[romprefix] Do not check for BBS compatibility

The existence and usage of the BEV entry point is covered by the PnP
spec, not the BBS spec; the BBS spec merely describes a policy for
selecting the boot device order.  iPXE should therefore check only for
a PnP BIOS in order to decide whether or not to hook INT19.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/arch/i386/prefix/romprefix.S b/src/arch/i386/prefix/romprefix.S
index c58fcdb7c35ddf6e05e9c8eabf671cd37768ad7a..c06a2e7fb9b17342918c5bd7f2a5da49909a5aef 100644 (file)
--- a/src/arch/i386/prefix/romprefix.S
+++ b/src/arch/i386/prefix/romprefix.S
@@ -14,7 +14,6 @@ FILE_LICENCE ( GPL2_OR_LATER )
 #define PMM_SIGNATURE ( '$' + ( 'P' << 8 ) + ( 'M' << 16 ) + ( 'M' << 24 ) )
 #define PCI_SIGNATURE ( 'P' + ( 'C' << 8 ) + ( 'I' << 16 ) + ( ' ' << 24 ) )
 #define STACK_MAGIC ( 'L' + ( 'R' << 8 ) + ( 'E' << 16 ) + ( 'T' << 24 ) )
-#define PNP_GET_BBS_VERSION 0x60
 #define PMM_ALLOCATE 0x0000
 #define PMM_FIND 0x0001
 #define PMM_HANDLE_BASE ( ( ( 'F' - 'A' + 1 ) << 26 ) + \
@@ -283,17 +282,8 @@ pnp_scan:
        movw    $init_message_pnp, %si
        xorw    %di, %di
        call    print_message
-       /* Check for BBS */
-       pushw   %es:0x1b        /* Real-mode data segment */
-       pushw   %ds             /* &(bbs_version) */
-       pushw   $bbs_version
-       pushw   $PNP_GET_BBS_VERSION
-       lcall   *%es:0xd
-       addw    $8, %sp
-       testw   %ax, %ax
-       je      got_bbs
-no_pnp:        /* Not PnP-compliant - therefore cannot be BBS-compliant */
-no_bbs:        /* Not BBS-compliant - must hook INT 19 */
+       jmp     pnp_done
+no_pnp:        /* Not PnP-compliant - hook INT 19 */
        movw    $init_message_int19, %si
        xorw    %di, %di
        call    print_message
@@ -304,12 +294,7 @@ no_bbs:    /* Not BBS-compliant - must hook INT 19 */
        pushw   %gs /* %gs contains runtime %cs */
        pushw   $int19_entry
        popl    %es:( 0x19 * 4 )
-       jmp     bbs_done
-got_bbs: /* BBS compliant - no need to hook INT 19 */
-       movw    $init_message_bbs, %si
-       xorw    %di, %di
-       call    print_message
-bbs_done:
+pnp_done:
 
        /* Check for PMM */
        movw    $( 0xe000 - 1 ), %bx
@@ -545,9 +530,6 @@ init_message_pci:
 init_message_pnp:
        .asciz  " PnP"
        .size   init_message_pnp, . - init_message_pnp
-init_message_bbs:
-       .asciz  " BBS"
-       .size   init_message_bbs, . - init_message_bbs
 init_message_pmm:
        .asciz  " PMM"
        .size   init_message_pmm, . - init_message_pmm
@@ -617,14 +599,6 @@ decompress_to:
        .long   0
        .size   decompress_to, . - decompress_to
 
-/* BBS version
- *
- * Filled in by BBS BIOS.  We ignore the value.
- */
-bbs_version:
-       .word   0
-       .size   bbs_version, . - bbs_version
-
 /* Boot Execution Vector entry point
  *
  * Called by the PnP BIOS when it wants to boot us.