Cut out almost all the optional code paths, drastically simplifying the

flow of control through this code.

We now always add PCI and PnP headers even for ISA ROMs; there's no harm
in doing so.

UNDI loader is still missing.

diff --git a/src/arch/i386/prefix/romprefix.S b/src/arch/i386/prefix/romprefix.S
index 4a5bd2e..ced0f49 100644 (file)
--- a/src/arch/i386/prefix/romprefix.S
+++ b/src/arch/i386/prefix/romprefix.S
@@ -6,412 +6,180 @@
  * table so using a noticeable amount of stack space is a no-no.
  */
 
  * table so using a noticeable amount of stack space is a no-no.
  */
 

-/* Define DELAYED_INT when NO_DELAYED_INT is not defined.
- * This allows positive tests instead of tests that contain
- * double negatives, and become confusing.
- */
-#ifndef NO_DELAYED_INT
-#define DELAYED_INT
-#endif
-
-/* We need some unique magic ID, if we defer startup thru the INT18H or INT19H
- * handler. This way, we can check if we have already been installed.
- */
-#ifndef MAGIC
-#define MAGIC          0xE44C
-#endif
-
-/* Hook into INT18H or INT19H handler */
-#ifdef BOOT_INT18H
-#define BOOT_INT       0x18
-#else
-#define BOOT_INT       0x19
-#endif
-
-#define BOOT_INT_VEC   BOOT_INT*4
-#define SCRATCHVEC     0x300
-
-/* Prefix exit codes.  We store these on the stack so that we will
- * know how to return control to the BIOS when Etherboot exits.
- */
-#define EXIT_VIA_LRET                  0x0
-#define EXIT_VIA_INT_18                0x1
-#define EXIT_VIA_BOOT_INT      0x2
-

        .text
        .code16
        .arch i386
        .text
        .code16
        .arch i386

-       .org 0

        .section ".prefix", "ax", @progbits
        .section ".prefix", "ax", @progbits

-_prefix: 
-       .word 0xAA55                    /* BIOS extension signature */
-size:  .byte 0                         /* number of 512 byte blocks */
-                                       /* = number of 256 word blocks */
-                                       /* filled in by makerom program */
-       jmp     over                    /* skip over checksum */
-       .byte 0                         /* checksum */
-       jmp     legacyentry             /* alternate entry point +6 */
-                                       /* used by mknbi-rom */
-
-#ifdef PCI_PNP_HEADER
-mfgstr:
-       .asciz  "Etherboot"

        
        

-#ifdef PXE_EXPORT
+       .org    0x00
+romheader:
+       .word   0xAA55                  /* BIOS extension signature */
+       .byte   _rom_size               /* Size in 512-byte blocks */
+       jmp     init_vector             /* Initialisation vector */

        .org    0x16
        .org    0x16

-       .word   UNDIROMID - _prefix
-#endif /* PXE_EXPORT */
-       
+       .word   undiheader

