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opengnsys_ipxe
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Since we now always unload the base code stack (even if we keep UNDI), 

we can never return to the PXE stack and must always use INT 18.
pull/1/head
Michael Brown 2007-01-09 02:46:58 +00:00
parent f2f492a536
commit 697bcc9d24
1 changed files with 24 additions and 83 deletions
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107
src/arch/i386/prefix/pxeprefix.S
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@ -3,8 +3,6 @@
#define PXENV_STOP_UNDI 0x0015 #define PXENV_STOP_UNDI 0x0015
#define PXENV_UNLOAD_STACK 0x0070 #define PXENV_UNLOAD_STACK 0x0070
#define PXE_STACK_MAGIC 0x57ac /* 'STac' */
.text .text
.arch i386 .arch i386
.org 0 .org 0
@ -17,31 +15,22 @@
***************************************************************************** *****************************************************************************
*/ */
.section ".prefix" .section ".prefix"
/* Set up our non-stack segment registers */
jmp $0x7c0, $1f jmp $0x7c0, $1f
1: /* Preserve registers for return to PXE stack */ 1: movw %cs, %ax
pushfl movw %ax, %ds
pushal movw $0x40, %ax /* BIOS data segment access */
pushw %gs movw %ax, %fs
pushw %fs /* Record PXENV+ and !PXE nominal addresses */
pushw %es movw %es, %ax /* PXENV+ address */
pushw %ds movw %ax, pxenv_segment
pushw %ss movw %bx, pxenv_offset
pushw %cs popl %eax /* Discard return address */
pushw $PXE_STACK_MAGIC /* PXE stack magic marker */ popl ppxe_segoff /* !PXE address */
/* Set up stack just below 0x7c00 */ /* Set up stack just below 0x7c00 */
pushw %ss
popw %gs
movw %sp, %bp /* %gs:%bp points to old PXE stack */
xorw %ax, %ax xorw %ax, %ax
movw %ax, %ss movw %ax, %ss
movw $0x7c00, %sp movw $0x7c00, %sp
pushw %gs /* Save old PXE stack pointer */
pushw %bp
/* Set up our other segment registers */
pushw %cs
popw %ds
movw $0x40, %ax /* BIOS data segment access */
movw %ax, %fs
/* Clear direction flag, for the sake of sanity */ /* Clear direction flag, for the sake of sanity */
cld cld
/* Print welcome message */ /* Print welcome message */
@ -57,21 +46,19 @@
*/ */
detect_pxenv: detect_pxenv:
/* Signature check */ /* Signature check */
cmpl $0x4e455850, %es:(%bx) /* 'PXEN' signature */ les pxenv_segoff, %di
cmpl $0x4e455850, %es:(%di) /* 'PXEN' signature */
jne 99f jne 99f
cmpw $0x2b56, %es:4(%bx) /* 'V+' signature */ cmpw $0x2b56, %es:4(%di) /* 'V+' signature */
jne 99f jne 99f
/* Record structure address, entry point, and UNDI segments */ /* Record entry point and UNDI segments */
pushw %es pushl %es:0x0a(%di) /* Entry point */
popw pxenv_segment
movw %bx, pxenv_offset
pushl %es:0x0a(%bx) /* Entry point */
popl entry_segoff popl entry_segoff
pushw %es:0x24(%bx) /* UNDI code segment */ pushw %es:0x24(%di) /* UNDI code segment */
pushw %es:0x26(%bx) /* UNDI code size */ pushw %es:0x26(%di) /* UNDI code size */
popl undi_code_segoff popl undi_code_segoff
pushw %es:0x20(%bx) /* UNDI data segment */ pushw %es:0x20(%di) /* UNDI data segment */
pushw %es:0x22(%bx) /* UNDI data size */ pushw %es:0x22(%di) /* UNDI data size */
popl undi_data_segoff popl undi_data_segoff
/* Print "PXENV+ at <address>" */ /* Print "PXENV+ at <address>" */
movw $10f, %si movw $10f, %si
@ -91,7 +78,7 @@ detect_pxenv:
*/ */
detect_ppxe: detect_ppxe:
/* Signature check */ /* Signature check */
les %gs:54(%bp), %di /* !PXE structure */ les ppxe_segoff, %di
cmpl $0x45585021, %es:(%di) /* '!PXE' signature */ cmpl $0x45585021, %es:(%di) /* '!PXE' signature */
jne 99f jne 99f
/* Record structure address, entry point, and UNDI segments */ /* Record structure address, entry point, and UNDI segments */
@ -700,65 +687,19 @@ run_etherboot:
rep movsb rep movsb
#endif #endif
/* Jump to .text16 segment with %ds pointing to .data16*/ /* Jump to .text16 segment with %ds pointing to .data16 */
movw %bx, %ds movw %bx, %ds
pushw %ax pushw %ax
pushw $1f pushw $1f
lret lret
.section ".text16", "ax", @progbits .section ".text16", "ax", @progbits
1: 1:
/* Original PXE stack pointer to es:di. We must hold it in
* registers, because our current stack may be vapourised by
* the time main() returns. (main() will still be able to
* return, because prot_call() transfers the return address to
* the internal stack and back again).
*/
popw %di
popw %es
/* Run main program */ /* Run main program */
pushl $main pushl $main
pushw %cs pushw %cs
call prot_call call prot_call
popl %eax /* discard */ popl %eax /* discard */
/* If original PXE stack is intact, return via PXE, else via INT 18 */ /* Boot next device */
cmpw $PXE_STACK_MAGIC, %es:0(%di)
jne exit_via_int18
exit_via_pxe: /* Stack OK, return to PXE */
movw $exit_via_pxe_message, %si
call print_exit_message
pushw %es /* Restore original PXE stack */
popw %ss
movw %di, %sp
popw %ax /* discard PXE_STACK_MAGIC */
popw %ax /* discard %cs */
popw %ax /* discard %ss */
popw %ds
popw %es
popw %fs
popw %gs
popal
popfl
xorw %ax, %ax /* Return PXENV_STATUS_SUCCESS */
lret
exit_via_int18: /* Stack damaged, do int 18 */
movw $exit_via_int18_message, %si
call print_exit_message
int $0x18 int $0x18
.previous
print_exit_message:
movw $0x0007, %bx /* page 0, attribute 7 (normal) */
movb $0x0e, %ah /* write char, tty mode */
1: lodsb
testb %al, %al
je 2f
int $0x10
jmp 1b
2: ret
.section ".data16", "aw", @progbits
exit_via_pxe_message:
.asciz "EB->PXE\r\n"
exit_via_int18_message:
.asciz "EB->BIOS\r\n"