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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.
This commit is contained in:
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"