        .org    0x18
        .org    0x18

-       .word   PCI - _prefix
-       .word   PnP - _prefix
-
-PCI: 
-       .ascii  "PCIR"
-       .word 0x0000                    /* vendor ID, filled in by makerom */
-       .word 0x0000                    /* device ID, filled in by makerom */
-       .word 0x0000                    /* pointer to vital product data */
-       .word 0x0018                    /* PCI data structure length */
-       .byte 0x00                      /* PCI data structure revision */
-       .byte 0x02                      /* Device Base Type code */
-       .byte 0x00                      /* Device Sub-Type code */
-       .byte 0x00                      /* Device Interface Type code */
-       .word 0x0000                    /* Image length same as offset 02h */
-       .word 0x0001                    /* revision level of code/data */
-       .byte 0x00                      /* code type */
-       .byte 0x80                      /* indicator (last PCI data structure) */
-       .word 0x0000                    /* reserved */
+       .word   pciheader
+       .org    0x1a
+       .word   pnpheader
+       .size romheader, . - romheader
+
+pciheader:
+       .ascii  "PCIR"                  /* Signature */
+       .word   pci_vendor_id           /* Vendor ID */ 
+       .word   pci_device_id           /* Device ID */
+       .word   0x0000                  /* pointer to vital product data */
+       .word   pciheader_len           /* PCI data structure length */
+       .byte   0x00                    /* PCI data structure revision */
+       .byte   0x02                    /* Device Base Type code */
+       .byte   0x00                    /* Device Sub-Type code */
+       .byte   0x00                    /* Device Interface Type code */
+       .word   _rom_size               /* Image length same as offset 02h */
+       .word   0x0001                  /* revision level of code/data */
+       .byte   0x00                    /* code type */
+       .byte   0x80                    /* Flags (last PCI data structure) */
+       .word   0x0000                  /* reserved */
+       .equ pciheader_len, . - pciheader
+       .size pciheader, . - pciheader
+
+pnpheader:
+       .ascii  "$PnP"                  /* Signature */
+       .byte   0x01                    /* Structure revision */
+       .byte   ( pnpheader_len / 16 )  /* Length (in 16 byte increments) */
+       .word   0x0000                  /* Offset of next header */
+       .byte   0x00                    /* Reserved */
+       .byte   0x00                    /* Checksum */
+       .long   0x00000000              /* Device identifier */
+       .word   mfgstr                  /* Manufacturer string */
+       .word   prodstr                 /* Product name */
+       .byte   0x02                    /* Device base type code */
+       .byte   0x00                    /* Device sub-type code */
+       .byte   0x00                    /* Device interface type code */
+       .byte   0x54                    /* Device indicator */
+       .word   0x0000                  /* Boot connection vector */
+       .word   0x0000                  /* Disconnect vector */
+       .word   exec_vector             /* Boot execution vector */
+       .word   0x0000                  /* Reserved */
+       .word   0x0000                  /* Static resource information vector*/
+       .equ pnpheader_len, . - pnpheader
+       .size pnpheader, . - pnpheader

 
 

-PnP:
-       .ascii  "$PnP"
-       .byte 0x01                      /* structure revision */
-       .byte 0x02                      /* length (in 16 byte increments) */
-       .word 0x0000                    /* offset of next header */
-       .byte 0x00                      /* Reserved */
-       .byte 0x00                      /* checksum filled by makerom */
-       .long 0x00000000                /* Device identifier */
-       .word mfgstr - _prefix
-       .word 0x0                       /* pointer to product name */
-                                       /* filled by makerom */
-       .byte 0x02                      /* Device Base Type code */
-       .byte 0x00                      /* Device Sub-Type code */
-       .byte 0x00                      /* Device Interface Type code */
-       .byte 0x14                      /* device indicator */
-       .word 0x0000                    /* boot connection vector */
-       .word 0x0000                    /* disconnect vector */
-       .word pnpentry - _prefix
-       .word 0x0000                    /* reserved */
-       .word 0x0000                    /* static resource information vector */
-#ifdef PXE_EXPORT
-UNDIROMID:
-       .ascii  "UNDI"
-       .byte   UNDIROMID_end - UNDIROMID /* length of structure */
+mfgstr:
+       .asciz  "http://etherboot.org"
+       .size mfgstr, . - mfgstr
+prodstr:
+       .asciz  "Etherboot"
+       .size prodstr, . - prodstr
+       
+undiheader:
+       .ascii  "UNDI"                  /* Signature */
+       .byte   undiheader_len          /* Length of structure */

        .byte   0                       /* Checksum */
        .byte   0                       /* Structure revision */
        .byte   0                       /* Checksum */
        .byte   0                       /* Structure revision */

