i386/96430: boot2 is unable to load kernel directly

[Yuichiro Goto]

>Number:         96430
>Category:       i386
>Synopsis:       boot2 is unable to load kernel directly
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Apr 27 19:30:12 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Yuichiro Goto
>Release:        FreeBSD 6.1-RC1
>Organization:
>Environment:
FreeBSD cobalt.my.domain 6.1-RC FreeBSD 6.1-RC #0: Wed Apr 26 10:38:08 JST 2006     root at cobalt.my.domain:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
Loading a kernel directly using boot2 causes the invalid-opcode fault like the
following:

int=00000006  err=00000000  efl=00010002  eip=c0445a90
eax=c0445a90  ebx=0007cd0f  ecx=c0b5e1a7  edx=a030001e
esi=c0b5e1a7  edi=c0445a90  ebp=00000002  esp=0009eb84
cs=0008  ds=0010  es=0010    fs=0010  gs=0010  ss=0010
cs:eip=ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff
       ff ff ff ff ff ff ff ff-ff ff ff ff ff ff ff ff
ss:esp=69 95 00 00 00 00 00 80-1e 00 30 a0 00 00 00 00
       00 00 00 00 00 00 00 00-60 dd 00 00 36 42 00 00
BTX halted

I tried to load a kernel directly that is a slightly modified
version of GENERIC.  The following 2 lines are added to
GENERIC:

makeoptions     CONF_CFLAGS=-DROOTDEVNAME=\"ufs:/dev/ad0s2a\"
makeoptions     NO_MODULES=yes
>How-To-Repeat:
Directly load a kernel using boot2.
>Fix:
load() in src/sys/boot/i386/boot2/boot2.c tries to copy kernel segments at a
phisical address on memory whose most significant 2 bits are set.  This is
because of changes between rev 1.70 and 1.71 of
src/sys/boot/i386/boot2/boot2.c.
>Release-Note:
>Audit-Trail:
>Unformatted: