignored, whereas matches are
                           copied from BIOS memory starting at their corresponding offset with
                           unprintable characters being replaced with space, and consecutive
                           spaces being suppressed.  This composed string is stored in buffer up
                           to the given maxlen bytes (including trailing ‘\0’, and any trailing
                           space surpressed).  If an error is encountered, i.e. trying to read
                           out of said BIOS range, other invalid input, or buffer overflow, a
                           negative integer is returned, otherwise the length of the composed
                           string is returned.  In particular, a return value of 0 means that
                           none of the given anchor strings were found in the specified BIOS
                           memory range.

     BIOS_VADDRTOPADDR()   Returns the effective physical address which corresponds to the kernel
                           virtual address addr.

     BIOS_PADDRTOVADDR()   Returns the kernel virtual address which corresponds to the effective
                           physical address addr.

     SMBIOStable           If not NULL, points to a struct SMBIOS_table structure containing
                           information read from the System Management BIOS table during system
                           startup.

     DMItable              If not NULL, points to a struct DMI_table structure containing
                           information read from the Desktop Management Interface parameter table
                           during system startup.

BIOS32

     At system startup, the BIOS is scanned for the BIOS32 Service Directory (part of the PCI
     specification), and the existence of the directory is recorded.  This can then be used to
     locate other services.

     bios32_SDlookup()     Attempts to locate the BIOS32 service matching the 4-byte identifier
                           passed in the ident field of the ent argument.

     bios32()              Calls a bios32 function.  This presumes that the function is capable
                           of working within the kernel segment (normally the case).  The virtual
                           address of the entrypoint is supplied in entry and the register
                           arguments to the function are supplied in args.

     PCIbios               If not NULL, points to a struct bios32_SDentry structure describing
                           the PCI BIOS entrypoint which was found during system startup.