-       .byte   0,1,2                   /* PXE version 2.1.0 */
-       .word   UNDILoader - _prefix    /* Offset to loader routine */
-       .word   _real_mode_stack_size   /* Stack segment size */
-       .word   _real_mode_stack_size   /* Data segment size */
-       .word   _pxe_stack_size         /* Code segment size */
-       .ascii  "PCIR"
-
-       /* The code segment contains our pxe_stack_t plus the PXE and
-        * RM callback interfaces.  We don't actually use a data
-        * segment, but we put a nonzero value here to avoid confusing
-        * things.  16k of stack space should be enough.
-        *
-        * When we claim our own memory, we fill out the data segment
-        * with the address and size of the real-mode stack, so that
-        * NBPs will free that area of memory for us.  When the UNDI
-        * loader is used to initialise us, we will never need a
-        * real-mode stack because we will only ever be called via the
-        * PXE API, hence our stack is already in base memory.
-        */
-       .equ    UNDICodeSize, _pxe_stack_size
-       .equ    UNDIDataSize, _real_mode_stack_size
-       .equ    UNDIStackSize, _real_mode_stack_size
-UNDIROMID_end: 
-#endif /* PXE_EXPORT */
-       
-#endif /* PCI_PNP_HEADER */
-
-/*
- *     Explicitly specify DI is wrt ES to avoid problems with some BIOSes
- *     Discovered by Eric Biederman
- *     In addition, some BIOSes don't point DI to the string $PnP so
- *     we need another #define to take care of that.
+       .byte   0,1,2                   /* PXE version: 2.1.0 */
+       .word   undiloader              /* Offset to loader routine */
+       .word   _data16_size            /* Stack segment size */
+       .word   _data16_size            /* Data segment size */
+       .word   _text16_size            /* Code segment size */
+       .equ undiheader_len, . - undiheader
+       .size undiheader, . - undiheader
+
+/* Initialisation vector
+ *
+ * Determine whether or not this is a PnP system via a signature
+ * check.  If it is PnP, return to the PnP BIOS indicating that we are
+ * a boot-capable device; the BIOS will call our boot execution vector
+ * if it wants to boot us.  If it is not PnP, hook INT 19.

  */
  */

-over:  
-#ifdef DEBUG_ROMPREFIX
-       call    print_bcv
-#endif
-/* Omit this test for ISA cards anyway */
-#ifdef PCI_PNP_HEADER
-/* Accept old name too for backward compatibility */
-#if    !defined(BBS_BUT_NOT_PNP_COMPLIANT) && !defined(PNP_BUT_NOT_BBS_COMPLIANT)
-       cmpw    $'$'+'P'*256,%es:0(%di)
+init_vector:
+       pushw   %si
+       cmpw    $'$'+'P'*256, %es:0(%di)

        jne     notpnp
        jne     notpnp

-       cmpw    $'n'+'P'*256,%es:2(%di)
+       cmpw    $'n'+'P'*256, %es:2(%di)

        jne     notpnp
        jne     notpnp

-#endif /* BBS_BUT_NOT_PNP_COMPLIANT */
-       movw    $0x20,%ax
-       lret
-#endif /* PCI_PNP_HEADER */
+ispnp:
+       movw    $ispnp_message, %si
+       jmp     99f

 notpnp:
 notpnp:

-#ifdef DEBUG_ROMPREFIX
-       call    print_notpnp
-#endif
-#ifdef  DELAYED_INT
-       pushw   %ax

        pushw   %ds
        pushw   %ds

-       xorw    %ax,%ax
-       movw    %ax,%ds                 /* access first 64kB segment */
-       movw    SCRATCHVEC+4, %ax       /* check if already installed */
-       cmpw    $MAGIC, %ax             /* check magic word */
-       jz      installed
-       movw    BOOT_INT_VEC, %ax       /* hook into INT18H or INT19H */
-       movw    %ax, SCRATCHVEC
-       movw    BOOT_INT_VEC+2, %ax
-       movw    %ax, SCRATCHVEC+2
-       movw    $start_int - _prefix, %ax
-       movw    %ax, BOOT_INT_VEC
-       movw    %cs,%ax
-       movw    %ax, BOOT_INT_VEC+2
-       movw    $MAGIC, %ax             /* set magic word */
-       movw    %ax, SCRATCHVEC+4
-#ifdef DEBUG_ROMPREFIX
-       call    print_installed
-#endif
-installed:
+       pushw   $0

        popw    %ds
        popw    %ds

-       popw    %ax
-       movw    $0x20,%ax
+       pushw   %cs
+       pushw   $exec_vector
+       popl    ( 0x19 * 4 )
+       popw    %ds
+       movw    $notpnp_message, %si
+99:
+       call    print_message
+       movw    $0x20, %ax
+       popw    %si

        lret
        lret

+       .size init_vector, . - init_vector

 
 

