Files
ipxe/src/arch/i386/prefix/romprefix.S
Michael Brown de7be480d6 [romprefix] Add more diagnostic messages to ROM prefix
Include PMM allocation result in POST banner.

Include full product string in "starting execution" message.

Also mark ourselves as supporting DDIM in PnP header, for
completeness.
2008-08-25 23:36:24 +01:00

554 lines
13 KiB
ArmAsm

/* At entry, the processor is in 16 bit real mode and the code is being
* executed from an address it was not linked to. Code must be pic and
* 32 bit sensitive until things are fixed up.
*
* Also be very careful as the stack is at the rear end of the interrupt
* table so using a noticeable amount of stack space is a no-no.
*/
#define PNP_SIGNATURE ( '$' + ( 'P' << 8 ) + ( 'n' << 16 ) + ( 'P' << 24 ) )
#define PMM_SIGNATURE ( '$' + ( '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
.text
.code16
.arch i386
.section ".prefix", "ax", @progbits
.org 0x00
romheader:
.word 0xAA55 /* BIOS extension signature */
romheader_size: .byte _load_size_sect /* Size in 512-byte blocks */
jmp init /* Initialisation vector */
checksum:
.byte 0
.org 0x16
.word undiheader
.org 0x18
.word pciheader
.org 0x1a
.word pnpheader
.size romheader, . - romheader
.section ".zinfo.fixup", "a" /* Compressor fixup information */
.ascii "SUBB"
.long romheader_size
.long 512
.long 0
.previous
pciheader:
.ascii "PCIR" /* Signature */
.word pci_vendor_id /* Vendor identification */
.word pci_device_id /* Device identification */
.word 0x0000 /* Device list pointer */
.word pciheader_len /* PCI data structure length */
.byte 0x03 /* PCI data structure revision */
.byte 0x02, 0x00, 0x00 /* Class code */
pciheader_image_length:
.word _load_size_sect /* Image length */
.word 0x0001 /* Revision level */
.byte 0x00 /* Code type */
.byte 0x80 /* Last image indicator */
pciheader_runtime_length:
.word _load_size_sect /* Maximum run-time image length */
.word 0x0000 /* Configuration utility code header */
.word 0x0000 /* DMTF CLP entry point */
.equ pciheader_len, . - pciheader
.size pciheader, . - pciheader
.section ".zinfo.fixup", "a" /* Compressor fixup information */
.ascii "SUBW"
.long pciheader_image_length
.long 512
.long 0
.ascii "SUBW"
.long pciheader_runtime_length
.long 512
.long 0
.previous
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 0xf4 /* Device indicator */
.word 0x0000 /* Boot connection vector */
.word 0x0000 /* Disconnect vector */
.word bev_entry /* Boot execution vector */
.word 0x0000 /* Reserved */
.word 0x0000 /* Static resource information vector*/
.equ pnpheader_len, . - pnpheader
.size pnpheader, . - pnpheader
/* Manufacturer string */
mfgstr:
.asciz "http://etherboot.org"
.size mfgstr, . - mfgstr
/* Product string
*
* Defaults to "gPXE". If the ROM image is writable at initialisation
* time, it will be filled in to include the PCI bus:dev.fn number of
* the card as well.
*/
prodstr:
.ascii "gPXE"
prodstr_separator:
.byte 0
.ascii "(PCI "
prodstr_pci_id:
.asciz "xx:xx.x)" /* Filled in by init code */
.size prodstr, . - prodstr
undiheader:
.ascii "UNDI" /* Signature */
.byte undiheader_len /* Length of structure */
.byte 0 /* Checksum */
.byte 0 /* Structure revision */
.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 (called once during POST)
*
* 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.
