Avoid leaving preloaded_undi with invalid PXENV+/!PXE structure

addresses if the signature checks fail.

diff --git a/src/arch/i386/prefix/pxeprefix.S b/src/arch/i386/prefix/pxeprefix.S
index 5bfd58f..55a228f 100644 (file)
--- a/src/arch/i386/prefix/pxeprefix.S
+++ b/src/arch/i386/prefix/pxeprefix.S
@@ -48,9 +48,9 @@ detect_pxenv:
        /* Signature check */
        les     pxenv_segoff, %di
        cmpl    $0x4e455850, %es:(%di)  /* 'PXEN' signature */
-       jne     99f
+       jne     no_pxenv
        cmpw    $0x2b56, %es:4(%di)     /* 'V+' signature */
-       jne     99f
+       jne     no_pxenv
        /* Record entry point and UNDI segments */
        pushl   %es:0x0a(%di)           /* Entry point */
        popl    entry_segoff
@@ -67,9 +67,15 @@ detect_pxenv:
        call    print_segoff
        movb    $',', %al
        call    print_character
+       jmp     99f
        .section ".prefix.data"
 10:    .asciz  " PXENV+ at "
        .previous
+
+no_pxenv:
+       xorl    %eax, %eax
+       movl    %eax, pxenv_segoff
+       
 99:
        
 /*****************************************************************************
@@ -80,7 +86,7 @@ detect_ppxe:
        /* Signature check */
        les     ppxe_segoff, %di
        cmpl    $0x45585021, %es:(%di)  /* '!PXE' signature */
-       jne     99f
+       jne     no_ppxe
        /* Record structure address, entry point, and UNDI segments */
        pushw   %es
        popw    ppxe_segment
@@ -99,9 +105,15 @@ detect_ppxe:
        call    print_segoff
        movb    $',', %al
        call    print_character
+       jmp     99f
        .section ".prefix.data"
 10:    .asciz  " !PXE at "
        .previous
+
+no_ppxe:
+       xorl    %eax, %eax
+       movl    %eax, ppxe_segoff
+
 99:
 
 /*****************************************************************************