-start_int:                             /* clobber magic id, so that we will */
-#ifdef DEBUG_ROMPREFIX
-       call    print_start_int
-#endif
-       xorw    %ax,%ax                 /* not inadvertendly end up in an */
-       movw    %ax,%ds                 /* endless loop */
-       movw    %ax, SCRATCHVEC+4
-       movw    SCRATCHVEC+2, %ax       /* restore original INT19h handler */
-       movw    %ax, BOOT_INT_VEC+2
-       movw    SCRATCHVEC, %ax
-       movw    %ax, BOOT_INT_VEC
-       pushl   %eax                    /* padding */
-       pushw   $EXIT_VIA_BOOT_INT
-       jmp     invoke
-#endif /* DELAYED_INT */
-
-
-
-       
-legacyentry:
-#ifdef DEBUG_ROMPREFIX
-       call    print_legacyentry
-#endif
-       pushw   $EXIT_VIA_LRET
-       jmp     invoke
+ispnp_message:
+       .asciz  "Etherboot detected PnP BIOS\r\n"
+       .size ispnp_message, . - ispnp_message
+notpnp_message:
+       .asciz  "Etherboot detected non-PnP BIOS\r\n"
+       .size notpnp_message, . - notpnp_message

 
 

+/* Boot execution vector
+ *
+ * Called by the PnP BIOS when it wants to boot us, or via the hooked
+ * INT 19 if we detected a non-PnP BIOS.
+ */    
+exec_vector:
+       /* Obtain a reasonably-sized stack */
+       xorw    %ax, %ax
+       movw    %ax, %ss
+       movw    $0x7c00, %sp

        
        

-       
-#ifdef PCI_PNP_HEADER
-pnpentry:
-#ifdef DEBUG_ROMPREFIX
-       call    print_bev
-#endif
-       pushl   %eax                    /* padding */
-       pushw   $EXIT_VIA_INT_18
-       jmp     invoke
-#endif /* PCI_PNP_HEADER */
+       movw    $exec_message, %si
+       call    print_message

 
 

+       call    install

 
 

-invoke:
-       /* Store ROM segment and size on stack */
+       /* Jump to .text16 segment */

        pushw   %ax
        pushw   %ax

-       pushw   %ds
+       pushw   $1f
+       lret
+       .section ".text16", "awx", @progbits
+1:
+       pushl   $main

        pushw   %cs
        pushw   %cs

-       movzbw  %cs:(size-_prefix), %ax
-       shlw    $9, %ax                 /* 512-byte blocks */
-       pushw   %ax
-       /* Relocate to free base memory, switch stacks */
-       pushw   $12                     /* Preserve exit code & far ret addr */
-       call    prelocate
-       /* We are now running in RAM */
-       popw    %ax                     /* padding */
-       movw    %cs, %ax
-       movw    %ax, %ds
-       popw    %ds:(_prefix_rom+2)     /* ROM size */
-       popw    %ds:(_prefix_rom+0)     /* ROM segment */
-       popw    %ds                     /* Original %ds */
-       popw    %ax                     /* Original %ax */
-       pushw   %ax                     /* 4-byte alignment */
-       pushl   $8                      /* Preserve exit code & far ret addr */
-       pushw   $0                      /* Set null return address */
-       jmp     _start
-       
+       call    prot_call
+       popl    %eax /* discard */

 
 

-       .section ".text16", "ax", @progbits
-prefix_exit:
-       popw    %ax                     /* padding */
-       popw    %ax                     /* %ax = exit code */
-       cmpw    $EXIT_VIA_LRET, %ax
-       jne     1f
-       /* Exit via LRET */
-       lret
-1:     addw    $4, %sp                 /* Strip padding */
-       cmpw    $EXIT_VIA_BOOT_INT, %ax
-       jne     2f
-       /* Exit via int BOOT_INT */
-       int     $BOOT_INT               /* Try original vector */
-2:     /* Exit via int $0x18 */
-       int     $0x18                   /* As per BIOS Boot Spec, next dev */
-prefix_exit_end:
+       /* Boot next device */
+       int     $0x18

        .previous
 
        .previous
 

-       
-
-/* UNDI loader needs to be rewritten to use new mechanism */
-#if 0
-               
-#ifdef         PXE_EXPORT
-
-#define PXENV_UNDI_LOADER              0x104d
+exec_message:
+       .asciz  "Etherboot starting boot\r\n"
+       .size exec_message, . - exec_message

 
 

