Re: ZFS boot problems with memory > 1MB

On Tuesday 23 February 2010 3:36:19 pm Brandon Gooch wrote:
> On Tue, Feb 23, 2010 at 1:01 PM, John Baldwin <jhb_at_freebsd.org> wrote:
> > On Tuesday 23 February 2010 12:36:31 pm Brandon Gooch wrote:
> >> On Tue, Feb 23, 2010 at 10:24 AM, John Baldwin <jhb_at_freebsd.org> wrote:
> >> > On Tuesday 23 February 2010 10:28:49 am Brandon Gooch wrote:
> >> >> On Tue, Feb 23, 2010 at 7:29 AM, Andriy Gapon <avg_at_icyb.net.ua> wrote:
> >> >> > on 23/02/2010 13:18 Renato Botelho said the following:
> >> >> >> On Mon, Feb 22, 2010 at 7:35 PM, Chris Hedley
> >> >> >> <freebsd-current_at_chrishedley.com> wrote:
> >> >> > [snip]
> >> >> >>> Do you have USB legacy support enabled in your BIOS?  I'm not sure 
if
> >> >> >>> there's an option for the loader to use USB devices natively, but 
the BIOS's
> >> >> >>> legacy option where it provides AT/PS2 emulation is probably the 
easiest way
> >> >> >>> to get the keyboard working.
> >> >> >>
> >> >> >> Yes, I do, but it seems to be a regression on FreeBSD itself, I had 
this problem
> >> >> >> in the past and I checked the same things i need to check in the 
past again and
> >> >> >> everything is fine.
> >> >> >
> >> >> > A more precise way to state that would be "a regression in FreeBSD 
boot/loader".
> >> >> > I think that you are referring to the issue that was fixed by 
r189017.
> >> >> > It might be worthwhile investigating what was done in that revision 
and what
> >> >> > happened in sys/boot code since then.
> >> >> >
> >> >> > One possibility is that your BIOS uses memory above 1MB for USB 
emulation, but
> >> >> > doesn't mark that memory as used in system memory map.  In that case 
that memory
> >> >> > could be overwritten by the loader.  If that's true then the blame 
is on the BIOS.
> >> >> >  Alternatively, our code might be parsing the system memory map 
incorrectly.
> >> >> > But I am just making wild guesses here.
> >> >> >
> >> >>
> >> >> I don't know if it is at all related, but this commit has caused
> >> >> problems for me booting at least one of my machines:
> >> >>
> >> >> 
http://svn.freebsd.org/viewvc/base/head/sys/boot/i386/zfsboot/zfsboot.c?r1=199714&r2=200309
> >> >>
> >> >> Commit message:
> >> >>
> >> >> Revision 200309 - (view) (annotate) - [select for diffs]
> >> >> Modified Wed Dec 9 20:36:56 2009 UTC (2 months, 2 weeks ago) by jhb
> >> >> File length: 24893 byte(s)
> >> >> Diff to previous 199714
> >> >> - Port bios_getmem() from libi386 to {gpt,}zfsboot() and use it to
> >> >>   safely allocate a heap region above 1MB.  This enables 
{gpt,}zfsboot()
> >> >>   to allocate much larger buffers than before.
> >> >> - Use a larger buffer (1MB instead of 128K) for temporary ZFS buffers. 
 This
> >> >>   allows more reliable reading of compressed files in a raidz/raidz2 
pool.
> >> >>
> >> >> Submitted by: Matt Reimer  mattjreimer of gmail
> >> >> MFC after:    1 week
> >> >
> >> > Starting a new thread, which problems are you seeing with this change? 
 ZFS is
> >> > a good bit more memory hungry than UFS, so it really needs to use high 
memory
> >> > for its heap.  Also, I wonder if you still have problems if you use the 
older
> >> > zfsboot with the newer zfsloader?  Finally, you need to use disklabel -
B or
> >> > some such to update the zfsboot bits for this change to take effect.
> >> >
> >> > --
> >> > John Baldwin
> >> >
> >>
> >> I filed a PR so it wouldn't fall through the cracks:
> >>
> >> http://www.freebsd.org/cgi/query-pr.cgi?pr=144234
> >>
> >> I guess I tried a combination of various revisions of bootstrap code
> >> and loaders when I first encountered the issue. It was when I wrote a
> >> recent gptzfsboot to the geom that I saw the symptoms:
> >>
> >> error 1 lba 48
> >> error 1 lba 1
> >> No ZFS pools located, can't boot
> >>
> >> I just wound up using sys/boot/i386/zfsboot/zfsboot.c revision 199714
> >> to build a working gptzfsboot on another system and wrote that to the
> >> disk to get the machine operational.
> >
> > Try this:
> >
> > Index: zfsboot.c
> > ===================================================================
> > --- zfsboot.c   (revision 204207)
> > +++ zfsboot.c   (working copy)
> > _at__at_ -467,6 +467,7 _at__at_
> >  static inline void
> >  putc(int c)
> >  {
> > +    v86.ctl = 0;
> >     v86.addr = 0x10;
> >     v86.eax = 0xe00 | (c & 0xff);
> >     v86.ebx = 0x7;
> > _at__at_ -617,6 +618,8 _at__at_
> >     off_t off;
> >     struct dsk *dsk;
> >
> > +    dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - 
__base);
> > +
> >     bios_getmem();
> >
> >     if (high_heap_size > 0) {
> > _at__at_ -627,9 +630,6 _at__at_
> >        heap_end = (char *) PTOV(bios_basemem);
> >     }
> >
> > -    dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - 
__base);
> > -    v86.ctl = V86_FLAGS;
> > -
> >     dsk = malloc(sizeof(struct dsk));
> >     dsk->drive = *(uint8_t *)PTOV(ARGS);
> >     dsk->type = dsk->drive & DRV_HARD ? TYPE_AD : TYPE_FD;
> > _at__at_ -1157,6 +1157,7 _at__at_
> >      * when no such key is pressed in reality. As far as I can tell,
> >      * this only happens shortly after a reboot.
> >      */
> > +    v86.ctl = V86_FLAGS;
> >     v86.addr = 0x16;
> >     v86.eax = fn << 8;
> >     v86int();
> >
> > --
> > John Baldwin
> >
> 
> It still breaks:
> 
> error 1 lba 48
> error 1 lba 1
> No ZFS pools located, can't boot

Ok.  Can you add a printf to zfsboot.c to print out dsk->start in the case 
that you get an error?  error 1 means that the BIOS thinks it got a bad 
parameter, presumably in the disk packet.  If you wanted to be ambitious, just 
print out all of the fields in the packet when it fails.

-- 
John Baldwin