diff options
Diffstat (limited to 'gpxe/src/arch/i386/prefix/pxeprefix.S')
| -rw-r--r-- | gpxe/src/arch/i386/prefix/pxeprefix.S | 129 |
1 files changed, 67 insertions, 62 deletions
diff --git a/gpxe/src/arch/i386/prefix/pxeprefix.S b/gpxe/src/arch/i386/prefix/pxeprefix.S index 302f8e5d..a5f0c711 100644 --- a/gpxe/src/arch/i386/prefix/pxeprefix.S +++ b/gpxe/src/arch/i386/prefix/pxeprefix.S @@ -2,7 +2,7 @@ #define PXENV_UNDI_GET_NIC_TYPE 0x0012 #define PXENV_STOP_UNDI 0x0015 #define PXENV_UNLOAD_STACK 0x0070 - + .text .arch i386 .org 0 @@ -12,36 +12,39 @@ #include <undi.h> +#define STACK_MAGIC ( 'L' + ( 'R' << 8 ) + ( 'E' << 16 ) + ( 'T' << 24 ) ) + /***************************************************************************** * Entry point: set operating context, print welcome message ***************************************************************************** */ .section ".prefix" - /* Set up our non-stack segment registers */ jmp $0x7c0, $1f -1: pushfl - /* %ax here is the default return type... */ - movw $5, %ax /* Keep PXE+UNDI */ +1: + /* Preserve registers for possible return to PXE */ + pushfl pushal - pushw %ds - pushw %es - pushw %fs pushw %gs + pushw %fs + pushw %es + pushw %ds + + /* Store magic word on PXE stack and remember PXE %ss:esp */ + pushl $STACK_MAGIC + movw %ss, %cs:pxe_ss + movl %esp, %cs:pxe_esp + + /* Set up our non-stack segment registers */ movw %cs, %ax movw %ax, %ds - movw $0x40, %ax /* BIOS data segment access */ movw %ax, %fs - - pushw %fs:0x13 /* Record PXENV+ and !PXE nominal addresses */ - movw %es, pxenv_segment + movw %es, %ax /* PXENV+ address */ + movw %ax, pxenv_segment movw %bx, pxenv_offset - movw %sp, %bp - movw %ss, return_stack_segment - movl %esp, return_stack_offset - movl 50(%bp), %eax - movl %eax, ppxe_segoff /* !PXE address */ + popl %eax /* Discard return address */ + popl ppxe_segoff /* !PXE address */ /* Set up stack just below 0x7c00 */ xorw %ax, %ax movw %ax, %ss @@ -60,7 +63,7 @@ * Verify PXENV+ structure and record parameters of interest ***************************************************************************** */ -detect_pxenv: +ect_pxenv: /* Signature check */ les pxenv_segoff, %bx cmpl $0x4e455850, %es:(%bx) /* 'PXEN' signature */ @@ -264,7 +267,7 @@ no_physical_device: * Leave NIC in a safe state ***************************************************************************** */ -#ifndef PXELOADER_KEEP_UNDI +#ifndef PXELOADER_KEEP_PXE shutdown_nic: /* Issue PXENV_UNDI_SHUTDOWN */ movw $PXENV_UNDI_SHUTDOWN, %bx @@ -272,11 +275,6 @@ shutdown_nic: jnc 1f call print_pxe_error 1: - -/***************************************************************************** - * Unload PXE base code - ***************************************************************************** - */ unload_base_code: /* Issue PXENV_UNLOAD_STACK */ movw $PXENV_UNLOAD_STACK, %bx @@ -289,12 +287,14 @@ unload_base_code: movw %fs:(0x13), %bx call free_basemem 99: + andw $~( UNDI_FL_INITIALIZED | UNDI_FL_KEEP_ALL ), flags +#endif /* PXELOADER_KEEP_PXE */ /***************************************************************************** * Unload UNDI driver ***************************************************************************** */ - +#ifndef PXELOADER_KEEP_UNDI unload_undi: /* Issue PXENV_STOP_UNDI */ movw $PXENV_STOP_UNDI, %bx @@ -309,6 +309,7 @@ unload_undi: /* Clear UNDI_FL_STARTED */ andw $~UNDI_FL_STARTED, flags 99: +#endif /* PXELOADER_KEEP_UNDI */ /***************************************************************************** * Print remaining free base memory @@ -325,15 +326,14 @@ print_free_basemem: 10: .asciz " " 20: .asciz "kB free base memory after PXE unload\n" .previous -#endif /* PXELOADER_KEEP_UNDI */ /***************************************************************************** * Exit point ***************************************************************************** */ finished: - jmp run_etherboot - + jmp run_gpxe + /***************************************************************************** * Subroutine: print segment:offset address * @@ -527,6 +527,10 @@ print_pxe_error: * PXE data structures ***************************************************************************** */ + .section ".prefix.data" + +pxe_ss: .word 0 +pxe_esp: .long 0 pxe_parameter_structure: .fill 20 @@ -554,12 +558,6 @@ entry_segoff: entry_offset: .word 0 entry_segment: .word 0 -return_stack_segoff: -return_stack_offset: .long 0 -return_stack_segment: .word 0 - -return_type: .word 0 /* Default: unload PXE and boot next */ - undi_fbms_start: .word 0 undi_fbms_end: .word 0 @@ -569,16 +567,18 @@ isapnp_read_port: .word UNDI_NO_ISAPNP_READ_PORT pci_vendor: .word 0 pci_device: .word 0 -flags: .word UNDI_FL_STARTED +flags: + .word ( UNDI_FL_INITIALIZED | UNDI_FL_STARTED | UNDI_FL_KEEP_ALL ) .equ undi_device_size, ( . - undi_device ) /***************************************************************************** - * Run Etherboot main code + * Run gPXE main code ***************************************************************************** - */ -run_etherboot: - /* Install Etherboot */ + */ + .section ".prefix" +run_gpxe: + /* Install gPXE */ call install /* Set up real-mode stack */ @@ -594,6 +594,10 @@ run_etherboot: rep movsb #endif + /* Retrieve PXE %ss:esp */ + movw pxe_ss, %di + movl pxe_esp, %ebp + /* Jump to .text16 segment with %ds pointing to .data16 */ movw %bx, %ds pushw %ax @@ -605,29 +609,30 @@ run_etherboot: pushl $main pushw %cs call prot_call - popl %eax /* discard */ + popl %ecx /* discard */ -#ifdef PXELOADER_KEEP_UNDI - /* Boot next device */ - movw $0x40, %ax - movw %ax, %fs - movw $preloaded_undi,%bx - - cli - movw %ss:return_type-undi_device(%bx),%ax - lssl %ss:return_stack_segoff-undi_device(%bx), %esp - movw %sp,%bp - movw %ax,38(%bp) /* Overwrite return AX value */ - popw %fs:0x13 /* 0 */ - popw %gs /* 2 */ - popw %fs /* 4 */ - popw %es /* 6 */ - popw %ds /* 8 */ - popal /* 10, 14, 18, 22, 26, 30, 34, 38 */ - popfl /* 42 */ - lret /* 46 */ -#else - int $0x18 -#endif + /* Uninstall gPXE */ + call uninstall + + /* Restore PXE stack */ + movw %di, %ss + movl %ebp, %esp + /* Check PXE stack magic */ + popl %eax + cmpl $STACK_MAGIC, %eax + jne 1f + + /* PXE stack OK: return to caller */ + popw %ds + popw %es + popw %fs + popw %gs + popal + popfl + xorw %ax, %ax /* Return success */ + lret + +1: /* PXE stack corrupt or removed: use INT 18 */ + int $0x18 .previous |