-       .section ".prefix"
-UNDILoader:
-       /* Loader API is different to the usual PXE API; there is no
-        * opcode on the stack.  We arrange the stack to look like a
-        * normal PXE API call; this makes the Etherboot internals
-        * cleaner and avoids adding an extra API type just for the
-        * PXE loader.
-        */
-       pushw   %bx
-       movw    %sp, %ax                /* Store original %ss:sp */
-       pushw   %ss
+/* UNDI loader
+ *
+ * Called by an external program to load our PXE stack.
+ */
+undiloader:
+       .size undiloader, . - undiloader
+                               
+/* Utility function: print string
+ */
+print_message:

        pushw   %ax
        pushw   %ax

-       pushl   %eax                    /* Space for loader structure ptr */
+       pushw   %bx

        pushw   %bp
        pushw   %bp

-       movw    %sp, %bp
-       movw    16(%bp), %ax            /* Copy loader structure ptr */
-       movw    %ax, 2(%bp)
-       movw    18(%bp), %ax
-       movw    %ax, 4(%bp)
-       popw    %bp
-       pushw   $PXENV_UNDI_LOADER      /* PXE 'opcode' */
-       pushl   %eax                    /* dummy return address */
-       /* Stack now looks like a normal PXE API call */
-       /* Store ROM segment and size on stack */
-       pushw   %ax
-       pushw   %cs
-       movzbw  %cs:(size-_prefix), %ax
-       shlw    $9, %ax                 /* 512-byte blocks */
-       pushw   %ax
-       /* Unpack Etherboot into temporarily claimed base memory */
-       pushw   $20                     /* Dummy ret, PXE params, orig ss:sp */
-       call    prelocate
-       popw    %ax                     /* discard */
-       popw    %cs:(_prefix_rom+2)     /* ROM size */
-       popw    %cs:(_prefix_rom+0)     /* ROM segment */
-       popw    %ax                     /* Original %ax */
-       /* Inhibit automatic deallocation of base memory */
-       movl    $0, %cs:_prefix_image_basemem
-       /* Make PXE API call to Etherboot */
-       pushl   $0x201                  /* PXE API version */
-       /* Need to USE_INTERNAL_STACK, since we will call relocate() */
-       pushl   $(EB_OPCODE_PXE|EB_USE_INTERNAL_STACK) /* PXE API call type */
-       call    _entry
-       addw    $18, %sp                /* discard */
-       popw    %bx                     /* Restore original %ss:sp */
-       popw    %ss
-       movw    %bx, %sp
-       popw    %bx
-       call    deprelocate
-       lret    $2                      /* Skip our PXE 'opcode' */
-#endif /* PXE_EXPORT */
-
-#endif /* 0 */
-                       
-#ifdef DEBUG_ROMPREFIX
-       .section ".prefix"
-
-print_bcv:
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_message
-       popw    %si
-       ret
-1:     .asciz  "ROM detected\r\n"
-
-print_bev:
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_message
-       popw    %si
-       ret
-1:     .asciz  "booting\r\n"
-
-print_notpnp:
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_message
-       popw    %si
-       ret
-1:     .asciz  ": Non-PnP BIOS detected!\r\n"
-
-print_legacyentry:
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_message
-       popw    %si
-       ret
-1:     .asciz  "ROM using legacy boot mechanism\r\n"
-
-print_installed:
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_message
-       popw    %si
-       ret
-1:     .ascii  "hooked boot via INT"
-#ifdef BOOT_INT18H
-       .asciz  "18\r\n"
-#else
-       .asciz  "19\r\n"
-#endif
-
-print_start_int:
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_message
-       popw    %si
-       ret
-1:     .asciz  "booting via hooked interrupt\r\n"
-
-print_message:
-       pushaw
-       pushw   %ds
-       pushw   %cs
-       popw    %ds
-       pushw   %si
-       movw    $1f-_prefix, %si
-       call    print_string
-       popw    %si
-       call    print_string
-       popw    %ds
-       popaw
-       ret
-1:     .asciz  "Etherboot "
-
-print_string:
-1:     lodsb
-       testb   %al,%al
+       movw    $0x0007, %bx
+1:     cs lodsb
+       testb   %al, %al

        je      2f
        je      2f

-       movw    $0x0007, %bx            /* page 0, attribute 7 (normal) */

        movb    $0x0e, %ah              /* write char, tty mode */
        int     $0x10
        jmp     1b
        movb    $0x0e, %ah              /* write char, tty mode */
        int     $0x10
        jmp     1b

-2:     ret
-       
-#endif
+2:     popw    %bp
+       popw    %bx
+       popw    %ax
+       ret
+       .size print_message, . - print_message