*/
init:
/* Preserve registers, clear direction flag, set %ds=%cs */
pushaw
pushw %ds
pushw %es
pushw %fs
pushw %gs
cld
pushw %cs
popw %ds
pushw $0x40
popw %fs
/* Shuffle some registers around. We need %di available for
* the print_xxx functions, and in a register that's
* addressable from %es, so shuffle as follows:
*
* %di (pointer to PnP structure) => %bx
* %bx (runtime segment address, for PCI 3.0) => %gs
*/
movw %bx, %gs
movw %di, %bx
/* Print message as early as possible */
movw $init_message, %si
xorw %di, %di
call print_message
call print_pci_busdevfn
/* Fill in product name string, if possible */
movw $prodstr_pci_id, %di
call print_pci_busdevfn
movb $' ', prodstr_separator
/* Print segment address */
movb $' ', %al
xorw %di, %di
call print_character
movw %cs, %ax
call print_hex_word
/* Check for PCI BIOS version */
pushl %ebx
pushl %edx
stc
movw $0xb101, %ax
int $0x1a
jc 1f
cmpl $PCI_SIGNATURE, %edx
jne 1f
testb %ah, %ah
jnz 1f
movw $init_message_pci, %si
xorw %di, %di
call print_message
movb %bh, %al
call print_hex_nibble
movb $'.', %al
call print_character
movb %bl, %al
call print_hex_byte
cmpb $3, %bh
jae 2f
1: /* PCI <3.0: set %gs (runtime segment) = %cs (init-time segment) */
pushw %cs
popw %gs
2: popl %edx
popl %ebx
/* Check for PnP BIOS */
testw $0x0f, %bx /* PnP signature must be aligned - bochs */
jnz no_bbs /* uses unalignment to indicate 'fake' PnP. */
cmpl $PNP_SIGNATURE, %es:0(%bx)
jne no_bbs
/* Is PnP: print PnP message */
movw $init_message_pnp, %si
xorw %di, %di
call print_message
/* Check for BBS */
pushw %es:0x1b(%bx) /* Real-mode data segment */
pushw %ds /* &(bbs_version) */
pushw $bbs_version
pushw $PNP_GET_BBS_VERSION
lcall *%es:0xd(%bx)
addw $8, %sp
testw %ax, %ax
je got_bbs
no_bbs: /* Not BBS-compliant - must hook INT 19 */
movw $init_message_int19, %si
xorw %di, %di
call print_message
xorw %ax, %ax
movw %ax, %es
pushl %es:( 0x19 * 4 )
popl orig_int19
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:
/* Check for PMM */
movw $( 0xe000 - 1 ), %bx
pmm_scan:
incw %bx
jz no_pmm
movw %bx, %es
cmpl $PMM_SIGNATURE, %es:0
jne pmm_scan
xorw %dx, %dx
xorw %si, %si
movzbw %es:5, %cx
1: es lodsb
addb %al, %dl
loop 1b
jnz pmm_scan
/* PMM found: print PMM message */
movw $init_message_pmm, %si
xorw %di, %di
call print_message
/* Try to allocate 2MB block via PMM */
pushw $0x0006 /* Aligned, extended memory */
pushl $0xffffffff /* No handle */
pushl $( 0x00200000 / 16 ) /* 2MB in paragraphs */
pushw $PMM_ALLOCATE
lcall *%es:7
addw $12, %sp
movw %dx, %ax
xorw %di, %di
call print_hex_word
movw %dx, ( image_source + 2 )
testw %dx, %dx /* %ax==0 even on success, since align=2MB */
jz no_pmm
/* PMM allocation succeeded: copy ROM to PMM block */
pushal /* PMM presence implies 1kB stack */
xorw %ax, %ax
movw %ax, %es
movl image_source, %edi
xorl %esi, %esi
movzbl romheader_size, %ecx
shll $9, %ecx
addr32 rep movsb /* PMM presence implies flat real mode */
movl %edi, decompress_to
/* Shrink ROM and update checksum */
xorw %bx, %bx
xorw %si, %si
movw $_prefix_size_sect, %cx
movb %cl, romheader_size
shlw $9, %cx
1: lodsb
addb %al, %bl
loop 1b
subb %bl, checksum
popal
no_pmm:
/* Copy self to option ROM space. Required for PCI3.0, which
* loads us to a temporary location in low memory. Will be a
* no-op for lower PCI versions.
*/
movb $' ', %al
xorw %di, %di
call print_character
movw %gs, %ax
call print_hex_word
movzbw romheader_size, %cx
shlw $9, %cx
movw %ax, %es
xorw %si, %si
xorw %di, %di
cs rep movsb
/* Prompt for POST-time shell */
movw $init_message_prompt, %si
xorw %di, %di
call print_message
/* Empty the keyboard buffer before waiting for input */
empty_keyboard_buffer:
movb $0x01, %ah
int $0x16
jz 1f
xorw %ax, %ax
int $0x16
jmp empty_keyboard_buffer
1: /* Wait for up to 3s for a key press */
movw $(18 * 3), %cx /* Approx 3s worth of timer ticks */
wait_for_key:
decw %cx
jz no_key_pressed
/* Wait for timer tick to be updated */
movl %fs:(0x6c), %eax
1: pushf
sti
hlt
popf
cmpl %fs:(0x6c), %eax
je 1b
/* Check to see if a key was pressed */
movb $0x01, %ah
int $0x16
jz wait_for_key
/* Check to see if key was Ctrl-B */
cmpb $0x02, %al
je 1f
/* Key was not Ctrl-B: remove from buffer and stop waiting */
xorw %ax, %ax
int $0x16
jmp no_key_pressed
1: /* Key was Ctrl-B: leave in keyboard buffer and invoke gPXE.
