port-i386/44079: i386 crash to BIOS with SIGTRAP plus no PT_INTERP no PT_NOTE

[jreiser%BitWagon.com@localhost]

>Number:         44079
>Category:       port-i386
>Synopsis:       i386 crash to BIOS with SIGTRAP plus no PT_INTERP no PT_NOTE
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Nov 10 16:45:00 +0000 2010
>Originator:     John Reiser
>Release:        5.0.2
>Organization:
BitWagon Software LLC
>Environment:
NetBSD NetBSD32.local 5.0.2 NetBSD 5.0.2 (GENERIC) #0: Sat Feb  6 17:53:27 UTC 
2010  
builds%b7.netbsd.org@localhost:/home/builds/ab/netbsd-5-0-2-RELEASE/i386/201002061851Z-obj/home/builds/ab/netbsd-5-0-2-RELEASE/src/sys/arch/i386/compile/GENERIC
 i386

>Description:
About 70% of the time, running a user-mode program causes a crash to BIOS when 
running port-i386 on a box with AMD64 hardware.  About 30% of the time the 
shell gives the correct answer "SIGTRAP - core dumped."  If gdb catches the 
signal, then pc==0x80010033 and sp==0, despite no pages mapped to either 
address.

-----/proc/cpuinfo
processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 15
model name      : AMD Athlon(tm) 64 Processor 3200+
stepping        : 2
cpu MHz         : 2010.38
fdiv_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov 
pat pse36 clflush mmx fxsr sse sse2 
-----

>How-To-Repeat:
----- nop.S
_start: .globl _start
        nop
        int3
        nop
-----
$ gcc -o nop -nostartfiles -nostdlib nop.S
$ ./nop



Other info:
$ readelf --headers ./nop
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x8048074
  Start of program headers:          52 (bytes into file)
  Start of section headers:          164 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         2
  Size of section headers:           40 (bytes)
  Number of section headers:         7
  Section header string table index: 4

Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
  LOAD           0x000000 0x08048000 0x08048000 0x00077 0x00077 R E 0x1000
  LOAD           0x000078 0x08049078 0x08049078 0x00000 0x00000 RW  0x1000

>Fix: