421 lines
10 KiB
ArmAsm
421 lines
10 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 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
|
|
.org 0
|
|
.section ".prefix", "ax", @progbits
|
|
.globl _prefix
|
|
_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 0x16
|
|
.word UNDIROMID - _prefix
|
|
#endif /* PXE_EXPORT */
|
|
|
|
.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 */
|
|
|
|
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 */
|
|
.byte 0 /* Checksum */
|
|
.byte 0 /* Structure revision */
|
|
.byte 0,1,2 /* PXE version 2.1.0 */
|
|
.word UNDILoader - _prefix /* Offset to loader routine */
|
|
.word UNDIStackSize /* Stack segment size */
|
|
.word UNDIDataSize /* Data segment size */
|
|
.word UNDICodeSize /* 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.
|
|
*/
|
|
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)
|
|
jne notpnp
|
|
cmpw $'n'+'P'*256,%es:2(%di)
|
|
jne notpnp
|
|
#endif /* BBS_BUT_NOT_PNP_COMPLIANT */
|
|
movw $0x20,%ax
|
|
lret
|
|
#endif /* PCI_PNP_HEADER */
|
|
notpnp:
|
|
#ifdef DEBUG_ROMPREFIX
|
|
call print_notpnp
|
|
#endif
|
|
#ifdef DELAYED_INT
|
|
pushw %ax
|
|
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:
|
|
popw %ds
|
|
popw %ax
|
|
movw $0x20,%ax
|
|
lret
|
|
|
|
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
|
|
|
|
|
|
|
|
#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 */
|
|
|
|
|
|
invoke:
|
|
/* Store ROM segment and size on stack */
|
|
pushw %ax
|
|
pushw %ds
|
|
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
|
|
|
|
|
|
.section ".text16", "ax", @progbits
|
|
.globl prefix_exit
|
|
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 */
|
|
.globl prefix_exit_end
|
|
prefix_exit_end:
|
|
.previous
|
|
|
|
|
|
|
|
/* UNDI loader needs to be rewritten to use new mechanism */
|
|
#if 0
|
|
|
|
#ifdef PXE_EXPORT
|
|
|
|
#define PXENV_UNDI_LOADER 0x104d
|
|
|
|
.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
|
|
pushw %ax
|
|
pushl %eax /* Space for loader structure ptr */
|
|
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
|
|
je 2f
|
|
movw $0x0007, %bx /* page 0, attribute 7 (normal) */
|
|
movb $0x0e, %ah /* write char, tty mode */
|
|
int $0x10
|
|
jmp 1b
|
|
2: ret
|
|
|
|
#endif
|