* The keypress will be picked up by the initial shell
* prompt, and we will drop into a shell.
*/
pushw %cs
call exec
no_key_pressed:
/* Print blank lines to terminate messages */
movw $init_message_end, %si
xorw %di, %di
call print_message
/* Restore registers */
popw %gs
popw %fs
popw %es
popw %ds
popaw
/* Indicate boot capability to PnP BIOS, if present */
movw $0x20, %ax
lret
.size init, . - init
init_message:
.asciz "gPXE (http://etherboot.org) - "
.size init_message, . - init_message
init_message_pci:
.asciz " PCI"
.size init_message_pci, . - 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
init_message_int19:
.asciz " INT19"
.size init_message_int19, . - init_message_int19
init_message_prompt:
.asciz "\nPress Ctrl-B to configure gPXE..."
.size init_message_prompt, . - init_message_prompt
init_message_end:
.asciz "\n\n\n"
.size init_message_end, . - init_message_end
/* ROM image location
*
* May be either within option ROM space, or within PMM-allocated block.
*/
image_source:
.long 0
.size image_source, . - image_source
/* Temporary decompression area
*
* May be either at HIGHMEM_LOADPOINT, or within PMM-allocated block.
*/
decompress_to:
.long HIGHMEM_LOADPOINT
.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.
*/
bev_entry:
pushw %cs
call exec
lret
.size bev_entry, . - bev_entry
/* INT19 entry point
*
* Called via the hooked INT 19 if we detected a non-PnP BIOS. We
* attempt to return via the original INT 19 vector (if we were able to
* store it).
*/
int19_entry:
pushw %cs
call exec
movl %cs:orig_int19, %eax
testl %eax, %eax
je 1f
/* Chain to original INT 19 vector */
ljmp *%cs:orig_int19
1: /* No chained vector: issue INT 18 as a last resort */
int $0x18
.size int19_entry, . - int19_entry
orig_int19:
.long 0
.size orig_int19, . - orig_int19
/* Execute as a boot device
*
*/
exec: /* Set %ds = %cs */
pushw %cs
popw %ds
/* Print message as soon as possible */
movw $prodstr, %si
xorw %di, %di
call print_message
movw $exec_message, %si
call print_message
/* Store magic word on BIOS stack and remember BIOS %ss:sp */
pushl $STACK_MAGIC
movw %ss, %dx
movw %sp, %bp
/* Obtain a reasonably-sized temporary stack */
xorw %ax, %ax
movw %ax, %ss
movw $0x7c00, %sp
/* Install gPXE */
movl image_source, %esi
movl decompress_to, %edi
call alloc_basemem
call install_prealloc
/* Set up real-mode stack */
movw %bx, %ss
movw $_estack16, %sp
/* Jump to .text16 segment */
pushw %ax
pushw $1f
lret
.section ".text16", "awx", @progbits
1: /* Call main() */
pushl $main
pushw %cs
call prot_call
/* No need to clean up stack; we are about to reload %ss:sp */
/* Restore BIOS stack */
movw %dx, %ss
movw %bp, %sp
/* Check magic word on BIOS stack */
popl %eax
cmpl $STACK_MAGIC, %eax
jne 1f
/* BIOS stack OK: return to caller */
lret
1: /* BIOS stack corrupt: use INT 18 */
int $0x18
.previous
exec_message:
.asciz " starting execution\n"
.size exec_message, . - exec_message
/* UNDI loader
*
* Called by an external program to load our PXE stack.
*/
undiloader:
/* Save registers */
pushl %esi
pushl %edi
pushw %es
pushw %bx
/* UNDI loader parameter structure address into %es:%di */
movw %sp, %bx
movw %ss:16(%bx), %di
movw %ss:18(%bx), %es
/* Install to specified real-mode addresses */
pushw %di
movw %es:12(%di), %bx
movw %es:14(%di), %ax
movl %cs:image_source, %esi
movl %cs:decompress_to, %edi
call install_prealloc
popw %di
/* Call UNDI loader C code */
pushl $pxe_loader_call
pushw %cs
pushw $1f
pushw %ax
pushw $prot_call
lret
1: popw %bx /* discard */
popw %bx /* discard */
/* Restore registers and return */
popw %bx
popw %es
popl %edi
popl %esi
lret
.size undiloader, . - undiloader